From va2hdd at aei.ca Wed Apr 1 01:18:33 2009 From: va2hdd at aei.ca (Claude Houde) Date: Tue, 31 Mar 2009 21:18:33 -0400 Subject: [time-nuts] Austron 2100F In-Reply-To: <49D2BF8B.3030904@aei.ca> References: <49D2BD5A.9080106@aei.ca> <49D2BF8B.3030904@aei.ca> Message-ID: <49D2C0E9.3020507@aei.ca> Hello ! I'm new to the list and I have been offered an Austron 2100F receiver at a good price. Before jumping in, I have a two questions: * I read that a new version of LORAN may come along soon. Will my old receiver be instantly obsolete as a frequency comparator ? * The receiver is priced reasonably because it needs repair. I diagnosed it as far as I could and found corrosion in the power supply section, but I had to stop as I had no luck finding the manual and schematic, can someone help me ? Thanks for your help ! Claude From cfharris at erols.com Wed Apr 1 01:33:16 2009 From: cfharris at erols.com (Chuck Harris) Date: Tue, 31 Mar 2009 21:33:16 -0400 Subject: [time-nuts] Austron 2100F In-Reply-To: <49D2C0E9.3020507@aei.ca> References: <49D2BD5A.9080106@aei.ca> <49D2BF8B.3030904@aei.ca> <49D2C0E9.3020507@aei.ca> Message-ID: <49D2C45C.6070307@erols.com> Manuals and schematics are available on Brooke's www.prc68.com website. They can be very hard to fix, because there is some really poorly designed logic circuitry, and the signature analysis functions really can't find very many problems. That said, I use a 2100T for my main timing receiver. The F is virtually identical... using the same PC boards, just populated less fully. -Chuck Harris Claude Houde wrote: > Hello ! > > I'm new to the list and I have been offered an Austron 2100F receiver at > a good price. > > Before jumping in, I have a two questions: > > * I read that a new version of LORAN may come along soon. Will my > old receiver be instantly obsolete as a frequency comparator ? > * The receiver is priced reasonably because it needs repair. I > diagnosed it as far as I could and found corrosion in the power supply > section, but I had to stop as I had no luck finding the manual and > schematic, can someone help me ? > > Thanks for your help ! > > Claude > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > From stanw1le at verizon.net Wed Apr 1 01:33:47 2009 From: stanw1le at verizon.net (Stan W1LE) Date: Tue, 31 Mar 2009 21:33:47 -0400 Subject: [time-nuts] Austron 2100F In-Reply-To: <49D2C0E9.3020507@aei.ca> References: <49D2BD5A.9080106@aei.ca> <49D2BF8B.3030904@aei.ca> <49D2C0E9.3020507@aei.ca> Message-ID: <49D2C47B.8050308@verizon.net> Hello Claude, Austron 2100F will only be good for the old LORAN-C, not any enhanced e-LORAN. Austron has been long out of business, so I would not expect any field upgrade options. I have not heard of others doing mods to the 2100F, to be fully e-LORAN capable. Brooke has the manual set on a CD. You will be happy with his product. Other commercial, laboratory grade, LORAN-C timing receivers like the Stanford Research Systems model FS700 will not do e-LORAN to the best of my knowledge. The LOCUS brand receivers are a modern RX, but I do not know their e-LORAN capability. Stan, W1LE Cape Cod Claude Houde wrote: > Hello ! > > I'm new to the list and I have been offered an Austron 2100F receiver at > a good price. > > Before jumping in, I have a two questions: > > * I read that a new version of LORAN may come along soon. Will my > old receiver be instantly obsolete as a frequency comparator ? > * The receiver is priced reasonably because it needs repair. I > diagnosed it as far as I could and found corrosion in the power supply > section, but I had to stop as I had no luck finding the manual and > schematic, can someone help me ? > > Thanks for your help ! > > Claude > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > From brooke at pacific.net Wed Apr 1 02:35:33 2009 From: brooke at pacific.net (brooke at pacific.net) Date: Tue, 31 Mar 2009 19:35:33 -0700 (PDT) Subject: [time-nuts] Austron 2100F In-Reply-To: <49D2C0E9.3020507@aei.ca> References: <49D2BD5A.9080106@aei.ca> <49D2BF8B.3030904@aei.ca> <49D2C0E9.3020507@aei.ca> Message-ID: <1489.SVVXXVxVQkI=.1238553333.squirrel@webmail.securepacific.net> Hi Claude: For manuals info see: http://www.prc68.com/I/A2100F.shtml#Man and ordering see: http://www.prc68.com/P/Prod.html#Austron The enhanced LORAN-C adds a pulse after the existing group with a variable time delay. All the existing receivers will continue to operate. Part of the new system is using UTC as the basis of the time of transmission for each station. The old way was to operate the transmitters in "chains" where the master station transmitted, then each of the slaves transmitted after a specified delay. Old navigation receivers only worked with a fixed GRI, i.e. only listened to stations in the same chain, since that's the only thing that made sense with a "chain" system. But with the new UTC system ALL the stations you can receive i.e. an "all in view" approach allows for better locations because of more stations. For timing applications you want to only listen to the nearest station. The more distance between you and the transmitter the more variation in the timing. Now since each station is UTC controlled the accuracy of slave stations used for timing should be very good. I think a PIC can be used as an add on to any existing LORAN-C receiver to decode the data packets. Have Fun, Brooke CLarke http://www.PRC68.com > Hello ! > > I'm new to the list and I have been offered an Austron 2100F receiver at > a good price. > > Before jumping in, I have a two questions: > > * I read that a new version of LORAN may come along soon. Will my > old receiver be instantly obsolete as a frequency comparator ? > * The receiver is priced reasonably because it needs repair. I > diagnosed it as far as I could and found corrosion in the power supply > section, but I had to stop as I had no luck finding the manual and > schematic, can someone help me ? > > Thanks for your help ! > > Claude > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > From ch at murgatroid.com Wed Apr 1 05:04:12 2009 From: ch at murgatroid.com (christopher hoover) Date: Tue, 31 Mar 2009 22:04:12 -0700 Subject: [time-nuts] Austron 2100F In-Reply-To: References: Message-ID: <49D2F5CC.1060701@murgatroid.com> Chuck Harris wrote: > They can be very hard to fix, because there is some really poorly designed > logic circuitry, and the signature analysis functions really can't find > very many problems. Interesting. Can you say more? I tried to repair mine -- I have a signature analyzer -- but did not ever get it to work. The initial indication was a bad memory chip. I carefully replaced it, but it never came back to life. Maybe that was a red herring. -ch From df6jb at ulrich-bangert.de Wed Apr 1 07:58:06 2009 From: df6jb at ulrich-bangert.de (Ulrich Bangert) Date: Wed, 1 Apr 2009 09:58:06 +0200 Subject: [time-nuts] Prologix In-Reply-To: <49D25BA6.1080407@adobe-labs.com> Message-ID: <9AB666163C5141BD91FF84C4B0D24E17@athlon> Mike, I would like to second Brent's information: That is exactly how it is done. Talking to the Prologix interface and talking to the NI interface is COMPLETELY different in that talking to the Prologix always means straightforward serial communication while talking to the NI involves DLL-calls from the application. The Prologix is cheap and easy to work with, thats why some time nuts use it. The NI interface is on the other hand more expensive and more complex to handle (and yes, it does some things that are not easily done with the Prologix). The biggest advantage of the DLL-calls is: The same application works with whatever NI interface you use: Plug in card, USB devices, ethernet dvices, you name it. All work by the SAME dll calls, so your application is not specific for a interface device. I do not forget to advertise my own solution to GPIB programming named EZGPIB which talks to Prologix (both LAN and USB based) as well to NI interfaces and thanks supporting basic VISA even to GPIB interfaces of other suppliers. It uses an easy to learn PASCAL like script language that your friend might get used to in a snap. Basically, if your friend writes a EZGPIB based script to talk to his counter over the Prologix, you will be able to use the SAME script to talk to your 5335A via a NI interface. Nice feature? EZGPIB has got mentioned in April's 2008 issue of "Test & Measurement World". See the last link on my "About me" page http://www.ulrich-bangert.de/html/about_me.html EZGIPB can be downloaded for free from http://www.ulrich-bangert.de/html/downloads.html Best regards Ulrich, DF6JB > -----Ursprungliche Nachricht----- > Von: time-nuts-bounces at febo.com > [mailto:time-nuts-bounces at febo.com] Im Auftrag von Brent Gordon > Gesendet: Dienstag, 31. Marz 2009 20:07 > An: Discussion of precise time and frequency measurement > Betreff: Re: [time-nuts] Prologix > > > Mike Feher wrote: > > A friend has a 5335A counter and bought a Prologix adaptor > for it to > > collect data. He wrote the software and has had extremely good > > results. He offered to do the same for me utilizing my NI > adaptor so I > > could use it for my various counters. Unfortunately he ran into > > problems and feels he needs a special version of basic in order to > > make my $500 NI adaptor work. I admit to my total lack of > programming > > ability. I still use GWBASIC, and only to crunch heavy > numbers. I have > > no idea how to interface any software to communicate with an > > instrument, and, maybe am too old to want to learn as it > seems a lot > > of people do it on a regular basis already. If this becomes too > > difficult I may have to buy a Prologix unit from Abdul. > While I am all > > for doing that, and I bought my NI before Abdul had his > version going, > > I was also under the impression that if the Prologix can do > it the NI > > can do it, but, not necessarily the other way around. My friend > > mentioned API calls, whatever they are. Any suggestions? > Thanks - Mike > > > > > > Mike B. Feher, N4FS > > 89 Arnold Blvd. > > Howell, NJ, 07731 > > 732-886-5960 > > > Mike, > > You should have gotten the NI-488.2 CD with your GPIB card. > On that CD > are the dlls (Dynamic Link Libraries) to talk to the card. > You can use > the dlls in any language that supports dlls or ActiveX. > Sorry to say, > GWBASIC is not one of those languages. Visual Basic 6 works well and > I've even done GPIB data acquisition directly into Excel using VBA > (Visual Basic for Applications, Excel's macro language). VBA > is part of > Excel. Alternatively, you can get a free Visual Basic Express at > http://www.microsoft.com/express/vb/ I haven't tried VB > Express, but I > think it will work. Normally, I do all my GPIB programming > in LabVIEW. > > Brent > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. From nils at stiebeleltronasia.com Wed Apr 1 07:54:36 2009 From: nils at stiebeleltronasia.com (Nils Palm) Date: Wed, 1 Apr 2009 14:54:36 +0700 Subject: [time-nuts] Datum / Efratom LPRO 101 - ebay Message-ID: <003101c9b2a7$e3e50750$2f00a8c0@stiebeleltronasia.com> Dear All, I am a new in this field and need some advice. For the adjustment of our quarz clocks we need a reference. I came across some cheap offers on ebay for a EFRATOM / DATUM LPRO Rubidium oscillator http://cgi.ebay.de/ws/eBayISAPI.dll?ViewItem&item=180338976648QQssPageNameZMERC_VI_RCRX_Pr4_PcY_BIN_Stores_IT&refitem=180340823127&itemcount=4&refwidgetloc=active_view_item&usedrule1=CrossSell_LogicX&refwidgettype=cross_promot_widget&_trksid=p284.m184&_trkparms=algo%3DCRX%26its%3DS%252BI%252BSS%26itu%3DISS%252BUCI%252BSI%26otn%3D4 Now I was wondering what about these oscillators. Why are they offered so cheap and so many. What have they be used for ? Also I cannot find any information about the manufacturer on the internet. Are they out of business ? Would such a oscillator be usefull for us, as we need a 10Mhz signal with about 1e-8 precision. Thanks a lot ! nils From sar10538 at gmail.com Wed Apr 1 09:56:55 2009 From: sar10538 at gmail.com (Steve Rooke) Date: Wed, 1 Apr 2009 22:56:55 +1300 Subject: [time-nuts] Prologix In-Reply-To: <9AB666163C5141BD91FF84C4B0D24E17@athlon> References: <49D25BA6.1080407@adobe-labs.com> <9AB666163C5141BD91FF84C4B0D24E17@athlon> Message-ID: <1231b6a80904010256p3dc5fa7bufc620a1817d0ef5c@mail.gmail.com> This man said the P word without any form of apology :-) 73 2009/4/1 Ulrich Bangert : > Mike, > > I would like to second Brent's information: That is exactly how it is done. > Talking to the Prologix interface and talking to the NI interface is > COMPLETELY different in that talking to the Prologix always means > straightforward serial communication while talking to the NI involves > DLL-calls from the application. > > The Prologix is cheap and easy to work with, thats why some time nuts use > it. The NI interface is on the other hand more expensive and more complex to > handle (and yes, it does some things that are not easily done with the > Prologix). The biggest advantage of the DLL-calls is: The same application > works with whatever NI interface you use: Plug in card, USB devices, > ethernet dvices, you name it. All work by the SAME dll calls, so your > application is not specific for a interface device. > > I do not forget to advertise my own solution to GPIB programming named > EZGPIB which talks to Prologix (both LAN and USB based) as well to NI > interfaces and thanks supporting basic VISA even to GPIB interfaces of other > suppliers. > > It uses an easy to learn PASCAL like script language that your friend might > get used to in a snap. Basically, if your friend writes a EZGPIB based > script to talk to his counter over the Prologix, you will be able to use the > SAME script to talk to your 5335A via a NI interface. Nice feature? EZGPIB > has got mentioned in April's 2008 issue of "Test & Measurement World". See > the last link on my "About me" page > > http://www.ulrich-bangert.de/html/about_me.html > > EZGIPB can be downloaded for free from > > http://www.ulrich-bangert.de/html/downloads.html > > Best regards > Ulrich, DF6JB > >> -----Ursprungliche Nachricht----- >> Von: time-nuts-bounces at febo.com >> [mailto:time-nuts-bounces at febo.com] Im Auftrag von Brent Gordon >> Gesendet: Dienstag, 31. Marz 2009 20:07 >> An: Discussion of precise time and frequency measurement >> Betreff: Re: [time-nuts] Prologix >> >> >> Mike Feher wrote: >> > A friend has a 5335A counter and bought a Prologix adaptor >> for it to >> > collect data. He wrote the software and has had extremely good >> > results. He offered to do the same for me utilizing my NI >> adaptor so I >> > could use it for my various counters. Unfortunately he ran into >> > problems and feels he needs a special version of basic in order to >> > make my $500 NI adaptor work. I admit to my total lack of >> programming >> > ability. I still use GWBASIC, and only to crunch heavy >> numbers. I have >> > no idea how to interface any software to communicate with an >> > instrument, and, maybe am too old to want to learn as it >> seems a lot >> > of people do it on a regular basis already. If this becomes too >> > difficult I may have to buy a Prologix unit from Abdul. >> While I am all >> > for doing that, and I bought my NI before Abdul had his >> version going, >> > I was also under the impression that if the Prologix can do >> it the NI >> > can do it, but, not necessarily the other way around. My friend >> > mentioned API calls, whatever they are. Any suggestions? >> Thanks - Mike >> > >> > >> > Mike B. Feher, N4FS >> > 89 Arnold Blvd. >> > Howell, NJ, 07731 >> > 732-886-5960 >> > >> Mike, >> >> You should have gotten the NI-488.2 CD with your GPIB card. >> On that CD >> are the dlls (Dynamic Link Libraries) to talk to the card. >> You can use >> the dlls in any language that supports dlls or ActiveX. >> Sorry to say, >> GWBASIC is not one of those languages. ?Visual Basic 6 works well and >> I've even done GPIB data acquisition directly into Excel using VBA >> (Visual Basic for Applications, Excel's macro language). ?VBA >> is part of >> Excel. ?Alternatively, you can get a free Visual Basic Express at >> http://www.microsoft.com/express/vb/ ?I haven't tried VB >> Express, but I >> think it will work. ?Normally, I do all my GPIB programming >> in LabVIEW. >> >> Brent >> >> _______________________________________________ >> time-nuts mailing list -- time-nuts at febo.com >> To unsubscribe, go to >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > -- Steve Rooke - ZL3TUV & G8KVD & JAKDTTNW Omnium finis imminet From hmurray at megapathdsl.net Wed Apr 1 10:13:11 2009 From: hmurray at megapathdsl.net (Hal Murray) Date: Wed, 01 Apr 2009 03:13:11 -0700 Subject: [time-nuts] Datum / Efratom LPRO 101 - ebay In-Reply-To: Message from "Nils Palm" of "Wed, 01 Apr 2009 14:54:36 +0700." <003101c9b2a7$e3e50750$2f00a8c0@stiebeleltronasia.com> Message-ID: <20090401101312.C8087BCDF@ip-64-139-1-69.sjc.megapath.net> > Now I was wondering what about these oscillators. Why are they offered > so cheap and so many. What have they be used for ? I think they are recycled from phone or cell phone upgrades. > Also I cannot find any information about the manufacturer on the > internet. Are they out of business ? Symmetricom has gobbled up most of the alternative sources. The data sheet is readily available. > Would such a oscillator be usefull for us, as we need a 10Mhz signal > with about 1e-8 precision. Probably. Do you have any way to sanity check it? The spec sheet says aging is <1E-9 over 10 years and it's within 5E-11 at shipment. The C-field adjustment covers +/- 1.5E-9. (Specs are from a 2003 sheet. Older units are probably a bit less good.) -- These are my opinions, not necessarily my employer's. I hate spam. From namichie at gmail.com Wed Apr 1 10:14:08 2009 From: namichie at gmail.com (Neville Michie) Date: Wed, 1 Apr 2009 21:14:08 +1100 Subject: [time-nuts] Datum / Efratom LPRO 101 - ebay In-Reply-To: <003101c9b2a7$e3e50750$2f00a8c0@stiebeleltronasia.com> References: <003101c9b2a7$e3e50750$2f00a8c0@stiebeleltronasia.com> Message-ID: Hi, The LPRO 101 was used in cell phone systems to provide a stand-by frequency source when the GPS was unavailable. As systems are made obsolete large numbers of units are being recycled through the amateur world. They are cheap because there are more LPRO units than time-nuts and so are in excess supply. This situation may not last forever. The spec. sheet and manual is widely available, try http://www.tenmhz.com/LPRO.htm The unit is compact, requires only a small power supply, and is very stable. Cheers, Neville Michie On 01/04/2009, at 6:54 PM, Nils Palm wrote: > Dear All, > > I am a new in this field and need some advice. > For the adjustment of our quarz clocks we need a reference. > I came across some cheap offers on ebay for a > > EFRATOM / DATUM LPRO Rubidium oscillator > > http://cgi.ebay.de/ws/eBayISAPI.dll? > ViewItem&item=180338976648QQssPageNameZMERC_VI_RCRX_Pr4_PcY_BIN_Stores > _IT&refitem=180340823127&itemcount=4&refwidgetloc=active_view_item&use > drule1=CrossSell_LogicX&refwidgettype=cross_promot_widget&_trksid=p284 > .m184&_trkparms=algo%3DCRX%26its%3DS%252BI%252BSS%26itu%3DISS% > 252BUCI%252BSI%26otn%3D4 > > Now I was wondering what about these oscillators. > Why are they offered so cheap and so many. What have > they be used for ? > Also I cannot find any information about the manufacturer > on the internet. Are they out of business ? > > Would such a oscillator be usefull for us, as we need > a 10Mhz signal with about 1e-8 precision. > > Thanks a lot ! > > nils > > > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/ > time-nuts > and follow the instructions there. From nospam at oceanfree.net Wed Apr 1 10:38:05 2009 From: nospam at oceanfree.net (Eamon Skelton) Date: Wed, 01 Apr 2009 11:38:05 +0100 Subject: [time-nuts] Datum / Efratom LPRO 101 - ebay In-Reply-To: <003101c9b2a7$e3e50750$2f00a8c0@stiebeleltronasia.com> References: <003101c9b2a7$e3e50750$2f00a8c0@stiebeleltronasia.com> Message-ID: <49D3440D.20304@oceanfree.net> > Now I was wondering what about these oscillators. > Why are they offered so cheap and so many. What have > they be used for ? These are from used equipment so they can't be expected to last as long as a new unit. They are probably from surplus telecomms equipment. > Also I cannot find any information about the manufacturer > on the internet. Are they out of business ? Datum were taken over by Symmetricom. http://www.symmetricom.com/ > Would such a oscillator be usefull for us, as we need > a 10Mhz signal with about 1e-8 precision. > > Thanks a lot ! > > nils The LPRO-101 sounds like the ideal candidate for this job. From memory, I think the long term stability spec is 1e-9/10 years, 5e-11/month. I have had very good service from this seller: http://myworld.ebay.de/fluke.l/ Friendly helpful and reliable. Very quick shipping from China by EMS. I'm not connected to this seller in any way, just another happy customer. A GPSDO is another cost effective solution that would easily meet your requirements. The Trimble Thunderbolt is widely available on eBay. You should also check out the CW12-TIM module from Navsync. Ed. -- Linux 2.6.26 From cfharris at erols.com Wed Apr 1 11:47:19 2009 From: cfharris at erols.com (Chuck Harris) Date: Wed, 01 Apr 2009 07:47:19 -0400 Subject: [time-nuts] Austron 2100F In-Reply-To: <49D2F5CC.1060701@murgatroid.com> References: <49D2F5CC.1060701@murgatroid.com> Message-ID: <49D35447.9060005@erols.com> You're asking me if I can say more? Most wish they could get me to shut up;-) The design for the receiver of the 2100T/F is a mishmash of synchronous and asynchronous logic. They mixed logic families in an apparent attempt to battle a few timing problems. On one board, there is 7400, 74LS, 74L, 74C, 25LS, and 74HC all at the same time, and all in the same signal path! Following the trend of the time, they used signature analysis to aid in troubleshooting... only they didn't try very hard. The signatures are fine for working out problems with the CPU, and IO section, but they do nothing for most of the logic in the receiver. And signature is unable to do anything for timing problems. So, how do you find a thermally related timing problem? I had two 2100F's one was rock solid, and one was rock solid, as long as my rack stayed below 75F. Summertime would hit, and the receiver would lock, run for about 2 hours, and then it would be unlocked. I swapped boards between the two receivers until I determined that it was without doubt the Acquire/Track board. Wherever that board was, the receiver in question would fail when it got warm. The Acquire/Track board is where they divide down the reference oscillator to form a mask of the loran signal. The mask is matched to the signal, and the divider is adjusted by adding, or subtracting counts, to track the loran signal. I checked every trace on that board, tested every chip for logical function, and ultimately replaced every part on that board with new, and it still had a thermal problem. I tried to concoct a method of even sensing the problem, but the very slow nature of the problem (due to the slow changes between the reference and the loran signal when you were within the range that the receiver could tolerate) defied my attempts. If your design needs 7400, 74LS, 74L, 74HC, 74C, and 25LS all in the same counter/comparator to work, you have botched the design! Although the manual is silent on the fact, I am pretty sure that they had to spec the parts on this circuit down to the manufacturer and lot number to come up with a set of parts that had all of the timing and threshold problems settled so that the board could work. I ultimately concluded that the use of 7400, 74L, and 74LS with its TTL (1.3V) threshold levels was only marginally compatible with the 74C and 74HC with their CMOS (2.5V) threshold levels, and could only work at lower temperatures. Bah! -Chuck Harris christopher hoover wrote: > Chuck Harris wrote: > >> They can be very hard to fix, because there is some really poorly designed >> logic circuitry, and the signature analysis functions really can't find >> very many problems. > > Interesting. Can you say more? > > I tried to repair mine -- I have a signature analyzer -- but did not ever get it to work. The initial indication was a bad memory chip. I carefully replaced it, but it never came back to life. Maybe that was a red herring. > > -ch > > > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > From cfharris at erols.com Wed Apr 1 11:54:42 2009 From: cfharris at erols.com (Chuck Harris) Date: Wed, 01 Apr 2009 07:54:42 -0400 Subject: [time-nuts] Prologix In-Reply-To: <1231b6a80904010256p3dc5fa7bufc620a1817d0ef5c@mail.gmail.com> References: <49D25BA6.1080407@adobe-labs.com> <9AB666163C5141BD91FF84C4B0D24E17@athlon> <1231b6a80904010256p3dc5fa7bufc620a1817d0ef5c@mail.gmail.com> Message-ID: <49D35602.4010601@erols.com> Steve Rooke wrote: > This man said the P word without any form of apology :-) I know, and I am still shaking from the thought of it! Anybody got a wooden stake? -Chuck Harris >> >> It uses an easy to learn PASCAL like script language that your friend might From robert8rpi at yahoo.co.uk Wed Apr 1 12:47:18 2009 From: robert8rpi at yahoo.co.uk (Robert Atkinson) Date: Wed, 1 Apr 2009 12:47:18 +0000 (GMT) Subject: [time-nuts] Datum / Efratom LPRO 101 - ebay Message-ID: <882814.25081.qm@web27104.mail.ukl.yahoo.com> I notice that this seller is using TVB's plots on his listing. This is a bit naughty. Did he ask you Tom? Robert G8RPI. --- On Wed, 1/4/09, Eamon Skelton wrote: > From: Eamon Skelton > Subject: Re: [time-nuts] Datum / Efratom LPRO 101 - ebay > To: "Nils Palm" , "Discussion of precise time and frequency measurement" > Date: Wednesday, 1 April, 2009, 11:38 AM > > > Now I was wondering what about these oscillators. > > Why are they offered so cheap and so many. What have > > they be used for ? > > These are from used equipment so they can't be expected > to last as long as a new unit. They are probably from > surplus telecomms equipment. > > > Also I cannot find any information about the > manufacturer > > on the internet. Are they out of business ? > > Datum were taken over by Symmetricom. > http://www.symmetricom.com/ > > > Would such a oscillator be usefull for us, as we need > > a 10Mhz signal with about 1e-8 precision. > > > > Thanks a lot ! > > > > nils > > The LPRO-101 sounds like the ideal candidate for this > job. From memory, I think the long term stability spec > is 1e-9/10 years, 5e-11/month. > > I have had very good service from this seller: > http://myworld.ebay.de/fluke.l/ > Friendly helpful and reliable. Very quick shipping from > China by EMS. I'm not connected to this seller in any > way, just another happy customer. > > A GPSDO is another cost effective solution that > would easily meet your requirements. The Trimble > Thunderbolt is widely available on eBay. You > should also check out the CW12-TIM module from > Navsync. > > Ed. > > -- > Linux 2.6.26 > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > From df6jb at ulrich-bangert.de Wed Apr 1 12:48:57 2009 From: df6jb at ulrich-bangert.de (Ulrich Bangert) Date: Wed, 1 Apr 2009 14:48:57 +0200 Subject: [time-nuts] P word in my mails In-Reply-To: <1231b6a80904010256p3dc5fa7bufc620a1817d0ef5c@mail.gmail.com> Message-ID: Steve, after I read your mail I have been completely perplexed because I could by no stretch of imagination detect where you had found the aforesaid P word in my mail. It needed the help of some English speaking friends and a search in my last mails to find out that I have (possibly over a range of more than 30 years) used an American 5 letter word in another sense than most/all of you seem to interprete it. I HAVE seen the aforesaid word on some doors during my visits to he United States and I HAVE understood the meaning of the word in this context. But I swear that I have not been aware of the fact that the aforesaid word is used EXCLUSIVELY for the location behind these doors. If I had been aware of that I would have never used this word in a conversation because that is simply not my style. Instead, I have been believing (and I swear this is the truth) that the aforesaid word is used by a gentlemen to address a group of other gentlemen just as a "Hi folks" among noble people but avoiding the highly offical salutation "Gentlemen", in a sense a laid-back use of "Gentlemen". Clearly this is a mistake of mine that I cannot other than to apologize for! If anyone of you has felt offended or in any other way been affected by my wrong use of this word: Sorry for that, that was NOT my intention in using this term. I have started a lot of my posts to this group with this word because of the high s/n ratio to be found here and the extremely well educated people in the group that I hold in high regard. Someone should have told me before! If you find this word in one of my earlier posts substitute it with "Gentlemen" because that is what was ment. Thank you Steve for pointing at that. If you had not done it I would propably have used the word in a wrong sense for the rest of my life. Best regards Ulrich Bangert > -----Urspr?ngliche Nachricht----- > Von: time-nuts-bounces at febo.com > [mailto:time-nuts-bounces at febo.com] Im Auftrag von Steve Rooke > Gesendet: Mittwoch, 1. April 2009 11:57 > An: Discussion of precise time and frequency measurement > Betreff: Re: [time-nuts] Prologix > > > This man said the P word without any form of apology :-) > > 73 > > 2009/4/1 Ulrich Bangert : > > Mike, > > > > I would like to second Brent's information: That is exactly > how it is > > done. Talking to the Prologix interface and talking to the NI > > interface is COMPLETELY different in that talking to the Prologix > > always means straightforward serial communication while > talking to the > > NI involves DLL-calls from the application. > > > > The Prologix is cheap and easy to work with, thats why some > time nuts > > use it. The NI interface is on the other hand more > expensive and more > > complex to handle (and yes, it does some things that are not easily > > done with the Prologix). The biggest advantage of the DLL-calls is: > > The same application works with whatever NI interface you > use: Plug in > > card, USB devices, ethernet dvices, you name it. All work > by the SAME > > dll calls, so your application is not specific for a > interface device. > > > > I do not forget to advertise my own solution to GPIB > programming named > > EZGPIB which talks to Prologix (both LAN and USB based) as > well to NI > > interfaces and thanks supporting basic VISA even to GPIB > interfaces of > > other suppliers. > > > > It uses an easy to learn PASCAL like script language that > your friend > > might get used to in a snap. Basically, if your friend > writes a EZGPIB > > based script to talk to his counter over the Prologix, you will be > > able to use the SAME script to talk to your 5335A via a NI > interface. > > Nice feature? EZGPIB has got mentioned in April's 2008 > issue of "Test > > & Measurement World". See the last link on my "About me" page > > > > http://www.ulrich-bangert.de/html/about_me.html > > > > EZGIPB can be downloaded for free from > > > > http://www.ulrich-bangert.de/html/downloads.html > > > > Best regards > > Ulrich, DF6JB > > > >> -----Ursprungliche Nachricht----- > >> Von: time-nuts-bounces at febo.com > [mailto:time-nuts-bounces at febo.com] > >> Im Auftrag von Brent Gordon > >> Gesendet: Dienstag, 31. Marz 2009 20:07 > >> An: Discussion of precise time and frequency measurement > >> Betreff: Re: [time-nuts] Prologix > >> > >> > >> Mike Feher wrote: > >> > A friend has a 5335A counter and bought a Prologix adaptor > >> for it to > >> > collect data. He wrote the software and has had extremely good > >> > results. He offered to do the same for me utilizing my NI > >> adaptor so I > >> > could use it for my various counters. Unfortunately he ran into > >> > problems and feels he needs a special version of basic > in order to > >> > make my $500 NI adaptor work. I admit to my total lack of > >> programming > >> > ability. I still use GWBASIC, and only to crunch heavy > >> numbers. I have > >> > no idea how to interface any software to communicate with an > >> > instrument, and, maybe am too old to want to learn as it > >> seems a lot > >> > of people do it on a regular basis already. If this becomes too > >> > difficult I may have to buy a Prologix unit from Abdul. > >> While I am all > >> > for doing that, and I bought my NI before Abdul had his > >> version going, > >> > I was also under the impression that if the Prologix can do > >> it the NI > >> > can do it, but, not necessarily the other way around. My friend > >> > mentioned API calls, whatever they are. Any suggestions? > >> Thanks - Mike > >> > > >> > > >> > Mike B. Feher, N4FS > >> > 89 Arnold Blvd. > >> > Howell, NJ, 07731 > >> > 732-886-5960 > >> > > >> Mike, > >> > >> You should have gotten the NI-488.2 CD with your GPIB > card. On that > >> CD are the dlls (Dynamic Link Libraries) to talk to the card. > >> You can use > >> the dlls in any language that supports dlls or ActiveX. > >> Sorry to say, > >> GWBASIC is not one of those languages. ?Visual Basic 6 > works well and > >> I've even done GPIB data acquisition directly into Excel using VBA > >> (Visual Basic for Applications, Excel's macro language). ?VBA > >> is part of > >> Excel. ?Alternatively, you can get a free Visual Basic Express at > >> http://www.microsoft.com/express/vb/ ?I haven't tried VB > >> Express, but I > >> think it will work. ?Normally, I do all my GPIB programming > >> in LabVIEW. > >> > >> Brent > >> > >> _______________________________________________ > >> time-nuts mailing list -- time-nuts at febo.com > >> To unsubscribe, go to > >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > >> and follow the instructions there. > > > > > > _______________________________________________ > > time-nuts mailing list -- time-nuts at febo.com > > To unsubscribe, go to > > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > > and follow the instructions there. > > > > > > -- > Steve Rooke - ZL3TUV & G8KVD & JAKDTTNW > Omnium finis imminet > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. From aa8k at comcast.net Wed Apr 1 13:04:37 2009 From: aa8k at comcast.net (Mike Naruta AA8K) Date: Wed, 01 Apr 2009 09:04:37 -0400 Subject: [time-nuts] P word in my mails In-Reply-To: References: Message-ID: <49D36665.3020003@comcast.net> Not to worry Ulrich, he was using a form of derisive humor. He was insulting Prologix as undesirable. It would be similar to referring to Microsoft as the M-word. Mike - AA8K Ulrich Bangert wrote: > Steve, > > after I read your mail I have been completely perplexed because I could by > no stretch of imagination detect where you had found the aforesaid P word in > my mail. It needed the help of some English speaking friends and a search in > my last mails to find out that I have (possibly over a range of more than 30 > years) used an American 5 letter word in another sense than most/all of you > seem to interprete it. > > I HAVE seen the aforesaid word on some doors during my visits to he United > States and I HAVE understood the meaning of the word in this context. But I > swear that I have not been aware of the fact that the aforesaid word is used > EXCLUSIVELY for the location behind these doors. If I had been aware of that > I would have never used this word in a conversation because that is simply > not my style. > > Instead, I have been believing (and I swear this is the truth) that the > aforesaid word is used by a gentlemen to address a group of other gentlemen > just as a "Hi folks" among noble people but avoiding the highly offical > salutation "Gentlemen", in a sense a laid-back use of "Gentlemen". > > Clearly this is a mistake of mine that I cannot other than to apologize for! > If anyone of you has felt offended or in any other way been affected by my > wrong use of this word: Sorry for that, that was NOT my intention in using > this term. I have started a lot of my posts to this group with this word > because of the high s/n ratio to be found here and the extremely well > educated people in the group that I hold in high regard. > > Someone should have told me before! If you find this word in one of my > earlier posts substitute it with "Gentlemen" because that is what was ment. > > Thank you Steve for pointing at that. If you had not done it I would > propably have used the word in a wrong sense for the rest of my life. > > Best regards > Ulrich Bangert > > >> -----Urspr?ngliche Nachricht----- >> Von: time-nuts-bounces at febo.com >> [mailto:time-nuts-bounces at febo.com] Im Auftrag von Steve Rooke >> Gesendet: Mittwoch, 1. April 2009 11:57 >> An: Discussion of precise time and frequency measurement >> Betreff: Re: [time-nuts] Prologix >> >> >> This man said the P word without any form of apology :-) >> >> 73 >> From cfharris at erols.com Wed Apr 1 13:11:56 2009 From: cfharris at erols.com (Chuck Harris) Date: Wed, 01 Apr 2009 09:11:56 -0400 Subject: [time-nuts] P word in my mails In-Reply-To: <49D36665.3020003@comcast.net> References: <49D36665.3020003@comcast.net> Message-ID: <49D3681C.4090203@erols.com> Mike Naruta AA8K wrote: > Not to worry Ulrich, he was using a form > of derisive humor. He was insulting Prologix > as undesirable. Surely, you jest! He was complaining about PASCAL. A really bad word among those forced to use it. -Chuck Harris From jra at febo.com Wed Apr 1 13:12:24 2009 From: jra at febo.com (John Ackermann N8UR) Date: Wed, 01 Apr 2009 09:12:24 -0400 Subject: [time-nuts] P word in my mails In-Reply-To: <49D36665.3020003@comcast.net> References: <49D36665.3020003@comcast.net> Message-ID: <49D36838.2090701@febo.com> Gee, and I thought he was talking about Pascal. :-) John ---- Mike Naruta AA8K wrote: > Not to worry Ulrich, he was using a form > of derisive humor. He was insulting Prologix > as undesirable. > > It would be similar to referring to Microsoft > as the M-word. > > > Mike - AA8K > > > Ulrich Bangert wrote: >> Steve, >> >> after I read your mail I have been completely perplexed because I could by >> no stretch of imagination detect where you had found the aforesaid P word in >> my mail. It needed the help of some English speaking friends and a search in >> my last mails to find out that I have (possibly over a range of more than 30 >> years) used an American 5 letter word in another sense than most/all of you >> seem to interprete it. >> >> I HAVE seen the aforesaid word on some doors during my visits to he United >> States and I HAVE understood the meaning of the word in this context. But I >> swear that I have not been aware of the fact that the aforesaid word is used >> EXCLUSIVELY for the location behind these doors. If I had been aware of that >> I would have never used this word in a conversation because that is simply >> not my style. >> >> Instead, I have been believing (and I swear this is the truth) that the >> aforesaid word is used by a gentlemen to address a group of other gentlemen >> just as a "Hi folks" among noble people but avoiding the highly offical >> salutation "Gentlemen", in a sense a laid-back use of "Gentlemen". >> >> Clearly this is a mistake of mine that I cannot other than to apologize for! >> If anyone of you has felt offended or in any other way been affected by my >> wrong use of this word: Sorry for that, that was NOT my intention in using >> this term. I have started a lot of my posts to this group with this word >> because of the high s/n ratio to be found here and the extremely well >> educated people in the group that I hold in high regard. >> >> Someone should have told me before! If you find this word in one of my >> earlier posts substitute it with "Gentlemen" because that is what was ment. >> >> Thank you Steve for pointing at that. If you had not done it I would >> propably have used the word in a wrong sense for the rest of my life. >> >> Best regards >> Ulrich Bangert >> >> >>> -----Urspr?ngliche Nachricht----- >>> Von: time-nuts-bounces at febo.com >>> [mailto:time-nuts-bounces at febo.com] Im Auftrag von Steve Rooke >>> Gesendet: Mittwoch, 1. April 2009 11:57 >>> An: Discussion of precise time and frequency measurement >>> Betreff: Re: [time-nuts] Prologix >>> >>> >>> This man said the P word without any form of apology :-) >>> >>> 73 >>> > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. From aa8k at comcast.net Wed Apr 1 13:33:31 2009 From: aa8k at comcast.net (Mike Naruta AA8K) Date: Wed, 01 Apr 2009 09:33:31 -0400 Subject: [time-nuts] P word in my mails In-Reply-To: <49D3681C.4090203@erols.com> References: <49D36665.3020003@comcast.net> <49D3681C.4090203@erols.com> Message-ID: <49D36D2B.7040203@comcast.net> Opps, my bad. :) Chuck Harris wrote: > Mike Naruta AA8K wrote: >> Not to worry Ulrich, he was using a form >> of derisive humor. He was insulting Prologix >> as undesirable. > > Surely, you jest! > > He was complaining about PASCAL. A really bad word > among those forced to use it. > > -Chuck Harris > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > From tvb at LeapSecond.com Wed Apr 1 13:35:50 2009 From: tvb at LeapSecond.com (Tom Van Baak) Date: Wed, 1 Apr 2009 06:35:50 -0700 Subject: [time-nuts] Datum / Efratom LPRO 101 - ebay References: <882814.25081.qm@web27104.mail.ukl.yahoo.com> Message-ID: <2D64D5541A3447929D857A0E6B07822A@pc52> > I notice that this seller is using TVB's plots on his listing. This is a bit naughty. Did he ask you Tom? No, he didn't ask. I was a little surprised too. /tvb From df6jb at ulrich-bangert.de Wed Apr 1 14:03:30 2009 From: df6jb at ulrich-bangert.de (Ulrich Bangert) Date: Wed, 1 Apr 2009 16:03:30 +0200 Subject: [time-nuts] P word in my mails In-Reply-To: <49D36838.2090701@febo.com> Message-ID: <553B2985563B4D679777EBF4F9023ADF@athlon> Gentlemen, > Gee, and I thought he was talking about Pascal. :-) > > John > ---- Pascal = P word ??? I am a professional programmer and regulary program in a number of different languages among them Pascal, the language that comes after "B" and assembler for some microcontroller families. I have been thinking that among professionals the question which is the better programming language is as modern as the last centuries 80th. But if a reheated discussion is necessary, here is something that I can lough about: ------------------------------------------------------------------------ Unix/Linux an elaborate April Fools prank - Ben Dover 30-May-07 09:52:22 FOR IMMEDIATE RELEASE In an announcement that has stunned the computer industry, Ken Thompson, Dennis Ritchie and Brian Kernighan admitted that the Unix operating system and C programming language created by them is an elaborate April Fools prank kept alive for over 20 years. Speaking at the recent UnixWorld Software Development Forum, Thompson revealed the following: In 1969, AT&T had just terminated their work with the GE/AT&T Multics project. Brian and I had just started working with an early release of Pascal from Professor Nichlaus Wirth's ETH labs in Switzerland and we were impressed with its elegant simplicity and power. Dennis had just finished reading Bored of the Rings, a hilarious National Lampoon parody of the great Tolkien Lord of the Rings trilogy. As a lark, we decided to do parodies of the Multics environment and Pascal. Dennis and I were responsible for the operating environment. We looked at Multics and designed the new system to be as complex and cryptic as possible to maximize casual users' frustration levels, calling it Unix as a parody of Multics, as well as other more risque allusions. Then Dennis and Brian worked on a truly warped version of Pascal, called "A." When we found others were actually trying to create real programs with A, we quickly added additional cryptic features and evolved into B, BCPL and finally C. We stopped when we got a clean compile on the following syntax: for(;P("\n"),R=;P("|"))for(e=C;e=P("_"+(*u++/8)%2))P("|"+(*u/4)%2); To think that modern programmers would try to use a language that allowed such a statement was beyond our comprehension! We actually thought of selling this to the Soviets to set their computer science progress back 20 or more years. Imagine our surprise when AT&T and other US corporations actually began trying to use Unix and C! It has taken them 20 years to develop enough expertise to generate even marginally useful applications using this 1960's technological parody, but we are impressed with the tenacity (if not common sense) of the general Unix and C programmer. In any event, Brian, Dennis and I have been working exclusively in Pascal on the Apple Macintosh for the past few years and feel really guilty about the chaos, confusion and truly bad programming that has resulted from our silly prank so long ago. Major Unix and C vendors and customers, including AT&T, Microsoft, Hewlett-Packard, GTE, NCR, and DEC have refused comment at this time. Borland International, a leading vendor of Pascal and C tools, including the popular Turbo Pascal, Turbo C and Turbo C++, stated they had suspected this for a number of years and would continue to enhance their Pascal products and halt further efforts to develop C. An IBM spokesman broke into uncontrolled laughter and had to postpone a hastely convened news conference concerning the fate of the RS-6000, merely stating "VM will be available Real Soon Now." In a cryptic statement, Professor Wirth of the ETH institute and father of the Pascal, Modula 2 and Oberon structured languages, merely stated that P. T. Barnum was correct. ---------------------------------------------------------------------------- Best regards Ulrich Bangert > -----Urspr?ngliche Nachricht----- > Von: time-nuts-bounces at febo.com > [mailto:time-nuts-bounces at febo.com] Im Auftrag von John Ackermann N8UR > Gesendet: Mittwoch, 1. April 2009 15:12 > An: aa8k at comcast.net; Discussion of precise time and > frequency measurement > Betreff: Re: [time-nuts] P word in my mails > > > Gee, and I thought he was talking about Pascal. :-) > > John > ---- > > Mike Naruta AA8K wrote: > > Not to worry Ulrich, he was using a form > > of derisive humor. He was insulting Prologix > > as undesirable. > > > > It would be similar to referring to Microsoft > > as the M-word. > > > > > > Mike - AA8K > > > > > > Ulrich Bangert wrote: > >> Steve, > >> > >> after I read your mail I have been completely perplexed because I > >> could by no stretch of imagination detect where you had found the > >> aforesaid P word in my mail. It needed the help of some English > >> speaking friends and a search in my last mails to find out that I > >> have (possibly over a range of more than 30 > >> years) used an American 5 letter word in another sense > than most/all of you > >> seem to interprete it. > >> > >> I HAVE seen the aforesaid word on some doors during my > visits to he > >> United States and I HAVE understood the meaning of the > word in this > >> context. But I swear that I have not been aware of the > fact that the > >> aforesaid word is used EXCLUSIVELY for the location behind these > >> doors. If I had been aware of that I would have never used > this word > >> in a conversation because that is simply not my style. > >> > >> Instead, I have been believing (and I swear this is the > truth) that > >> the aforesaid word is used by a gentlemen to address a > group of other > >> gentlemen just as a "Hi folks" among noble people but avoiding the > >> highly offical salutation "Gentlemen", in a sense a > laid-back use of > >> "Gentlemen". > >> > >> Clearly this is a mistake of mine that I cannot other than to > >> apologize for! If anyone of you has felt offended or in > any other way > >> been affected by my wrong use of this word: Sorry for > that, that was > >> NOT my intention in using this term. I have started a lot > of my posts > >> to this group with this word because of the high s/n ratio to be > >> found here and the extremely well educated people in the > group that I > >> hold in high regard. > >> > >> Someone should have told me before! If you find this word > in one of > >> my earlier posts substitute it with "Gentlemen" because > that is what > >> was ment. > >> > >> Thank you Steve for pointing at that. If you had not done > it I would > >> propably have used the word in a wrong sense for the rest > of my life. > >> > >> Best regards > >> Ulrich Bangert > >> > >> > >>> -----Urspr?ngliche Nachricht----- > >>> Von: time-nuts-bounces at febo.com > >>> [mailto:time-nuts-bounces at febo.com] Im Auftrag von Steve Rooke > >>> Gesendet: Mittwoch, 1. April 2009 11:57 > >>> An: Discussion of precise time and frequency measurement > >>> Betreff: Re: [time-nuts] Prologix > >>> > >>> > >>> This man said the P word without any form of apology :-) > >>> > >>> 73 > >>> > > > > _______________________________________________ > > time-nuts mailing list -- time-nuts at febo.com > > To unsubscribe, go to > > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > > and follow the instructions there. > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. From stanley_reynolds at yahoo.com Wed Apr 1 14:11:24 2009 From: stanley_reynolds at yahoo.com (Stanley Reynolds) Date: Wed, 1 Apr 2009 07:11:24 -0700 (PDT) Subject: [time-nuts] Datum / Efratom LPRO 101 - ebay In-Reply-To: <2D64D5541A3447929D857A0E6B07822A@pc52> References: <882814.25081.qm@web27104.mail.ukl.yahoo.com> <2D64D5541A3447929D857A0E6B07822A@pc52> Message-ID: <952068.14969.qm@web30308.mail.mud.yahoo.com> I have had mixed results with ebay, this seller has always been helpful and willing to make things right. But you should remember with used items reliability will be less than new and this makes ebay a poor choice where time is important. You should be able to evaluate any purchase as soon as possible. I have been able to play with many items that I would never be able to see at new prices, but my use is as a hobby and repair opportunities are fun and not a crisis. Stanley ----- Original Message ---- From: Tom Van Baak To: Discussion of precise time and frequency measurement Sent: Wednesday, April 1, 2009 8:35:50 AM Subject: Re: [time-nuts] Datum / Efratom LPRO 101 - ebay > I notice that this seller is using TVB's plots on his listing. This is a bit naughty. Did he ask you Tom? No, he didn't ask. I was a little surprised too. /tvb _______________________________________________ time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. From stanley_reynolds at yahoo.com Wed Apr 1 14:12:35 2009 From: stanley_reynolds at yahoo.com (Stanley Reynolds) Date: Wed, 1 Apr 2009 07:12:35 -0700 (PDT) Subject: [time-nuts] Datum / Efratom LPRO 101 - ebay Message-ID: <930919.35362.qm@web30302.mail.mud.yahoo.com> ----- Forwarded Message ---- From: Stanley Reynolds To: Tom Van Baak ; Discussion of precise time and frequency measurement Sent: Wednesday, April 1, 2009 9:11:24 AM Subject: Re: [time-nuts] Datum / Efratom LPRO 101 - ebay I have had mixed results with ebay, this seller has always been helpful and willing to make things right. But you should remember with used items reliability will be less than new and this makes ebay a poor choice where time is important. You should be able to evaluate any purchase as soon as possible. I have been able to play with many items that I would never be able to see at new prices, but my use is as a hobby and repair opportunities are fun and not a crisis. Stanley ----- Original Message ---- From: Tom Van Baak To: Discussion of precise time and frequency measurement Sent: Wednesday, April 1, 2009 8:35:50 AM Subject: Re: [time-nuts] Datum / Efratom LPRO 101 - ebay > I notice that this seller is using TVB's plots on his listing. This is a bit naughty. Did he ask you Tom? No, he didn't ask. I was a little surprised too. /tvb _______________________________________________ time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. From jra at febo.com Wed Apr 1 14:40:09 2009 From: jra at febo.com (John Ackermann N8UR) Date: Wed, 01 Apr 2009 10:40:09 -0400 Subject: [time-nuts] P word in my mails In-Reply-To: <553B2985563B4D679777EBF4F9023ADF@athlon> References: <553B2985563B4D679777EBF4F9023ADF@athlon> Message-ID: <49D37CC9.4030708@febo.com> Sorry, Ulrich -- just a joke! I actually wrote a lot of code in Turbo Pascal back in the 80s, and liked it a lot. (I know that Wirth et al never viewed the TP extensions to Pascal as valid, but they sure made it more useful.) John ---- Ulrich Bangert wrote: > Gentlemen, > >> Gee, and I thought he was talking about Pascal. :-) >> >> John >> ---- > > Pascal = P word ??? I am a professional programmer and regulary program in a > number of different languages among them Pascal, the language that comes > after "B" and assembler for some microcontroller families. I have been > thinking that among professionals the question which is the better > programming language is as modern as the last centuries 80th. But if a > reheated discussion is necessary, here is something that I can lough about: > > ------------------------------------------------------------------------ > Unix/Linux an elaborate April Fools prank - Ben Dover > 30-May-07 09:52:22 > > FOR IMMEDIATE RELEASE > > In an announcement that has stunned the computer industry, Ken > Thompson, Dennis Ritchie and Brian Kernighan admitted that the Unix > operating system and C programming language created by them is an > elaborate April Fools prank kept alive for over 20 years. Speaking at > the recent UnixWorld Software Development Forum, Thompson revealed the > following: > > In 1969, AT&T had just terminated their work with the GE/AT&T Multics > project. Brian and I had just started working with an early release > of Pascal from Professor Nichlaus Wirth's ETH labs in Switzerland and > we were impressed with its elegant simplicity and power. Dennis had > just finished reading Bored of the Rings, a hilarious National Lampoon > parody of the great Tolkien Lord of the Rings trilogy. As a lark, we > decided to do parodies of the Multics environment and Pascal. Dennis > and I were responsible for the operating environment. We looked at > Multics and designed the new system to be as complex and cryptic as > possible to maximize casual users' frustration levels, calling it Unix > as a parody of Multics, as well as other more risque allusions. > > Then Dennis and Brian worked on a truly warped version of Pascal, > called "A." When we found others were actually trying to create real > programs with A, we quickly added additional cryptic features and > evolved into B, BCPL and finally C. We stopped when we got a clean > compile on the following syntax: > > for(;P("\n"),R=;P("|"))for(e=C;e=P("_"+(*u++/8)%2))P("|"+(*u/4)%2); > > To think that modern programmers would try to use a language that > allowed such a statement was beyond our comprehension! We actually > thought of selling this to the Soviets to set their computer science > progress back 20 or more years. Imagine our surprise when AT&T and > other US corporations actually began trying to use Unix and C! It has > taken them 20 years to develop enough expertise to generate even > marginally useful applications using this 1960's technological parody, > but we are impressed with the tenacity (if not common sense) of the > general Unix and C programmer. > > In any event, Brian, Dennis and I have been working exclusively in > Pascal on the Apple Macintosh for the past few years and feel really > guilty about the chaos, confusion and truly bad programming that has > resulted from our silly prank so long ago. > > Major Unix and C vendors and customers, including AT&T, Microsoft, > Hewlett-Packard, GTE, NCR, and DEC have refused comment at this time. > Borland International, a leading vendor of Pascal and C tools, > including the popular Turbo Pascal, Turbo C and Turbo C++, stated they > had suspected this for a number of years and would continue to enhance > their Pascal products and halt further efforts to develop C. An IBM > spokesman broke into uncontrolled laughter and had to postpone a > hastely convened news conference concerning the fate of the RS-6000, > merely stating "VM will be available Real Soon Now." In a cryptic > statement, Professor Wirth of the ETH institute and father of the > Pascal, Modula 2 and Oberon structured languages, merely stated that > P. T. Barnum was correct. > ---------------------------------------------------------------------------- > > Best regards > Ulrich Bangert > >> -----Urspr?ngliche Nachricht----- >> Von: time-nuts-bounces at febo.com >> [mailto:time-nuts-bounces at febo.com] Im Auftrag von John Ackermann N8UR >> Gesendet: Mittwoch, 1. April 2009 15:12 >> An: aa8k at comcast.net; Discussion of precise time and >> frequency measurement >> Betreff: Re: [time-nuts] P word in my mails >> >> >> Gee, and I thought he was talking about Pascal. :-) >> >> John >> ---- >> >> Mike Naruta AA8K wrote: >>> Not to worry Ulrich, he was using a form >>> of derisive humor. He was insulting Prologix >>> as undesirable. >>> >>> It would be similar to referring to Microsoft >>> as the M-word. >>> >>> >>> Mike - AA8K >>> >>> >>> Ulrich Bangert wrote: >>>> Steve, >>>> >>>> after I read your mail I have been completely perplexed because I >>>> could by no stretch of imagination detect where you had found the >>>> aforesaid P word in my mail. It needed the help of some English >>>> speaking friends and a search in my last mails to find out that I >>>> have (possibly over a range of more than 30 >>>> years) used an American 5 letter word in another sense >> than most/all of you >>>> seem to interprete it. >>>> >>>> I HAVE seen the aforesaid word on some doors during my >> visits to he >>>> United States and I HAVE understood the meaning of the >> word in this >>>> context. But I swear that I have not been aware of the >> fact that the >>>> aforesaid word is used EXCLUSIVELY for the location behind these >>>> doors. If I had been aware of that I would have never used >> this word >>>> in a conversation because that is simply not my style. >>>> >>>> Instead, I have been believing (and I swear this is the >> truth) that >>>> the aforesaid word is used by a gentlemen to address a >> group of other >>>> gentlemen just as a "Hi folks" among noble people but avoiding the >>>> highly offical salutation "Gentlemen", in a sense a >> laid-back use of >>>> "Gentlemen". >>>> >>>> Clearly this is a mistake of mine that I cannot other than to >>>> apologize for! If anyone of you has felt offended or in >> any other way >>>> been affected by my wrong use of this word: Sorry for >> that, that was >>>> NOT my intention in using this term. I have started a lot >> of my posts >>>> to this group with this word because of the high s/n ratio to be >>>> found here and the extremely well educated people in the >> group that I >>>> hold in high regard. >>>> >>>> Someone should have told me before! If you find this word >> in one of >>>> my earlier posts substitute it with "Gentlemen" because >> that is what >>>> was ment. >>>> >>>> Thank you Steve for pointing at that. If you had not done >> it I would >>>> propably have used the word in a wrong sense for the rest >> of my life. >>>> >>>> Best regards >>>> Ulrich Bangert >>>> >>>> >>>>> -----Urspr?ngliche Nachricht----- >>>>> Von: time-nuts-bounces at febo.com >>>>> [mailto:time-nuts-bounces at febo.com] Im Auftrag von Steve Rooke >>>>> Gesendet: Mittwoch, 1. April 2009 11:57 >>>>> An: Discussion of precise time and frequency measurement >>>>> Betreff: Re: [time-nuts] Prologix >>>>> >>>>> >>>>> This man said the P word without any form of apology :-) >>>>> >>>>> 73 >>>>> >>> _______________________________________________ >>> time-nuts mailing list -- time-nuts at febo.com >>> To unsubscribe, go to >>> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >>> and follow the instructions there. >> >> _______________________________________________ >> time-nuts mailing list -- time-nuts at febo.com >> To unsubscribe, go to >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. From robinkimberley at btinternet.com Wed Apr 1 21:21:49 2009 From: robinkimberley at btinternet.com (Rob Kimberley) Date: Wed, 1 Apr 2009 22:21:49 +0100 Subject: [time-nuts] Odetics Time Code Translator Model 300-413 Message-ID: All, I've just had an enquiry from a US Military T&F user in CA wanting repair support on this product. Odetics (Zyfer) don't support them any more. If anyone knows of a US repair house I can point him to, I'd appreciate it. Thanks Rob Kimberley From majanoff at verizon.net Wed Apr 1 21:37:33 2009 From: majanoff at verizon.net (Mitchell Janoff) Date: Wed, 1 Apr 2009 16:37:33 -0500 Subject: [time-nuts] PPS Divider (John Ackermann N8UR) In-Reply-To: References: Message-ID: <002c01c9b312$118fa6a0$0601a8c0@delldesktop> In your post, you mentioned that the TADD-2, will have six low impedance outputs that can be individually jumpered to 1 PPS or 10 Hz through 10 kHz outputs. I was wondering if there was a way to provide outputs of 100k, 1MHz and 5MHz (assuming a 10MHz source). I am looking for a way to use a single source such as a z3801 as the standard for my various counters and clocks. There was also a post to build this using divide by 10,2 and 5 IC's. If someone is going to build this circuit can they provide the schematic? If there multiple people interested we can have a circuit board created for this project. Thanks, Mitch KC2MFB From jra at febo.com Wed Apr 1 21:56:46 2009 From: jra at febo.com (John Ackermann N8UR) Date: Wed, 01 Apr 2009 17:56:46 -0400 Subject: [time-nuts] PPS Divider (John Ackermann N8UR) In-Reply-To: <002c01c9b312$118fa6a0$0601a8c0@delldesktop> References: <002c01c9b312$118fa6a0$0601a8c0@delldesktop> Message-ID: <49D3E31E.4090906@febo.com> You could probably get those output frequencies with a custom version of the PIC code. There shouldn't be any hardware changes needed, though the circuit board layout wasn't optimized for high frequencies so no guarantee on 5 MHz. The PIC source code will be available, so anyone who wants to modify it for other outputs can have at it. John ---- Mitchell Janoff said the following on 04/01/2009 05:37 PM: > In your post, you mentioned that the TADD-2, will have six low impedance > outputs that can be individually jumpered to 1 PPS or 10 Hz through 10 kHz > outputs. I was wondering if there was a way to provide outputs of 100k, 1MHz > and 5MHz (assuming a 10MHz source). I am looking for a way to use a single > source such as a z3801 as the standard for my various counters and clocks. > There was also a post to build this using divide by 10,2 and 5 IC's. If > someone is going to build this circuit can they provide the schematic? If > there multiple people interested we can have a circuit board created for > this project. > > Thanks, > > Mitch > KC2MFB > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. From bruce.griffiths at xtra.co.nz Wed Apr 1 22:11:06 2009 From: bruce.griffiths at xtra.co.nz (Bruce Griffiths) Date: Thu, 02 Apr 2009 11:11:06 +1300 Subject: [time-nuts] PPS Divider (John Ackermann N8UR) In-Reply-To: <49D3E31E.4090906@febo.com> References: <002c01c9b312$118fa6a0$0601a8c0@delldesktop> <49D3E31E.4090906@febo.com> Message-ID: <49D3E67A.6010509@xtra.co.nz> John Providing a 5MHz output will be difficult/impossible if the PIC is clocked at 10MHz as a pin will have to be toggled with every instruction. Surely this will leave no time for executing other instructions to produce other output frequencies? It may be possible to do this using inline code with no conditional branches if and only if one can loop back to the start of the code without requiring an extra cycle. It would probably be easier to use a dedicated hardware divider (external flipflop or internal timer) to generate the 5MHz output. Bruce John Ackermann N8UR wrote: > You could probably get those output frequencies with a custom version of > the PIC code. There shouldn't be any hardware changes needed, though > the circuit board layout wasn't optimized for high frequencies so no > guarantee on 5 MHz. > > The PIC source code will be available, so anyone who wants to modify it > for other outputs can have at it. > > John > ---- > > Mitchell Janoff said the following on 04/01/2009 05:37 PM: > >> In your post, you mentioned that the TADD-2, will have six low impedance >> outputs that can be individually jumpered to 1 PPS or 10 Hz through 10 kHz >> outputs. I was wondering if there was a way to provide outputs of 100k, 1MHz >> and 5MHz (assuming a 10MHz source). I am looking for a way to use a single >> source such as a z3801 as the standard for my various counters and clocks. >> There was also a post to build this using divide by 10,2 and 5 IC's. If >> someone is going to build this circuit can they provide the schematic? If >> there multiple people interested we can have a circuit board created for >> this project. >> >> Thanks, >> >> Mitch >> KC2MFB >> >> >> _______________________________________________ >> time-nuts mailing list -- time-nuts at febo.com >> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. >> > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > From magnus at rubidium.dyndns.org Wed Apr 1 22:11:17 2009 From: magnus at rubidium.dyndns.org (Magnus Danielson) Date: Thu, 02 Apr 2009 00:11:17 +0200 Subject: [time-nuts] Datum / Efratom LPRO 101 - ebay In-Reply-To: <2D64D5541A3447929D857A0E6B07822A@pc52> References: <882814.25081.qm@web27104.mail.ukl.yahoo.com> <2D64D5541A3447929D857A0E6B07822A@pc52> Message-ID: <49D3E685.6010708@rubidium.dyndns.org> Tom Van Baak skrev: >> I notice that this seller is using TVB's plots on his listing. This is a bit naughty. Did he ask you Tom? > > No, he didn't ask. I was a little surprised too. Me too. I saw just from the first plot that it should be one of Toms. At least you are credited, so it is not a total rip-off. On the other hand, it is somewhat a sign of recognition... again. Cheers, Magnus From tvb at LeapSecond.com Wed Apr 1 23:09:16 2009 From: tvb at LeapSecond.com (Tom Van Baak) Date: Wed, 1 Apr 2009 16:09:16 -0700 Subject: [time-nuts] PPS Divider (John Ackermann N8UR) References: <002c01c9b312$118fa6a0$0601a8c0@delldesktop><49D3E31E.4090906@febo.com> <49D3E67A.6010509@xtra.co.nz> Message-ID: <238B295422F5472D822FB97207A176B1@pc52> Mitch, Ah, I can see a new TADD idea: a multi-purpose 2x multiplier or 2x divider, or 5x and 10x too. In your case, though, perhaps you could add a single flip-flop to a TADD-2 to get 5 MHz from 10 MHz, the old-fashioned way. You can't divide by two on a PIC because the minimum loop is a couple of instructions and each instruction takes 4 clock cycles. For those of you who know PIC code, the upper limit is the one mentioned by Bruce where pairs of instructions set and clear an output pin and then the entire memory is those pairs. The instruction counter quietly wraps around avoiding the need for a branch instruction. The result is a divide by 8 counter (2 instructions times 4 clocks per instruction). Ulrich, I assume the AVR is better in this respect (with a 1:1 clock vs. cycle count?). Of course, if you add any programming at all you can't use the wrapping-pair trick. Anyway, that's why all the PIC dividers you see specialize in lower frequencies, from very sub-Hz to Hz to maybe several 100 kHz. /tvb ----- Original Message ----- From: "Bruce Griffiths" To: "Discussion of precise time and frequency measurement" Sent: Wednesday, April 01, 2009 3:11 PM Subject: Re: [time-nuts] PPS Divider (John Ackermann N8UR) > John > > Providing a 5MHz output will be difficult/impossible if the PIC is > clocked at 10MHz as a pin will have to be toggled with every instruction. > Surely this will leave no time for executing other instructions to > produce other output frequencies? > > It may be possible to do this using inline code with no conditional > branches if and only if one can loop back to the start of the code > without requiring an extra cycle. > It would probably be easier to use a dedicated hardware divider > (external flipflop or internal timer) to generate the 5MHz output. > > Bruce > > John Ackermann N8UR wrote: >> You could probably get those output frequencies with a custom version of >> the PIC code. There shouldn't be any hardware changes needed, though >> the circuit board layout wasn't optimized for high frequencies so no >> guarantee on 5 MHz. >> >> The PIC source code will be available, so anyone who wants to modify it >> for other outputs can have at it. >> >> John >> ---- >> >> Mitchell Janoff said the following on 04/01/2009 05:37 PM: >> >>> In your post, you mentioned that the TADD-2, will have six low impedance >>> outputs that can be individually jumpered to 1 PPS or 10 Hz through 10 kHz >>> outputs. I was wondering if there was a way to provide outputs of 100k, 1MHz >>> and 5MHz (assuming a 10MHz source). I am looking for a way to use a single >>> source such as a z3801 as the standard for my various counters and clocks. >>> There was also a post to build this using divide by 10,2 and 5 IC's. If >>> someone is going to build this circuit can they provide the schematic? If >>> there multiple people interested we can have a circuit board created for >>> this project. >>> >>> Thanks, >>> >>> Mitch >>> KC2MFB From jra at febo.com Wed Apr 1 23:32:40 2009 From: jra at febo.com (John Ackermann N8UR) Date: Wed, 01 Apr 2009 19:32:40 -0400 Subject: [time-nuts] PPS Divider (John Ackermann N8UR) In-Reply-To: <49D3E67A.6010509@xtra.co.nz> References: <002c01c9b312$118fa6a0$0601a8c0@delldesktop> <49D3E31E.4090906@febo.com> <49D3E67A.6010509@xtra.co.nz> Message-ID: <49D3F998.5080009@febo.com> Hi Bruce -- Good point; I'll leave it to the software guys to figure that out. :-) John ---- Bruce Griffiths said the following on 04/01/2009 06:11 PM: > John > > Providing a 5MHz output will be difficult/impossible if the PIC is > clocked at 10MHz as a pin will have to be toggled with every instruction. > Surely this will leave no time for executing other instructions to > produce other output frequencies? > > It may be possible to do this using inline code with no conditional > branches if and only if one can loop back to the start of the code > without requiring an extra cycle. > It would probably be easier to use a dedicated hardware divider > (external flipflop or internal timer) to generate the 5MHz output. > > Bruce > > John Ackermann N8UR wrote: >> You could probably get those output frequencies with a custom version of >> the PIC code. There shouldn't be any hardware changes needed, though >> the circuit board layout wasn't optimized for high frequencies so no >> guarantee on 5 MHz. >> >> The PIC source code will be available, so anyone who wants to modify it >> for other outputs can have at it. >> >> John >> ---- >> >> Mitchell Janoff said the following on 04/01/2009 05:37 PM: >> >>> In your post, you mentioned that the TADD-2, will have six low impedance >>> outputs that can be individually jumpered to 1 PPS or 10 Hz through 10 kHz >>> outputs. I was wondering if there was a way to provide outputs of 100k, 1MHz >>> and 5MHz (assuming a 10MHz source). I am looking for a way to use a single >>> source such as a z3801 as the standard for my various counters and clocks. >>> There was also a post to build this using divide by 10,2 and 5 IC's. If >>> someone is going to build this circuit can they provide the schematic? If >>> there multiple people interested we can have a circuit board created for >>> this project. >>> >>> Thanks, >>> >>> Mitch >>> KC2MFB >>> >>> >>> _______________________________________________ >>> time-nuts mailing list -- time-nuts at febo.com >>> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >>> and follow the instructions there. >>> >> _______________________________________________ >> time-nuts mailing list -- time-nuts at febo.com >> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. >> >> > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. From va2hdd at aei.ca Thu Apr 2 01:30:15 2009 From: va2hdd at aei.ca (Claude Houde) Date: Wed, 01 Apr 2009 21:30:15 -0400 Subject: [time-nuts] Austron 2100F References: 49D2C0E9.3020507@aei.ca Message-ID: <49D41527.1000201@aei.ca> Hi everybody ! Thanks for your fast answers. If I can resume it is OK to buy the 2100F, but at a bargain price as it may be a really tough job to bring it back to life. Thanks also for the user's manual source, I will order it to start troubleshooting. Again thanks and best regards ! 73 from Claude VA2HDD From kilodelta4foxmike at gmail.com Thu Apr 2 02:17:13 2009 From: kilodelta4foxmike at gmail.com (Brian Kirby) Date: Wed, 01 Apr 2009 21:17:13 -0500 Subject: [time-nuts] Frequency Divider In-Reply-To: <49D3F998.5080009@febo.com> References: <002c01c9b312$118fa6a0$0601a8c0@delldesktop> <49D3E31E.4090906@febo.com> <49D3E67A.6010509@xtra.co.nz> <49D3F998.5080009@febo.com> Message-ID: <49D42029.3000304@gmail.com> Maybe we all could come up with a separate new board to take 10 Mhz and give us 5 Mhz and 1 Mhz out. Start with a buffer amp and then a decent Schmidt trigger. Feed it to a symmetrical divide by 2 for 5 Mhz, and a symmetrical dive by 10 for 1 Mhz. These out puts could be buffered with 74AC04 for TTL. Another set of outputs could be derived and filtered to give sine wave outputs. It seems the crowd is against 7490s, and 74390s - and I would like to know what the crowd recommends as suitable. Brian KD4FM John Ackermann N8UR wrote: > Hi Bruce -- > > Good point; I'll leave it to the software guys to figure that out. :-) > > John > ---- > > Br > From bruce.griffiths at xtra.co.nz Thu Apr 2 02:49:32 2009 From: bruce.griffiths at xtra.co.nz (Bruce Griffiths) Date: Thu, 02 Apr 2009 15:49:32 +1300 Subject: [time-nuts] Frequency Divider In-Reply-To: <49D42029.3000304@gmail.com> References: <002c01c9b312$118fa6a0$0601a8c0@delldesktop> <49D3E31E.4090906@febo.com> <49D3E67A.6010509@xtra.co.nz> <49D3F998.5080009@febo.com> <49D42029.3000304@gmail.com> Message-ID: <49D427BC.20507@xtra.co.nz> Brian Ideally one would use something like a Johnson counter or a Grey code counter, decode the required outputs and then resynchronise the decoded outputs using a set of dedicated flipflops. Since such counters only change the state of one flipflop at a time it is possible to avoid decoding glitches. The resynchronisation flipflops minimise the clock to output delay and its associated tempco as well as minimise the jitter. Although the decoders can have glitch free outputs there will be some edge delay patterns that repeat every ten input clock periods. If one is using a set of retiming/resynchronisation flipflops then decoder deglitches are relatively unimportant as they are eliminated by the retiming flipflops. One could use a 74HC4017 and produce the 5MHz output as: 5MHz = Q0 +Q2+ Q4 + Q6 + Q8 which will be glitch free. However resynchronisation will be necessary to minimise periodic variations in edge delay for this output. 1MHz = Carry Out Bruce Brian Kirby wrote: > Maybe we all could come up with a separate new board to take 10 Mhz and > give us 5 Mhz and 1 Mhz out. > > Start with a buffer amp and then a decent Schmidt trigger. Feed it to a > symmetrical divide by 2 for 5 Mhz, and a symmetrical dive by 10 for 1 > Mhz. These out puts could be buffered with 74AC04 for TTL. Another set > of outputs could be derived and filtered to give sine wave outputs. > > It seems the crowd is against 7490s, and 74390s - and I would like to > know what the crowd recommends as suitable. > > Brian KD4FM > > John Ackermann N8UR wrote: > >> Hi Bruce -- >> >> Good point; I'll leave it to the software guys to figure that out. :-) >> >> John >> ---- >> >> Br >> >> > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > From hmurray at megapathdsl.net Thu Apr 2 09:09:59 2009 From: hmurray at megapathdsl.net (Hal Murray) Date: Thu, 02 Apr 2009 02:09:59 -0700 Subject: [time-nuts] Frequency Divider In-Reply-To: Message from Brian Kirby of "Wed, 01 Apr 2009 21:17:13 CDT." <49D42029.3000304@gmail.com> Message-ID: <20090402091000.506D3BCE2@ip-64-139-1-69.sjc.megapath.net> > Start with a buffer amp and then a decent Schmidt trigger. If you have a clean input signal, a Schmitt trigger doesn't solve any problems. It does help if you have a slowly rising signal such that noise might be significant while the signal is near threshold. A 10 MHz sine wave is slow relative to AC logic. Since we were recently speaking of LPROs, their user manual has a section on how to convert 10 MHz sine waves into TTL signals. None of their suggestions used Schmitt triggers. This feels like the sort of thing that should have been hashed out here by now. Is it time to start a FAQ? My straw man would be to capacitive couple into a 74AC00 that's biased halfway between VCC and GND. That's clean and simple. A transformer would break ground loops. A differential input chip might reduce jitter from noise on the power supply. > Feed it to a symmetrical divide by 2 for 5 Mhz, and a symmetrical > dive by 10 for 1 Mhz. > It seems the crowd is against 7490s, and 74390s - and I would like to > know what the crowd recommends as suitable. Dividing by 10 is simple. Doing it with symmetrical output takes a bit more/different logic than comes prepackaged in a single DIP, or at least not any that I'm familiar with. Plan A would use a 4 bit loadable counter and load it with 3 when it reads 12 so the top bit would be off for 5 cycles, 3 through 7, then on for 5 cycles, 8 through 12. That's reasonable to implement in old TTL DIPs. 12 is easy to decode, just a 2 input gate since states 13-15 won't happen. 74xx163 and 74xx00 Plan B would be to use a PAL or CPLD. I don't know of any that are available in DIP, have free design software, and are easy to program without a fancy programmer. There could easily be something I don't know about. I know that Xilinx CPLDs have free software (WebPACK) but they don't come in DIP. A friend has written software to program them, but he's a wizard so I don't know if mortals could do it. WebPACK may do the programming if you have a gizmo. One is available at a reasonable price from Digilent. This technology is too handy. There is probably some hobbyist friendly setup out there. You may have to build a programmer. -- These are my opinions, not necessarily my employer's. I hate spam. From sar10538 at gmail.com Thu Apr 2 09:10:50 2009 From: sar10538 at gmail.com (Steve Rooke) Date: Thu, 2 Apr 2009 22:10:50 +1300 Subject: [time-nuts] P word in my mails In-Reply-To: References: <1231b6a80904010256p3dc5fa7bufc620a1817d0ef5c@mail.gmail.com> Message-ID: <1231b6a80904020210h314d13f5q9ca46aab31f7fc2@mail.gmail.com> Dear Ulrich, After writhing around on the floor for some time, with my sides splitting, I have managed to stop laughing, hopefully, long enough to reply to your post. The P word in question is, as already pointed out, PASCAL (hack, spit). To my understanding, almost universally loathed throughout the coding community, and which, I thought, was put to rest many moons ago, much to the relief of the programming community. Now I have gone to the vault and dusted off the copy of The Historium Evilis Computium which I keep wrapped in a black silk scarf and locked in a lead lined container. It always gives me shivers whenever I open this book and it takes some while to get back into a decent sleep pattern after each reading. Searching through the book, I find many sections referring to the M word, the I word, the BG words, and that's not to forget the GOTO word. I went past the sections printed in special ink where the text can only be read by those who are pure of heart, as it is a protection against the evil IT masters who would send their vile lawyers to suppress this work, until I came upon this ancient writing which I reproduce below. WARNING: if you are of a nervous disposition, or suffer from heart problems, I urge to to delete this message immediately and wipe the free-space on your hard drive with a 35 pass Gutmann method. -- And it came to pass that the Dark One was troubled. Mankind had discovered this mighty power they called computing And this made the Dark One angy. He ruminated for many days and nights until he came to a solution. He would create something so grave, so terrible, it would make mankind think of IT as Instant Terror. And the vile thing would dumbfound the masses with it's heavily typed variables, It's unwillingness to perform functions with mixed types And it's difficulty of getting anything useful through the compiler. But mankind would see it as a wondrous system, so neat, so clean, producing nothing but goodness. With a wave of his hands, out of his ASR-33 there spat the most vile, the most evil of all things. And the thing was called PASCAL! And the Dark One roared with a laughter that would be heard from all around. And the P thing was sent down to the educational establishments And darkness came over the computing land And the comp science students were forced to use it. It was pitiful to hear their cries as they flagellated themselves when they coded For it was only the pain that could keep them sane But many failed and were dragged off to the asylums screaming. Infrequently there would be a cry of "I finally got it past the compiler!" And the students would rejoiced as they carried the victor at shoulder height all around. And there rose up others who challenged the P thing And they created new programming languages And their resistance drove out the P thing Expunging it from mankind. It still lurked in some places but it's hold on mankind was broken. And programmers throughout the whole of mankind rejoiced And the dark clouds that covered IT dispersed. But there was no real rejoicing in the end as all that used the P thing succumbed to its vile purpose. And in later years, those that had survived were a pitiful sight Oft-times found in dark corners, chanting, monotonously, "I must not mix types, I must not mix types, I must..." For hours on end, it was a sorrowful sight. And it was said that the Dark One was displeased His plan to destroy the will of mankind was thwarted But only for the moment For he was already working on his next evil plan And it came to pass that he came down onto the World And he took on a human guise And he created an evil empire... -- This is all I am prepared to transcribe from the book for fear that even worse things will happen. I will have to get my whip from the vault and flagellate myself for hours to get this P thing out of my mind and try to keep myself sane, such is the power of this evil thing. That's all folks!!! 73, Steve 2009/4/2 Ulrich Bangert : > Steve, > > after I read your mail I have been completely perplexed because I could by > no stretch of imagination detect where you had found the aforesaid P word in > my mail. It needed the help of some English speaking friends and a search in > my last mails to find out that I have (possibly over a range of more than 30 > years) used an American 5 letter word in another sense than most/all of you > seem to interprete it. > > I HAVE seen the aforesaid word on some doors during my visits to he United > States and I HAVE understood the meaning of the word in this context. But I > swear that I have not been aware of the fact that the aforesaid word is used > EXCLUSIVELY for the location behind these doors. If I had been aware of that > I would have never used this word in a conversation because that is simply > not my style. > > Instead, I have been believing (and I swear this is the truth) that the > aforesaid word is used by a gentlemen to address a group of other gentlemen > just as a "Hi folks" among noble people but avoiding the highly offical > salutation "Gentlemen", in a sense a laid-back use of "Gentlemen". > > Clearly this is a mistake of mine that I cannot other than to apologize for! > If anyone of you has felt offended or in any other way been affected by my > wrong use of this word: Sorry for that, that was NOT my intention in using > this term. I have started a lot of my posts to this group with this word > because of the high s/n ratio to be found here and the extremely well > educated people in the group that I hold in high regard. > > Someone should have told me before! If you find this word in one of my > earlier posts substitute it with "Gentlemen" because that is what was ment. > > Thank you Steve for pointing at that. If you had not done it I would > propably have used the word in a wrong sense for the rest of my life. > > Best regards > Ulrich Bangert > > >> -----Urspr?ngliche Nachricht----- >> Von: time-nuts-bounces at febo.com >> [mailto:time-nuts-bounces at febo.com] Im Auftrag von Steve Rooke >> Gesendet: Mittwoch, 1. April 2009 11:57 >> An: Discussion of precise time and frequency measurement >> Betreff: Re: [time-nuts] Prologix >> >> >> This man said the P word without any form of apology :-) >> >> 73 >> >> 2009/4/1 Ulrich Bangert : >> > Mike, >> > >> > I would like to second Brent's information: That is exactly >> how it is >> > done. Talking to the Prologix interface and talking to the NI >> > interface is COMPLETELY different in that talking to the Prologix >> > always means straightforward serial communication while >> talking to the >> > NI involves DLL-calls from the application. >> > >> > The Prologix is cheap and easy to work with, thats why some >> time nuts >> > use it. The NI interface is on the other hand more >> expensive and more >> > complex to handle (and yes, it does some things that are not easily >> > done with the Prologix). The biggest advantage of the DLL-calls is: >> > The same application works with whatever NI interface you >> use: Plug in >> > card, USB devices, ethernet dvices, you name it. All work >> by the SAME >> > dll calls, so your application is not specific for a >> interface device. >> > >> > I do not forget to advertise my own solution to GPIB >> programming named >> > EZGPIB which talks to Prologix (both LAN and USB based) as >> well to NI >> > interfaces and thanks supporting basic VISA even to GPIB >> interfaces of >> > other suppliers. >> > >> > It uses an easy to learn PASCAL like script language that >> your friend >> > might get used to in a snap. Basically, if your friend >> writes a EZGPIB >> > based script to talk to his counter over the Prologix, you will be >> > able to use the SAME script to talk to your 5335A via a NI >> interface. >> > Nice feature? EZGPIB has got mentioned in April's 2008 >> issue of "Test >> > & Measurement World". See the last link on my "About me" page >> > >> > http://www.ulrich-bangert.de/html/about_me.html >> > >> > EZGIPB can be downloaded for free from >> > >> > http://www.ulrich-bangert.de/html/downloads.html >> > >> > Best regards >> > Ulrich, DF6JB >> > >> >> -----Ursprungliche Nachricht----- >> >> Von: time-nuts-bounces at febo.com >> [mailto:time-nuts-bounces at febo.com] >> >> Im Auftrag von Brent Gordon >> >> Gesendet: Dienstag, 31. Marz 2009 20:07 >> >> An: Discussion of precise time and frequency measurement >> >> Betreff: Re: [time-nuts] Prologix >> >> >> >> >> >> Mike Feher wrote: >> >> > A friend has a 5335A counter and bought a Prologix adaptor >> >> for it to >> >> > collect data. He wrote the software and has had extremely good >> >> > results. He offered to do the same for me utilizing my NI >> >> adaptor so I >> >> > could use it for my various counters. Unfortunately he ran into >> >> > problems and feels he needs a special version of basic >> in order to >> >> > make my $500 NI adaptor work. I admit to my total lack of >> >> programming >> >> > ability. I still use GWBASIC, and only to crunch heavy >> >> numbers. I have >> >> > no idea how to interface any software to communicate with an >> >> > instrument, and, maybe am too old to want to learn as it >> >> seems a lot >> >> > of people do it on a regular basis already. If this becomes too >> >> > difficult I may have to buy a Prologix unit from Abdul. >> >> While I am all >> >> > for doing that, and I bought my NI before Abdul had his >> >> version going, >> >> > I was also under the impression that if the Prologix can do >> >> it the NI >> >> > can do it, but, not necessarily the other way around. My friend >> >> > mentioned API calls, whatever they are. Any suggestions? >> >> Thanks - Mike >> >> > >> >> > >> >> > Mike B. Feher, N4FS >> >> > 89 Arnold Blvd. >> >> > Howell, NJ, 07731 >> >> > 732-886-5960 >> >> > >> >> Mike, >> >> >> >> You should have gotten the NI-488.2 CD with your GPIB >> card. On that >> >> CD are the dlls (Dynamic Link Libraries) to talk to the card. >> >> You can use >> >> the dlls in any language that supports dlls or ActiveX. >> >> Sorry to say, >> >> GWBASIC is not one of those languages. ?Visual Basic 6 >> works well and >> >> I've even done GPIB data acquisition directly into Excel using VBA >> >> (Visual Basic for Applications, Excel's macro language). ?VBA >> >> is part of >> >> Excel. ?Alternatively, you can get a free Visual Basic Express at >> >> http://www.microsoft.com/express/vb/ ?I haven't tried VB >> >> Express, but I >> >> think it will work. ?Normally, I do all my GPIB programming >> >> in LabVIEW. >> >> >> >> Brent >> >> >> >> _______________________________________________ >> >> time-nuts mailing list -- time-nuts at febo.com >> >> To unsubscribe, go to >> >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> >> and follow the instructions there. >> > >> > >> > _______________________________________________ >> > time-nuts mailing list -- time-nuts at febo.com >> > To unsubscribe, go to >> > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> > and follow the instructions there. >> > >> >> >> >> -- >> Steve Rooke - ZL3TUV & G8KVD & JAKDTTNW >> Omnium finis imminet >> >> _______________________________________________ >> time-nuts mailing list -- time-nuts at febo.com >> To unsubscribe, go to >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > -- Steve Rooke - ZL3TUV & G8KVD & JAKDTTNW Omnium finis imminet From jra at febo.com Thu Apr 2 12:19:12 2009 From: jra at febo.com (John Ackermann N8UR) Date: Thu, 02 Apr 2009 08:19:12 -0400 Subject: [time-nuts] Frequency Divider In-Reply-To: <20090402091000.506D3BCE2@ip-64-139-1-69.sjc.megapath.net> References: <20090402091000.506D3BCE2@ip-64-139-1-69.sjc.megapath.net> Message-ID: <49D4AD40.6020300@febo.com> Hal Murray wrote: >> Start with a buffer amp and then a decent Schmidt trigger. > > If you have a clean input signal, a Schmitt trigger doesn't solve any > problems. It does help if you have a slowly rising signal such that noise > might be significant while the signal is near threshold. A 10 MHz sine wave > is slow relative to AC logic. > > Since we were recently speaking of LPROs, their user manual has a section on > how to convert 10 MHz sine waves into TTL signals. None of their suggestions > used Schmitt triggers. > > This feels like the sort of thing that should have been hashed out here by > now. Is it time to start a FAQ? The TADD-2 uses an input circuit published by Wenzel in their "Waveform Conversion" document at http://www.wenzel.com/documents/waveform.html. I haven't measured its standalone jitter, but its input sensitivity is great -- it will reliably trigger a CMOS gate from an input at least down to -10 dBm, maybe lower (I don't recall the exact limits I found when I tested). If you build this, note one thing -- with the 100 ohm emitter resistor specified, the square wave output is more like 6V than 5V p-p. I use 120 ohms instead to get a 5 volt output. While the Wenzel circuit requires a modest handful of discrete components, I think it's the most useful solution by a pretty clear margin for our typical requirement of driving a single-ended logic gate from an HF source. John From bruce.griffiths at xtra.co.nz Thu Apr 2 12:21:03 2009 From: bruce.griffiths at xtra.co.nz (Bruce Griffiths) Date: Fri, 03 Apr 2009 01:21:03 +1300 Subject: [time-nuts] Frequency Divider In-Reply-To: <20090402091000.506D3BCE2@ip-64-139-1-69.sjc.megapath.net> References: <20090402091000.506D3BCE2@ip-64-139-1-69.sjc.megapath.net> Message-ID: <49D4ADAF.20703@xtra.co.nz> Hal Hal Murray wrote: >> Start with a buffer amp and then a decent Schmidt trigger. >> > > If you have a clean input signal, a Schmitt trigger doesn't solve any > problems. It does help if you have a slowly rising signal such that noise > might be significant while the signal is near threshold. A 10 MHz sine wave > is slow relative to AC logic. > > Since we were recently speaking of LPROs, their user manual has a section on > how to convert 10 MHz sine waves into TTL signals. None of their suggestions > used Schmitt triggers. > > This feels like the sort of thing that should have been hashed out here by > now. Is it time to start a FAQ? > > My straw man would be to capacitive couple into a 74AC00 that's biased > halfway between VCC and GND. That's clean and simple. A transformer would > break ground loops. A differential input chip might reduce jitter from noise > on the power supply. > > > A large resistor connected between the input and output would accommodate threshold variations better. Even better would be a feedback loop that adjusts the input bias point to maintain the output duty cycle at 50%. However if you use such a threshold adjustment lop with a Schmitt trigger it will oscillate at a low frequency when there is no input signal. A simple low Q tuned circuit can be used to boost the signal amplitude at the gate input if necessary. > >> Feed it to a symmetrical divide by 2 for 5 Mhz, and a symmetrical >> dive by 10 for 1 Mhz. >> It seems the crowd is against 7490s, and 74390s - and I would like to >> know what the crowd recommends as suitable. >> > > Dividing by 10 is simple. Doing it with symmetrical output takes a bit > more/different logic than comes prepackaged in a single DIP, or at least not > any that I'm familiar with. > > The venerable Johnson decade counter such as a 4017 or 74HC4017 does this in a DIP package. > Plan A would use a 4 bit loadable counter and load it with 3 when it reads 12 > so the top bit would be off for 5 cycles, 3 through 7, then on for 5 cycles, > 8 through 12. That's reasonable to implement in old TTL DIPs. 12 is easy to > decode, just a 2 input gate since states 13-15 won't happen. 74xx163 and > 74xx00 > > Plan B would be to use a PAL or CPLD. I don't know of any that are available > in DIP, have free design software, and are easy to program without a fancy > programmer. There could easily be something I don't know about. I know that > Xilinx CPLDs have free software (WebPACK) but they don't come in DIP. A > friend has written software to program them, but he's a wizard so I don't > know if mortals could do it. WebPACK may do the programming if you have a > gizmo. One is available at a reasonable price from Digilent. > Digilent have suitable Xilinx CPLDs mounted on DIP compatible daughter boards. The CPLDs are programmed via the JTAG port. Suitable JTAG programming cables are readily availble. > This technology is too handy. There is probably some hobbyist friendly setup > out there. You may have to build a programmer. > > > Bruce From bruce.griffiths at xtra.co.nz Thu Apr 2 12:31:46 2009 From: bruce.griffiths at xtra.co.nz (Bruce Griffiths) Date: Fri, 03 Apr 2009 01:31:46 +1300 Subject: [time-nuts] Frequency Divider In-Reply-To: <49D4AD40.6020300@febo.com> References: <20090402091000.506D3BCE2@ip-64-139-1-69.sjc.megapath.net> <49D4AD40.6020300@febo.com> Message-ID: <49D4B032.3050804@xtra.co.nz> John Ackermann N8UR wrote: > Hal Murray wrote: > >>> Start with a buffer amp and then a decent Schmidt trigger. >>> >> If you have a clean input signal, a Schmitt trigger doesn't solve any >> problems. It does help if you have a slowly rising signal such that noise >> might be significant while the signal is near threshold. A 10 MHz sine wave >> is slow relative to AC logic. >> >> Since we were recently speaking of LPROs, their user manual has a section on >> how to convert 10 MHz sine waves into TTL signals. None of their suggestions >> used Schmitt triggers. >> >> This feels like the sort of thing that should have been hashed out here by >> now. Is it time to start a FAQ? >> > > The TADD-2 uses an input circuit published by Wenzel in their "Waveform > Conversion" document at http://www.wenzel.com/documents/waveform.html. > > I haven't measured its standalone jitter, but its input sensitivity is > great -- it will reliably trigger a CMOS gate from an input at least > down to -10 dBm, maybe lower (I don't recall the exact limits I found > when I tested). If you build this, note one thing -- with the 100 ohm > emitter resistor specified, the square wave output is more like 6V than > 5V p-p. I use 120 ohms instead to get a 5 volt output. > > While the Wenzel circuit requires a modest handful of discrete > components, I think it's the most useful solution by a pretty clear > margin for our typical requirement of driving a single-ended logic gate > from an HF source. > > John > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > John One could also use a PECL to TTL level translator. JPL have used ECL dividers throughout to produce 10MHz, 1MHz and 100KHz outputs from the 100MHz signal derived from a Hydrogen maser: http://tmo.jpl.nasa.gov/progress_report2/42-30/30I.PDF Where TTL outputs are required an ECL to TTl translator followed by a discrete amplifier to drive TTL levels in a 50 ohm load was used. Bruce From cupido at mail.ua.pt Thu Apr 2 12:42:23 2009 From: cupido at mail.ua.pt (Luis Cupido) Date: Thu, 02 Apr 2009 13:42:23 +0100 Subject: [time-nuts] Frequency Divider In-Reply-To: <49D4ADAF.20703@xtra.co.nz> References: <20090402091000.506D3BCE2@ip-64-139-1-69.sjc.megapath.net> <49D4ADAF.20703@xtra.co.nz> Message-ID: <49D4B2AF.3040300@mail.ua.pt> > The CPLDs are programmed via the JTAG port. > Suitable JTAG programming cables are readily availble. Or you can build one to use the LPT port of your PC using just a 74HC244. Luis Cupido. ct1dmk. From brooke at pacific.net Thu Apr 2 14:46:21 2009 From: brooke at pacific.net (brooke at pacific.net) Date: Thu, 2 Apr 2009 07:46:21 -0700 (PDT) Subject: [time-nuts] P word in my mails In-Reply-To: <1231b6a80904020210h314d13f5q9ca46aab31f7fc2@mail.gmail.com> References: <1231b6a80904010256p3dc5fa7bufc620a1817d0ef5c@mail.gmail.com> <1231b6a80904020210h314d13f5q9ca46aab31f7fc2@mail.gmail.com> Message-ID: <1192.SVVXXVxVQkI=.1238683581.squirrel@webmail.securepacific.net> Hi Steve: I came across this Programmer's Language Guide on Prof Kelly's web page related to his 68000 assembler software at: http://www.monroeccc.edu/ckelly/default.htm Have Fun, Brooke Clarke http://www.PRC68.com -------------------------------------------- PROGRAMMERS LANGUAGE REFERENCE GUIDE C You shoot yourself in the foot. C++ You shoot yourself in the foot and then accidentally delete the pointer that points to it. Your foot is now in the garbage and there is no way to retrieve it. Java It looks like your gun but some things are missing and others are in the wrong place. While trying to figure out how to use it you accidentally shoot yourself in the groin. Modula-2 After realizing that you can't actually accomplish anything in the language, you shoot yourself in the head. Pascal Same as Modula-2, except that the bullets are the wrong type and won't pass through the barrel. The gun explodes. FORTRAN You shoot yourself in each toe, iteratively, until you run out of toes, then you read in the next foot and repeat. If you run out of bullets, you continue anyway because you have no exception-processing ability. ALGOL You shoot yourself in the foot with a musket. The musket is aesthetically fascinating, and the wound baffles the adolescent medic in the emergency room. COBOL You describe the gun, the foot, and the process of shooting the foot with the gun in great detail. You then shoot yourself in the head. APL You hear a bang, your foot hurts, but you don't know enough linear algebra to figure out what happened. LISP You shoot yourself in the appendage which holds the gun with which you shoot yourself in the appendage which holds the gun with which you shoot yourself in the appendage which holds the gun with which .... FORTH Foot in yourself shoot. ASSEMBLY You shoot yourself in the foot with a machine gun. You attempt to slow down the fire rate but are unable to understand the program because there are no comments. XBASE Shooting yourself is no problem. If you want to shoot yourself in the foot, you have to use Clipper. BASIC Shoot yourself in the foot with a water-pistol. On big systems, continue until entire lower body is waterlogged. VISUAL BASIC You spend days designing the perfect user interface and then shoot yourself in the foot. Everyone is so impressed with the user interface you created they all use your program and shoot themselves in the foot. HTML Shoot here SQL You cut off your foot, send it to the service bureau and when it returns it has a hole in it, but no longer fits the end of your leg Dbase You pull the trigger, but the bullet moves so slowly that by the time it reaches your foot, you've forgotten why you shot yourself in the first place Python You shoot yourself in every other toe in order to create more whitespace and then show your foot to all your friends while bragging about how much better Python is than every other programming language. Perl You shoot yourself in the foot 12 different ways. -------------------------------------------- > Dear Ulrich, > > After writhing around on the floor for some time, with my sides > splitting, I have managed to stop laughing, hopefully, long enough to > reply to your post. The P word in question is, as already pointed out, > PASCAL (hack, spit). To my understanding, almost universally loathed > throughout the coding community, and which, I thought, was put to rest > many moons ago, much to the relief of the programming community. > > Now I have gone to the vault and dusted off the copy of The Historium > Evilis Computium which I keep wrapped in a black silk scarf and locked > in a lead lined container. It always gives me shivers whenever I open > this book and it takes some while to get back into a decent sleep > pattern after each reading. Searching through the book, I find many > sections referring to the M word, the I word, the BG words, and that's > not to forget the GOTO word. I went past the sections printed in > special ink where the text can only be read by those who are pure of > heart, as it is a protection against the evil IT masters who would > send their vile lawyers to suppress this work, until I came upon this > ancient writing which I reproduce below. > > WARNING: if you are of a nervous disposition, or suffer from heart > problems, I urge to to delete this message immediately and wipe the > free-space on your hard drive with a 35 pass Gutmann method. > > -- > > And it came to pass that the Dark One was troubled. > Mankind had discovered this mighty power they called computing > And this made the Dark One angy. > > He ruminated for many days and nights until he came to a solution. > He would create something so grave, so terrible, it would make mankind > think of IT as Instant Terror. > And the vile thing would dumbfound the masses with it's heavily typed > variables, > It's unwillingness to perform functions with mixed types > And it's difficulty of getting anything useful through the compiler. > But mankind would see it as a wondrous system, so neat, so clean, > producing nothing but goodness. > > With a wave of his hands, out of his ASR-33 there spat the most vile, > the most evil of all things. > And the thing was called PASCAL! > And the Dark One roared with a laughter that would be heard from all > around. > > And the P thing was sent down to the educational establishments > And darkness came over the computing land > And the comp science students were forced to use it. > It was pitiful to hear their cries as they flagellated themselves when > they coded > For it was only the pain that could keep them sane > But many failed and were dragged off to the asylums screaming. > Infrequently there would be a cry of "I finally got it past the compiler!" > And the students would rejoiced as they carried the victor at shoulder > height all around. > > And there rose up others who challenged the P thing > And they created new programming languages > And their resistance drove out the P thing > Expunging it from mankind. > It still lurked in some places but it's hold on mankind was broken. > And programmers throughout the whole of mankind rejoiced > And the dark clouds that covered IT dispersed. > > But there was no real rejoicing in the end as all that used the P > thing succumbed to its vile purpose. > And in later years, those that had survived were a pitiful sight > Oft-times found in dark corners, chanting, monotonously, > "I must not mix types, I must not mix types, I must..." > For hours on end, it was a sorrowful sight. > > And it was said that the Dark One was displeased > His plan to destroy the will of mankind was thwarted > But only for the moment > For he was already working on his next evil plan > And it came to pass that he came down onto the World > And he took on a human guise > And he created an evil empire... > > -- > > This is all I am prepared to transcribe from the book for fear that > even worse things will happen. I will have to get my whip from the > vault and flagellate myself for hours to get this P thing out of my > mind and try to keep myself sane, such is the power of this evil > thing. > > That's all folks!!! > 73, Steve > > 2009/4/2 Ulrich Bangert : >> Steve, >> >> after I read your mail I have been completely perplexed because I could >> by >> no stretch of imagination detect where you had found the aforesaid P >> word in >> my mail. It needed the help of some English speaking friends and a >> search in >> my last mails to find out that I have (possibly over a range of more >> than 30 >> years) used an American 5 letter word in another sense than most/all of >> you >> seem to interprete it. >> >> I HAVE seen the aforesaid word on some doors during my visits to he >> United >> States and I HAVE understood the meaning of the word in this context. >> But I >> swear that I have not been aware of the fact that the aforesaid word is >> used >> EXCLUSIVELY for the location behind these doors. If I had been aware of >> that >> I would have never used this word in a conversation because that is >> simply >> not my style. >> >> Instead, I have been believing (and I swear this is the truth) that the >> aforesaid word is used by a gentlemen to address a group of other >> gentlemen >> just as a "Hi folks" among noble people but avoiding the highly offical >> salutation "Gentlemen", in a sense a laid-back use of "Gentlemen". >> >> Clearly this is a mistake of mine that I cannot other than to apologize >> for! >> If anyone of you has felt offended or in any other way been affected by >> my >> wrong use of this word: Sorry for that, that was NOT my intention in >> using >> this term. I have started a lot of my posts to this group with this word >> because of the high s/n ratio to be found here and the extremely well >> educated people in the group that I hold in high regard. >> >> Someone should have told me before! If you find this word in one of my >> earlier posts substitute it with "Gentlemen" because that is what was >> ment. >> >> Thank you Steve for pointing at that. If you had not done it I would >> propably have used the word in a wrong sense for the rest of my life. >> >> Best regards >> Ulrich Bangert >> >> >>> -----Urspr?ngliche Nachricht----- >>> Von: time-nuts-bounces at febo.com >>> [mailto:time-nuts-bounces at febo.com] Im Auftrag von Steve Rooke >>> Gesendet: Mittwoch, 1. April 2009 11:57 >>> An: Discussion of precise time and frequency measurement >>> Betreff: Re: [time-nuts] Prologix >>> >>> >>> This man said the P word without any form of apology :-) >>> >>> 73 >>> >>> 2009/4/1 Ulrich Bangert : >>> > Mike, >>> > >>> > I would like to second Brent's information: That is exactly >>> how it is >>> > done. Talking to the Prologix interface and talking to the NI >>> > interface is COMPLETELY different in that talking to the Prologix >>> > always means straightforward serial communication while >>> talking to the >>> > NI involves DLL-calls from the application. >>> > >>> > The Prologix is cheap and easy to work with, thats why some >>> time nuts >>> > use it. The NI interface is on the other hand more >>> expensive and more >>> > complex to handle (and yes, it does some things that are not easily >>> > done with the Prologix). The biggest advantage of the DLL-calls is: >>> > The same application works with whatever NI interface you >>> use: Plug in >>> > card, USB devices, ethernet dvices, you name it. All work >>> by the SAME >>> > dll calls, so your application is not specific for a >>> interface device. >>> > >>> > I do not forget to advertise my own solution to GPIB >>> programming named >>> > EZGPIB which talks to Prologix (both LAN and USB based) as >>> well to NI >>> > interfaces and thanks supporting basic VISA even to GPIB >>> interfaces of >>> > other suppliers. >>> > >>> > It uses an easy to learn PASCAL like script language that >>> your friend >>> > might get used to in a snap. Basically, if your friend >>> writes a EZGPIB >>> > based script to talk to his counter over the Prologix, you will be >>> > able to use the SAME script to talk to your 5335A via a NI >>> interface. >>> > Nice feature? EZGPIB has got mentioned in April's 2008 >>> issue of "Test >>> > & Measurement World". See the last link on my "About me" page >>> > >>> > http://www.ulrich-bangert.de/html/about_me.html >>> > >>> > EZGIPB can be downloaded for free from >>> > >>> > http://www.ulrich-bangert.de/html/downloads.html >>> > >>> > Best regards >>> > Ulrich, DF6JB >>> > >>> >> -----Ursprungliche Nachricht----- >>> >> Von: time-nuts-bounces at febo.com >>> [mailto:time-nuts-bounces at febo.com] >>> >> Im Auftrag von Brent Gordon >>> >> Gesendet: Dienstag, 31. Marz 2009 20:07 >>> >> An: Discussion of precise time and frequency measurement >>> >> Betreff: Re: [time-nuts] Prologix >>> >> >>> >> >>> >> Mike Feher wrote: >>> >> > A friend has a 5335A counter and bought a Prologix adaptor >>> >> for it to >>> >> > collect data. He wrote the software and has had extremely good >>> >> > results. He offered to do the same for me utilizing my NI >>> >> adaptor so I >>> >> > could use it for my various counters. Unfortunately he ran into >>> >> > problems and feels he needs a special version of basic >>> in order to >>> >> > make my $500 NI adaptor work. I admit to my total lack of >>> >> programming >>> >> > ability. I still use GWBASIC, and only to crunch heavy >>> >> numbers. I have >>> >> > no idea how to interface any software to communicate with an >>> >> > instrument, and, maybe am too old to want to learn as it >>> >> seems a lot >>> >> > of people do it on a regular basis already. If this becomes too >>> >> > difficult I may have to buy a Prologix unit from Abdul. >>> >> While I am all >>> >> > for doing that, and I bought my NI before Abdul had his >>> >> version going, >>> >> > I was also under the impression that if the Prologix can do >>> >> it the NI >>> >> > can do it, but, not necessarily the other way around. My friend >>> >> > mentioned API calls, whatever they are. Any suggestions? >>> >> Thanks - Mike >>> >> > >>> >> > >>> >> > Mike B. Feher, N4FS >>> >> > 89 Arnold Blvd. >>> >> > Howell, NJ, 07731 >>> >> > 732-886-5960 >>> >> > >>> >> Mike, >>> >> >>> >> You should have gotten the NI-488.2 CD with your GPIB >>> card. On that >>> >> CD are the dlls (Dynamic Link Libraries) to talk to the card. >>> >> You can use >>> >> the dlls in any language that supports dlls or ActiveX. >>> >> Sorry to say, >>> >> GWBASIC is not one of those languages. ?Visual Basic 6 >>> works well and >>> >> I've even done GPIB data acquisition directly into Excel using VBA >>> >> (Visual Basic for Applications, Excel's macro language). ?VBA >>> >> is part of >>> >> Excel. ?Alternatively, you can get a free Visual Basic Express at >>> >> http://www.microsoft.com/express/vb/ ?I haven't tried VB >>> >> Express, but I >>> >> think it will work. ?Normally, I do all my GPIB programming >>> >> in LabVIEW. >>> >> >>> >> Brent >>> >> >>> >> _______________________________________________ >>> >> time-nuts mailing list -- time-nuts at febo.com >>> >> To unsubscribe, go to >>> >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >>> >> and follow the instructions there. >>> > >>> > >>> > _______________________________________________ >>> > time-nuts mailing list -- time-nuts at febo.com >>> > To unsubscribe, go to >>> > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >>> > and follow the instructions there. >>> > >>> >>> >>> >>> -- >>> Steve Rooke - ZL3TUV & G8KVD & JAKDTTNW >>> Omnium finis imminet >>> >>> _______________________________________________ >>> time-nuts mailing list -- time-nuts at febo.com >>> To unsubscribe, go to >>> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >>> and follow the instructions there. >> >> >> _______________________________________________ >> time-nuts mailing list -- time-nuts at febo.com >> To unsubscribe, go to >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. >> > > > > -- > Steve Rooke - ZL3TUV & G8KVD & JAKDTTNW > Omnium finis imminet > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > From djl at montana.com Thu Apr 2 17:52:05 2009 From: djl at montana.com (Don Latham) Date: Thu, 2 Apr 2009 11:52:05 -0600 Subject: [time-nuts] P word in my mails References: <1231b6a80904010256p3dc5fa7bufc620a1817d0ef5c@mail.gmail.com> <1231b6a80904020210h314d13f5q9ca46aab31f7fc2@mail.gmail.com> Message-ID: <98872D7FC56E46EFBD3E55E8C9D08739@OFFICE2> Lovely, Steve. Many many years ago, I started a meme around that computer languages reflect the culture of their originators; finally saw it appear in Byte after 7-10 years. Won't bore the list, but note that Nicklaus Wirth (P) is a German Swiss. He also named the computer he had built that used P as its operating system Lilith, the wife of Satan (true!). Then Western Digital put out a chipset computer that had P as its native tounge. Got the chipset, never built the computer. I preferred Chuck Peddle's Basic machine (Commodore Pet). Don Latham ----- Original Message ----- From: "Steve Rooke" To: "Discussion of precise time and frequency measurement" Sent: Thursday, April 02, 2009 3:10 AM Subject: Re: [time-nuts] P word in my mails > Dear Ulrich, > > After writhing around on the floor for some time, with my sides > splitting, I have managed to stop laughing, hopefully, long enough to > reply to your post. The P word in question is, as already pointed out, > PASCAL (hack, spit). To my understanding, almost universally loathed > throughout the coding community, and which, I thought, was put to rest > many moons ago, much to the relief of the programming community. > > Now I have gone to the vault and dusted off the copy of The Historium > Evilis Computium which I keep wrapped in a black silk scarf and locked > in a lead lined container. It always gives me shivers whenever I open > this book and it takes some while to get back into a decent sleep > pattern after each reading. Searching through the book, I find many > sections referring to the M word, the I word, the BG words, and that's > not to forget the GOTO word. I went past the sections printed in > special ink where the text can only be read by those who are pure of > heart, as it is a protection against the evil IT masters who would > send their vile lawyers to suppress this work, until I came upon this > ancient writing which I reproduce below. > > WARNING: if you are of a nervous disposition, or suffer from heart > problems, I urge to to delete this message immediately and wipe the > free-space on your hard drive with a 35 pass Gutmann method. > > -- > > And it came to pass that the Dark One was troubled. > Mankind had discovered this mighty power they called computing > And this made the Dark One angy. > > He ruminated for many days and nights until he came to a solution. > He would create something so grave, so terrible, it would make mankind > think of IT as Instant Terror. > And the vile thing would dumbfound the masses with it's heavily typed > variables, > It's unwillingness to perform functions with mixed types > And it's difficulty of getting anything useful through the compiler. > But mankind would see it as a wondrous system, so neat, so clean, > producing nothing but goodness. > > With a wave of his hands, out of his ASR-33 there spat the most vile, > the most evil of all things. > And the thing was called PASCAL! > And the Dark One roared with a laughter that would be heard from all > around. > > And the P thing was sent down to the educational establishments > And darkness came over the computing land > And the comp science students were forced to use it. > It was pitiful to hear their cries as they flagellated themselves when > they coded > For it was only the pain that could keep them sane > But many failed and were dragged off to the asylums screaming. > Infrequently there would be a cry of "I finally got it past the compiler!" > And the students would rejoiced as they carried the victor at shoulder > height all around. > > And there rose up others who challenged the P thing > And they created new programming languages > And their resistance drove out the P thing > Expunging it from mankind. > It still lurked in some places but it's hold on mankind was broken. > And programmers throughout the whole of mankind rejoiced > And the dark clouds that covered IT dispersed. > > But there was no real rejoicing in the end as all that used the P > thing succumbed to its vile purpose. > And in later years, those that had survived were a pitiful sight > Oft-times found in dark corners, chanting, monotonously, > "I must not mix types, I must not mix types, I must..." > For hours on end, it was a sorrowful sight. > > And it was said that the Dark One was displeased > His plan to destroy the will of mankind was thwarted > But only for the moment > For he was already working on his next evil plan > And it came to pass that he came down onto the World > And he took on a human guise > And he created an evil empire... > > -- > > This is all I am prepared to transcribe from the book for fear that > even worse things will happen. I will have to get my whip from the > vault and flagellate myself for hours to get this P thing out of my > mind and try to keep myself sane, such is the power of this evil > thing. > > That's all folks!!! > 73, Steve > > 2009/4/2 Ulrich Bangert : >> Steve, >> >> after I read your mail I have been completely perplexed because I could >> by >> no stretch of imagination detect where you had found the aforesaid P word >> in >> my mail. It needed the help of some English speaking friends and a search >> in >> my last mails to find out that I have (possibly over a range of more than >> 30 >> years) used an American 5 letter word in another sense than most/all of >> you >> seem to interprete it. >> >> I HAVE seen the aforesaid word on some doors during my visits to he >> United >> States and I HAVE understood the meaning of the word in this context. But >> I >> swear that I have not been aware of the fact that the aforesaid word is >> used >> EXCLUSIVELY for the location behind these doors. If I had been aware of >> that >> I would have never used this word in a conversation because that is >> simply >> not my style. >> >> Instead, I have been believing (and I swear this is the truth) that the >> aforesaid word is used by a gentlemen to address a group of other >> gentlemen >> just as a "Hi folks" among noble people but avoiding the highly offical >> salutation "Gentlemen", in a sense a laid-back use of "Gentlemen". >> >> Clearly this is a mistake of mine that I cannot other than to apologize >> for! >> If anyone of you has felt offended or in any other way been affected by >> my >> wrong use of this word: Sorry for that, that was NOT my intention in >> using >> this term. I have started a lot of my posts to this group with this word >> because of the high s/n ratio to be found here and the extremely well >> educated people in the group that I hold in high regard. >> >> Someone should have told me before! If you find this word in one of my >> earlier posts substitute it with "Gentlemen" because that is what was >> ment. >> >> Thank you Steve for pointing at that. If you had not done it I would >> propably have used the word in a wrong sense for the rest of my life. >> >> Best regards >> Ulrich Bangert >> >> >>> -----Urspr?ngliche Nachricht----- >>> Von: time-nuts-bounces at febo.com >>> [mailto:time-nuts-bounces at febo.com] Im Auftrag von Steve Rooke >>> Gesendet: Mittwoch, 1. April 2009 11:57 >>> An: Discussion of precise time and frequency measurement >>> Betreff: Re: [time-nuts] Prologix >>> >>> >>> This man said the P word without any form of apology :-) >>> >>> 73 >>> >>> 2009/4/1 Ulrich Bangert : >>> > Mike, >>> > >>> > I would like to second Brent's information: That is exactly >>> how it is >>> > done. Talking to the Prologix interface and talking to the NI >>> > interface is COMPLETELY different in that talking to the Prologix >>> > always means straightforward serial communication while >>> talking to the >>> > NI involves DLL-calls from the application. >>> > >>> > The Prologix is cheap and easy to work with, thats why some >>> time nuts >>> > use it. The NI interface is on the other hand more >>> expensive and more >>> > complex to handle (and yes, it does some things that are not easily >>> > done with the Prologix). The biggest advantage of the DLL-calls is: >>> > The same application works with whatever NI interface you >>> use: Plug in >>> > card, USB devices, ethernet dvices, you name it. All work >>> by the SAME >>> > dll calls, so your application is not specific for a >>> interface device. >>> > >>> > I do not forget to advertise my own solution to GPIB >>> programming named >>> > EZGPIB which talks to Prologix (both LAN and USB based) as >>> well to NI >>> > interfaces and thanks supporting basic VISA even to GPIB >>> interfaces of >>> > other suppliers. >>> > >>> > It uses an easy to learn PASCAL like script language that >>> your friend >>> > might get used to in a snap. Basically, if your friend >>> writes a EZGPIB >>> > based script to talk to his counter over the Prologix, you will be >>> > able to use the SAME script to talk to your 5335A via a NI >>> interface. >>> > Nice feature? EZGPIB has got mentioned in April's 2008 >>> issue of "Test >>> > & Measurement World". See the last link on my "About me" page >>> > >>> > http://www.ulrich-bangert.de/html/about_me.html >>> > >>> > EZGIPB can be downloaded for free from >>> > >>> > http://www.ulrich-bangert.de/html/downloads.html >>> > >>> > Best regards >>> > Ulrich, DF6JB >>> > >>> >> -----Ursprungliche Nachricht----- >>> >> Von: time-nuts-bounces at febo.com >>> [mailto:time-nuts-bounces at febo.com] >>> >> Im Auftrag von Brent Gordon >>> >> Gesendet: Dienstag, 31. Marz 2009 20:07 >>> >> An: Discussion of precise time and frequency measurement >>> >> Betreff: Re: [time-nuts] Prologix >>> >> >>> >> >>> >> Mike Feher wrote: >>> >> > A friend has a 5335A counter and bought a Prologix adaptor >>> >> for it to >>> >> > collect data. He wrote the software and has had extremely good >>> >> > results. He offered to do the same for me utilizing my NI >>> >> adaptor so I >>> >> > could use it for my various counters. Unfortunately he ran into >>> >> > problems and feels he needs a special version of basic >>> in order to >>> >> > make my $500 NI adaptor work. I admit to my total lack of >>> >> programming >>> >> > ability. I still use GWBASIC, and only to crunch heavy >>> >> numbers. I have >>> >> > no idea how to interface any software to communicate with an >>> >> > instrument, and, maybe am too old to want to learn as it >>> >> seems a lot >>> >> > of people do it on a regular basis already. If this becomes too >>> >> > difficult I may have to buy a Prologix unit from Abdul. >>> >> While I am all >>> >> > for doing that, and I bought my NI before Abdul had his >>> >> version going, >>> >> > I was also under the impression that if the Prologix can do >>> >> it the NI >>> >> > can do it, but, not necessarily the other way around. My friend >>> >> > mentioned API calls, whatever they are. Any suggestions? >>> >> Thanks - Mike >>> >> > >>> >> > >>> >> > Mike B. Feher, N4FS >>> >> > 89 Arnold Blvd. >>> >> > Howell, NJ, 07731 >>> >> > 732-886-5960 >>> >> > >>> >> Mike, >>> >> >>> >> You should have gotten the NI-488.2 CD with your GPIB >>> card. On that >>> >> CD are the dlls (Dynamic Link Libraries) to talk to the card. >>> >> You can use >>> >> the dlls in any language that supports dlls or ActiveX. >>> >> Sorry to say, >>> >> GWBASIC is not one of those languages. Visual Basic 6 >>> works well and >>> >> I've even done GPIB data acquisition directly into Excel using VBA >>> >> (Visual Basic for Applications, Excel's macro language). VBA >>> >> is part of >>> >> Excel. Alternatively, you can get a free Visual Basic Express at >>> >> http://www.microsoft.com/express/vb/ I haven't tried VB >>> >> Express, but I >>> >> think it will work. Normally, I do all my GPIB programming >>> >> in LabVIEW. >>> >> >>> >> Brent >>> >> >>> >> _______________________________________________ >>> >> time-nuts mailing list -- time-nuts at febo.com >>> >> To unsubscribe, go to >>> >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >>> >> and follow the instructions there. >>> > >>> > >>> > _______________________________________________ >>> > time-nuts mailing list -- time-nuts at febo.com >>> > To unsubscribe, go to >>> > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >>> > and follow the instructions there. >>> > >>> >>> >>> >>> -- >>> Steve Rooke - ZL3TUV & G8KVD & JAKDTTNW >>> Omnium finis imminet >>> >>> _______________________________________________ >>> time-nuts mailing list -- time-nuts at febo.com >>> To unsubscribe, go to >>> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >>> and follow the instructions there. >> >> >> _______________________________________________ >> time-nuts mailing list -- time-nuts at febo.com >> To unsubscribe, go to >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. >> > > > > -- > Steve Rooke - ZL3TUV & G8KVD & JAKDTTNW > Omnium finis imminet > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. From hmurray at megapathdsl.net Thu Apr 2 19:21:21 2009 From: hmurray at megapathdsl.net (Hal Murray) Date: Thu, 02 Apr 2009 12:21:21 -0700 Subject: [time-nuts] Frequency Divider In-Reply-To: Message from Bruce Griffiths of "Fri, 03 Apr 2009 01:21:03 +1300." <49D4ADAF.20703@xtra.co.nz> Message-ID: <20090402192122.936F6BCE2@ip-64-139-1-69.sjc.megapath.net> > A large resistor connected between the input and output would > accommodate threshold variations better. Even better would be a > feedback loop that adjusts the input bias point to maintain the output > duty cycle at 50%. Isn't that resistor a feedback loop? I played with that setup in the lab many years ago. It didn't work as well as I was expecting. I didn't figure out why it didn't work better. Maybe some gain in the feedback path would help. Then we have to consider stability. Ugh. -- These are my opinions, not necessarily my employer's. I hate spam. From bruce.griffiths at xtra.co.nz Thu Apr 2 20:04:59 2009 From: bruce.griffiths at xtra.co.nz (Bruce Griffiths) Date: Fri, 03 Apr 2009 09:04:59 +1300 Subject: [time-nuts] Frequency Divider In-Reply-To: <20090402192122.936F6BCE2@ip-64-139-1-69.sjc.megapath.net> References: <20090402192122.936F6BCE2@ip-64-139-1-69.sjc.megapath.net> Message-ID: <49D51A6B.9020006@xtra.co.nz> Hal Murray wrote: >> A large resistor connected between the input and output would >> accommodate threshold variations better. Even better would be a >> feedback loop that adjusts the input bias point to maintain the output >> duty cycle at 50%. >> > > Isn't that resistor a feedback loop? > > I played with that setup in the lab many years ago. It didn't work as well > as I was expecting. I didn't figure out why it didn't work better. > > Maybe some gain in the feedback path would help. Then we have to consider > stability. Ugh. > > > Hal Yes, a resistor connected between the input and output of an inverter is a feedback loop but the loop gain is relatively low. With a high amplitude input threshold variations from the nominal can cause the input protection diodes to conduct. Once these diodes conduct the output jitter may deteriorate significantly (it does for HCMOS inverters). Using a non inverting integrator in the feedback path can accurately stabilise the duty cycle . Bruce From hmurray at megapathdsl.net Thu Apr 2 20:06:40 2009 From: hmurray at megapathdsl.net (Hal Murray) Date: Thu, 02 Apr 2009 13:06:40 -0700 Subject: [time-nuts] Frequency Divider In-Reply-To: Message from Bruce Griffiths of "Fri, 03 Apr 2009 01:31:46 +1300." <49D4B032.3050804@xtra.co.nz> Message-ID: <20090402200641.21009BCE2@ip-64-139-1-69.sjc.megapath.net> > JPL have used ECL dividers throughout to produce 10MHz, 1MHz and > 100KHz outputs from the 100MHz signal derived from a Hydrogen maser: > http://tmo.jpl.nasa.gov/progress_report2/42-30/30I.PDF We've been discussion converting sine to TTL. JPL seems to be distributing ECL rather than sine. This seems like more bait for a FAQ. What are the (dis)advantages of using ECL or TTL vs sine for distribution? (I'm assuming "TTL" covers HC/AHC and 3V CMOS levels too.) At the board level, digital designers often series terminate clocks. There is no termination at the far end. There is a resistor between the (low impedance) driver and the transmission line. The lock goes out at half height and reflects off the far end. The sum of the outgoing edge and the ref;ection give the input gate a clean full height signal. The resistor back at the driver absorbs the reflection. That works great for point-to-point links. It's a disaster for clocks if you have multiple receivers along the transmission line since they see the signal at half height until the reflection gets back to them, a great opportunity for multiple clocking. Does that work OK for distribution via coax? If there is the classic 50 ohm to ground input termination the signal will only be half height. What are the properties of various conversion approaches? how much noise/jitter is added? how much leaks through from the power supply? what is the phase drift with temperature? I think the same questions are interesting for dividers using various technologies. I think the simple divide by 2 with a FF covers all the different combinations of gates and FFs if you use a retiming FF at the end. -- These are my opinions, not necessarily my employer's. I hate spam. From bruce.griffiths at xtra.co.nz Thu Apr 2 20:39:26 2009 From: bruce.griffiths at xtra.co.nz (Bruce Griffiths) Date: Fri, 03 Apr 2009 09:39:26 +1300 Subject: [time-nuts] Frequency Divider In-Reply-To: <20090402200641.21009BCE2@ip-64-139-1-69.sjc.megapath.net> References: <20090402200641.21009BCE2@ip-64-139-1-69.sjc.megapath.net> Message-ID: <49D5227E.60707@xtra.co.nz> Hal Hal Murray wrote: >> JPL have used ECL dividers throughout to produce 10MHz, 1MHz and >> 100KHz outputs from the 100MHz signal derived from a Hydrogen maser: >> http://tmo.jpl.nasa.gov/progress_report2/42-30/30I.PDF >> > > We've been discussion converting sine to TTL. JPL seems to be distributing > ECL rather than sine. > > This seems like more bait for a FAQ. > > What are the (dis)advantages of using ECL or TTL vs sine for distribution? > (I'm assuming "TTL" covers HC/AHC and 3V CMOS levels too.) > > CMOS dividers are supposed to have a lower phase noise floor than ECL dividers but the measurements in the literature are poorly specified. Comparing a CMOS divider with at 20MHz input with an ECL divider with a 200MHz input probably isnt very helpful. > At the board level, digital designers often series terminate clocks. There > is no termination at the far end. There is a resistor between the (low > impedance) driver and the transmission line. The lock goes out at half > height and reflects off the far end. The sum of the outgoing edge and the > ref;ection give the input gate a clean full height signal. The resistor back > at the driver absorbs the reflection. That works great for point-to-point > links. It's a disaster for clocks if you have multiple receivers along the > transmission line since they see the signal at half height until the > reflection gets back to them, a great opportunity for multiple clocking. > > Does that work OK for distribution via coax? If there is the classic 50 ohm > to ground input termination the signal will only be half height. > > It works well provided that the receiver switches on the incident wave and the residual reflections aren't too large. In particular the input capacitance of a counter when configured for a high input R can be problematic with fast rise time signals. Accurate matching of the driver output impedance to the coax characteristic impedance is desirable. LVDS may be useful for frequency distribution between circuit boards. > What are the properties of various conversion approaches? > how much noise/jitter is added? > how much leaks through from the power supply? > what is the phase drift with temperature? > The propagation delay of CMOS typically increases by ~0.4%/C. e.g. 10ns of CMOS propagation delay typically has a tempco of ~ + 40ps/C. > I think the same questions are interesting for dividers using various > technologies. I think the simple divide by 2 with a FF covers all the > different combinations of gates and FFs if you use a retiming FF at the end. > > > Most of the claims and graphs of digital divider phase noise in the literature are very poorly documented. The performance of JPL's ECL dividers at 10Hz offset from the carrier seem to be better than the literature would have one believe. It would be useful to measure the output phase noise of digital divide by 2 circuits with 5MHz and 10MHz inputs for various logic families. It may actually be easier to use divide by 4 switch tail (Johnson) ring counters as achieving the required 90 degree phase shift (for most phase noise measurement setups ) between a pair of dividers is then much easier to achieve by selecting appropriate divider outputs. Bruce From mccorkle at ptialaska.net Thu Apr 2 21:15:23 2009 From: mccorkle at ptialaska.net (Richard H McCorkle) Date: Thu, 2 Apr 2009 13:15:23 -0800 (AKDT) Subject: [time-nuts] PPS Divider (John Ackermann N8UR) In-Reply-To: <49D3E31E.4090906@febo.com> References: <002c01c9b312$118fa6a0$0601a8c0@delldesktop> <49D3E31E.4090906@febo.com> Message-ID: <11244.206.174.20.67.1238706923.squirrel@mymail.acsalaska.net> John, Output frequencies above 10 KHz with the PIC divider require separate manipulation of the port bits within the main timing loop. A 100 KHz output can be added this way as tvb did in his original divider code, but if you also want the divider to work properly with both 5M and 10M input rates the bit manipulation code gets a little dicey. For the faster rates I recommend using one of the output port bits as a reset line to start an external high speed divider exactly in sync with the first PIC output. The external divider provides the 1MHz and 100 KHz outputs and the PIC provides the 10 KHz to 1PPS outputs. Richard > You could probably get those output frequencies with a custom version of > the PIC code. There shouldn't be any hardware changes needed, though > the circuit board layout wasn't optimized for high frequencies so no > guarantee on 5 MHz. > > The PIC source code will be available, so anyone who wants to modify it > for other outputs can have at it. > > John > ---- > > Mitchell Janoff said the following on 04/01/2009 05:37 PM: >> In your post, you mentioned that the TADD-2, will have six low impedance >> outputs that can be individually jumpered to 1 PPS or 10 Hz through 10 kHz >> outputs. I was wondering if there was a way to provide outputs of 100k, 1MHz >> and 5MHz (assuming a 10MHz source). I am looking for a way to use a single >> source such as a z3801 as the standard for my various counters and clocks. >> There was also a post to build this using divide by 10,2 and 5 IC's. If >> someone is going to build this circuit can they provide the schematic? If >> there multiple people interested we can have a circuit board created for >> this project. >> >> Thanks, >> >> Mitch >> KC2MFB >> >> >> _______________________________________________ >> time-nuts mailing list -- time-nuts at febo.com >> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > From nhbbobb at gmail.com Thu Apr 2 21:27:37 2009 From: nhbbobb at gmail.com (bbobb mokai) Date: Fri, 3 Apr 2009 05:27:37 +0800 Subject: [time-nuts] Datum / Efratom LPRO 101 - ebay Message-ID: <3eb99ee60904021427p3372b53w465a107430562b14@mail.gmail.com> hi,i am fluke.l. About Mr.TVB's photos on my ebay listings.sorry for these surprise. if Tom ask me for any copyright problem,i will remove them.i think,tom has deal with me twice in last early year ,he also have no ask me to removed them. Regards Bob 2009/4/2 > Send time-nuts mailing list submissions to > time-nuts at febo.com > > To subscribe or unsubscribe via the World Wide Web, visit > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > or, via email, send a message with subject or body 'help' to > time-nuts-request at febo.com > > You can reach the person managing the list at > time-nuts-owner at febo.com > > When replying, please edit your Subject line so it is more specific > than "Re: Contents of time-nuts digest..." > > > Today's Topics: > > 1. Re: PPS Divider (John Ackermann N8UR) (John Ackermann N8UR) > 2. Re: PPS Divider (John Ackermann N8UR) (Bruce Griffiths) > 3. Re: Datum / Efratom LPRO 101 - ebay (Magnus Danielson) > 4. Re: PPS Divider (John Ackermann N8UR) (Tom Van Baak) > 5. Re: PPS Divider (John Ackermann N8UR) (John Ackermann N8UR) > 6. Austron 2100F (Claude Houde) > 7. Frequency Divider (Brian Kirby) > 8. Re: Frequency Divider (Bruce Griffiths) > > > ---------------------------------------------------------------------- > > Message: 1 > Date: Wed, 01 Apr 2009 17:56:46 -0400 > From: John Ackermann N8UR > Subject: Re: [time-nuts] PPS Divider (John Ackermann N8UR) > To: Discussion of precise time and frequency measurement > > Message-ID: <49D3E31E.4090906 at febo.com> > Content-Type: text/plain; charset=us-ascii; format=flowed > > You could probably get those output frequencies with a custom version of > the PIC code. There shouldn't be any hardware changes needed, though > the circuit board layout wasn't optimized for high frequencies so no > guarantee on 5 MHz. > > The PIC source code will be available, so anyone who wants to modify it > for other outputs can have at it. > > John > ---- > > Mitchell Janoff said the following on 04/01/2009 05:37 PM: > > In your post, you mentioned that the TADD-2, will have six low impedance > > outputs that can be individually jumpered to 1 PPS or 10 Hz through 10 > kHz > > outputs. I was wondering if there was a way to provide outputs of 100k, > 1MHz > > and 5MHz (assuming a 10MHz source). I am looking for a way to use a > single > > source such as a z3801 as the standard for my various counters and > clocks. > > There was also a post to build this using divide by 10,2 and 5 IC's. If > > someone is going to build this circuit can they provide the schematic? If > > there multiple people interested we can have a circuit board created for > > this project. > > > > Thanks, > > > > Mitch > > KC2MFB > > > > > > _______________________________________________ > > time-nuts mailing list -- time-nuts at febo.com > > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > > and follow the instructions there. > > > > ------------------------------ > > Message: 2 > Date: Thu, 02 Apr 2009 11:11:06 +1300 > From: Bruce Griffiths > Subject: Re: [time-nuts] PPS Divider (John Ackermann N8UR) > To: Discussion of precise time and frequency measurement > > Message-ID: <49D3E67A.6010509 at xtra.co.nz> > Content-Type: text/plain; charset=ISO-8859-1 > > John > > Providing a 5MHz output will be difficult/impossible if the PIC is > clocked at 10MHz as a pin will have to be toggled with every instruction. > Surely this will leave no time for executing other instructions to > produce other output frequencies? > > It may be possible to do this using inline code with no conditional > branches if and only if one can loop back to the start of the code > without requiring an extra cycle. > It would probably be easier to use a dedicated hardware divider > (external flipflop or internal timer) to generate the 5MHz output. > > Bruce > > John Ackermann N8UR wrote: > > You could probably get those output frequencies with a custom version of > > the PIC code. There shouldn't be any hardware changes needed, though > > the circuit board layout wasn't optimized for high frequencies so no > > guarantee on 5 MHz. > > > > The PIC source code will be available, so anyone who wants to modify it > > for other outputs can have at it. > > > > John > > ---- > > > > Mitchell Janoff said the following on 04/01/2009 05:37 PM: > > > >> In your post, you mentioned that the TADD-2, will have six low impedance > >> outputs that can be individually jumpered to 1 PPS or 10 Hz through 10 > kHz > >> outputs. I was wondering if there was a way to provide outputs of 100k, > 1MHz > >> and 5MHz (assuming a 10MHz source). I am looking for a way to use a > single > >> source such as a z3801 as the standard for my various counters and > clocks. > >> There was also a post to build this using divide by 10,2 and 5 IC's. If > >> someone is going to build this circuit can they provide the schematic? > If > >> there multiple people interested we can have a circuit board created for > >> this project. > >> > >> Thanks, > >> > >> Mitch > >> KC2MFB > >> > >> > >> _______________________________________________ > >> time-nuts mailing list -- time-nuts at febo.com > >> To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > >> and follow the instructions there. > >> > > > > _______________________________________________ > > time-nuts mailing list -- time-nuts at febo.com > > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > > and follow the instructions there. > > > > > > > > > ------------------------------ > > Message: 3 > Date: Thu, 02 Apr 2009 00:11:17 +0200 > From: Magnus Danielson > Subject: Re: [time-nuts] Datum / Efratom LPRO 101 - ebay > To: Tom Van Baak , Discussion of precise time and > frequency measurement > Message-ID: <49D3E685.6010708 at rubidium.dyndns.org> > Content-Type: text/plain; charset=ISO-8859-1; format=flowed > > Tom Van Baak skrev: > >> I notice that this seller is using TVB's plots on his listing. This is a > bit naughty. Did he ask you Tom? > > > > No, he didn't ask. I was a little surprised too. > > Me too. I saw just from the first plot that it should be one of Toms. At > least you are credited, so it is not a total rip-off. On the other hand, > it is somewhat a sign of recognition... again. > > Cheers, > Magnus > > > > ------------------------------ > > Message: 4 > Date: Wed, 1 Apr 2009 16:09:16 -0700 > From: "Tom Van Baak" > Subject: Re: [time-nuts] PPS Divider (John Ackermann N8UR) > To: "Discussion of precise time and frequency measurement" > > Message-ID: <238B295422F5472D822FB97207A176B1 at pc52> > Content-Type: text/plain; format=flowed; charset="Windows-1252"; > reply-type=original > > Mitch, > > Ah, I can see a new TADD idea: a multi-purpose 2x multiplier > or 2x divider, or 5x and 10x too. > > In your case, though, perhaps you could add a single flip-flop > to a TADD-2 to get 5 MHz from 10 MHz, the old-fashioned way. > > You can't divide by two on a PIC because the minimum loop > is a couple of instructions and each instruction takes 4 clock > cycles. For those of you who know PIC code, the upper limit > is the one mentioned by Bruce where pairs of instructions set > and clear an output pin and then the entire memory is those > pairs. The instruction counter quietly wraps around avoiding > the need for a branch instruction. The result is a divide by 8 > counter (2 instructions times 4 clocks per instruction). Ulrich, > I assume the AVR is better in this respect (with a 1:1 clock vs. > cycle count?). Of course, if you add any programming at all > you can't use the wrapping-pair trick. > > Anyway, that's why all the PIC dividers you see specialize in > lower frequencies, from very sub-Hz to Hz to maybe several > 100 kHz. > > /tvb > > ----- Original Message ----- > From: "Bruce Griffiths" > To: "Discussion of precise time and frequency measurement" < > time-nuts at febo.com> > Sent: Wednesday, April 01, 2009 3:11 PM > Subject: Re: [time-nuts] PPS Divider (John Ackermann N8UR) > > > > John > > > > Providing a 5MHz output will be difficult/impossible if the PIC is > > clocked at 10MHz as a pin will have to be toggled with every instruction. > > Surely this will leave no time for executing other instructions to > > produce other output frequencies? > > > > It may be possible to do this using inline code with no conditional > > branches if and only if one can loop back to the start of the code > > without requiring an extra cycle. > > It would probably be easier to use a dedicated hardware divider > > (external flipflop or internal timer) to generate the 5MHz output. > > > > Bruce > > > > John Ackermann N8UR wrote: > >> You could probably get those output frequencies with a custom version of > >> the PIC code. There shouldn't be any hardware changes needed, though > >> the circuit board layout wasn't optimized for high frequencies so no > >> guarantee on 5 MHz. > >> > >> The PIC source code will be available, so anyone who wants to modify it > >> for other outputs can have at it. > >> > >> John > >> ---- > >> > >> Mitchell Janoff said the following on 04/01/2009 05:37 PM: > >> > >>> In your post, you mentioned that the TADD-2, will have six low > impedance > >>> outputs that can be individually jumpered to 1 PPS or 10 Hz through 10 > kHz > >>> outputs. I was wondering if there was a way to provide outputs of 100k, > 1MHz > >>> and 5MHz (assuming a 10MHz source). I am looking for a way to use a > single > >>> source such as a z3801 as the standard for my various counters and > clocks. > >>> There was also a post to build this using divide by 10,2 and 5 IC's. If > >>> someone is going to build this circuit can they provide the schematic? > If > >>> there multiple people interested we can have a circuit board created > for > >>> this project. > >>> > >>> Thanks, > >>> > >>> Mitch > >>> KC2MFB > > > > > > ------------------------------ > > Message: 5 > Date: Wed, 01 Apr 2009 19:32:40 -0400 > From: John Ackermann N8UR > Subject: Re: [time-nuts] PPS Divider (John Ackermann N8UR) > To: Discussion of precise time and frequency measurement > > Message-ID: <49D3F998.5080009 at febo.com> > Content-Type: text/plain; charset=us-ascii; format=flowed > > Hi Bruce -- > > Good point; I'll leave it to the software guys to figure that out. :-) > > John > ---- > > Bruce Griffiths said the following on 04/01/2009 06:11 PM: > > John > > > > Providing a 5MHz output will be difficult/impossible if the PIC is > > clocked at 10MHz as a pin will have to be toggled with every instruction. > > Surely this will leave no time for executing other instructions to > > produce other output frequencies? > > > > It may be possible to do this using inline code with no conditional > > branches if and only if one can loop back to the start of the code > > without requiring an extra cycle. > > It would probably be easier to use a dedicated hardware divider > > (external flipflop or internal timer) to generate the 5MHz output. > > > > Bruce > > > > John Ackermann N8UR wrote: > >> You could probably get those output frequencies with a custom version of > >> the PIC code. There shouldn't be any hardware changes needed, though > >> the circuit board layout wasn't optimized for high frequencies so no > >> guarantee on 5 MHz. > >> > >> The PIC source code will be available, so anyone who wants to modify it > >> for other outputs can have at it. > >> > >> John > >> ---- > >> > >> Mitchell Janoff said the following on 04/01/2009 05:37 PM: > >> > >>> In your post, you mentioned that the TADD-2, will have six low > impedance > >>> outputs that can be individually jumpered to 1 PPS or 10 Hz through 10 > kHz > >>> outputs. I was wondering if there was a way to provide outputs of 100k, > 1MHz > >>> and 5MHz (assuming a 10MHz source). I am looking for a way to use a > single > >>> source such as a z3801 as the standard for my various counters and > clocks. > >>> There was also a post to build this using divide by 10,2 and 5 IC's. If > >>> someone is going to build this circuit can they provide the schematic? > If > >>> there multiple people interested we can have a circuit board created > for > >>> this project. > >>> > >>> Thanks, > >>> > >>> Mitch > >>> KC2MFB > >>> > >>> > >>> _______________________________________________ > >>> time-nuts mailing list -- time-nuts at febo.com > >>> To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > >>> and follow the instructions there. > >>> > >> _______________________________________________ > >> time-nuts mailing list -- time-nuts at febo.com > >> To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > >> and follow the instructions there. > >> > >> > > > > > > _______________________________________________ > > time-nuts mailing list -- time-nuts at febo.com > > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > > and follow the instructions there. > > > > ------------------------------ > > Message: 6 > Date: Wed, 01 Apr 2009 21:30:15 -0400 > From: Claude Houde > Subject: [time-nuts] Austron 2100F > To: time-nuts at febo.com > Message-ID: <49D41527.1000201 at aei.ca> > Content-Type: text/plain; charset=ISO-8859-1; format=flowed > > Hi everybody ! > > Thanks for your fast answers. > > If I can resume it is OK to buy the 2100F, but at a bargain price as it > may be a really tough job to bring it back to life. > > Thanks also for the user's manual source, I will order it to start > troubleshooting. > > Again thanks and best regards ! > > 73 from Claude VA2HDD > > > > ------------------------------ > > Message: 7 > Date: Wed, 01 Apr 2009 21:17:13 -0500 > From: Brian Kirby > Subject: [time-nuts] Frequency Divider > To: Discussion of precise time and frequency measurement > > Message-ID: <49D42029.3000304 at gmail.com> > Content-Type: text/plain; charset=ISO-8859-1; format=flowed > > Maybe we all could come up with a separate new board to take 10 Mhz and > give us 5 Mhz and 1 Mhz out. > > Start with a buffer amp and then a decent Schmidt trigger. Feed it to a > symmetrical divide by 2 for 5 Mhz, and a symmetrical dive by 10 for 1 > Mhz. These out puts could be buffered with 74AC04 for TTL. Another set > of outputs could be derived and filtered to give sine wave outputs. > > It seems the crowd is against 7490s, and 74390s - and I would like to > know what the crowd recommends as suitable. > > Brian KD4FM > > John Ackermann N8UR wrote: > > Hi Bruce -- > > > > Good point; I'll leave it to the software guys to figure that out. :-) > > > > John > > ---- > > > > Br > > > > > > ------------------------------ > > Message: 8 > Date: Thu, 02 Apr 2009 15:49:32 +1300 > From: Bruce Griffiths > Subject: Re: [time-nuts] Frequency Divider > To: Discussion of precise time and frequency measurement > > Message-ID: <49D427BC.20507 at xtra.co.nz> > Content-Type: text/plain; charset=ISO-8859-1 > > Brian > > Ideally one would use something like a Johnson counter or a Grey code > counter, decode the required outputs and then resynchronise the decoded > outputs using a set of dedicated flipflops. > Since such counters only change the state of one flipflop at a time it > is possible to avoid decoding glitches. > The resynchronisation flipflops minimise the clock to output delay and > its associated tempco as well as minimise the jitter. > Although the decoders can have glitch free outputs there will be some > edge delay patterns that repeat every ten input clock periods. > > If one is using a set of retiming/resynchronisation flipflops then > decoder deglitches are relatively unimportant as they are eliminated by > the retiming flipflops. > > One could use a 74HC4017 and produce the 5MHz output as: > > 5MHz = Q0 +Q2+ Q4 + Q6 + Q8 > which will be glitch free. > However resynchronisation will be necessary to minimise periodic > variations in edge delay for this output. > > 1MHz = Carry Out > > > Bruce > > Brian Kirby wrote: > > Maybe we all could come up with a separate new board to take 10 Mhz and > > give us 5 Mhz and 1 Mhz out. > > > > Start with a buffer amp and then a decent Schmidt trigger. Feed it to a > > symmetrical divide by 2 for 5 Mhz, and a symmetrical dive by 10 for 1 > > Mhz. These out puts could be buffered with 74AC04 for TTL. Another set > > of outputs could be derived and filtered to give sine wave outputs. > > > > It seems the crowd is against 7490s, and 74390s - and I would like to > > know what the crowd recommends as suitable. > > > > Brian KD4FM > > > > John Ackermann N8UR wrote: > > > >> Hi Bruce -- > >> > >> Good point; I'll leave it to the software guys to figure that out. :-) > >> > >> John > >> ---- > >> > >> Br > >> > >> > > > > _______________________________________________ > > time-nuts mailing list -- time-nuts at febo.com > > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > > and follow the instructions there. > > > > > > > > > ------------------------------ > > _______________________________________________ > time-nuts mailing list > time-nuts at febo.com > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > > End of time-nuts Digest, Vol 57, Issue 6 > **************************************** > From bruce.griffiths at xtra.co.nz Thu Apr 2 21:37:37 2009 From: bruce.griffiths at xtra.co.nz (Bruce Griffiths) Date: Fri, 03 Apr 2009 10:37:37 +1300 Subject: [time-nuts] Frequency Divider In-Reply-To: <49D4B2AF.3040300@mail.ua.pt> References: <20090402091000.506D3BCE2@ip-64-139-1-69.sjc.megapath.net> <49D4ADAF.20703@xtra.co.nz> <49D4B2AF.3040300@mail.ua.pt> Message-ID: <49D53021.2010200@xtra.co.nz> Luis Cupido wrote: > > >> The CPLDs are programmed via the JTAG port. >> Suitable JTAG programming cables are readily availble. >> > > Or you can build one to use the LPT port of your PC using just a 74HC244. > > > Luis Cupido. > ct1dmk. > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > Luis Using a 74HC244 may be somewhat problematic with CPLDs that don't have 5V tolerant inputs. Even when using a device with 5V tolerant inputs a 74HCT244 may be more suitable for translating LVCMOS logic level outputs from the CPLD. Bruce From hmurray at megapathdsl.net Thu Apr 2 21:40:53 2009 From: hmurray at megapathdsl.net (Hal Murray) Date: Thu, 02 Apr 2009 14:40:53 -0700 Subject: [time-nuts] Frequency Divider In-Reply-To: Message from Bruce Griffiths of "Fri, 03 Apr 2009 09:39:26 +1300." <49D5227E.60707@xtra.co.nz> Message-ID: <20090402214054.D5587BCE2@ip-64-139-1-69.sjc.megapath.net> > LVDS may be useful for frequency distribution between circuit boards. Good idea thanks. Receivers designed for LVDS are probably good even if the input signal is single ended. Just couple the input signal through a cap and bias the inputs someplace sensible. Ethernet cables/connectors are low cost and widely available. Is there anything better for just a single twisted pair? -- These are my opinions, not necessarily my employer's. I hate spam. From bruce.griffiths at xtra.co.nz Thu Apr 2 21:53:21 2009 From: bruce.griffiths at xtra.co.nz (Bruce Griffiths) Date: Fri, 03 Apr 2009 10:53:21 +1300 Subject: [time-nuts] Frequency Divider In-Reply-To: <20090402214054.D5587BCE2@ip-64-139-1-69.sjc.megapath.net> References: <20090402214054.D5587BCE2@ip-64-139-1-69.sjc.megapath.net> Message-ID: <49D533D1.5020204@xtra.co.nz> Hal Murray wrote: >> LVDS may be useful for frequency distribution between circuit boards. >> > > Good idea thanks. > > Receivers designed for LVDS are probably good even if the input signal is > single ended. Just couple the input signal through a cap and bias the inputs > someplace sensible. > > Ethernet cables/connectors are low cost and widely available. Is there > anything better for just a single twisted pair? > > > Hal SATA drives use LVDS signals. The SATA data connector includes a transmit and a receive pair plus 3 grounds. Bruce From bruce.griffiths at xtra.co.nz Thu Apr 2 22:00:17 2009 From: bruce.griffiths at xtra.co.nz (Bruce Griffiths) Date: Fri, 03 Apr 2009 11:00:17 +1300 Subject: [time-nuts] Frequency Divider In-Reply-To: <20090402214054.D5587BCE2@ip-64-139-1-69.sjc.megapath.net> References: <20090402214054.D5587BCE2@ip-64-139-1-69.sjc.megapath.net> Message-ID: <49D53571.6010409@xtra.co.nz> Hal Murray wrote: >> LVDS may be useful for frequency distribution between circuit boards. >> > > Good idea thanks. > > Receivers designed for LVDS are probably good even if the input signal is > single ended. Just couple the input signal through a cap and bias the inputs > someplace sensible. > > Ethernet cables/connectors are low cost and widely available. Is there > anything better for just a single twisted pair? > > > Hal Twinax, Miniature twinax connectors? Bruce From james.p.lux at jpl.nasa.gov Thu Apr 2 22:02:32 2009 From: james.p.lux at jpl.nasa.gov (Lux, James P) Date: Thu, 2 Apr 2009 15:02:32 -0700 Subject: [time-nuts] Frequency Divider In-Reply-To: <49D533D1.5020204@xtra.co.nz> References: <20090402214054.D5587BCE2@ip-64-139-1-69.sjc.megapath.net> <49D533D1.5020204@xtra.co.nz> Message-ID: > -----Original Message----- > From: time-nuts-bounces at febo.com > [mailto:time-nuts-bounces at febo.com] On Behalf Of Bruce Griffiths > Sent: Thursday, April 02, 2009 2:53 PM > To: Discussion of precise time and frequency measurement > Subject: Re: [time-nuts] Frequency Divider > > Hal Murray wrote: > >> LVDS may be useful for frequency distribution between > circuit boards. > >> > > > > Good idea thanks. > > > > Receivers designed for LVDS are probably good even if the > input signal > > is single ended. Just couple the input signal through a > cap and bias > > the inputs someplace sensible. And watch out for the limited common mode voltage range of most LVDS receivers. From gwinn at raytheon.com Thu Apr 2 22:04:07 2009 From: gwinn at raytheon.com (Joseph M Gwinn) Date: Thu, 2 Apr 2009 18:04:07 -0400 Subject: [time-nuts] Frequency Divider In-Reply-To: <49D53571.6010409@xtra.co.nz> Message-ID: time-nuts-bounces at febo.com wrote on 04/02/2009 06:00:17 PM: > Hal Murray wrote: > >> LVDS may be useful for frequency distribution between circuit boards. > >> > > > > Good idea thanks. > > > > Receivers designed for LVDS are probably good even if the > input signal is > > single ended. Just couple the input signal through a cap and > bias the inputs > > someplace sensible. > > > > Ethernet cables/connectors are low cost and widely available.Is there > > anything better for just a single twisted pair? > > > > > > > Hal > > Twinax, Miniature twinax connectors? Or CAT7 cable, which is multiple shielded twisted pairs. Joe From james.p.lux at jpl.nasa.gov Thu Apr 2 22:16:49 2009 From: james.p.lux at jpl.nasa.gov (Lux, James P) Date: Thu, 2 Apr 2009 15:16:49 -0700 Subject: [time-nuts] Frequency Divider In-Reply-To: <49D53571.6010409@xtra.co.nz> References: <20090402214054.D5587BCE2@ip-64-139-1-69.sjc.megapath.net> <49D53571.6010409@xtra.co.nz> Message-ID: > -----Original Message----- > From: time-nuts-bounces at febo.com > [mailto:time-nuts-bounces at febo.com] On Behalf Of Bruce Griffiths > Sent: Thursday, April 02, 2009 3:00 PM > To: Discussion of precise time and frequency measurement > Subject: Re: [time-nuts] Frequency Divider > > Hal Murray wrote: > >> LVDS may be useful for frequency distribution between > circuit boards. > >> > > > > Good idea thanks. > > > > Receivers designed for LVDS are probably good even if the > input signal > > is single ended. Just couple the input signal through a > cap and bias > > the inputs someplace sensible. > > > > Ethernet cables/connectors are low cost and widely available. Is > > there anything better for just a single twisted pair? > > > > > > > Hal > > Twinax, Miniature twinax connectors? > WAY more expensive than a 8 pin modular, and probably not as good high speed performance. From rputz at bnin.net Thu Apr 2 22:20:09 2009 From: rputz at bnin.net (Rich and Marcia Putz) Date: Thu, 2 Apr 2009 18:20:09 -0400 Subject: [time-nuts] Frequency dividers Message-ID: <059d01c9b3e1$339ab440$9d83e262@newiw112a268qp> Hi All; All this frequency divider conjecture makes me think someone ought to come up with a modern design regenerative divider! Perhaps a double balanced mixer and a couple of high speed OP amps! Regards; Rich From bruce.griffiths at xtra.co.nz Thu Apr 2 22:35:45 2009 From: bruce.griffiths at xtra.co.nz (Bruce Griffiths) Date: Fri, 03 Apr 2009 11:35:45 +1300 Subject: [time-nuts] Frequency dividers In-Reply-To: <059d01c9b3e1$339ab440$9d83e262@newiw112a268qp> References: <059d01c9b3e1$339ab440$9d83e262@newiw112a268qp> Message-ID: <49D53DC1.6000800@xtra.co.nz> Rich and Marcia Putz wrote: > Hi All; > > All this frequency divider conjecture makes me think someone ought to come up with a modern design regenerative divider! > Perhaps a double balanced mixer and a couple of high speed OP amps! > > Regards; Rich > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > Rich Wide band opamps are far too noisy for such state of the art applications particularly in the flicker noise region. A well designed discrete component RF amplifier with negative RF feedback will have much lower phase noise. Some MMICs can have phase noise that is almost as low as a discrete component amplifier. Schottky diode based double balanced mixers have lower phase noise than active double balanced mixers. Bruce From xde-l2g3 at myamail.com Thu Apr 2 22:55:49 2009 From: xde-l2g3 at myamail.com (Mike Monett) Date: Thu, 02 Apr 2009 18:55:49 -0400 Subject: [time-nuts] time-nuts Frequency Divider References: Message-ID: > Message: 3 > Date: Fri, 03 Apr 2009 09:04:59 +1300 > From: Bruce Griffiths > Subject: Re: [time-nuts] Frequency Divider > Hal Murray wrote: >>> A large resistor connected between the input and output would >>> accommodate threshold variations better. Even better would be a >>> feedback loop that adjusts the input bias point to maintain the >>> output duty cycle at 50%. >> Isn't that resistor a feedback loop? >> I played with that setup in the lab many years ago. It didn't >> work as well as I was expecting. I didn't figure out why it >> didn't work better. >> Maybe some gain in the feedback path would help. Then we have to >> consider stability. Ugh. > Hal > Yes, a resistor connected between the input and output of an > inverter is a feedback loop but the loop gain is relatively low. > With a high amplitude input threshold variations from the nominal > can cause the input protection diodes to conduct. > Once these diodes conduct the output jitter may deteriorate > significantly (it does for HCMOS inverters). > Using a non inverting integrator in the feedback path can > accurately stabilise the duty cycle. > Bruce The 74HC and 74AC input threshold tolerance is +/- 30%. This means the threshold can vary from 1.5V to 3.5V with a Vcc of 5V. This limits the maximum input signal to 3V p-p or +13.5dBm, and leads to a very subtle flaw discovered in some amazing engineering work by Martein Bakker, PA3AKE. If the threshold is not controlled, it can cause AM noise to convert to PM noise and degrade the jitter. This occurs in the Analog Devices AD9910 1GHz DDS chip. Martein Bakker discovered this in his noise analysis, and Kevin Wheatly gave a nice entry in his blog on how to fix it: http://www.m0khz.com/?p=589 Mike From bruce.griffiths at xtra.co.nz Thu Apr 2 23:28:31 2009 From: bruce.griffiths at xtra.co.nz (Bruce Griffiths) Date: Fri, 03 Apr 2009 12:28:31 +1300 Subject: [time-nuts] time-nuts Frequency Divider In-Reply-To: References: Message-ID: <49D54A1F.9080005@xtra.co.nz> Mike The problem is more accurately described as: When the bias network dc level at the 74AC04 (or 74HC04) inverter input isn't equal to the switching threshold of the particular device then AM modulation on the input signal is converted to phase noise as switching no longer occurs at the zero crossing of the input signal. Such behaviour is inherent when using a Schmitt trigger circuit and it cannot be cured with a feedback circuit that stabilises the output duty cycle. A well designed limiter + filter cascade in front of the comparator, Schmitt trigger or logic gate can be used to minimise such AM to PM conversion whilst minimising the output jitter. Bruce Mike Monett wrote: > > Message: 3 > > Date: Fri, 03 Apr 2009 09:04:59 +1300 > > From: Bruce Griffiths > > Subject: Re: [time-nuts] Frequency Divider > > > Hal Murray wrote: > > >>> A large resistor connected between the input and output would > >>> accommodate threshold variations better. Even better would be a > >>> feedback loop that adjusts the input bias point to maintain the > >>> output duty cycle at 50%. > > >> Isn't that resistor a feedback loop? > > >> I played with that setup in the lab many years ago. It didn't > >> work as well as I was expecting. I didn't figure out why it > >> didn't work better. > > >> Maybe some gain in the feedback path would help. Then we have to > >> consider stability. Ugh. > > > Hal > > > Yes, a resistor connected between the input and output of an > > inverter is a feedback loop but the loop gain is relatively low. > > > With a high amplitude input threshold variations from the nominal > > can cause the input protection diodes to conduct. > > > Once these diodes conduct the output jitter may deteriorate > > significantly (it does for HCMOS inverters). > > > Using a non inverting integrator in the feedback path can > > accurately stabilise the duty cycle. > > > Bruce > > The 74HC and 74AC input threshold tolerance is +/- 30%. This means > the threshold can vary from 1.5V to 3.5V with a Vcc of 5V. > > This limits the maximum input signal to 3V p-p or +13.5dBm, and > leads to a very subtle flaw discovered in some amazing engineering > work by Martein Bakker, PA3AKE. > > If the threshold is not controlled, it can cause AM noise to convert > to PM noise and degrade the jitter. This occurs in the Analog > Devices AD9910 1GHz DDS chip. > > Martein Bakker discovered this in his noise analysis, and Kevin > Wheatly gave a nice entry in his blog on how to fix it: > > http://www.m0khz.com/?p=589 > > Mike > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > From bruce.griffiths at xtra.co.nz Fri Apr 3 00:55:04 2009 From: bruce.griffiths at xtra.co.nz (Bruce Griffiths) Date: Fri, 03 Apr 2009 13:55:04 +1300 Subject: [time-nuts] time-nuts Frequency Divider In-Reply-To: References: Message-ID: <49D55E68.9070004@xtra.co.nz> Mike Its well worthwhile estimating the additional jitter due to this effect when using such a circuit to square up the output of an OCXO: If the input signal characteristics are: Frequency 10MHz Amplitude at the gate input: A = 1.4V pk Threshold mismatch Vt = 1V AM noise: Am = -120dBc/Hz Input signal AM noise bandwidth: BW = 1MHz (eg a low Q bandpass filter). Rms Output jitter due to AM noise is given by delta(t) ~ (1/(2*PI*f))*((Vt/A)/(1 + (Vt/A)*(Vt/A)))*(BW*1)^(Am/20)) i.e. delta(t) ~ 0.5*1.6E-8 *(1E-3) sec ~ 8ps rms. Wideband AM noise as high as -120dBc/Hz is somewhat higher than is typical for a good OCXO. Thus in applications such as a PPS divider this effect is probably insignificant. However it may be useful to use a low Q bandpass filter to limit the integrated AM and PM noise seen at the gate input. Bruce Mike Monett wrote: > > Message: 3 > > Date: Fri, 03 Apr 2009 09:04:59 +1300 > > From: Bruce Griffiths > > Subject: Re: [time-nuts] Frequency Divider > > > Hal Murray wrote: > > >>> A large resistor connected between the input and output would > >>> accommodate threshold variations better. Even better would be a > >>> feedback loop that adjusts the input bias point to maintain the > >>> output duty cycle at 50%. > > >> Isn't that resistor a feedback loop? > > >> I played with that setup in the lab many years ago. It didn't > >> work as well as I was expecting. I didn't figure out why it > >> didn't work better. > > >> Maybe some gain in the feedback path would help. Then we have to > >> consider stability. Ugh. > > > Hal > > > Yes, a resistor connected between the input and output of an > > inverter is a feedback loop but the loop gain is relatively low. > > > With a high amplitude input threshold variations from the nominal > > can cause the input protection diodes to conduct. > > > Once these diodes conduct the output jitter may deteriorate > > significantly (it does for HCMOS inverters). > > > Using a non inverting integrator in the feedback path can > > accurately stabilise the duty cycle. > > > Bruce > > The 74HC and 74AC input threshold tolerance is +/- 30%. This means > the threshold can vary from 1.5V to 3.5V with a Vcc of 5V. > > This limits the maximum input signal to 3V p-p or +13.5dBm, and > leads to a very subtle flaw discovered in some amazing engineering > work by Martein Bakker, PA3AKE. > > If the threshold is not controlled, it can cause AM noise to convert > to PM noise and degrade the jitter. This occurs in the Analog > Devices AD9910 1GHz DDS chip. > > Martein Bakker discovered this in his noise analysis, and Kevin > Wheatly gave a nice entry in his blog on how to fix it: > > http://www.m0khz.com/?p=589 > > Mike > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > From bruce.griffiths at xtra.co.nz Fri Apr 3 01:14:35 2009 From: bruce.griffiths at xtra.co.nz (Bruce Griffiths) Date: Fri, 03 Apr 2009 14:14:35 +1300 Subject: [time-nuts] time-nuts Frequency Divider In-Reply-To: <49D55E68.9070004@xtra.co.nz> References: <49D55E68.9070004@xtra.co.nz> Message-ID: <49D562FB.40800@xtra.co.nz> Correction: For those who didn't spot it, the formula should have been: delta(t) ~ (1/(2*PI*f))*((Vt/A)/(1 + (Vt/A)*(Vt/A)))*SQRT(BW)*10^(Am/20)); Bruce Bruce Griffiths wrote: > Mike > > Its well worthwhile estimating the additional jitter due to this effect > when using such a circuit to square up the output of an OCXO: > > If the input signal characteristics are: > > Frequency 10MHz > Amplitude at the gate input: A = 1.4V pk > Threshold mismatch Vt = 1V > AM noise: Am = -120dBc/Hz > Input signal AM noise bandwidth: BW = 1MHz (eg a low Q bandpass filter). > > Rms Output jitter due to AM noise is given by > > delta(t) ~ (1/(2*PI*f))*((Vt/A)/(1 + (Vt/A)*(Vt/A)))*(BW*1)^(Am/20)) > > i.e. > delta(t) ~ 0.5*1.6E-8 *(1E-3) sec > ~ 8ps rms. > > Wideband AM noise as high as -120dBc/Hz is somewhat higher than is > typical for a good OCXO. > > Thus in applications such as a PPS divider this effect is probably > insignificant. > However it may be useful to use a low Q bandpass filter to limit the > integrated AM and PM noise seen at the gate input. > > Bruce > > > Mike Monett wrote: > >> > Message: 3 >> > Date: Fri, 03 Apr 2009 09:04:59 +1300 >> > From: Bruce Griffiths >> > Subject: Re: [time-nuts] Frequency Divider >> >> > Hal Murray wrote: >> >> >>> A large resistor connected between the input and output would >> >>> accommodate threshold variations better. Even better would be a >> >>> feedback loop that adjusts the input bias point to maintain the >> >>> output duty cycle at 50%. >> >> >> Isn't that resistor a feedback loop? >> >> >> I played with that setup in the lab many years ago. It didn't >> >> work as well as I was expecting. I didn't figure out why it >> >> didn't work better. >> >> >> Maybe some gain in the feedback path would help. Then we have to >> >> consider stability. Ugh. >> >> > Hal >> >> > Yes, a resistor connected between the input and output of an >> > inverter is a feedback loop but the loop gain is relatively low. >> >> > With a high amplitude input threshold variations from the nominal >> > can cause the input protection diodes to conduct. >> >> > Once these diodes conduct the output jitter may deteriorate >> > significantly (it does for HCMOS inverters). >> >> > Using a non inverting integrator in the feedback path can >> > accurately stabilise the duty cycle. >> >> > Bruce >> >> The 74HC and 74AC input threshold tolerance is +/- 30%. This means >> the threshold can vary from 1.5V to 3.5V with a Vcc of 5V. >> >> This limits the maximum input signal to 3V p-p or +13.5dBm, and >> leads to a very subtle flaw discovered in some amazing engineering >> work by Martein Bakker, PA3AKE. >> >> If the threshold is not controlled, it can cause AM noise to convert >> to PM noise and degrade the jitter. This occurs in the Analog >> Devices AD9910 1GHz DDS chip. >> >> Martein Bakker discovered this in his noise analysis, and Kevin >> Wheatly gave a nice entry in his blog on how to fix it: >> >> http://www.m0khz.com/?p=589 >> >> Mike >> >> _______________________________________________ >> time-nuts mailing list -- time-nuts at febo.com >> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. >> >> >> > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > From xde-l2g3 at myamail.com Fri Apr 3 02:02:29 2009 From: xde-l2g3 at myamail.com (Mike Monett) Date: Thu, 02 Apr 2009 22:02:29 -0400 Subject: [time-nuts] time-nuts Frequency Divider References: Message-ID: > Message: 8 > Date: Fri, 03 Apr 2009 12:28:31 +1300 > From: Bruce Griffiths > Subject: Re: [time-nuts] time-nuts Frequency Divider > Mike > The problem is more accurately described as: > When the bias network dc level at the 74AC04 (or 74HC04) inverter > input isn't equal to the switching threshold of the particular > device then AM modulation on the input signal is converted to > phase noise as switching no longer occurs at the zero crossing of > the input signal. The problem is adequately described in my article. I show the AM/PM conversion in "Fig 3. Threshold Switching", in http://pstca.com/spice/74ac04/limiter.htm > Such behaviour is inherent when using a Schmitt trigger circuit > and it cannot be cured with a feedback circuit that stabilises the > output duty cycle. The 74AC04 and 74HC04 are not Schmitt triggers, and are useful as limiters as discussed here previously. The +/- 30% tolerance on the switching threshold applies to the 74XX04 and pretty much all the CMOS gates and flops as well. It is an inherent problem with matching N and P channel mosfets. However, in any limiter, the duty cycle must be controlled to avoid AM/PM conversion, not just the 74XX series. This problem is solved with the feedback method described in my article. One of the surprises is the circuit is remarkably stable even with huge changes in loop gain. I describe this near the bottom. The 74XX14 is a Schmitt trigger, and it will have unavoidable problems with AM/PM conversion. I mention this in the section, "Cascading 74AC04's For More Gain", about 2/3 of the way down the page: http://pstca.com/spice/74ac04/limiter.htm If the limiter has hysteresis, you can minimize AM/PM conversion on one edge, but not both. > A well designed limiter + filter cascade in front of the > comparator, Schmitt trigger or logic gate can be used to minimise > such AM to PM conversion whilst minimising the output jitter. It doesn't matter what you put in front of the limiter. Adding another one in front just moves the problem further upstream, and adds more phase noise. Unless the switching threshold in the limiter is controlled to set the duty cycle to 50%, you will have problems with AM/PM conversion. Also, it might be desirable to add some voltage trim to compensate for harmonic distortion. > Bruce Mike ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Here is the response to your next post to save time: > Mike > Its well worthwhile estimating the additional jitter due to this > effect when using such a circuit to square up the output of an OCXO: > If the input signal characteristics are: > Frequency 10MHz Amplitude at the gate input: A = 1.4V pk Threshold > mismatch Vt = 1V AM noise: Am = -120dBc/Hz Input signal AM noise > bandwidth: BW = 1MHz (eg a low Q bandpass filter). > Rms Output jitter due to AM noise is given by > delta(t) ~ (1/(2*PI*f))*((Vt/A)/(1 + (Vt/A)*(Vt/A)))*(BW*1)^(Am/20)) > i.e. > delta(t) ~ 0.5*1.6E-8 *(1E-3) sec ~ 8ps rms. > Wideband AM noise as high as -120dBc/Hz is somewhat higher than is > typical for a good OCXO. > Thus in applications such as a PPS divider this effect is probably > insignificant. > However it may be useful to use a low Q bandpass filter to limit the > integrated AM and PM noise seen at the gate input. > Bruce I did not have time to check your math. However, 8ps rms jitter would be unacceptable in many applications. A low Q bandpass filter has been discussed here often. It may not help the jitter until the bandwidth is quite narrow, and it will cause other problems with drift due to aging and tempco. I am unfortunately very busy at the moment, and will not have time to follow this thread further. Mike From cupido at mail.ua.pt Fri Apr 3 02:48:08 2009 From: cupido at mail.ua.pt (Luis Cupido) Date: Fri, 03 Apr 2009 03:48:08 +0100 Subject: [time-nuts] Frequency Divider In-Reply-To: <49D53021.2010200@xtra.co.nz> References: <20090402091000.506D3BCE2@ip-64-139-1-69.sjc.megapath.net> <49D4ADAF.20703@xtra.co.nz> <49D4B2AF.3040300@mail.ua.pt> <49D53021.2010200@xtra.co.nz> Message-ID: <49D578E8.9080006@mail.ua.pt> Bruce, There is a trick... That JTAG interface made with a 74HC244 is powered from the target board, If the target board runs at 5v so it will work at 5v. No doubts here... But if the target runs at 3v3 the 74HC244 gets powered at 3v3 (and it works fine, no need for the target device to be tolerant to anything, it gets within whatever VDD it uses...) and the 74HC244 seems to be tolerant to whatever comes out of the PC LPT port, but has a few series resistors though. Amazingly it even works at 2v5 ! The byteblasterMV from Altera is just like that and it works great, and programs from the small CPLDs up to most of the FPGA's (except for some more recent ones that require someting else... but is not a voltage issue). I'm running one for ages now with zero issues in both 5v chips and 3v3 chips. I even made a byteblasterII (to use on the more recent FPGA's) with the same 74HC244 (adding a few bits to the original byteblasterMV for the additional features required) and it works just fine even with Cyclone devices. Luis Cupido. ct1dmk. Bruce Griffiths wrote: > Luis Cupido wrote: >> >>> The CPLDs are programmed via the JTAG port. >>> Suitable JTAG programming cables are readily availble. >>> >> Or you can build one to use the LPT port of your PC using just a 74HC244. >> >> >> Luis Cupido. >> ct1dmk. >> >> _______________________________________________ >> time-nuts mailing list -- time-nuts at febo.com >> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. >> >> > Luis > > Using a 74HC244 may be somewhat problematic with CPLDs that don't have > 5V tolerant inputs. > Even when using a device with 5V tolerant inputs a 74HCT244 may be more > suitable for translating LVCMOS logic level outputs from the CPLD. > > Bruce > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > From bruce.griffiths at xtra.co.nz Fri Apr 3 03:15:07 2009 From: bruce.griffiths at xtra.co.nz (Bruce Griffiths) Date: Fri, 03 Apr 2009 16:15:07 +1300 Subject: [time-nuts] time-nuts Frequency Divider In-Reply-To: References: Message-ID: <49D57F3B.7090701@xtra.co.nz> Mike Monett wrote: > > Message: 8 > > Date: Fri, 03 Apr 2009 12:28:31 +1300 > > From: Bruce Griffiths > > Subject: Re: [time-nuts] time-nuts Frequency Divider > > > Mike > > > The problem is more accurately described as: > > > When the bias network dc level at the 74AC04 (or 74HC04) inverter > > input isn't equal to the switching threshold of the particular > > device then AM modulation on the input signal is converted to > > phase noise as switching no longer occurs at the zero crossing of > > the input signal. > > The problem is adequately described in my article. I show the AM/PM > conversion in "Fig 3. Threshold Switching", in > > http://pstca.com/spice/74ac04/limiter.htm > > > Such behaviour is inherent when using a Schmitt trigger circuit > > and it cannot be cured with a feedback circuit that stabilises the > > output duty cycle. > > The 74AC04 and 74HC04 are not Schmitt triggers, and are useful as > limiters as discussed here previously. The +/- 30% tolerance on the > switching threshold applies to the 74XX04 and pretty much all the > CMOS gates and flops as well. It is an inherent problem with > matching N and P channel mosfets. > No one said they were, However a previous post mentioned using schmitt triggers. I was merely pointing out that a feedback duty cycle stabiliser won't eliminate the AM to PM conversion characteristic inherent with a Schmitt trigger device. > However, in any limiter, the duty cycle must be controlled to avoid > AM/PM conversion, not just the 74XX series. This problem is solved > with the feedback method described in my article. > > Which is not necessary if one is using a good OCXO with low AM output noise. Well designed OCXOs tend to have very low AM noise. > One of the surprises is the circuit is remarkably stable even with > huge changes in loop gain. I describe this near the bottom. > > The 74XX14 is a Schmitt trigger, and it will have unavoidable > problems with AM/PM conversion. I mention this in the section, > "Cascading 74AC04's For More Gain", about 2/3 of the way down the > page: > > http://pstca.com/spice/74ac04/limiter.htm > > If the limiter has hysteresis, you can minimize AM/PM conversion on > one edge, but not both. > > > A well designed limiter + filter cascade in front of the > > comparator, Schmitt trigger or logic gate can be used to minimise > > such AM to PM conversion whilst minimising the output jitter. > > It doesn't matter what you put in front of the limiter. Adding > another one in front just moves the problem further upstream, and > adds more phase noise. > > Nonsense, it has been shown (during the 1990's) that if designed correctly (with an appropriate and well defined gain and filter cutoff frequency for each limiter stage) a cascade of limiters and low pass filters works much better than merely cascading a series of limiter stages with ill defined gain either with or without an input threshold stabilisation feedback loop. > Unless the switching threshold in the limiter is controlled to set > the duty cycle to 50%, you will have problems with AM/PM conversion. > Also, it might be desirable to add some voltage trim to compensate > for harmonic distortion. > > > Bruce > > Mike > ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > Here is the response to your next post to save time: > > > Mike > > > Its well worthwhile estimating the additional jitter due to this > > effect when using such a circuit to square up the output of an OCXO: > > > If the input signal characteristics are: > > > Frequency 10MHz Amplitude at the gate input: A = 1.4V pk Threshold > > mismatch Vt = 1V AM noise: Am = -120dBc/Hz Input signal AM noise > > bandwidth: BW = 1MHz (eg a low Q bandpass filter). > > > Rms Output jitter due to AM noise is given by > > > delta(t) ~ (1/(2*PI*f))*((Vt/A)/(1 + (Vt/A)*(Vt/A)))*(BW*1)^(Am/20)) > > > i.e. > > > delta(t) ~ 0.5*1.6E-8 *(1E-3) sec ~ 8ps rms. > > > Wideband AM noise as high as -120dBc/Hz is somewhat higher than is > > typical for a good OCXO. > > > Thus in applications such as a PPS divider this effect is probably > > insignificant. > > > However it may be useful to use a low Q bandpass filter to limit the > > integrated AM and PM noise seen at the gate input. > > > Bruce > > I did not have time to check your math. However, 8ps rms jitter > would be unacceptable in many applications. > > In practice it will be much smaller than that with a good OCXO. When using a divider to compare the frequency of an OCXO with the PPS output of a GPS timing receiver a jitter of 8ps is insignificant. If one uses a typical CPLD or FPGA to implement a divider without any external retiming flipflops the typical output jitter is much larger than 8ps. A CPLD or FPGA with LVDS outputs and inputs may have somewhat lower jitter. > A low Q bandpass filter has been discussed here often. It may not > help the jitter until the bandwidth is quite narrow, and it will > cause other problems with drift due to aging and tempco. > The effectiveness of the filter depends on the AM (and PM )noise spectrum, if this is very broad then even a low Q bandpass filter will help. With a good OCXO the broadband AM (and PM) noise is low and filtering isnt usually required. > I am unfortunately very busy at the moment, and will not have time > to follow this thread further. > > Mike > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > From bruce.griffiths at xtra.co.nz Fri Apr 3 04:20:12 2009 From: bruce.griffiths at xtra.co.nz (Bruce Griffiths) Date: Fri, 03 Apr 2009 17:20:12 +1300 Subject: [time-nuts] Frequency Divider In-Reply-To: <49D578E8.9080006@mail.ua.pt> References: <20090402091000.506D3BCE2@ip-64-139-1-69.sjc.megapath.net> <49D4ADAF.20703@xtra.co.nz> <49D4B2AF.3040300@mail.ua.pt> <49D53021.2010200@xtra.co.nz> <49D578E8.9080006@mail.ua.pt> Message-ID: <49D58E7C.30505@xtra.co.nz> Luis Luis Cupido wrote: > Bruce, > > There is a trick... > That JTAG interface made with a 74HC244 is > powered from the target board, > If the target board runs at 5v so it will work > at 5v. No doubts here... > > But if the target runs at 3v3 the 74HC244 gets powered > at 3v3 (and it works fine, no need for the target > device to be tolerant to anything, it gets within > whatever VDD it uses...) > and the 74HC244 seems to be tolerant to whatever comes > out of the PC LPT port, but has a few series resistors though. > > The current flowing in the input protection diodes of the 74HC244 needs to be limited to protect both the 74NC244 and the driving device in the PC. The potential increased jitter when current flows in the protection diodes isn't significant here. > Amazingly it even works at 2v5 ! > > Since 74HC244 is specified to work with power supply range of 2V to 6V that isn't too surprising as long as the ~ 4x increase in propagation delay when going from a 5V supply to a 2.5V supply is acceptable. With a power supply below 2.5V the 74HC244 output swing wont meet the upper TTL threshold of the parallel port input, > The byteblasterMV from Altera is just like that and it > works great, and programs from the small CPLDs up to > most of the FPGA's (except for some more recent ones that > require someting else... but is not a voltage issue). > > I'm running one for ages now with zero issues in both > 5v chips and 3v3 chips. > > I even made a byteblasterII (to use on the more recent FPGA's) > with the same 74HC244 (adding a few bits to the > original byteblasterMV for the additional features required) > and it works just fine even with Cyclone devices. > > Luis Cupido. > ct1dmk. > > > > Bruce Griffiths wrote: > >> Luis Cupido wrote: >> >>> >>> >>>> The CPLDs are programmed via the JTAG port. >>>> Suitable JTAG programming cables are readily availble. >>>> >>>> >>> Or you can build one to use the LPT port of your PC using just a 74HC244. >>> >>> >>> Luis Cupido. >>> ct1dmk. >>> >>> _______________________________________________ >>> time-nuts mailing list -- time-nuts at febo.com >>> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >>> and follow the instructions there. >>> >>> >>> >> Luis >> >> Using a 74HC244 may be somewhat problematic with CPLDs that don't have >> 5V tolerant inputs. >> Even when using a device with 5V tolerant inputs a 74HCT244 may be more >> suitable for translating LVCMOS logic level outputs from the CPLD. >> >> Bruce >> >> _______________________________________________ >> time-nuts mailing list -- time-nuts at febo.com >> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. >> >> > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > Bruce From ed_palmer at sasktel.net Fri Apr 3 06:51:42 2009 From: ed_palmer at sasktel.net (Ed Palmer) Date: Fri, 03 Apr 2009 00:51:42 -0600 Subject: [time-nuts] External Frequency Standard Inputs on Counters Message-ID: <49D5B1FE.8020803@sasktel.net> I see that on many counters (e.g. SR620, HP 5370, HP 5372) the external frequency standard input has an impedance of 1Kohm. Why such a high value? Are they implying that it's acceptable to daisy-chain a single reference to multiple devices like an old 10Base2 ethernet network? Should such a link be terminated in 50 ohms like a 10Base2 network? Ed From magnus at rubidium.dyndns.org Fri Apr 3 07:16:14 2009 From: magnus at rubidium.dyndns.org (Magnus Danielson) Date: Fri, 03 Apr 2009 09:16:14 +0200 Subject: [time-nuts] External Frequency Standard Inputs on Counters In-Reply-To: <49D5B1FE.8020803@sasktel.net> References: <49D5B1FE.8020803@sasktel.net> Message-ID: <49D5B7BE.8050700@rubidium.dyndns.org> Ed Palmer skrev: > I see that on many counters (e.g. SR620, HP 5370, HP 5372) the external > frequency standard input has an impedance of 1Kohm. Why such a high > value? Are they implying that it's acceptable to daisy-chain a single > reference to multiple devices like an old 10Base2 ethernet network? You can do that. If you have a larger setup you can avoid a distribution amplifier, but having one provides you with the isolation that hubs to for basically the same reason. > Should such a link be terminated in 50 ohms like a 10Base2 network? Yes. Cheers, Magnus From magnus at rubidium.dyndns.org Fri Apr 3 07:32:02 2009 From: magnus at rubidium.dyndns.org (Magnus Danielson) Date: Fri, 03 Apr 2009 09:32:02 +0200 Subject: [time-nuts] Frequency Divider In-Reply-To: <20090402091000.506D3BCE2@ip-64-139-1-69.sjc.megapath.net> References: <20090402091000.506D3BCE2@ip-64-139-1-69.sjc.megapath.net> Message-ID: <49D5BB72.8050900@rubidium.dyndns.org> Hal Murray skrev: >> Start with a buffer amp and then a decent Schmidt trigger. > > If you have a clean input signal, a Schmitt trigger doesn't solve any > problems. It does help if you have a slowly rising signal such that noise > might be significant while the signal is near threshold. A 10 MHz sine wave > is slow relative to AC logic. > > Since we were recently speaking of LPROs, their user manual has a section on > how to convert 10 MHz sine waves into TTL signals. None of their suggestions > used Schmitt triggers. Schmitt triggers seems to be misunderstood by many. They do NOT magically solve all issues with noise in the correct way. It seems strange that one actually has to say that, but it seems to be a widely accepted fact that if one uses a schmitt trigger one is doing the right thing. The answer is really maybe, it depends. There are many things where it is just what should be used. For trigger signals where jitter may be of concern you can do better. If the signal first hits a Schmitt trigger, then the noise will modulate the trigger point with the achieved slope at that stage, and no further processing will improve on that but a full sufficiently narrow bandwidth PLL. If instead the slope was linearly amplified to increase the slew rate at the desired trigger voltage, then a much lower trigger jitter can be achived. Anyone following the conversations of Bruce and myself should recognise this as a reoccurring thing. > This feels like the sort of thing that should have been hashed out here by > now. Is it time to start a FAQ? Bruce already has a bit of useful information, TvB certainly has, along side of several other good members. Besides, folks here is very helpful and eager to help a fellow time-nut. We also have archives. > My straw man would be to capacitive couple into a 74AC00 that's biased > halfway between VCC and GND. That's clean and simple. A transformer would > break ground loops. A differential input chip might reduce jitter from noise > on the power supply. You can use self-biasing unbuffered CMOS inverters such as 4069UB as a first stage amplifier and then use a few more in sequence to achieve further gain. This trick have been used before and while certainly not optimum it could be a useful little trick for simple single-chip solutions where no major performance is expected. Hmm... I should actually measure that one... >> Feed it to a symmetrical divide by 2 for 5 Mhz, and a symmetrical >> dive by 10 for 1 Mhz. >> It seems the crowd is against 7490s, and 74390s - and I would like to >> know what the crowd recommends as suitable. > > Dividing by 10 is simple. Doing it with symmetrical output takes a bit > more/different logic than comes prepackaged in a single DIP, or at least not > any that I'm familiar with. > > Plan A would use a 4 bit loadable counter and load it with 3 when it reads 12 > so the top bit would be off for 5 cycles, 3 through 7, then on for 5 cycles, > 8 through 12. That's reasonable to implement in old TTL DIPs. 12 is easy to > decode, just a 2 input gate since states 13-15 won't happen. 74xx163 and > 74xx00 The problem with the '90 is really that the output is not properly synchronised. A half '74 solves that problem. The '90 is doing the needed state-change, the '74 does the needed clock alignment. > Plan B would be to use a PAL or CPLD. I don't know of any that are available > in DIP, have free design software, and are easy to program without a fancy > programmer. There could easily be something I don't know about. I know that > Xilinx CPLDs have free software (WebPACK) but they don't come in DIP. A > friend has written software to program them, but he's a wizard so I don't > know if mortals could do it. WebPACK may do the programming if you have a > gizmo. One is available at a reasonable price from Digilent. > > This technology is too handy. There is probably some hobbyist friendly setup > out there. You may have to build a programmer. The parallel port adapter is soooo easy. Infact you will find the schematic of Xilinx dongle on their web. The JTAG variant is however not so simple... Cheers, Magnus From df6jb at ulrich-bangert.de Fri Apr 3 07:34:15 2009 From: df6jb at ulrich-bangert.de (Ulrich Bangert) Date: Fri, 3 Apr 2009 09:34:15 +0200 Subject: [time-nuts] time-nuts Frequency Divider In-Reply-To: <49D54A1F.9080005@xtra.co.nz> Message-ID: Bruce, > The problem is more accurately described as: > When the bias network dc level at the 74AC04 (or 74HC04) > inverter input isn't equal to the switching threshold of the > particular device then AM modulation on the input signal is > converted to phase noise as switching no longer occurs at the > zero crossing of the input signal. Such behaviour is inherent > when using a Schmitt trigger circuit and it cannot be cured > with a feedback circuit that stabilises the output duty cycle. In order to generate stable and low noise signals on the 10 GHz microwave band it is common among radio amateurs to multiply the signal of a 106.5 MHx xtal oscillator by 96. Clearly the oscillator's phase noise should be as low as possible due to the multiplication process. If high stability is needed, the 106.5 MHz has to be phase locked to a 10 MHz reference. In "UKW Berichte 4/2003" (VHF Communications) Andre Jamet, F9HX, and Gil Feraud, F5CAU, decribe a circuit in which a 106,5 MHz signal is directly synthesized out of a 10 MHz reference by multiplication, division and addition. With respect to the requested low phase noise at it's output it is interesting to inspect what they use for sine to ttl translation inside. Much to my surprise they use the self-biasing input of phase comparator II of an ordinary 74HCT4046 (with everything else of the pll disabled) for this purpose. I have since then made some experiments on my own which indicate that the 74HC(T)4046 works really good as a sine to ttl translator. For a quick test I use this: A SR620 is started by it's internal 1kHz reference and stopped by the signal under test. Then I let the counter compute the AD over 1000 samples or so. Say I get a reading of X with the reference sine connected to the stop input I get X+Y with the sine to ttl translator inserted after the reference with most if not all circuits that I tried before. However, with a 4046 based sine to ttl translator I get a result of X-Y (!). No no, I am not going to claim that the circuit "improves" the reference's phase noise. I just would like to draw your attention to the fact that the ouput of a sine to ttl translator is influenced by the jitter inherent in the used logic family AND the trigger noise to appear at the translation process at the input. In this sense I would judge the X-Y result so that the 4046's trigger noise @ 10 MHz is better than that of the SR620's trigger circuitry. Best reagrds Ulrich > -----Ursprungliche Nachricht----- > Von: time-nuts-bounces at febo.com > [mailto:time-nuts-bounces at febo.com] Im Auftrag von Bruce Griffiths > Gesendet: Freitag, 3. April 2009 01:29 > An: Discussion of precise time and frequency measurement > Betreff: Re: [time-nuts] time-nuts Frequency Divider > > > Mike > > The problem is more accurately described as: > When the bias network dc level at the 74AC04 (or 74HC04) > inverter input isn't equal to the switching threshold of the > particular device then AM modulation on the input signal is > converted to phase noise as switching no longer occurs at the > zero crossing of the input signal. Such behaviour is inherent > when using a Schmitt trigger circuit and it cannot be cured > with a feedback circuit that stabilises the output duty cycle. > > A well designed limiter + filter cascade in front of the > comparator, Schmitt trigger or logic gate can be used to > minimise such AM to PM conversion whilst minimising the output jitter. > > Bruce > > Mike Monett wrote: > > > Message: 3 > > > Date: Fri, 03 Apr 2009 09:04:59 +1300 > > > From: Bruce Griffiths > > > Subject: Re: [time-nuts] Frequency Divider > > > > > Hal Murray wrote: > > > > >>> A large resistor connected between the input and > output would > > >>> accommodate threshold variations better. Even better > would be a > > >>> feedback loop that adjusts the input bias point to > maintain the > > >>> output duty cycle at 50%. > > > > >> Isn't that resistor a feedback loop? > > > > >> I played with that setup in the lab many years ago. > It didn't > > >> work as well as I was expecting. I didn't figure > out why it > > >> didn't work better. > > > > >> Maybe some gain in the feedback path would help. Then > we have to > > >> consider stability. Ugh. > > > > > Hal > > > > > Yes, a resistor connected between the input and > output of an > > > inverter is a feedback loop but the loop gain is relatively low. > > > > > With a high amplitude input threshold variations from > the nominal > > > can cause the input protection diodes to conduct. > > > > > Once these diodes conduct the output jitter may > deteriorate > > > significantly (it does for HCMOS inverters). > > > > > Using a non inverting integrator in the > feedback path can > > > accurately stabilise the duty cycle. > > > > > Bruce > > > > The 74HC and 74AC input threshold tolerance is +/- 30%. > This means > > the threshold can vary from 1.5V to 3.5V with a Vcc of 5V. > > > > This limits the maximum input signal to 3V p-p or > +13.5dBm, and > > leads to a very subtle flaw discovered in some amazing > engineering > > work by Martein Bakker, PA3AKE. > > > > If the threshold is not controlled, it can cause AM noise > to convert > > to PM noise and degrade the jitter. This occurs in > the Analog > > Devices AD9910 1GHz DDS chip. > > > > Martein Bakker discovered this in his noise analysis, > and Kevin > > Wheatly gave a nice entry in his blog on how to fix it: > > > > http://www.m0khz.com/?p=589 > > > > Mike > > > > _______________________________________________ > > time-nuts mailing list -- time-nuts at febo.com > > To unsubscribe, go to > > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > > and follow the instructions there. > > > > > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. From df6jb at ulrich-bangert.de Fri Apr 3 07:34:15 2009 From: df6jb at ulrich-bangert.de (Ulrich Bangert) Date: Fri, 3 Apr 2009 09:34:15 +0200 Subject: [time-nuts] Frequency Divider In-Reply-To: <49D53021.2010200@xtra.co.nz> Message-ID: Bruce and Luis, > Using a 74HC244 may be somewhat problematic with CPLDs that > don't have 5V tolerant inputs. Even when using a device with > 5V tolerant inputs a 74HCT244 may be more suitable for > translating LVCMOS logic level outputs from the CPLD. One chip that works very well for TDI/TMS/TCK translation from the printer port into the cpld is the 74AHC125 with its VCC connected to the cpld's VCC. This one can work with VCC as low as 2.0 V and is still 5 V tolerant on all inputs. At least with 3.3 cplds it's output swing is high enough for TDO back-translation. With 2.5 / 1.8 V cplds a separate TDO back-translation may become necessary. Best regards Ulrich > -----Ursprungliche Nachricht----- > Von: time-nuts-bounces at febo.com > [mailto:time-nuts-bounces at febo.com] Im Auftrag von Bruce Griffiths > Gesendet: Donnerstag, 2. April 2009 23:38 > An: Discussion of precise time and frequency measurement > Betreff: Re: [time-nuts] Frequency Divider > > > Luis Cupido wrote: > > > > > >> The CPLDs are programmed via the JTAG port. > >> Suitable JTAG programming cables are readily availble. > >> > > > > Or you can build one to use the LPT port of your PC using just a > > 74HC244. > > > > > > Luis Cupido. > > ct1dmk. > > > > _______________________________________________ > > time-nuts mailing list -- time-nuts at febo.com > > To unsubscribe, go to > > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > > and follow the instructions there. > > > > > Luis > > Using a 74HC244 may be somewhat problematic with CPLDs that > don't have 5V tolerant inputs. Even when using a device with > 5V tolerant inputs a 74HCT244 may be more suitable for > translating LVCMOS logic level outputs from the CPLD. > > Bruce > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. From magnus at rubidium.dyndns.org Fri Apr 3 07:44:06 2009 From: magnus at rubidium.dyndns.org (Magnus Danielson) Date: Fri, 03 Apr 2009 09:44:06 +0200 Subject: [time-nuts] Frequency Divider In-Reply-To: <49D5227E.60707@xtra.co.nz> References: <20090402200641.21009BCE2@ip-64-139-1-69.sjc.megapath.net> <49D5227E.60707@xtra.co.nz> Message-ID: <49D5BE46.6070700@rubidium.dyndns.org> Bruce Griffiths skrev: > Hal > > Hal Murray wrote: >>> JPL have used ECL dividers throughout to produce 10MHz, 1MHz and >>> 100KHz outputs from the 100MHz signal derived from a Hydrogen maser: >>> http://tmo.jpl.nasa.gov/progress_report2/42-30/30I.PDF >>> >> We've been discussion converting sine to TTL. JPL seems to be distributing >> ECL rather than sine. >> >> This seems like more bait for a FAQ. >> >> What are the (dis)advantages of using ECL or TTL vs sine for distribution? >> (I'm assuming "TTL" covers HC/AHC and 3V CMOS levels too.) >> >> > > CMOS dividers are supposed to have a lower phase noise floor than ECL > dividers but the measurements in the literature are poorly specified. > Comparing a CMOS divider with at 20MHz input with an ECL divider with a > 200MHz input probably isnt very helpful. CMOS is moving fast. Using old measurements may not indicate anything meaningful of today with modern devices. CMOS is also not as homogenic as one may first believe since there exists various tricks to speed CMOS up in especially clocked environments. CMOS is nothing but a collective name these days rather than a very particular technique as it once where, if ever. Cheers, Magnus From bruce.griffiths at xtra.co.nz Fri Apr 3 10:49:28 2009 From: bruce.griffiths at xtra.co.nz (Bruce Griffiths) Date: Fri, 03 Apr 2009 23:49:28 +1300 Subject: [time-nuts] time-nuts Frequency Divider In-Reply-To: References: Message-ID: <49D5E9B8.9030108@xtra.co.nz> Ulrich Your experience with the SR620 illustrates the point I was making quite well. It really does matter what you do in front of the limiter circuit built into the counter. A bandpass or any other filter by itself is ineffective unless the signal is exceptionally noisy. By using the inverter in the 74HCT4046 you have added a low gain limiter stage the bandwidth of which is smaller than that of the SR620 input circuit. This has the effect of increasing the slew rate of the input signal whilst producing an output with less jitter than the SR620 input circuit would without this low pass filtered limiter circuit (the inverter from the 74HCT4046). The slew rate at the 74HCT4046 inverter output is greater than that of the input signal which means that the jitter due the counter input circuit noise is smaller than when this low gain low bandwidth limiter isn't used. The input circuit of the SR620 has a wide noise bandwidth (~ 470MHz assuming a single pole response with a 300MHz 3dB high frequency cutoff) and a correspondingly high total input noise (~350uV rms). If the slew rate of the SR 620 input signal at the trigger point the jitter due to this noise dominates the trigger circuit output jitter. The HP5370 time interval counter input circuit has a lower noise bandwidth (~160MHz??) and is quieter (~ 100uV rms) than the input circuit of the SR620 and thus the HP5370 jitter (without the 74HCT4046 limiter) for the same 10MHz signal should be less than that of the SR620 (without the 74HCT4046 limiter). If one uses a state of the art trigger circuit with a noise bandwidth of 1GHz or more then the total input noise will be even larger so it becomes even more important to use an optimised cascade of limiter+ low output pass filter stages to increase the slew rate of the counter input trigger circuit at the trigger threshold. Careful optimisation of the gain of each stage and the corresponding output filter cutoff frequency for each stage is necessary to minimise the output jitter of the counter trigger circuit. There is also an optimum number of such stages that minimises the trigger jitter. The optimisation problem for Limiter stages with gaussian wideband input noise was solved in the 1990's. Unfortunately the optimum number of stages, associated gains and output filter bandwidths depends on the input signal frequency and amplitude so that in general it isn't possible to use the same limiter cascade for a wide range of signal amplitudes and frequencies and minimise the jitter for each frequency and amplitude. Thus such circuits aren't usually employed in general purpose frequency counters. However if the input signal frequency and amplitude are known and stable then using such a limiter filter cascade is feasible. Bruce Ulrich Bangert wrote: > Bruce, > > >> The problem is more accurately described as: >> When the bias network dc level at the 74AC04 (or 74HC04) >> inverter input isn't equal to the switching threshold of the >> particular device then AM modulation on the input signal is >> converted to phase noise as switching no longer occurs at the >> zero crossing of the input signal. Such behaviour is inherent >> when using a Schmitt trigger circuit and it cannot be cured >> with a feedback circuit that stabilises the output duty cycle. >> > > In order to generate stable and low noise signals on the 10 GHz microwave > band it is common among radio amateurs to multiply the signal of a 106.5 MHx > xtal oscillator by 96. Clearly the oscillator's phase noise should be as low > as possible due to the multiplication process. If high stability is needed, > the 106.5 MHz has to be phase locked to a 10 MHz reference. > > In "UKW Berichte 4/2003" (VHF Communications) Andre Jamet, F9HX, and Gil > Feraud, F5CAU, decribe a circuit in which a 106,5 MHz signal is directly > synthesized out of a 10 MHz reference by multiplication, division and > addition. With respect to the requested low phase noise at it's output it is > interesting to inspect what they use for sine to ttl translation inside. > Much to my surprise they use the self-biasing input of phase comparator II > of an ordinary 74HCT4046 (with everything else of the pll disabled) for this > purpose. > > I have since then made some experiments on my own which indicate that the > 74HC(T)4046 works really good as a sine to ttl translator. For a quick test > I use this: A SR620 is started by it's internal 1kHz reference and stopped > by the signal under test. Then I let the counter compute the AD over 1000 > samples or so. Say I get a reading of X with the reference sine connected to > the stop input I get X+Y with the sine to ttl translator inserted after the > reference with most if not all circuits that I tried before. However, with a > 4046 based sine to ttl translator I get a result of X-Y (!). > > No no, I am not going to claim that the circuit "improves" the reference's > phase noise. I just would like to draw your attention to the fact that the > ouput of a sine to ttl translator is influenced by the jitter inherent in > the used logic family AND the trigger noise to appear at the translation > process at the input. In this sense I would judge the X-Y result so that the > 4046's trigger noise @ 10 MHz is better than that of the SR620's trigger > circuitry. > > Best reagrds > Ulrich > > > >> -----Ursprungliche Nachricht----- >> Von: time-nuts-bounces at febo.com >> [mailto:time-nuts-bounces at febo.com] Im Auftrag von Bruce Griffiths >> Gesendet: Freitag, 3. April 2009 01:29 >> An: Discussion of precise time and frequency measurement >> Betreff: Re: [time-nuts] time-nuts Frequency Divider >> >> >> Mike >> >> The problem is more accurately described as: >> When the bias network dc level at the 74AC04 (or 74HC04) >> inverter input isn't equal to the switching threshold of the >> particular device then AM modulation on the input signal is >> converted to phase noise as switching no longer occurs at the >> zero crossing of the input signal. Such behaviour is inherent >> when using a Schmitt trigger circuit and it cannot be cured >> with a feedback circuit that stabilises the output duty cycle. >> >> A well designed limiter + filter cascade in front of the >> comparator, Schmitt trigger or logic gate can be used to >> minimise such AM to PM conversion whilst minimising the output jitter. >> >> Bruce >> >> Mike Monett wrote: >> >>> > Message: 3 >>> > Date: Fri, 03 Apr 2009 09:04:59 +1300 >>> > From: Bruce Griffiths >>> > Subject: Re: [time-nuts] Frequency Divider >>> >>> > Hal Murray wrote: >>> >>> >>> A large resistor connected between the input and >>> >> output would >> >>> >>> accommodate threshold variations better. Even better >>> >> would be a >> >>> >>> feedback loop that adjusts the input bias point to >>> >> maintain the >> >>> >>> output duty cycle at 50%. >>> >>> >> Isn't that resistor a feedback loop? >>> >>> >> I played with that setup in the lab many years ago. >>> >> It didn't >> >>> >> work as well as I was expecting. I didn't figure >>> >> out why it >> >>> >> didn't work better. >>> >>> >> Maybe some gain in the feedback path would help. Then >>> >> we have to >> >>> >> consider stability. Ugh. >>> >>> > Hal >>> >>> > Yes, a resistor connected between the input and >>> >> output of an >> >>> > inverter is a feedback loop but the loop gain is relatively low. >>> >>> > With a high amplitude input threshold variations from >>> >> the nominal >> >>> > can cause the input protection diodes to conduct. >>> >>> > Once these diodes conduct the output jitter may >>> >> deteriorate >> >>> > significantly (it does for HCMOS inverters). >>> >>> > Using a non inverting integrator in the >>> >> feedback path can >> >>> > accurately stabilise the duty cycle. >>> >>> > Bruce >>> >>> The 74HC and 74AC input threshold tolerance is +/- 30%. >>> >> This means >> >>> the threshold can vary from 1.5V to 3.5V with a Vcc of 5V. >>> >>> This limits the maximum input signal to 3V p-p or >>> >> +13.5dBm, and >> >>> leads to a very subtle flaw discovered in some amazing >>> >> engineering >> >>> work by Martein Bakker, PA3AKE. >>> >>> If the threshold is not controlled, it can cause AM noise >>> >> to convert >> >>> to PM noise and degrade the jitter. This occurs in >>> >> the Analog >> >>> Devices AD9910 1GHz DDS chip. >>> >>> Martein Bakker discovered this in his noise analysis, >>> >> and Kevin >> >>> Wheatly gave a nice entry in his blog on how to fix it: >>> >>> http://www.m0khz.com/?p=589 >>> >>> Mike >>> >>> _______________________________________________ >>> time-nuts mailing list -- time-nuts at febo.com >>> To unsubscribe, go to >>> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >>> and follow the instructions there. >>> >>> >>> >> _______________________________________________ >> time-nuts mailing list -- time-nuts at febo.com >> To unsubscribe, go to >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. >> > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > From bruce.griffiths at xtra.co.nz Fri Apr 3 11:01:49 2009 From: bruce.griffiths at xtra.co.nz (Bruce Griffiths) Date: Sat, 04 Apr 2009 00:01:49 +1300 Subject: [time-nuts] Frequency Divider In-Reply-To: References: Message-ID: <49D5EC9D.2080804@xtra.co.nz> Ulrich An open drain output buffer with a resistor pullup (and an drain voltage rating of 5V or more ) would be ideal for the TDO level translator for 2.5V or 1.8V CPDs or FPGAs. The open drain output could then be buffered by 1/4 74HC125 or similar buffer with a 3.3V or 5V supply. Bruce Ulrich Bangert wrote: > Bruce and Luis, > > >> Using a 74HC244 may be somewhat problematic with CPLDs that >> don't have 5V tolerant inputs. Even when using a device with >> 5V tolerant inputs a 74HCT244 may be more suitable for >> translating LVCMOS logic level outputs from the CPLD. >> > > One chip that works very well for TDI/TMS/TCK translation from the printer > port into the cpld is the 74AHC125 with its VCC connected to the cpld's VCC. > This one can work with VCC as low as 2.0 V and is still 5 V tolerant on all > inputs. At least with 3.3 cplds it's output swing is high enough for TDO > back-translation. With 2.5 / 1.8 V cplds a separate TDO back-translation may > become necessary. > > Best regards > Ulrich > > >> -----Ursprungliche Nachricht----- >> Von: time-nuts-bounces at febo.com >> [mailto:time-nuts-bounces at febo.com] Im Auftrag von Bruce Griffiths >> Gesendet: Donnerstag, 2. April 2009 23:38 >> An: Discussion of precise time and frequency measurement >> Betreff: Re: [time-nuts] Frequency Divider >> >> >> Luis Cupido wrote: >> >>> >>> >>>> The CPLDs are programmed via the JTAG port. >>>> Suitable JTAG programming cables are readily availble. >>>> >>>> >>> Or you can build one to use the LPT port of your PC using just a >>> 74HC244. >>> >>> >>> Luis Cupido. >>> ct1dmk. >>> >>> _______________________________________________ >>> time-nuts mailing list -- time-nuts at febo.com >>> To unsubscribe, go to >>> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >>> and follow the instructions there. >>> >>> >>> >> Luis >> >> Using a 74HC244 may be somewhat problematic with CPLDs that >> don't have 5V tolerant inputs. Even when using a device with >> 5V tolerant inputs a 74HCT244 may be more suitable for >> translating LVCMOS logic level outputs from the CPLD. >> >> Bruce >> >> _______________________________________________ >> time-nuts mailing list -- time-nuts at febo.com >> To unsubscribe, go to >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. >> > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > From bruce.griffiths at xtra.co.nz Fri Apr 3 11:34:50 2009 From: bruce.griffiths at xtra.co.nz (Bruce Griffiths) Date: Sat, 04 Apr 2009 00:34:50 +1300 Subject: [time-nuts] Frequency Divider In-Reply-To: <49D5EC9D.2080804@xtra.co.nz> References: <49D5EC9D.2080804@xtra.co.nz> Message-ID: <49D5F45A.20500@xtra.co.nz> Since a good OCXO may have an AM noise floor well below -170dBc/Hz the resultant output jitter due to AM noise using the amplitude, frequency, bandwidth and threshold offset of my previous example would be 80fs rms or less. Now unless one uses a logic family with sub 250ps intrinsic jitter the effect of AM to PM conversion in this case is insignificant. Even if one found such a logic family the threshold mismatch of such a logic is likely to be much smaller than 1V further reducing the jitter due to AM to PM conversion via the threshold mismatch. Bruce From david.partridge at dsl.pipex.com Fri Apr 3 11:58:35 2009 From: david.partridge at dsl.pipex.com (David C. Partridge) Date: Fri, 3 Apr 2009 12:58:35 +0100 Subject: [time-nuts] Frequency Divider In-Reply-To: <49D42029.3000304@gmail.com> References: <002c01c9b312$118fa6a0$0601a8c0@delldesktop> <49D3E31E.4090906@febo.com> <49D3E67A.6010509@xtra.co.nz><49D3F998.5080009@febo.com> <49D42029.3000304@gmail.com> Message-ID: <9071A73A7CA64003AAFDE2BC4F246342@APOLLO> That's what the board I did last year does, 10 MHz sine in, and 5V p-p square wave out at 10MHz, 5MHz, 1MHz and one additional output with frequency selectable by decade from 100kHz down to 1Hz. Dave -----Original Message----- From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On Behalf Of Brian Kirby Sent: 02 April 2009 03:17 To: Discussion of precise time and frequency measurement Subject: [time-nuts] Frequency Divider Maybe we all could come up with a separate new board to take 10 Mhz and give us 5 Mhz and 1 Mhz out. Start with a buffer amp and then a decent Schmidt trigger. Feed it to a symmetrical divide by 2 for 5 Mhz, and a symmetrical dive by 10 for 1 Mhz. These out puts could be buffered with 74AC04 for TTL. Another set of outputs could be derived and filtered to give sine wave outputs. It seems the crowd is against 7490s, and 74390s - and I would like to know what the crowd recommends as suitable. Brian KD4FM John Ackermann N8UR wrote: > Hi Bruce -- > > Good point; I'll leave it to the software guys to figure that out. :-) > > John > ---- > > Br > _______________________________________________ time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. From david.partridge at dsl.pipex.com Fri Apr 3 12:03:23 2009 From: david.partridge at dsl.pipex.com (David C. Partridge) Date: Fri, 3 Apr 2009 13:03:23 +0100 Subject: [time-nuts] Frequency Divider In-Reply-To: <9071A73A7CA64003AAFDE2BC4F246342@APOLLO> References: <002c01c9b312$118fa6a0$0601a8c0@delldesktop> <49D3E31E.4090906@febo.com> <49D3E67A.6010509@xtra.co.nz><49D3F998.5080009@febo.com><49D42029.3000304@gmail.com> <9071A73A7CA64003AAFDE2BC4F246342@APOLLO> Message-ID: <54998AD60406479D9A435ACAD8AD09D3@APOLLO> Except it's not a Schmidt trigger at the input, it's a MAX999 or ADCMP600 - see Bruce's page on Didier's web site for the basic design of this part of the circuit. D. -----Original Message----- From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On Behalf Of David C. Partridge Sent: 03 April 2009 12:59 To: 'Discussion of precise time and frequency measurement' Subject: Re: [time-nuts] Frequency Divider That's what the board I did last year does, 10 MHz sine in, and 5V p-p square wave out at 10MHz, 5MHz, 1MHz and one additional output with frequency selectable by decade from 100kHz down to 1Hz. Dave -----Original Message----- From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On Behalf Of Brian Kirby Sent: 02 April 2009 03:17 To: Discussion of precise time and frequency measurement Subject: [time-nuts] Frequency Divider Maybe we all could come up with a separate new board to take 10 Mhz and give us 5 Mhz and 1 Mhz out. Start with a buffer amp and then a decent Schmidt trigger. Feed it to a symmetrical divide by 2 for 5 Mhz, and a symmetrical dive by 10 for 1 Mhz. These out puts could be buffered with 74AC04 for TTL. Another set of outputs could be derived and filtered to give sine wave outputs. It seems the crowd is against 7490s, and 74390s - and I would like to know what the crowd recommends as suitable. Brian KD4FM John Ackermann N8UR wrote: > Hi Bruce -- > > Good point; I'll leave it to the software guys to figure that out. :-) > > John > ---- > > Br > _______________________________________________ time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. _______________________________________________ time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. From jra at febo.com Fri Apr 3 12:07:52 2009 From: jra at febo.com (John Ackermann N8UR) Date: Fri, 03 Apr 2009 08:07:52 -0400 Subject: [time-nuts] External Frequency Standard Inputs on Counters In-Reply-To: <49D5B1FE.8020803@sasktel.net> References: <49D5B1FE.8020803@sasktel.net> Message-ID: <49D5FC18.60002@febo.com> I think you guessed it, Ed. There are a number of applications where you want to drive at least two devices from the same reference so using a moderate input impedance facilitates that. I've done some goofy things like trying to drive 3 or more 5334A counters or 3586C VLF receivers from a single reference. My feeling as a result is that you can safely daisychain two devices, but three may be tricky. Ideally, you should terminate the end of the chain with 50 ohms, but depending on the drive level you might not be able to get away with that. John ---- Ed Palmer wrote: > I see that on many counters (e.g. SR620, HP 5370, HP 5372) the external > frequency standard input has an impedance of 1Kohm. Why such a high > value? Are they implying that it's acceptable to daisy-chain a single > reference to multiple devices like an old 10Base2 ethernet network? > Should such a link be terminated in 50 ohms like a 10Base2 network? > > Ed > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. From dk4xp at hoffmann-hochfrequenz.de Fri Apr 3 12:25:21 2009 From: dk4xp at hoffmann-hochfrequenz.de (Gerhard Hoffmann) Date: Fri, 03 Apr 2009 14:25:21 +0200 Subject: [time-nuts] homebrew 13 dBm distribution amplifier based on NIST design 5 to 100 MHz In-Reply-To: <1fkdd4p9jpu3f6sn7qmchc7n8ft7j0gaph@4ax.com> References: <1fkdd4p9jpu3f6sn7qmchc7n8ft7j0gaph@4ax.com> Message-ID: <400ct4hknngm4uleuhpchtt1tthq5mk9g0@4ax.com> On Mon, 22 Sep 2008 01:01:31 +0200, you wrote: >after reading "A low noise 100 MHz distribution amplifier for precision metrology" >by M. Siccardi, S. R?misch, F. W. Walls, and A. De Marchi (NIST), >I have implemented a homebrew version of their design. > >Circuits, simulation & measurement data are contained in: I have done a new revision of the distribution amplifier. It has now 6 + 1 channels on a double EuroCard (usual VME bus size) http://www.bilder-hochladen.net/files/9hqp-5-jpg.html I got first silicon^W^W^W epoxy a few days ago, the board is not yet completely populated, but channel 1 works already as expected. I will characterize it after the easter holidays. The circuit is essentially the LT-spice circuit that I have published already. There are no transformers / ferrites in the signal path, so the amplifier should be immune to modulation from transformer or fan magnetic fields. Output power is > 13 dBm. The 7th channel is for cascading or for feeding that 1pps generator. There is also a new low noise preamplifier for phase noise measurements and inspecting noise behaviour of voltage references and such. http://www.bilder-hochladen.net/files/9hqp-6-jpg.html Stages are 3 pairs of SSM2210, cascode, AD797, AD797 and an Opa2132 for *1 Gain and offset regulation. Gain is *1 for phase detector calibration & 60 & 80 dB. Can be made smaller if wanted. The *1 output is always available and DC coupled if needed for VCXO locking. Bandwidth is >1 MHz completely flat with any gain setting. lower BW corner is abt 0.5Hz or DC if the offset loop is defeated(but switching this off makes only sense for lower gains). Noise is the expected 700 pV/sqrtHz. The high gain path can absorb upto 20 mV offset as it is currently dimensioned. All interesting I/O points are on a 100 mil grid, so the amplifier can be used as a "macro" on predrilled board (like Vero Powerplane (r)) if the shielding is to be done for the whole assembly. All switching is performed with gettered bistable relays. Monostable relays had too much power dissipation, messing up the offset when switched on or off. It's fun when your scope setting reads 200 nV / div and you still have a meaningful display, at least for small bandwidth. regards, Gerhard From jim77742 at gmail.com Fri Apr 3 13:59:35 2009 From: jim77742 at gmail.com (Jim Palfreyman) Date: Sat, 4 Apr 2009 00:59:35 +1100 Subject: [time-nuts] 100 hours of astronomy Message-ID: Hi Folks, Blatant advertising spam here. I'm on the 100 hours of astronomy webcast. I will be broadcasting from the University of Tasmania's radio telescope in Australia. It begins at 0100 UT. I'll be briefly discussing my pulsar observations. Go to http://100hoursofastronomy.org/ to check it out. Regards, Jim From cdelect at juno.com Fri Apr 3 16:21:26 2009 From: cdelect at juno.com (Corby Dawson) Date: Fri, 3 Apr 2009 09:21:26 -0700 Subject: [time-nuts] HP 5062C on eBay Message-ID: <20090403.092127.2340.2.cdelect@juno.com> There is another 5062C on eBay from the same source as the last one. Corby Dawson ____________________________________________________________ Faster loans with less paperwork. Compare rates. Click to find the right loan. http://thirdpartyoffers.juno.com/TGL2141/fc/BLSrjpTIrTo8ci9jT1JAj2ebvhCQcBjsj0mgjb38zl0NvwjlvavWtuA1zN2/ From tvb at LeapSecond.com Fri Apr 3 16:40:00 2009 From: tvb at LeapSecond.com (Tom Van Baak) Date: Fri, 3 Apr 2009 09:40:00 -0700 Subject: [time-nuts] Datum / Efratom LPRO 101 - ebay References: <3eb99ee60904021427p3372b53w465a107430562b14@mail.gmail.com> Message-ID: <69307BEBB42A4681BBFD976922FB8497@pc52> Hi Bob, Usually what eBay sellers do is provide a URL reference *link* to my site; rather than a full *copy* of all the text and images into their eBay item description. It's not that big a problem, really. I don't "copyright" web pages or email postings and couldn't enforce it worldwide even if I did. What we want to prevent is an eBay seller giving the impression that the particular item being sold somehow exactly matches the plots included in the item description or that the overseas item being offered for sale has somehow been personally tested by me. You've done a good job supplying low cost surplus gear to the amateur community. You'll often find that the more honest you are with the eBay item description the greater the trust gained. Showing the actual results of your LPRO tests is one thing; but showing the results of my tests as if they were one your tests maybe crosses the line. While we're on this subject, just where do all these surplus LPRO rubidium oscillators come from? If they are old cell towers, what timing equipment is replacing them? Thanks, /tvb ----- Original Message ----- From: "bbobb mokai" To: Sent: Thursday, April 02, 2009 2:27 PM Subject: Re: [time-nuts] Datum / Efratom LPRO 101 - ebay > hi,i am fluke.l. About Mr.TVB's photos on my ebay listings.sorry for > these surprise. > if Tom ask me for any copyright problem,i will remove them.i think,tom has > deal with me twice in last early year ,he also have no ask me to removed > them. > Regards > Bob From w1ksz at earthlink.net Fri Apr 3 16:58:09 2009 From: w1ksz at earthlink.net (Richard W. Solomon) Date: Fri, 3 Apr 2009 12:58:09 -0400 (EDT) Subject: [time-nuts] HP 5062C on eBay Message-ID: <27505635.1238777889961.JavaMail.root@elwamui-little.atl.sa.earthlink.net> ..."Doesn't Lock Up"... Looks like all the Cesium spilled out !! Nice for parts. 73, Dick, W1KSZ -----Original Message----- >From: Corby Dawson >Sent: Apr 3, 2009 12:21 PM >To: time-nuts at febo.com >Subject: [time-nuts] HP 5062C on eBay > >There is another 5062C on eBay from the same source as the last one. > >Corby Dawson >____________________________________________________________ >Faster loans with less paperwork. Compare rates. Click to find the right loan. >http://thirdpartyoffers.juno.com/TGL2141/fc/BLSrjpTIrTo8ci9jT1JAj2ebvhCQcBjsj0mgjb38zl0NvwjlvavWtuA1zN2/ > >_______________________________________________ >time-nuts mailing list -- time-nuts at febo.com >To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >and follow the instructions there. From magnus at rubidium.dyndns.org Fri Apr 3 17:57:28 2009 From: magnus at rubidium.dyndns.org (Magnus Danielson) Date: Fri, 03 Apr 2009 19:57:28 +0200 Subject: [time-nuts] time-nuts Frequency Divider In-Reply-To: <49D5E9B8.9030108@xtra.co.nz> References: <49D5E9B8.9030108@xtra.co.nz> Message-ID: <49D64E08.3020200@rubidium.dyndns.org> Bruce Griffiths skrev: > Ulrich > > Your experience with the SR620 illustrates the point I was making quite > well. > It really does matter what you do in front of the limiter circuit built > into the counter. > A bandpass or any other filter by itself is ineffective unless the > signal is exceptionally noisy. > > By using the inverter in the 74HCT4046 you have added a low gain limiter > stage the bandwidth of which is smaller than that of the SR620 input > circuit. > This has the effect of increasing the slew rate of the input signal > whilst producing an output with less jitter than the SR620 input circuit > would without this low pass filtered limiter circuit (the inverter from > the 74HCT4046). The slew rate at the 74HCT4046 inverter output is > greater than that of the input signal which means that the jitter due > the counter input circuit noise is smaller than when this low gain low > bandwidth limiter isn't used. > The input circuit of the SR620 has a wide noise bandwidth (~ 470MHz > assuming a single pole response with a 300MHz 3dB high frequency cutoff) > and a correspondingly high total input noise (~350uV rms). > If the slew rate of the SR 620 input signal at the trigger point the > jitter due to this noise dominates the trigger circuit output jitter. > The HP5370 time interval counter input circuit has a lower noise > bandwidth (~160MHz??) and is quieter (~ 100uV rms) than the input > circuit of the SR620 and thus the HP5370 jitter (without the 74HCT4046 > limiter) for the same 10MHz signal should be less than that of the SR620 > (without the 74HCT4046 limiter). As a curiosity, there are various variants of the original 4046 which has different sensitivity on the input side... one of them has several inverters in a row to get the needed gain where as the other variant does not. This difference made a huge difference in some applications. > If one uses a state of the art trigger circuit with a noise bandwidth of > 1GHz or more then the total input noise will be even larger so it > becomes even more important to use an optimised cascade of limiter+ low > output pass filter stages to increase the slew rate of the counter > input trigger circuit at the trigger threshold. > Careful optimisation of the gain of each stage and the corresponding > output filter cutoff frequency for each stage is necessary to minimise > the output jitter of the counter trigger circuit. > There is also an optimum number of such stages that minimises the > trigger jitter. > > The optimisation problem for Limiter stages with gaussian wideband input > noise was solved in the 1990's. > Unfortunately the optimum number of stages, associated gains and output > filter bandwidths depends on the input signal frequency and amplitude so > that in general it isn't possible to use the same limiter cascade for a > wide range of signal amplitudes and frequencies and minimise the jitter > for each frequency and amplitude. Actually, you can make a cascade setup which is approaching optimum and insert signal at the stage where the signals slewrate matches the range for each stage. Since the gain steps is larger later in a slew rate amplifier chain, the last stages may have a little coarse slew rate range, but additional mid-range amplifiers that can act as alternative input amps could curcumvent that such that a wide range but and fairly good trigger jitter could be achieved. The comparator level is fed to whatever stage is the first stage. Such an approach could lead to much improved jitter values for lower frequency signals with associated gain in measurement accuracy. It is easy to make a pre-amplifier set that achieves this, but you want to integrate the control algorithms for automatic use. > Thus such circuits aren't usually employed in general purpose frequency counters. Certainly true. A generic counter is usually equipped with triggers such that they can measure slewrate without too much difficulty. > However if the input signal frequency and amplitude are known and stable > then using such a limiter filter cascade is feasible. Indeed. Cheers, Magnus From magnus at rubidium.dyndns.org Fri Apr 3 18:57:38 2009 From: magnus at rubidium.dyndns.org (Magnus Danielson) Date: Fri, 03 Apr 2009 20:57:38 +0200 Subject: [time-nuts] External Frequency Standard Inputs on Counters In-Reply-To: <49D5FC18.60002@febo.com> References: <49D5B1FE.8020803@sasktel.net> <49D5FC18.60002@febo.com> Message-ID: <49D65C22.3060501@rubidium.dyndns.org> John Ackermann N8UR skrev: > I think you guessed it, Ed. There are a number of applications where > you want to drive at least two devices from the same reference so using > a moderate input impedance facilitates that. > > I've done some goofy things like trying to drive 3 or more 5334A > counters or 3586C VLF receivers from a single reference. My feeling as > a result is that you can safely daisychain two devices, but three may be > tricky. > > Ideally, you should terminate the end of the chain with 50 ohms, but > depending on the drive level you might not be able to get away with that. Not terminating could create a null at or near one of them... thus resulting in no input signal for that box. Overcoming that would require more drive level than the other boxes wants... Cheers, Magnus From swithrow at idcomm.com Fri Apr 3 20:04:06 2009 From: swithrow at idcomm.com (Skip Withrow) Date: Fri, 03 Apr 2009 14:04:06 -0600 Subject: [time-nuts] Need Austron 2110 manual Message-ID: <20090403200407.1E685C5EA2C8@mailhost.idcomm.com> Hello Time-Nuts, I am in need of a manual for the Austron 2110 Disciplined Frequency Standard. Anyone have an electronic copy? I have already tried KO4BB's site and BAMA. I would be more than happy to pay shipping so that I could copy/scan a hard-copy if you have one. Guaranteed to be returned promptly. Regards, Skip Withrow From cfharris at erols.com Fri Apr 3 20:11:47 2009 From: cfharris at erols.com (Chuck Harris) Date: Fri, 03 Apr 2009 16:11:47 -0400 Subject: [time-nuts] Need Austron 2110 manual In-Reply-To: <20090403200407.1E685C5EA2C8@mailhost.idcomm.com> References: <20090403200407.1E685C5EA2C8@mailhost.idcomm.com> Message-ID: <49D66D83.5030507@erols.com> Try PRC68.com Skip Withrow wrote: > Hello Time-Nuts, > > I am in need of a manual for the Austron 2110 Disciplined Frequency > Standard. Anyone have an electronic copy? I have already tried KO4BB's > site and BAMA. > > I would be more than happy to pay shipping so that I could copy/scan a > hard-copy if you have one. Guaranteed to be returned promptly. > > Regards, > Skip Withrow > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > From bruce.griffiths at xtra.co.nz Fri Apr 3 20:17:28 2009 From: bruce.griffiths at xtra.co.nz (Bruce Griffiths) Date: Sat, 04 Apr 2009 09:17:28 +1300 Subject: [time-nuts] External Frequency Standard Inputs on Counters In-Reply-To: <49D65C22.3060501@rubidium.dyndns.org> References: <49D5B1FE.8020803@sasktel.net> <49D5FC18.60002@febo.com> <49D65C22.3060501@rubidium.dyndns.org> Message-ID: <49D66ED8.3040306@xtra.co.nz> Magnus Another option (useful when the source amplitude is such that terminating isn't an option and there isn't a suitable amplifier available to boost the source amplitude) is to trim the cable lengths to eliminate such standing wave nulls at the counter inputs. Bruce Magnus Danielson wrote: > John Ackermann N8UR skrev: > >> I think you guessed it, Ed. There are a number of applications where >> you want to drive at least two devices from the same reference so using >> a moderate input impedance facilitates that. >> >> I've done some goofy things like trying to drive 3 or more 5334A >> counters or 3586C VLF receivers from a single reference. My feeling as >> a result is that you can safely daisychain two devices, but three may be >> tricky. >> >> Ideally, you should terminate the end of the chain with 50 ohms, but >> depending on the drive level you might not be able to get away with that. >> > > Not terminating could create a null at or near one of them... thus > resulting in no input signal for that box. Overcoming that would require > more drive level than the other boxes wants... > > Cheers, > Magnus > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > From EWKehren at aol.com Fri Apr 3 20:17:58 2009 From: EWKehren at aol.com (EWKehren at aol.com) Date: Fri, 3 Apr 2009 16:17:58 EDT Subject: [time-nuts] Need Austron 2110 manual Message-ID: Skip, where are you located. Since I have always gotten my manuals back I will be glad to send it to you if you do not find an electronic one. Bert Kehren Miami In a message dated 4/3/2009 4:15:04 P.M. Eastern Daylight Time, cfharris at erols.com writes: Try PRC68.com Skip Withrow wrote: > Hello Time-Nuts, > > I am in need of a manual for the Austron 2110 Disciplined Frequency > Standard. Anyone have an electronic copy? I have already tried KO4BB's > site and BAMA. > > I would be more than happy to pay shipping so that I could copy/scan a > hard-copy if you have one. Guaranteed to be returned promptly. > > Regards, > Skip Withrow > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > _______________________________________________ time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. **************Worried about job security? Check out the 5 safest jobs in a recession. (http://jobs.aol.com/gallery/growing-job-industries?ncid=emlcntuscare00000003) From w1ksz at earthlink.net Fri Apr 3 20:27:51 2009 From: w1ksz at earthlink.net (Richard W. Solomon) Date: Fri, 3 Apr 2009 16:27:51 -0400 (EDT) Subject: [time-nuts] 100 hours of astronomy Message-ID: <1319549.1238790472114.JavaMail.root@mswamui-cedar.atl.sa.earthlink.net> I have been watching now for a couple of hours. Very interesting to this old veteran of several X-Ray Telescopes !! Too bad it wasn't publicized more ... If not for this post I would not have known about it. 73, Dick, W1KSZ Apollo Alpha & X-Ray Spectrometers Uhuru HRAO LOXT Skylab ATM -----Original Message----- >From: Jim Palfreyman >Sent: Apr 3, 2009 9:59 AM >To: Discussion of precise time and frequency measurement >Subject: [time-nuts] 100 hours of astronomy > >Hi Folks, > >Blatant advertising spam here. > >I'm on the 100 hours of astronomy webcast. I will be broadcasting from the >University of Tasmania's radio telescope in Australia. It begins at 0100 UT. > >I'll be briefly discussing my pulsar observations. > >Go to http://100hoursofastronomy.org/ to check it out. > >Regards, > >Jim >_______________________________________________ >time-nuts mailing list -- time-nuts at febo.com >To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >and follow the instructions there. From hmurray at megapathdsl.net Fri Apr 3 20:40:59 2009 From: hmurray at megapathdsl.net (Hal Murray) Date: Fri, 03 Apr 2009 13:40:59 -0700 Subject: [time-nuts] External Frequency Standard Inputs on Counters In-Reply-To: Message from Magnus Danielson of "Fri, 03 Apr 2009 20:57:38 +0200." <49D65C22.3060501@rubidium.dyndns.org> Message-ID: <20090403204100.9D8D5BCE2@ip-64-139-1-69.sjc.megapath.net> > Not terminating could create a null at or near one of them... thus > resulting in no input signal for that box. Overcoming that would > require more drive level than the other boxes wants... 10 MHz is 100 ns. The speed of light is 1 ft per ns. (Yes, coax is slower. I'm just looking for the ballpark.) So if you have several instruments in a rack with short chunks of coax between them, they will all see (close to) the same signal. If the source is in the same rack, everybody sees (close to) the output of the driver. I'm assuming we are talking about a sine wave. With an edge, you will get reflections which can lead to double triggering. -- These are my opinions, not necessarily my employer's. I hate spam. From bruce.griffiths at xtra.co.nz Fri Apr 3 21:10:18 2009 From: bruce.griffiths at xtra.co.nz (Bruce Griffiths) Date: Sat, 04 Apr 2009 10:10:18 +1300 Subject: [time-nuts] time-nuts Frequency Divider In-Reply-To: <49D64E08.3020200@rubidium.dyndns.org> References: <49D5E9B8.9030108@xtra.co.nz> <49D64E08.3020200@rubidium.dyndns.org> Message-ID: <49D67B3A.7010900@xtra.co.nz> Magnus The input noise of a logic inverter or other trigger device used as a clock shaper is important. If we have a logic inverter device with the following characteristics: Input noise: 100uV rms Intrinsic jitter: 1ps rms Then the input signal slew rate at the threshold crossing has to be greater than 3x1E-4/1E-12 = 3E8 V/s or 300 V/us to ensure that the output jitter isnt increased by more than 5% from the intrinsic jitter. With a 1.4V pk 10MHz sinewave input the maximum slew rate is ~89V/us (at the zero crossing). For such an input signal the output jitter will be about 1.14 ps. This increases to about 1.4ps if there is a threshold offset of 1V. This can be reduced to about 1.05ps by amplifying the slope of the input signal by ~ 3.4x. The intrinsic jitter (RJ. DDJ isn't important when the input signal is a low distortion sinewave) of a 74AC04 inverter is about 1ps. However the equivalent input noise is unknown. The noise could, in principle, be determined by measuring the output jitter as a function of the input signal slew rate. Whilst AM and other noise associated with the source can be reduced by filtering, the input noise of a trigger circuit cannot (except perhaps for the trigger circuits input current noise). Magnus Danielson wrote: > Bruce Griffiths skrev: > >> Ulrich >> >> Your experience with the SR620 illustrates the point I was making quite >> well. >> It really does matter what you do in front of the limiter circuit built >> into the counter. >> A bandpass or any other filter by itself is ineffective unless the >> signal is exceptionally noisy. >> >> By using the inverter in the 74HCT4046 you have added a low gain limiter >> stage the bandwidth of which is smaller than that of the SR620 input >> circuit. >> This has the effect of increasing the slew rate of the input signal >> whilst producing an output with less jitter than the SR620 input circuit >> would without this low pass filtered limiter circuit (the inverter from >> the 74HCT4046). The slew rate at the 74HCT4046 inverter output is >> greater than that of the input signal which means that the jitter due >> the counter input circuit noise is smaller than when this low gain low >> bandwidth limiter isn't used. >> The input circuit of the SR620 has a wide noise bandwidth (~ 470MHz >> assuming a single pole response with a 300MHz 3dB high frequency cutoff) >> and a correspondingly high total input noise (~350uV rms). >> If the slew rate of the SR 620 input signal at the trigger point the >> jitter due to this noise dominates the trigger circuit output jitter. >> The HP5370 time interval counter input circuit has a lower noise >> bandwidth (~160MHz??) and is quieter (~ 100uV rms) than the input >> circuit of the SR620 and thus the HP5370 jitter (without the 74HCT4046 >> limiter) for the same 10MHz signal should be less than that of the SR620 >> (without the 74HCT4046 limiter). >> > > As a curiosity, there are various variants of the original 4046 which > has different sensitivity on the input side... one of them has several > inverters in a row to get the needed gain where as the other variant > does not. This difference made a huge difference in some applications. > > The appropriate device (one that will have the least output jitter) to use will vary with the input signal zero crossing slew rate. That is it depends on both the input signal frequency and amplitude. >> If one uses a state of the art trigger circuit with a noise bandwidth of >> 1GHz or more then the total input noise will be even larger so it >> becomes even more important to use an optimised cascade of limiter+ low >> output pass filter stages to increase the slew rate of the counter >> input trigger circuit at the trigger threshold. >> Careful optimisation of the gain of each stage and the corresponding >> output filter cutoff frequency for each stage is necessary to minimise >> the output jitter of the counter trigger circuit. >> There is also an optimum number of such stages that minimises the >> trigger jitter. >> >> The optimisation problem for Limiter stages with gaussian wideband input >> noise was solved in the 1990's. >> Unfortunately the optimum number of stages, associated gains and output >> filter bandwidths depends on the input signal frequency and amplitude so >> that in general it isn't possible to use the same limiter cascade for a >> wide range of signal amplitudes and frequencies and minimise the jitter >> for each frequency and amplitude. >> > > Actually, you can make a cascade setup which is approaching optimum and > insert signal at the stage where the signals slewrate matches the range > for each stage. Since the gain steps is larger later in a slew rate > amplifier chain, the last stages may have a little coarse slew rate > range, but additional mid-range amplifiers that can act as alternative > input amps could curcumvent that such that a wide range but and fairly > good trigger jitter could be achieved. > > The comparator level is fed to whatever stage is the first stage. > > Such an approach could lead to much improved jitter values for lower > frequency signals with associated gain in measurement accuracy. > > It is easy to make a pre-amplifier set that achieves this, but you want > to integrate the control algorithms for automatic use. > > That would constitute an interesting design challenge. >> Thus such circuits aren't usually employed in general purpose frequency counters. >> > > Certainly true. A generic counter is usually equipped with triggers such > that they can measure slewrate without too much difficulty. > > >> However if the input signal frequency and amplitude are known and stable >> then using such a limiter filter cascade is feasible. >> > > Indeed. > > Cheers, > Magnus > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > Bruce From bruce.griffiths at xtra.co.nz Fri Apr 3 21:16:01 2009 From: bruce.griffiths at xtra.co.nz (Bruce Griffiths) Date: Sat, 04 Apr 2009 10:16:01 +1300 Subject: [time-nuts] time-nuts Frequency Divider In-Reply-To: <49D67B3A.7010900@xtra.co.nz> References: <49D5E9B8.9030108@xtra.co.nz> <49D64E08.3020200@rubidium.dyndns.org> <49D67B3A.7010900@xtra.co.nz> Message-ID: <49D67C91.3070605@xtra.co.nz> Correction: I forgot to include the intrinsic jitter of the gate in the calculations. See underlined corrections below. Bruce Bruce Griffiths wrote: > Magnus > > The input noise of a logic inverter or other trigger device used as a > clock shaper is important. > If we have a logic inverter device with the following characteristics: > > Input noise: 100uV rms > Intrinsic jitter: 1ps rms > > Then the input signal slew rate at the threshold crossing has to be > greater than > > 3x1E-4/1E-12 = 3E8 V/s or 300 V/us > > to ensure that the output jitter isnt increased by more than 5% from the > intrinsic jitter. > > With a 1.4V pk 10MHz sinewave input the maximum slew rate is ~89V/us (at > the zero crossing). > For such an input signal the output jitter will be about _1.5 ps_. > This increases to about _1.72ps_ if there is a threshold offset of 1V. > This can be reduced to about 1.05ps by amplifying the slope of the input > signal by ~ 3.4x. > > The intrinsic jitter (RJ. DDJ isn't important when the input signal is a > low distortion sinewave) of a 74AC04 inverter is about 1ps. > However the equivalent input noise is unknown. > The noise could, in principle, be determined by measuring the output > jitter as a function of the input signal slew rate. > > Whilst AM and other noise associated with the source can be reduced by > filtering, the input noise of a trigger circuit cannot (except perhaps > for the trigger circuits input current noise). > > Magnus Danielson wrote: > >> Bruce Griffiths skrev: >> >> >>> Ulrich >>> >>> Your experience with the SR620 illustrates the point I was making quite >>> well. >>> It really does matter what you do in front of the limiter circuit built >>> into the counter. >>> A bandpass or any other filter by itself is ineffective unless the >>> signal is exceptionally noisy. >>> >>> By using the inverter in the 74HCT4046 you have added a low gain limiter >>> stage the bandwidth of which is smaller than that of the SR620 input >>> circuit. >>> This has the effect of increasing the slew rate of the input signal >>> whilst producing an output with less jitter than the SR620 input circuit >>> would without this low pass filtered limiter circuit (the inverter from >>> the 74HCT4046). The slew rate at the 74HCT4046 inverter output is >>> greater than that of the input signal which means that the jitter due >>> the counter input circuit noise is smaller than when this low gain low >>> bandwidth limiter isn't used. >>> The input circuit of the SR620 has a wide noise bandwidth (~ 470MHz >>> assuming a single pole response with a 300MHz 3dB high frequency cutoff) >>> and a correspondingly high total input noise (~350uV rms). >>> If the slew rate of the SR 620 input signal at the trigger point the >>> jitter due to this noise dominates the trigger circuit output jitter. >>> The HP5370 time interval counter input circuit has a lower noise >>> bandwidth (~160MHz??) and is quieter (~ 100uV rms) than the input >>> circuit of the SR620 and thus the HP5370 jitter (without the 74HCT4046 >>> limiter) for the same 10MHz signal should be less than that of the SR620 >>> (without the 74HCT4046 limiter). >>> >>> >> As a curiosity, there are various variants of the original 4046 which >> has different sensitivity on the input side... one of them has several >> inverters in a row to get the needed gain where as the other variant >> does not. This difference made a huge difference in some applications. >> >> >> > > The appropriate device (one that will have the least output jitter) to > use will vary with the input signal zero crossing slew rate. > That is it depends on both the input signal frequency and amplitude. > > >>> If one uses a state of the art trigger circuit with a noise bandwidth of >>> 1GHz or more then the total input noise will be even larger so it >>> becomes even more important to use an optimised cascade of limiter+ low >>> output pass filter stages to increase the slew rate of the counter >>> input trigger circuit at the trigger threshold. >>> Careful optimisation of the gain of each stage and the corresponding >>> output filter cutoff frequency for each stage is necessary to minimise >>> the output jitter of the counter trigger circuit. >>> There is also an optimum number of such stages that minimises the >>> trigger jitter. >>> >>> The optimisation problem for Limiter stages with gaussian wideband input >>> noise was solved in the 1990's. >>> Unfortunately the optimum number of stages, associated gains and output >>> filter bandwidths depends on the input signal frequency and amplitude so >>> that in general it isn't possible to use the same limiter cascade for a >>> wide range of signal amplitudes and frequencies and minimise the jitter >>> for each frequency and amplitude. >>> >>> >> Actually, you can make a cascade setup which is approaching optimum and >> insert signal at the stage where the signals slewrate matches the range >> for each stage. Since the gain steps is larger later in a slew rate >> amplifier chain, the last stages may have a little coarse slew rate >> range, but additional mid-range amplifiers that can act as alternative >> input amps could curcumvent that such that a wide range but and fairly >> good trigger jitter could be achieved. >> >> The comparator level is fed to whatever stage is the first stage. >> >> Such an approach could lead to much improved jitter values for lower >> frequency signals with associated gain in measurement accuracy. >> >> It is easy to make a pre-amplifier set that achieves this, but you want >> to integrate the control algorithms for automatic use. >> >> >> > That would constitute an interesting design challenge. > >>> Thus such circuits aren't usually employed in general purpose frequency counters. >>> >>> >> Certainly true. A generic counter is usually equipped with triggers such >> that they can measure slewrate without too much difficulty. >> >> >> >>> However if the input signal frequency and amplitude are known and stable >>> then using such a limiter filter cascade is feasible. >>> >>> >> Indeed. >> >> Cheers, >> Magnus >> >> _______________________________________________ >> time-nuts mailing list -- time-nuts at febo.com >> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. >> >> >> > > Bruce > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > From magnus at rubidium.dyndns.org Fri Apr 3 21:22:46 2009 From: magnus at rubidium.dyndns.org (Magnus Danielson) Date: Fri, 03 Apr 2009 23:22:46 +0200 Subject: [time-nuts] External Frequency Standard Inputs on Counters In-Reply-To: <49D66ED8.3040306@xtra.co.nz> References: <49D5B1FE.8020803@sasktel.net> <49D5FC18.60002@febo.com> <49D65C22.3060501@rubidium.dyndns.org> <49D66ED8.3040306@xtra.co.nz> Message-ID: <49D67E26.9070700@rubidium.dyndns.org> Bruce Griffiths skrev: > Magnus > > Another option (useful when the source amplitude is such that > terminating isn't an option and there isn't a suitable amplifier > available to boost the source amplitude) is to trim the cable lengths to > eliminate such standing wave nulls at the counter inputs. Certainly, but consider the frequency of 10 MHz, 100 ns. 1 ns is 2 dm one-way, so a full-wave is 20 m, a half-wave is 10 m and a quarter-wave is 5 m. It is certainly possible, but a lot of cable. I'd think this is when I would recommend tossing a distribution amplifier on it or rely on the outputs to form chains that way. Cheers, Magnus From bruce.griffiths at xtra.co.nz Fri Apr 3 21:36:05 2009 From: bruce.griffiths at xtra.co.nz (Bruce Griffiths) Date: Sat, 04 Apr 2009 10:36:05 +1300 Subject: [time-nuts] External Frequency Standard Inputs on Counters In-Reply-To: <49D67E26.9070700@rubidium.dyndns.org> References: <49D5B1FE.8020803@sasktel.net> <49D5FC18.60002@febo.com> <49D65C22.3060501@rubidium.dyndns.org> <49D66ED8.3040306@xtra.co.nz> <49D67E26.9070700@rubidium.dyndns.org> Message-ID: <49D68145.9030105@xtra.co.nz> Hej Magnus I wasn't recommending this method for anything but a possible solution when no other method was feasible. Of course the other solution is to use a sufficiently short total cable length. The only questions are: How short ? How does the counter reference input impedance (R and C) affect the maximum total cable length? Daisy chaining via the reference output signal provided by some counters will increase the noise of the reference for counters further along the chain. The significance of this depends on the application and the performance of the reference frequency buffers inside the counters. Using a high performance distribution amplifier reduces interaction between counters and the potential degradation due to each counter's reference output buffer. Bruce Magnus Danielson wrote: > Bruce Griffiths skrev: > >> Magnus >> >> Another option (useful when the source amplitude is such that >> terminating isn't an option and there isn't a suitable amplifier >> available to boost the source amplitude) is to trim the cable lengths to >> eliminate such standing wave nulls at the counter inputs. >> > > Certainly, but consider the frequency of 10 MHz, 100 ns. 1 ns is 2 dm > one-way, so a full-wave is 20 m, a half-wave is 10 m and a quarter-wave > is 5 m. It is certainly possible, but a lot of cable. > > Thats true only for cable like RG58 with a solid PE dielectric. For cables having gas injected PE or PTFE foam dielectric the corresponding lengths are a little greater. > I'd think this is when I would recommend tossing a distribution > amplifier on it or rely on the outputs to form chains that way. > > Cheers, > Magnus > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > From jra at febo.com Fri Apr 3 22:01:24 2009 From: jra at febo.com (John Ackermann N8UR) Date: Fri, 03 Apr 2009 18:01:24 -0400 Subject: [time-nuts] Updated Divider Jitter Results Message-ID: <49D68734.3020900@febo.com> I just finished a jitter test of the first TADD-2 built on the production circuit board. The configuration was somewhat optimized from what I used for the earlier tests. A single 10 MHz source was daisy-chained to the TADD-2 input, to the 5370B external reference input, and to the 5370B STOP channel. The 1 PPS output from the TADD-2 was connected to the 5370B START channel. Thus any reference jitter shouldn't be common-mode, and using the reference clock on the STOP channel avoids the need for a second divider, and ensures that the time interval is small (always less than 100 ns; in this case, about 90 ns). For a 10,000 sample run, the standard deviation was 12.1 picoseconds, and the peak-to-peak variation was 70 picoseconds. Based on experiments I ran a few years ago, I think this is pretty much the noise floor of the 5370B and the divider could be better than this. John From phk at phk.freebsd.dk Sat Apr 4 07:08:39 2009 From: phk at phk.freebsd.dk (Poul-Henning Kamp) Date: Sat, 04 Apr 2009 07:08:39 +0000 Subject: [time-nuts] Updated Divider Jitter Results In-Reply-To: Your message of "Fri, 03 Apr 2009 18:01:24 -0400." <49D68734.3020900@febo.com> Message-ID: <10005.1238828919@critter.freebsd.dk> In message <49D68734.3020900 at febo.com>, John Ackermann N8UR writes: >A single 10 MHz source was daisy-chained to the TADD-2 input, to the >5370B external reference input, Can you do the test again running the 5370B on a different clock or free-running ? Running synchronized clocks like you do makes the calibration of the input circuits in the 5370B very very critical for the measured value. -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 phk at FreeBSD.ORG | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. From df6jb at ulrich-bangert.de Sat Apr 4 10:13:40 2009 From: df6jb at ulrich-bangert.de (Ulrich Bangert) Date: Sat, 4 Apr 2009 12:13:40 +0200 Subject: [time-nuts] time-nuts Frequency Divider In-Reply-To: <49D64E08.3020200@rubidium.dyndns.org> Message-ID: Magnus, > As a curiosity, there are various variants of the original 4046 which > has different sensitivity on the input side... one of them > has several inverters in a row to get the needed gain where as the other variant > does not. This difference made a huge difference in some applications. are you going to say with that it would be reasonable to test different brands for input sensivity? I have been believing that all brands have this inverter chain. Best regards Ulrich > -----Ursprungliche Nachricht----- > Von: time-nuts-bounces at febo.com > [mailto:time-nuts-bounces at febo.com] Im Auftrag von Magnus Danielson > Gesendet: Freitag, 3. April 2009 19:57 > An: Discussion of precise time and frequency measurement > Betreff: Re: [time-nuts] time-nuts Frequency Divider > > > Bruce Griffiths skrev: > > Ulrich > > > > Your experience with the SR620 illustrates the point I was making > > quite well. It really does matter what you do in front of > the limiter > > circuit built into the counter. > > A bandpass or any other filter by itself is ineffective unless the > > signal is exceptionally noisy. > > > > By using the inverter in the 74HCT4046 you have added a low gain > > limiter stage the bandwidth of which is smaller than that > of the SR620 > > input circuit. This has the effect of increasing the slew > rate of the > > input signal whilst producing an output with less jitter than the > > SR620 input circuit would without this low pass filtered limiter > > circuit (the inverter from the 74HCT4046). The slew rate at the > > 74HCT4046 inverter output is greater than that of the input signal > > which means that the jitter due the counter input circuit noise is > > smaller than when this low gain low bandwidth limiter isn't used. > > The input circuit of the SR620 has a wide noise bandwidth (~ 470MHz > > assuming a single pole response with a 300MHz 3dB high > frequency cutoff) > > and a correspondingly high total input noise (~350uV rms). > > If the slew rate of the SR 620 input signal at the trigger point the > > jitter due to this noise dominates the trigger circuit > output jitter. > > The HP5370 time interval counter input circuit has a lower noise > > bandwidth (~160MHz??) and is quieter (~ 100uV rms) than the input > > circuit of the SR620 and thus the HP5370 jitter (without > the 74HCT4046 > > limiter) for the same 10MHz signal should be less than that > of the SR620 > > (without the 74HCT4046 limiter). > > As a curiosity, there are various variants of the original 4046 which > has different sensitivity on the input side... one of them > has several > inverters in a row to get the needed gain where as the other variant > does not. This difference made a huge difference in some applications. > > > If one uses a state of the art trigger circuit with a noise > bandwidth > > of 1GHz or more then the total input noise will be even > larger so it > > becomes even more important to use an optimised cascade of limiter+ > > low output pass filter stages to increase the slew rate of > the counter > > input trigger circuit at the trigger threshold. Careful > optimisation > > of the gain of each stage and the corresponding output > filter cutoff > > frequency for each stage is necessary to minimise the > output jitter of > > the counter trigger circuit. There is also an optimum > number of such > > stages that minimises the trigger jitter. > > > > The optimisation problem for Limiter stages with gaussian wideband > > input noise was solved in the 1990's. Unfortunately the > optimum number > > of stages, associated gains and output filter bandwidths depends on > > the input signal frequency and amplitude so that in general > it isn't > > possible to use the same limiter cascade for a wide range of signal > > amplitudes and frequencies and minimise the jitter for each > frequency > > and amplitude. > > Actually, you can make a cascade setup which is approaching > optimum and insert signal at the stage where the signals > slewrate matches the range > for each stage. Since the gain steps is larger later in a slew rate > amplifier chain, the last stages may have a little coarse slew rate > range, but additional mid-range amplifiers that can act as > alternative > input amps could curcumvent that such that a wide range but > and fairly > good trigger jitter could be achieved. > > The comparator level is fed to whatever stage is the first stage. > > Such an approach could lead to much improved jitter values for lower > frequency signals with associated gain in measurement accuracy. > > It is easy to make a pre-amplifier set that achieves this, > but you want > to integrate the control algorithms for automatic use. > > > Thus such circuits aren't usually employed in general purpose > > frequency counters. > > Certainly true. A generic counter is usually equipped with > triggers such > that they can measure slewrate without too much difficulty. > > > However if the input signal frequency and amplitude are known and > > stable then using such a limiter filter cascade is feasible. > > Indeed. > > Cheers, > Magnus > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. From bruce.griffiths at xtra.co.nz Sat Apr 4 11:11:13 2009 From: bruce.griffiths at xtra.co.nz (Bruce Griffiths) Date: Sun, 05 Apr 2009 00:11:13 +1300 Subject: [time-nuts] time-nuts Frequency Divider In-Reply-To: References: Message-ID: <49D74051.3020806@xtra.co.nz> Ulrich All manufacturers claim that their 74HC4046 or 74HCT4046 have the self biased inverter chains on SIGIN and COMPIN pins. However the AC sensitivity of these inputs differs for each manufacturer. For example the Philips/NXP version is more sensitive than The Fairchild version. The ON semiconductor version datasheet has no AC sensitivity specification. Bruce Ulrich Bangert wrote: > Magnus, > > >> As a curiosity, there are various variants of the original 4046 which >> has different sensitivity on the input side... one of them >> has several inverters in a row to get the needed gain where as the other >> > variant > >> does not. This difference made a huge difference in some applications. >> > > are you going to say with that it would be reasonable to test different > brands for input sensivity? I have been believing that all brands have this > inverter chain. > > Best regards > Ulrich > > >> -----Ursprungliche Nachricht----- >> Von: time-nuts-bounces at febo.com >> [mailto:time-nuts-bounces at febo.com] Im Auftrag von Magnus Danielson >> Gesendet: Freitag, 3. April 2009 19:57 >> An: Discussion of precise time and frequency measurement >> Betreff: Re: [time-nuts] time-nuts Frequency Divider >> >> >> Bruce Griffiths skrev: >> >>> Ulrich >>> >>> Your experience with the SR620 illustrates the point I was making >>> quite well. It really does matter what you do in front of >>> >> the limiter >> >>> circuit built into the counter. >>> A bandpass or any other filter by itself is ineffective unless the >>> signal is exceptionally noisy. >>> >>> By using the inverter in the 74HCT4046 you have added a low gain >>> limiter stage the bandwidth of which is smaller than that >>> >> of the SR620 >> >>> input circuit. This has the effect of increasing the slew >>> >> rate of the >> >>> input signal whilst producing an output with less jitter than the >>> SR620 input circuit would without this low pass filtered limiter >>> circuit (the inverter from the 74HCT4046). The slew rate at the >>> 74HCT4046 inverter output is greater than that of the input signal >>> which means that the jitter due the counter input circuit noise is >>> smaller than when this low gain low bandwidth limiter isn't used. >>> The input circuit of the SR620 has a wide noise bandwidth (~ 470MHz >>> assuming a single pole response with a 300MHz 3dB high >>> >> frequency cutoff) >> >>> and a correspondingly high total input noise (~350uV rms). >>> If the slew rate of the SR 620 input signal at the trigger point the >>> jitter due to this noise dominates the trigger circuit >>> >> output jitter. >> >>> The HP5370 time interval counter input circuit has a lower noise >>> bandwidth (~160MHz??) and is quieter (~ 100uV rms) than the input >>> circuit of the SR620 and thus the HP5370 jitter (without >>> >> the 74HCT4046 >> >>> limiter) for the same 10MHz signal should be less than that >>> >> of the SR620 >> >>> (without the 74HCT4046 limiter). >>> >> As a curiosity, there are various variants of the original 4046 which >> has different sensitivity on the input side... one of them >> has several >> inverters in a row to get the needed gain where as the other variant >> does not. This difference made a huge difference in some applications. >> >> >>> If one uses a state of the art trigger circuit with a noise >>> >> bandwidth >> >>> of 1GHz or more then the total input noise will be even >>> >> larger so it >> >>> becomes even more important to use an optimised cascade of limiter+ >>> low output pass filter stages to increase the slew rate of >>> >> the counter >> >>> input trigger circuit at the trigger threshold. Careful >>> >> optimisation >> >>> of the gain of each stage and the corresponding output >>> >> filter cutoff >> >>> frequency for each stage is necessary to minimise the >>> >> output jitter of >> >>> the counter trigger circuit. There is also an optimum >>> >> number of such >> >>> stages that minimises the trigger jitter. >>> >>> The optimisation problem for Limiter stages with gaussian wideband >>> input noise was solved in the 1990's. Unfortunately the >>> >> optimum number >> >>> of stages, associated gains and output filter bandwidths depends on >>> the input signal frequency and amplitude so that in general >>> >> it isn't >> >>> possible to use the same limiter cascade for a wide range of signal >>> amplitudes and frequencies and minimise the jitter for each >>> >> frequency >> >>> and amplitude. >>> >> Actually, you can make a cascade setup which is approaching >> optimum and insert signal at the stage where the signals >> slewrate matches the range >> for each stage. Since the gain steps is larger later in a slew rate >> amplifier chain, the last stages may have a little coarse slew rate >> range, but additional mid-range amplifiers that can act as >> alternative >> input amps could curcumvent that such that a wide range but >> and fairly >> good trigger jitter could be achieved. >> >> The comparator level is fed to whatever stage is the first stage. >> >> Such an approach could lead to much improved jitter values for lower >> frequency signals with associated gain in measurement accuracy. >> >> It is easy to make a pre-amplifier set that achieves this, >> but you want >> to integrate the control algorithms for automatic use. >> >> >>> Thus such circuits aren't usually employed in general purpose >>> frequency counters. >>> >> Certainly true. A generic counter is usually equipped with >> triggers such >> that they can measure slewrate without too much difficulty. >> >> >>> However if the input signal frequency and amplitude are known and >>> stable then using such a limiter filter cascade is feasible. >>> >> Indeed. >> >> Cheers, >> Magnus >> >> _______________________________________________ >> time-nuts mailing list -- time-nuts at febo.com >> To unsubscribe, go to >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. >> > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > From jra at febo.com Sat Apr 4 11:13:21 2009 From: jra at febo.com (John Ackermann N8UR) Date: Sat, 04 Apr 2009 07:13:21 -0400 Subject: [time-nuts] Updated Divider Jitter Results In-Reply-To: <10005.1238828919@critter.freebsd.dk> References: <10005.1238828919@critter.freebsd.dk> Message-ID: <49D740D1.1030600@febo.com> Sure. I didn't write down the numbers because it was an interim step, but I earlier did that and IIRC the std dev was around 20-25 ps. Would error in the cal circuit tend to falsely increase, or decrease, the result? Or both? John ---- Poul-Henning Kamp said the following on 04/04/2009 03:08 AM: > In message <49D68734.3020900 at febo.com>, John Ackermann N8UR writes: > >> A single 10 MHz source was daisy-chained to the TADD-2 input, to the >> 5370B external reference input, > > Can you do the test again running the 5370B on a different clock or > free-running ? > > Running synchronized clocks like you do makes the calibration of > the input circuits in the 5370B very very critical for the measured > value. > From jra at febo.com Sat Apr 4 11:16:27 2009 From: jra at febo.com (John Ackermann N8UR) Date: Sat, 04 Apr 2009 07:16:27 -0400 Subject: [time-nuts] time-nuts Frequency Divider In-Reply-To: References: Message-ID: <49D7418B.9090503@febo.com> Ulrich Bangert said the following on 04/04/2009 06:13 AM: >> As a curiosity, there are various variants of the original 4046 which >> has different sensitivity on the input side... one of them >> has several inverters in a row to get the needed gain where as the other > variant >> does not. This difference made a huge difference in some applications. > > are you going to say with that it would be reasonable to test different > brands for input sensivity? I have been believing that all brands have this > inverter chain. Brooks Shera used the 4046 as the input conditioning circuit in his GPSDO that was published quite a while ago. I seem to recall that he noted only certain brands seemed to work well, but I don't recall the details. John From phk at phk.freebsd.dk Sat Apr 4 11:30:29 2009 From: phk at phk.freebsd.dk (Poul-Henning Kamp) Date: Sat, 04 Apr 2009 11:30:29 +0000 Subject: [time-nuts] Updated Divider Jitter Results In-Reply-To: Your message of "Sat, 04 Apr 2009 07:13:21 -0400." <49D740D1.1030600@febo.com> Message-ID: <11109.1238844629@critter.freebsd.dk> In message <49D740D1.1030600 at febo.com>, John Ackermann N8UR writes: >Sure. I didn't write down the numbers because it was an interim step, >but I earlier did that and IIRC the std dev was around 20-25 ps. > >Would error in the cal circuit tend to falsely increase, or decrease, >the result? Or both? In my experience it generally skews your result downwards, but I have seen it move upwards also, it all depends on the phase. By running the 5370 from a unlocked source makes the input signals "precess" over the input windows and averages stuff out. I only lock my 5370 if I need to measure long timeintervals, for short intervals the timebase error is lost in the noise. -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 phk at FreeBSD.ORG | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. From magnus at rubidium.dyndns.org Sat Apr 4 12:18:35 2009 From: magnus at rubidium.dyndns.org (Magnus Danielson) Date: Sat, 04 Apr 2009 14:18:35 +0200 Subject: [time-nuts] External Frequency Standard Inputs on Counters In-Reply-To: <49D68145.9030105@xtra.co.nz> References: <49D5B1FE.8020803@sasktel.net> <49D5FC18.60002@febo.com> <49D65C22.3060501@rubidium.dyndns.org> <49D66ED8.3040306@xtra.co.nz> <49D67E26.9070700@rubidium.dyndns.org> <49D68145.9030105@xtra.co.nz> Message-ID: <49D7501B.8020003@rubidium.dyndns.org> Bruce Griffiths skrev: > Hej Magnus > > I wasn't recommending this method for anything but a possible solution > when no other method was feasible. > Of course the other solution is to use a sufficiently short total cable > length. > The only questions are: > How short ? > How does the counter reference input impedance (R and C) affect the > maximum total cable length? > > Daisy chaining via the reference output signal provided by some counters > will increase the noise of the reference for counters further along the > chain. > The significance of this depends on the application and the performance > of the reference frequency buffers inside the counters. Naturally. But one can put the less sensitive or needing boxes down the line. It is worth mentioning that there is two principles for using external clock, one is to just select it in and distribute it inside where as the other is to phase-lock the internal crystal oscillator. The later variant is better for those systems that has a low noise clock and frequency steering is needed. > Using a high performance distribution amplifier reduces interaction > between counters and the potential degradation due to each counter's > reference output buffer. Certainly. It also isolates various cables from each other. Thus, disconnecting a box does not become a problem. Also, there is no need to have all boxes turned on. > Bruce > > Magnus Danielson wrote: >> Bruce Griffiths skrev: >> >>> Magnus >>> >>> Another option (useful when the source amplitude is such that >>> terminating isn't an option and there isn't a suitable amplifier >>> available to boost the source amplitude) is to trim the cable lengths to >>> eliminate such standing wave nulls at the counter inputs. >>> >> Certainly, but consider the frequency of 10 MHz, 100 ns. 1 ns is 2 dm >> one-way, so a full-wave is 20 m, a half-wave is 10 m and a quarter-wave >> is 5 m. It is certainly possible, but a lot of cable. >> >> > Thats true only for cable like RG58 with a solid PE dielectric. > For cables having gas injected PE or PTFE foam dielectric the > corresponding lengths are a little greater. Certainly, but it does not help against the main point, it's alot of cable. Cheers, Magnus From magnus at rubidium.dyndns.org Sat Apr 4 12:27:49 2009 From: magnus at rubidium.dyndns.org (Magnus Danielson) Date: Sat, 04 Apr 2009 14:27:49 +0200 Subject: [time-nuts] Updated Divider Jitter Results In-Reply-To: <11109.1238844629@critter.freebsd.dk> References: <11109.1238844629@critter.freebsd.dk> Message-ID: <49D75245.50606@rubidium.dyndns.org> Poul-Henning Kamp skrev: > In message <49D740D1.1030600 at febo.com>, John Ackermann N8UR writes: >> Sure. I didn't write down the numbers because it was an interim step, >> but I earlier did that and IIRC the std dev was around 20-25 ps. >> >> Would error in the cal circuit tend to falsely increase, or decrease, >> the result? Or both? > > In my experience it generally skews your result downwards, but I have > seen it move upwards also, it all depends on the phase. I have seen how it skews both ways. With a very sensitive hand a minimum can be found which can be fairly low, such as 13 ps but then I had tuned the 200 MHz section carefully. Getting such low results on a general signal is not possible. Also, the ref out of the HP5370 has a wideband 5 MHz signal with overtones noise which can be removed if modified. Modifications requires one little short-out. Cheers, Magnus From magnus at rubidium.dyndns.org Sat Apr 4 12:32:57 2009 From: magnus at rubidium.dyndns.org (Magnus Danielson) Date: Sat, 04 Apr 2009 14:32:57 +0200 Subject: [time-nuts] time-nuts Frequency Divider In-Reply-To: References: Message-ID: <49D75379.3080203@rubidium.dyndns.org> Ulrich Bangert skrev: > Magnus, > >> As a curiosity, there are various variants of the original 4046 which >> has different sensitivity on the input side... one of them >> has several inverters in a row to get the needed gain where as the other > variant >> does not. This difference made a huge difference in some applications. > > are you going to say with that it would be reasonable to test different > brands for input sensivity? I have been believing that all brands have this > inverter chain. I don't know for sure about the situation now, but I do know there existed two variants where one had a shorter chain. It caused trouble in the production where they had prototyped and built the initial run with one brand and then second sourced in another brand just to have the box fail. I can't recall the details of where I saw it, but yes, this is an issue. Cheers, Magnus From magnus at rubidium.dyndns.org Sat Apr 4 12:35:56 2009 From: magnus at rubidium.dyndns.org (Magnus Danielson) Date: Sat, 04 Apr 2009 14:35:56 +0200 Subject: [time-nuts] time-nuts Frequency Divider In-Reply-To: <49D7418B.9090503@febo.com> References: <49D7418B.9090503@febo.com> Message-ID: <49D7542C.4030604@rubidium.dyndns.org> John Ackermann N8UR skrev: > Ulrich Bangert said the following on 04/04/2009 06:13 AM: > >>> As a curiosity, there are various variants of the original 4046 which >>> has different sensitivity on the input side... one of them >>> has several inverters in a row to get the needed gain where as the other >> variant >>> does not. This difference made a huge difference in some applications. >> are you going to say with that it would be reasonable to test different >> brands for input sensivity? I have been believing that all brands have this >> inverter chain. > > Brooks Shera used the 4046 as the input conditioning circuit in his > GPSDO that was published quite a while ago. I seem to recall that he > noted only certain brands seemed to work well, but I don't recall the > details. Maybe using a 4069UB and a small handful of passives would be a better solution? Cheers, Magnus From ed_palmer at sasktel.net Sat Apr 4 15:30:01 2009 From: ed_palmer at sasktel.net (Ed Palmer) Date: Sat, 04 Apr 2009 09:30:01 -0600 Subject: [time-nuts] time-nuts Frequency Divider In-Reply-To: References: Message-ID: <49D77CF9.8040501@sasktel.net> I was recently reviewing Brook Shera's GPSDO info and he stated that Fairchild 74HCT4046 chips don't work, but didn't give any details. ( [1]http://www.rt66.com/~shera/setup_notes.html in item 1 of the Parts Procurement Problems/Solutions section.) Is this an example of the input sensitivity problem? A quick Google search didn't turn up a Fairchild data sheet. Ed Ulrich Bangert wrote: Magnus, As a curiosity, there are various variants of the original 4046 which has different sensitivity on the input side... one of them has several inverters in a row to get the needed gain where as the other variant does not. This difference made a huge difference in some applications. are you going to say with that it would be reasonable to test different brands for input sensivity? I have been believing that all brands have this inverter chain. Best regards Ulrich -----Ursprungliche Nachricht----- Von: [2]time-nuts-bounces at febo.com [[3]mailto:time-nuts-bounces at febo.com] Im Auftrag von Magnus Danielson Gesendet: Freitag, 3. April 2009 19:57 An: Discussion of precise time and frequency measurement Betreff: Re: [time-nuts] time-nuts Frequency Divider Bruce Griffiths skrev: Ulrich Your experience with the SR620 illustrates the point I was making quite well. It really does matter what you do in front of the limiter circuit built into the counter. A bandpass or any other filter by itself is ineffective unless the signal is exceptionally noisy. By using the inverter in the 74HCT4046 you have added a low gain limiter stage the bandwidth of which is smaller than that of the SR620 input circuit. This has the effect of increasing the slew rate of the input signal whilst producing an output with less jitter than the SR620 input circuit would without this low pass filtered limiter circuit (the inverter from the 74HCT4046). The slew rate at the 74HCT4046 inverter output is greater than that of the input signal which means that the jitter due the counter input circuit noise is smaller than when this low gain low bandwidth limiter isn't used. The input circuit of the SR620 has a wide noise bandwidth (~ 470MHz assuming a single pole response with a 300MHz 3dB high frequency cutoff) and a correspondingly high total input noise (~350uV rms). If the slew rate of the SR 620 input signal at the trigger point the jitter due to this noise dominates the trigger circuit output jitter. The HP5370 time interval counter input circuit has a lower noise bandwidth (~160MHz??) and is quieter (~ 100uV rms) than the input circuit of the SR620 and thus the HP5370 jitter (without the 74HCT4046 limiter) for the same 10MHz signal should be less than that of the SR620 (without the 74HCT4046 limiter). As a curiosity, there are various variants of the original 4046 which has different sensitivity on the input side... one of them has several inverters in a row to get the needed gain where as the other variant does not. This difference made a huge difference in some applications. If one uses a state of the art trigger circuit with a noise bandwidth of 1GHz or more then the total input noise will be even larger so it becomes even more important to use an optimised cascade of limiter+ low output pass filter stages to increase the slew rate of the counter input trigger circuit at the trigger threshold. Careful optimisation of the gain of each stage and the corresponding output filter cutoff frequency for each stage is necessary to minimise the output jitter of the counter trigger circuit. There is also an optimum number of such stages that minimises the trigger jitter. The optimisation problem for Limiter stages with gaussian wideband input noise was solved in the 1990's. Unfortunately the optimum number of stages, associated gains and output filter bandwidths depends on the input signal frequency and amplitude so that in general it isn't possible to use the same limiter cascade for a wide range of signal amplitudes and frequencies and minimise the jitter for each frequency and amplitude. Actually, you can make a cascade setup which is approaching optimum and insert signal at the stage where the signals slewrate matches the range for each stage. Since the gain steps is larger later in a slew rate amplifier chain, the last stages may have a little coarse slew rate range, but additional mid-range amplifiers that can act as alternative input amps could curcumvent that such that a wide range but and fairly good trigger jitter could be achieved. The comparator level is fed to whatever stage is the first stage. Such an approach could lead to much improved jitter values for lower frequency signals with associated gain in measurement accuracy. It is easy to make a pre-amplifier set that achieves this, but you want to integrate the control algorithms for automatic use. Thus such circuits aren't usually employed in general purpose frequency counters. Certainly true. A generic counter is usually equipped with triggers such that they can measure slewrate without too much difficulty. However if the input signal frequency and amplitude are known and stable then using such a limiter filter cascade is feasible. Indeed. Cheers, Magnus _______________________________________________ time-nuts mailing list -- [4]time-nuts at febo.com To unsubscribe, go to [5]https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. _______________________________________________ time-nuts mailing list -- [6]time-nuts at febo.com To unsubscribe, go to [7]https://www.febo.com/cgi-bin/mailman/listinfo/time-nut s and follow the instructions there. References 1. http://www.rt66.com/~shera/setup_notes.html 2. mailto:time-nuts-bounces at febo.com 3. mailto:time-nuts-bounces at febo.com 4. mailto:time-nuts at febo.com 5. https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts 6. mailto:time-nuts at febo.com 7. https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts From mccorkle at ptialaska.net Sat Apr 4 19:20:40 2009 From: mccorkle at ptialaska.net (Richard H McCorkle) Date: Sat, 4 Apr 2009 11:20:40 -0800 (AKDT) Subject: [time-nuts] time-nuts Frequency Divider In-Reply-To: <49D7418B.9090503@febo.com> References: <49D7418B.9090503@febo.com> Message-ID: <13414.206.174.20.67.1238872840.squirrel@mymail.acsalaska.net> John, The specifications for AC coupled input sensitivity of the 74HC4046 from the major manufacturers are shown below. Brooks found that the Fairchild device had lower sensitivity and recommended using devices from TI or Phillips. Fairchild MM74HC4046 Ac coupled input sensitivity @ 500 KHz 25mv p-p typical, 100mv p-p guaranteed at 25C @ 2v 50mv p-p typical, 150mv p-p guaranteed at 25C @ 4.5v 135mv p-p typical, 250mv p-p guaranteed at 25C @ 6v Phillips 74HC4046A, TI CD74HC4046 Ac coupled input sensitivity @ 1 MHz 9mv p-p typical @ 2v 11mv p-p typical @ 3v 15mv p-p typical @ 4.5v 33mv p-p typical @ 6v On Semiconductor MC74HC4046A Ac coupled input sensitivity not specified Richard > Ulrich Bangert said the following on 04/04/2009 06:13 AM: > >>> As a curiosity, there are various variants of the original 4046 which >>> has different sensitivity on the input side... one of them >>> has several inverters in a row to get the needed gain where as the other >> variant >>> does not. This difference made a huge difference in some applications. >> >> are you going to say with that it would be reasonable to test different >> brands for input sensivity? I have been believing that all brands have this >> inverter chain. > > Brooks Shera used the 4046 as the input conditioning circuit in his > GPSDO that was published quite a while ago. I seem to recall that he > noted only certain brands seemed to work well, but I don't recall the > details. > > John > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > From EWKehren at aol.com Sat Apr 4 20:04:01 2009 From: EWKehren at aol.com (EWKehren at aol.com) Date: Sat, 4 Apr 2009 16:04:01 EDT Subject: [time-nuts] time-nuts Frequency Divider Message-ID: Having built eight of Brooks units, my experience was that the problem was not with the amplifier but the way the RS F/F in the phase comparator II was working in some of the devices. For me they all worked in the oscillator input but some brands did not work properly with the GPS input. With all the dialog on the divider subject, is it not time to develop one design that combines KISS and all the collective know how? Bert Kehren WB5MZJ In a message dated 4/3/2009 5:17:18 P.M. Eastern Daylight Time, bruce.griffiths at xtra.co.nz writes: Correction: I forgot to include the intrinsic jitter of the gate in the calculations. See underlined corrections below. Bruce Bruce Griffiths wrote: > Magnus > > The input noise of a logic inverter or other trigger device used as a > clock shaper is important. > If we have a logic inverter device with the following characteristics: > > Input noise: 100uV rms > Intrinsic jitter: 1ps rms > > Then the input signal slew rate at the threshold crossing has to be > greater than > > 3x1E-4/1E-12 = 3E8 V/s or 300 V/us > > to ensure that the output jitter isnt increased by more than 5% from the > intrinsic jitter. > > With a 1.4V pk 10MHz sinewave input the maximum slew rate is ~89V/us (at > the zero crossing). > For such an input signal the output jitter will be about _1.5 ps_. > This increases to about _1.72ps_ if there is a threshold offset of 1V. > This can be reduced to about 1.05ps by amplifying the slope of the input > signal by ~ 3.4x. > > The intrinsic jitter (RJ. DDJ isn't important when the input signal is a > low distortion sinewave) of a 74AC04 inverter is about 1ps. > However the equivalent input noise is unknown. > The noise could, in principle, be determined by measuring the output > jitter as a function of the input signal slew rate. > > Whilst AM and other noise associated with the source can be reduced by > filtering, the input noise of a trigger circuit cannot (except perhaps > for the trigger circuits input current noise). > > Magnus Danielson wrote: > >> Bruce Griffiths skrev: >> >> >>> Ulrich >>> >>> Your experience with the SR620 illustrates the point I was making quite >>> well. >>> It really does matter what you do in front of the limiter circuit built >>> into the counter. >>> A bandpass or any other filter by itself is ineffective unless the >>> signal is exceptionally noisy. >>> >>> By using the inverter in the 74HCT4046 you have added a low gain limiter >>> stage the bandwidth of which is smaller than that of the SR620 input >>> circuit. >>> This has the effect of increasing the slew rate of the input signal >>> whilst producing an output with less jitter than the SR620 input circuit >>> would without this low pass filtered limiter circuit (the inverter from >>> the 74HCT4046). The slew rate at the 74HCT4046 inverter output is >>> greater than that of the input signal which means that the jitter due >>> the counter input circuit noise is smaller than when this low gain low >>> bandwidth limiter isn't used. >>> The input circuit of the SR620 has a wide noise bandwidth (~ 470MHz >>> assuming a single pole response with a 300MHz 3dB high frequency cutoff) >>> and a correspondingly high total input noise (~350uV rms). >>> If the slew rate of the SR 620 input signal at the trigger point the >>> jitter due to this noise dominates the trigger circuit output jitter. >>> The HP5370 time interval counter input circuit has a lower noise >>> bandwidth (~160MHz??) and is quieter (~ 100uV rms) than the input >>> circuit of the SR620 and thus the HP5370 jitter (without the 74HCT4046 >>> limiter) for the same 10MHz signal should be less than that of the SR620 >>> (without the 74HCT4046 limiter). >>> >>> >> As a curiosity, there are various variants of the original 4046 which >> has different sensitivity on the input side... one of them has several >> inverters in a row to get the needed gain where as the other variant >> does not. This difference made a huge difference in some applications. >> >> >> > > The appropriate device (one that will have the least output jitter) to > use will vary with the input signal zero crossing slew rate. > That is it depends on both the input signal frequency and amplitude. > > >>> If one uses a state of the art trigger circuit with a noise bandwidth of >>> 1GHz or more then the total input noise will be even larger so it >>> becomes even more important to use an optimised cascade of limiter+ low >>> output pass filter stages to increase the slew rate of the counter >>> input trigger circuit at the trigger threshold. >>> Careful optimisation of the gain of each stage and the corresponding >>> output filter cutoff frequency for each stage is necessary to minimise >>> the output jitter of the counter trigger circuit. >>> There is also an optimum number of such stages that minimises the >>> trigger jitter. >>> >>> The optimisation problem for Limiter stages with gaussian wideband input >>> noise was solved in the 1990's. >>> Unfortunately the optimum number of stages, associated gains and output >>> filter bandwidths depends on the input signal frequency and amplitude so >>> that in general it isn't possible to use the same limiter cascade for a >>> wide range of signal amplitudes and frequencies and minimise the jitter >>> for each frequency and amplitude. >>> >>> >> Actually, you can make a cascade setup which is approaching optimum and >> insert signal at the stage where the signals slewrate matches the range >> for each stage. Since the gain steps is larger later in a slew rate >> amplifier chain, the last stages may have a little coarse slew rate >> range, but additional mid-range amplifiers that can act as alternative >> input amps could curcumvent that such that a wide range but and fairly >> good trigger jitter could be achieved. >> >> The comparator level is fed to whatever stage is the first stage. >> >> Such an approach could lead to much improved jitter values for lower >> frequency signals with associated gain in measurement accuracy. >> >> It is easy to make a pre-amplifier set that achieves this, but you want >> to integrate the control algorithms for automatic use. >> >> >> > That would constitute an interesting design challenge. > >>> Thus such circuits aren't usually employed in general purpose frequency counters. >>> >>> >> Certainly true. A generic counter is usually equipped with triggers such >> that they can measure slewrate without too much difficulty. >> >> >> >>> However if the input signal frequency and amplitude are known and stable >>> then using such a limiter filter cascade is feasible. >>> >>> >> Indeed. >> >> Cheers, >> Magnus >> >> _______________________________________________ >> time-nuts mailing list -- time-nuts at febo.com >> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. >> >> >> > > Bruce > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > _______________________________________________ time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. **************Worried about job security? Check out the 5 safest jobs in a recession. (http://jobs.aol.com/gallery/growing-job-industries?ncid=emlcntuscare00000003) From kilodelta4foxmike at gmail.com Sat Apr 4 20:18:50 2009 From: kilodelta4foxmike at gmail.com (Brian Kirby) Date: Sat, 04 Apr 2009 15:18:50 -0500 Subject: [time-nuts] Updated Divider Jitter Results - 74HC390 In-Reply-To: <49D68734.3020900@febo.com> References: <49D68734.3020900@febo.com> Message-ID: <49D7C0AA.6060708@gmail.com> I will report some results on a asynchronous divider, which I basically copied from Dr. Thomas Clark's designs, which everybody likes to report as a bad design. The 10 MHz input signal is coupled thru a resistor and capacitor. On the other side of the capacitor is the resistive divider that is tied to Vcc and ground - it biases the signal to 2.5 volts, which is feed to the input of the 74HC132. The output of the 74HC132 feeds several 74HC390s until it becomes a buffered 1 pulse per second signal. I also have buffered 5 MHz and 1 MHz outputs. The other 3/4 of the 74HC132 are used to externally synchronize the 74HC390s. I used the Thunderbolt as the source of 10 MHz and it was feed to the divider, and the stop input on the HP5370B. The 5370B was run on internal clock. The 1 PPS from the divider feed the start input on the 5370B. 100 seconds TI 79.865 nS MIN 79.80 nS MAX 79.98 nS STD 36.4 pS. 1000 seconds TI 79.831 nS MIN 79.71 nS MAX 80.00 nS STD 49.9 pS 10K seconds TI 80.1552 nS MIN 79.79 nS MAX 80.88 nS STD 271 pS 100K planned Also a second test, using the Thunderbolt as a source of 10 MHz and it was feed to the divider, the stop input on the 5370B and the external clock of the 5370B. The 1 PPS from the divider feed the start input on the 5370B. 100 seconds TI 75.002 nS MIN 74.96 nS MAX 75.04 nS STD 22.5 pS 1000 seconds TI 74.931 nS MIN 74.80 nS MAX 75.04 nS STD 56.8 pS 10K seconds TI 77.5135 nS MIN 77.40 nS MAX 77.62 nS STD 35.9 pS 100K measurement in progress. I believe having STD in parts of 10-14th is fairly respectable for amateur designs.. Brian KD4FM John Ackermann N8UR wrote: > I just finished a jitter test of the first TADD-2 built on the > production circuit board. > > The configuration was somewhat optimized from what I used for the > earlier tests. > > A single 10 MHz source was daisy-chained to the TADD-2 input, to the > 5370B external reference input, and to the 5370B STOP channel. The 1 > PPS output from the TADD-2 was connected to the 5370B START channel. > Thus any reference jitter shouldn't be common-mode, and using the > reference clock on the STOP channel avoids the need for a second > divider, and ensures that the time interval is small (always less than > 100 ns; in this case, about 90 ns). > > For a 10,000 sample run, the standard deviation was 12.1 picoseconds, > and the peak-to-peak variation was 70 picoseconds. Based on experiments > I ran a few years ago, I think this is pretty much the noise floor of > the 5370B and the divider could be better than this. > > John > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > From bruce.griffiths at xtra.co.nz Sat Apr 4 20:33:41 2009 From: bruce.griffiths at xtra.co.nz (Bruce Griffiths) Date: Sun, 05 Apr 2009 08:33:41 +1200 Subject: [time-nuts] time-nuts Frequency Divider In-Reply-To: References: Message-ID: <49D7C425.8080605@xtra.co.nz> Bert Neither the HP5370 nor the SR620 have low enough internal jitter to accurately characterise the intrinisic output jitter of either a 74HC04 (~4ps) or a 74AC04 (~1ps). Rather than just tossing together a divider from various parts though to produce an output with low jitter its better to be able to characterise the jitter properties (intrinsic as well as that due to logic device input noise with a finite input signal slew rate) of various logic families. It is then possible to actually design a sine to logic level converter that achieves the lowest possible output jitter for a given complexity and specified input frequency and amplitude. The real problem is that one needs to accurately measure jitter of 1ps or so. There are few time interval counters that allow this. One can also measure the change in noise floor when such a device is placed in the clock input path of a high frequency ADC and thence derive the jitter. In principle, the output jitter of a divider can also be calculated from the phase noise spectrum of its output. Bruce EWKehren at aol.com wrote: > Having built eight of Brooks units, my experience was that the problem was > not with the amplifier but the way the RS F/F in the phase comparator II was > working in some of the devices. For me they all worked in the oscillator input > but some brands did not work properly with the GPS input. With all the dialog > on the divider subject, is it not time to develop one design that combines > KISS and all the collective know how? Bert Kehren WB5MZJ > > > In a message dated 4/3/2009 5:17:18 P.M. Eastern Daylight Time, > bruce.griffiths at xtra.co.nz writes: > > Correction: > > I forgot to include the intrinsic jitter of the gate in the calculations. > See underlined corrections below. > > > Bruce > > Bruce Griffiths wrote: > > > >> Magnus >> >> The input noise of a logic inverter or other trigger device used as a >> clock shaper is important. >> If we have a logic inverter device with the following characteristics: >> >> Input noise: 100uV rms >> Intrinsic jitter: 1ps rms >> >> Then the input signal slew rate at the threshold crossing has to be >> greater than >> >> 3x1E-4/1E-12 = 3E8 V/s or 300 V/us >> >> to ensure that the output jitter isnt increased by more than 5% from the >> intrinsic jitter. >> >> With a 1.4V pk 10MHz sinewave input the maximum slew rate is ~89V/us (at >> the zero crossing). >> For such an input signal the output jitter will be about _1.5 ps_. >> This increases to about _1.72ps_ if there is a threshold offset of 1V. >> This can be reduced to about 1.05ps by amplifying the slope of the input >> signal by ~ 3.4x. >> >> The intrinsic jitter (RJ. DDJ isn't important when the input signal is a >> low distortion sinewave) of a 74AC04 inverter is about 1ps. >> However the equivalent input noise is unknown. >> The noise could, in principle, be determined by measuring the output >> jitter as a function of the input signal slew rate. >> >> Whilst AM and other noise associated with the source can be reduced by >> filtering, the input noise of a trigger circuit cannot (except perhaps >> for the trigger circuits input current noise). >> >> Magnus Danielson wrote: >> >> >>> Bruce Griffiths skrev: >>> >>> >>> >>>> Ulrich >>>> >>>> Your experience with the SR620 illustrates the point I was making quite >>>> well. >>>> It really does matter what you do in front of the limiter circuit built >>>> into the counter. >>>> A bandpass or any other filter by itself is ineffective unless the >>>> signal is exceptionally noisy. >>>> >>>> By using the inverter in the 74HCT4046 you have added a low gain limiter >>>> stage the bandwidth of which is smaller than that of the SR620 input >>>> circuit. >>>> This has the effect of increasing the slew rate of the input signal >>>> whilst producing an output with less jitter than the SR620 input circuit >>>> would without this low pass filtered limiter circuit (the inverter from >>>> the 74HCT4046). The slew rate at the 74HCT4046 inverter output is >>>> greater than that of the input signal which means that the jitter due >>>> the counter input circuit noise is smaller than when this low gain low >>>> bandwidth limiter isn't used. >>>> The input circuit of the SR620 has a wide noise bandwidth (~ 470MHz >>>> assuming a single pole response with a 300MHz 3dB high frequency cutoff) >>>> and a correspondingly high total input noise (~350uV rms). >>>> If the slew rate of the SR 620 input signal at the trigger point the >>>> jitter due to this noise dominates the trigger circuit output jitter. >>>> The HP5370 time interval counter input circuit has a lower noise >>>> bandwidth (~160MHz??) and is quieter (~ 100uV rms) than the input >>>> circuit of the SR620 and thus the HP5370 jitter (without the 74HCT4046 >>>> limiter) for the same 10MHz signal should be less than that of the SR620 >>>> (without the 74HCT4046 limiter). >>>> >>>> >>>> >>> As a curiosity, there are various variants of the original 4046 which >>> has different sensitivity on the input side... one of them has several >>> inverters in a row to get the needed gain where as the other variant >>> does not. This difference made a huge difference in some applications. >>> >>> >>> >>> >> The appropriate device (one that will have the least output jitter) to >> use will vary with the input signal zero crossing slew rate. >> That is it depends on both the input signal frequency and amplitude. >> >> >> >>>> If one uses a state of the art trigger circuit with a noise bandwidth of >>>> 1GHz or more then the total input noise will be even larger so it >>>> becomes even more important to use an optimised cascade of limiter+ low >>>> output pass filter stages to increase the slew rate of the counter >>>> input trigger circuit at the trigger threshold. >>>> Careful optimisation of the gain of each stage and the corresponding >>>> output filter cutoff frequency for each stage is necessary to minimise >>>> the output jitter of the counter trigger circuit. >>>> There is also an optimum number of such stages that minimises the >>>> trigger jitter. >>>> >>>> The optimisation problem for Limiter stages with gaussian wideband input >>>> noise was solved in the 1990's. >>>> Unfortunately the optimum number of stages, associated gains and output >>>> filter bandwidths depends on the input signal frequency and amplitude so >>>> that in general it isn't possible to use the same limiter cascade for a >>>> wide range of signal amplitudes and frequencies and minimise the jitter >>>> for each frequency and amplitude. >>>> >>>> >>>> >>> Actually, you can make a cascade setup which is approaching optimum and >>> insert signal at the stage where the signals slewrate matches the range >>> for each stage. Since the gain steps is larger later in a slew rate >>> amplifier chain, the last stages may have a little coarse slew rate >>> range, but additional mid-range amplifiers that can act as alternative >>> input amps could curcumvent that such that a wide range but and fairly >>> good trigger jitter could be achieved. >>> >>> The comparator level is fed to whatever stage is the first stage. >>> >>> Such an approach could lead to much improved jitter values for lower >>> frequency signals with associated gain in measurement accuracy. >>> >>> It is easy to make a pre-amplifier set that achieves this, but you want >>> to integrate the control algorithms for automatic use. >>> >>> >>> >>> >> That would constitute an interesting design challenge. >> >> >>>> Thus such circuits aren't usually employed in general purpose frequency >>>> > counters. > >>>> >>>> >>>> >>> Certainly true. A generic counter is usually equipped with triggers such >>> that they can measure slewrate without too much difficulty. >>> >>> >>> >>> >>>> However if the input signal frequency and amplitude are known and stable >>>> then using such a limiter filter cascade is feasible. >>>> >>>> >>>> >>> Indeed. >>> >>> Cheers, >>> Magnus >>> >>> _______________________________________________ >>> time-nuts mailing list -- time-nuts at febo.com >>> To unsubscribe, go to >>> > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > >>> and follow the instructions there. >>> >>> >>> >>> >> Bruce >> >> _______________________________________________ >> time-nuts mailing list -- time-nuts at febo.com >> To unsubscribe, go to >> > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > >> and follow the instructions there. >> >> >> > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > > **************Worried about job security? Check out the 5 safest jobs in a > recession. > (http://jobs.aol.com/gallery/growing-job-industries?ncid=emlcntuscare00000003) > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > From jra at febo.com Sat Apr 4 20:44:39 2009 From: jra at febo.com (John Ackermann N8UR) Date: Sat, 04 Apr 2009 16:44:39 -0400 Subject: [time-nuts] Updated Divider Jitter Results - 74HC390 In-Reply-To: <49D7C0AA.6060708@gmail.com> References: <49D68734.3020900@febo.com> <49D7C0AA.6060708@gmail.com> Message-ID: <49D7C6B7.1090801@febo.com> Hi Brian -- It's good to collect this data; thanks. It's interesting that your std dev in the first test seems to increase significantly with the number of samples; I haven't seen that kind of scaling here (1K sample and 10k sample turned in very similar std dev). From what Poul-Henning said earlier, your first run may suffer the same distortion as my data at the bottom of this thread. I just finished rerunning the TADD-2 test using a Wavecrest DTS-2075 (the first real use I've had for that box!) and with 1 PPS input on the start channel, 10 MHz from the same source on the stop channel, and 10K samples, I got 22.0 ps of jitter, and a 92 ps min/max range. (As far as I can determine, the Wavecrest doesn't allow you to use an external reference, and its internal reference runs at 100 MHz so it probably wouldn't be useful in this measurement.) That's consistent with what I measured earlier with the 5370B when I didn't have the reference and the inputs in coherence. It appears that the test below, where I used the same reference for *everything* triggered the problem that Poul-Henning warned about, so those results should be disregarded. While I haven't done any testing to validate this, I think the complaint about the 74HC390 dividers isn't so much their jitter in normal use, but the tempco problems the cascaded stages can cause. If you can do it, it would be interesting to measure the phase change over temperature -- I've done a preliminary experiment on that for the TADD-2, but plan to rerun it with much better measurement technique. I'm also hoping to do a jitter and tempco test of the Wenzel input conditioning circuit by itself. I really like that circuit for its wide input amplitude range. John ---- Brian Kirby said the following on 04/04/2009 04:18 PM: > I will report some results on a asynchronous divider, which I basically > copied from Dr. Thomas Clark's designs, which everybody likes to report > as a bad design. > > The 10 MHz input signal is coupled thru a resistor and capacitor. On > the other side of the capacitor is the resistive divider that is tied to > Vcc and ground - it biases the signal to 2.5 volts, which is feed to the > input of the 74HC132. The output of the 74HC132 feeds several 74HC390s > until it becomes a buffered 1 pulse per second signal. I also have > buffered 5 MHz and 1 MHz outputs. The other 3/4 of the 74HC132 are used > to externally synchronize the 74HC390s. > > I used the Thunderbolt as the source of 10 MHz and it was feed to the > divider, and the stop input on the HP5370B. The 5370B was run on > internal clock. The 1 PPS from the divider feed the start input on the > 5370B. > > 100 seconds TI 79.865 nS MIN 79.80 nS MAX 79.98 nS STD 36.4 pS. > 1000 seconds TI 79.831 nS MIN 79.71 nS MAX 80.00 nS STD 49.9 pS > 10K seconds TI 80.1552 nS MIN 79.79 nS MAX 80.88 nS STD 271 pS > 100K planned > > Also a second test, using the Thunderbolt as a source of 10 MHz and it > was feed to the divider, the stop input on the 5370B and the external > clock of the 5370B. The 1 PPS from the divider feed the start input on > the 5370B. > > 100 seconds TI 75.002 nS MIN 74.96 nS MAX 75.04 nS STD 22.5 pS > 1000 seconds TI 74.931 nS MIN 74.80 nS MAX 75.04 nS STD 56.8 pS > 10K seconds TI 77.5135 nS MIN 77.40 nS MAX 77.62 nS STD 35.9 pS > 100K measurement in progress. > > I believe having STD in parts of 10-14th is fairly respectable for > amateur designs.. > > Brian KD4FM > > John Ackermann N8UR wrote: >> I just finished a jitter test of the first TADD-2 built on the >> production circuit board. >> >> The configuration was somewhat optimized from what I used for the >> earlier tests. >> >> A single 10 MHz source was daisy-chained to the TADD-2 input, to the >> 5370B external reference input, and to the 5370B STOP channel. The 1 >> PPS output from the TADD-2 was connected to the 5370B START channel. >> Thus any reference jitter shouldn't be common-mode, and using the >> reference clock on the STOP channel avoids the need for a second >> divider, and ensures that the time interval is small (always less than >> 100 ns; in this case, about 90 ns). >> >> For a 10,000 sample run, the standard deviation was 12.1 picoseconds, >> and the peak-to-peak variation was 70 picoseconds. Based on experiments >> I ran a few years ago, I think this is pretty much the noise floor of >> the 5370B and the divider could be better than this. >> >> John >> >> _______________________________________________ >> time-nuts mailing list -- time-nuts at febo.com >> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. >> >> > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. From bruce.griffiths at xtra.co.nz Sat Apr 4 20:46:38 2009 From: bruce.griffiths at xtra.co.nz (Bruce Griffiths) Date: Sun, 05 Apr 2009 08:46:38 +1200 Subject: [time-nuts] Updated Divider Jitter Results - 74HC390 In-Reply-To: <49D7C0AA.6060708@gmail.com> References: <49D68734.3020900@febo.com> <49D7C0AA.6060708@gmail.com> Message-ID: <49D7C72E.50501@xtra.co.nz> Brian The 5370B has inadequate resolution and noise to allow detection of the difference between a jitter of say 1ps or one 4x that. Your longer term measurements probably reflect the combined effect of thermal drift in the 5370B and thermal drift in the divider propagation delay. The acceptable output jitter of a divider depends on the application for which it is intended. For generating a PPS signal for comparing with other PPS signals using a time interval counter like the SR620 or HP5370A/B almost any reasonable design will have an output jitter that is difficult to measure with such a time interval counter. However for long term measurements the clock to output delay tempco will be rather large for a non fully sysnchronous divider. If one wishes to use the output as a frequency standard for a low noise synthesizer or similar application then the phase noise characteristics of the divider output are more critical. Bruce Brian Kirby wrote: > I will report some results on a asynchronous divider, which I basically > copied from Dr. Thomas Clark's designs, which everybody likes to report > as a bad design. > > The 10 MHz input signal is coupled thru a resistor and capacitor. On > the other side of the capacitor is the resistive divider that is tied to > Vcc and ground - it biases the signal to 2.5 volts, which is feed to the > input of the 74HC132. The output of the 74HC132 feeds several 74HC390s > until it becomes a buffered 1 pulse per second signal. I also have > buffered 5 MHz and 1 MHz outputs. The other 3/4 of the 74HC132 are used > to externally synchronize the 74HC390s. > > I used the Thunderbolt as the source of 10 MHz and it was feed to the > divider, and the stop input on the HP5370B. The 5370B was run on > internal clock. The 1 PPS from the divider feed the start input on the > 5370B. > > 100 seconds TI 79.865 nS MIN 79.80 nS MAX 79.98 nS STD 36.4 pS. > 1000 seconds TI 79.831 nS MIN 79.71 nS MAX 80.00 nS STD 49.9 pS > 10K seconds TI 80.1552 nS MIN 79.79 nS MAX 80.88 nS STD 271 pS > 100K planned > > Also a second test, using the Thunderbolt as a source of 10 MHz and it > was feed to the divider, the stop input on the 5370B and the external > clock of the 5370B. The 1 PPS from the divider feed the start input on > the 5370B. > > 100 seconds TI 75.002 nS MIN 74.96 nS MAX 75.04 nS STD 22.5 pS > 1000 seconds TI 74.931 nS MIN 74.80 nS MAX 75.04 nS STD 56.8 pS > 10K seconds TI 77.5135 nS MIN 77.40 nS MAX 77.62 nS STD 35.9 pS > 100K measurement in progress. > > I believe having STD in parts of 10-14th is fairly respectable for > amateur designs.. > > Brian KD4FM > > John Ackermann N8UR wrote: > >> I just finished a jitter test of the first TADD-2 built on the >> production circuit board. >> >> The configuration was somewhat optimized from what I used for the >> earlier tests. >> >> A single 10 MHz source was daisy-chained to the TADD-2 input, to the >> 5370B external reference input, and to the 5370B STOP channel. The 1 >> PPS output from the TADD-2 was connected to the 5370B START channel. >> Thus any reference jitter shouldn't be common-mode, and using the >> reference clock on the STOP channel avoids the need for a second >> divider, and ensures that the time interval is small (always less than >> 100 ns; in this case, about 90 ns). >> >> For a 10,000 sample run, the standard deviation was 12.1 picoseconds, >> and the peak-to-peak variation was 70 picoseconds. Based on experiments >> I ran a few years ago, I think this is pretty much the noise floor of >> the 5370B and the divider could be better than this. >> >> John >> >> _______________________________________________ >> time-nuts mailing list -- time-nuts at febo.com >> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. >> >> >> > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > From EWKehren at aol.com Sat Apr 4 20:51:46 2009 From: EWKehren at aol.com (EWKehren at aol.com) Date: Sat, 4 Apr 2009 16:51:46 EDT Subject: [time-nuts] time-nuts Frequency Divider Message-ID: Bruce, thank you for the info. I have never had the need or desire to get 1 ps accuracy however in designing low noise signal sources I have always had to battle reference oscillator noise and was often nor sure if it was the oscillator or the input circuit. However I would like to see a recommendation as to an attainable design. Thanks again Bert In a message dated 4/4/2009 4:35:09 P.M. Eastern Daylight Time, bruce.griffiths at xtra.co.nz writes: Bert Neither the HP5370 nor the SR620 have low enough internal jitter to accurately characterise the intrinisic output jitter of either a 74HC04 (~4ps) or a 74AC04 (~1ps). Rather than just tossing together a divider from various parts though to produce an output with low jitter its better to be able to characterise the jitter properties (intrinsic as well as that due to logic device input noise with a finite input signal slew rate) of various logic families. It is then possible to actually design a sine to logic level converter that achieves the lowest possible output jitter for a given complexity and specified input frequency and amplitude. The real problem is that one needs to accurately measure jitter of 1ps or so. There are few time interval counters that allow this. One can also measure the change in noise floor when such a device is placed in the clock input path of a high frequency ADC and thence derive the jitter. In principle, the output jitter of a divider can also be calculated from the phase noise spectrum of its output. Bruce EWKehren at aol.com wrote: > Having built eight of Brooks units, my experience was that the problem was > not with the amplifier but the way the RS F/F in the phase comparator II was > working in some of the devices. For me they all worked in the oscillator input > but some brands did not work properly with the GPS input. With all the dialog > on the divider subject, is it not time to develop one design that combines > KISS and all the collective know how? Bert Kehren WB5MZJ > > > In a message dated 4/3/2009 5:17:18 P.M. Eastern Daylight Time, > bruce.griffiths at xtra.co.nz writes: > > Correction: > > I forgot to include the intrinsic jitter of the gate in the calculations. > See underlined corrections below. > > > Bruce > > Bruce Griffiths wrote: > > > >> Magnus >> >> The input noise of a logic inverter or other trigger device used as a >> clock shaper is important. >> If we have a logic inverter device with the following characteristics: >> >> Input noise: 100uV rms >> Intrinsic jitter: 1ps rms >> >> Then the input signal slew rate at the threshold crossing has to be >> greater than >> >> 3x1E-4/1E-12 = 3E8 V/s or 300 V/us >> >> to ensure that the output jitter isnt increased by more than 5% from the >> intrinsic jitter. >> >> With a 1.4V pk 10MHz sinewave input the maximum slew rate is ~89V/us (at >> the zero crossing). >> For such an input signal the output jitter will be about _1.5 ps_. >> This increases to about _1.72ps_ if there is a threshold offset of 1V. >> This can be reduced to about 1.05ps by amplifying the slope of the input >> signal by ~ 3.4x. >> >> The intrinsic jitter (RJ. DDJ isn't important when the input signal is a >> low distortion sinewave) of a 74AC04 inverter is about 1ps. >> However the equivalent input noise is unknown. >> The noise could, in principle, be determined by measuring the output >> jitter as a function of the input signal slew rate. >> >> Whilst AM and other noise associated with the source can be reduced by >> filtering, the input noise of a trigger circuit cannot (except perhaps >> for the trigger circuits input current noise). >> >> Magnus Danielson wrote: >> >> >>> Bruce Griffiths skrev: >>> >>> >>> >>>> Ulrich >>>> >>>> Your experience with the SR620 illustrates the point I was making quite >>>> well. >>>> It really does matter what you do in front of the limiter circuit built >>>> into the counter. >>>> A bandpass or any other filter by itself is ineffective unless the >>>> signal is exceptionally noisy. >>>> >>>> By using the inverter in the 74HCT4046 you have added a low gain limiter >>>> stage the bandwidth of which is smaller than that of the SR620 input >>>> circuit. >>>> This has the effect of increasing the slew rate of the input signal >>>> whilst producing an output with less jitter than the SR620 input circuit >>>> would without this low pass filtered limiter circuit (the inverter from >>>> the 74HCT4046). The slew rate at the 74HCT4046 inverter output is >>>> greater than that of the input signal which means that the jitter due >>>> the counter input circuit noise is smaller than when this low gain low >>>> bandwidth limiter isn't used. >>>> The input circuit of the SR620 has a wide noise bandwidth (~ 470MHz >>>> assuming a single pole response with a 300MHz 3dB high frequency cutoff) >>>> and a correspondingly high total input noise (~350uV rms). >>>> If the slew rate of the SR 620 input signal at the trigger point the >>>> jitter due to this noise dominates the trigger circuit output jitter. >>>> The HP5370 time interval counter input circuit has a lower noise >>>> bandwidth (~160MHz??) and is quieter (~ 100uV rms) than the input >>>> circuit of the SR620 and thus the HP5370 jitter (without the 74HCT4046 >>>> limiter) for the same 10MHz signal should be less than that of the SR620 >>>> (without the 74HCT4046 limiter). >>>> >>>> >>>> >>> As a curiosity, there are various variants of the original 4046 which >>> has different sensitivity on the input side... one of them has several >>> inverters in a row to get the needed gain where as the other variant >>> does not. This difference made a huge difference in some applications. >>> >>> >>> >>> >> The appropriate device (one that will have the least output jitter) to >> use will vary with the input signal zero crossing slew rate. >> That is it depends on both the input signal frequency and amplitude. >> >> >> >>>> If one uses a state of the art trigger circuit with a noise bandwidth of >>>> 1GHz or more then the total input noise will be even larger so it >>>> becomes even more important to use an optimised cascade of limiter+ low >>>> output pass filter stages to increase the slew rate of the counter >>>> input trigger circuit at the trigger threshold. >>>> Careful optimisation of the gain of each stage and the corresponding >>>> output filter cutoff frequency for each stage is necessary to minimise >>>> the output jitter of the counter trigger circuit. >>>> There is also an optimum number of such stages that minimises the >>>> trigger jitter. >>>> >>>> The optimisation problem for Limiter stages with gaussian wideband input >>>> noise was solved in the 1990's. >>>> Unfortunately the optimum number of stages, associated gains and output >>>> filter bandwidths depends on the input signal frequency and amplitude so >>>> that in general it isn't possible to use the same limiter cascade for a >>>> wide range of signal amplitudes and frequencies and minimise the jitter >>>> for each frequency and amplitude. >>>> >>>> >>>> >>> Actually, you can make a cascade setup which is approaching optimum and >>> insert signal at the stage where the signals slewrate matches the range >>> for each stage. Since the gain steps is larger later in a slew rate >>> amplifier chain, the last stages may have a little coarse slew rate >>> range, but additional mid-range amplifiers that can act as alternative >>> input amps could curcumvent that such that a wide range but and fairly >>> good trigger jitter could be achieved. >>> >>> The comparator level is fed to whatever stage is the first stage. >>> >>> Such an approach could lead to much improved jitter values for lower >>> frequency signals with associated gain in measurement accuracy. >>> >>> It is easy to make a pre-amplifier set that achieves this, but you want >>> to integrate the control algorithms for automatic use. >>> >>> >>> >>> >> That would constitute an interesting design challenge. >> >> >>>> Thus such circuits aren't usually employed in general purpose frequency >>>> > counters. > >>>> >>>> >>>> >>> Certainly true. A generic counter is usually equipped with triggers such >>> that they can measure slewrate without too much difficulty. >>> >>> >>> >>> >>>> However if the input signal frequency and amplitude are known and stable >>>> then using such a limiter filter cascade is feasible. >>>> >>>> >>>> >>> Indeed. >>> >>> Cheers, >>> Magnus >>> >>> _______________________________________________ >>> time-nuts mailing list -- time-nuts at febo.com >>> To unsubscribe, go to >>> > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > >>> and follow the instructions there. >>> >>> >>> >>> >> Bruce >> >> _______________________________________________ >> time-nuts mailing list -- time-nuts at febo.com >> To unsubscribe, go to >> > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > >> and follow the instructions there. >> >> >> > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > > **************Worried about job security? Check out the 5 safest jobs in a > recession. > (http://jobs.aol.com/gallery/growing-job-industries?ncid=emlcntuscare00000003) > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > _______________________________________________ time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. **************Worried about job security? Check out the 5 safest jobs in a recession. (http://jobs.aol.com/gallery/growing-job-industries?ncid=emlcntuscare00000003) From bruce.griffiths at xtra.co.nz Sat Apr 4 21:33:01 2009 From: bruce.griffiths at xtra.co.nz (Bruce Griffiths) Date: Sun, 05 Apr 2009 09:33:01 +1200 Subject: [time-nuts] Updated Divider Jitter Results - 74HC390 In-Reply-To: <49D7C6B7.1090801@febo.com> References: <49D68734.3020900@febo.com> <49D7C0AA.6060708@gmail.com> <49D7C6B7.1090801@febo.com> Message-ID: <49D7D20D.5030208@xtra.co.nz> John One can cure the propagation delay tempco associated with a 74HC390 divider string by resynchronising the output to the input clock. However worst case design means that a 3 stage synchroniser is required. Assuming a 10Mhz input clock frequency: First resychronise the output to 1MHz (worst case propagation delay for PPS output is < 1us) Then resynchronise this output to 2MHz (assumes a biquinary configuration for the 1st 1/2 of the input '390) Finally resynchronise this output to the 10MHz input clock. Bruce John Ackermann N8UR wrote: > Hi Brian -- > > It's good to collect this data; thanks. It's interesting that your std > dev in the first test seems to increase significantly with the number of > samples; I haven't seen that kind of scaling here (1K sample and 10k > sample turned in very similar std dev). From what Poul-Henning said > earlier, your first run may suffer the same distortion as my data at the > bottom of this thread. > > I just finished rerunning the TADD-2 test using a Wavecrest DTS-2075 > (the first real use I've had for that box!) and with 1 PPS input on the > start channel, 10 MHz from the same source on the stop channel, and 10K > samples, I got 22.0 ps of jitter, and a 92 ps min/max range. (As far as > I can determine, the Wavecrest doesn't allow you to use an external > reference, and its internal reference runs at 100 MHz so it probably > wouldn't be useful in this measurement.) > > That's consistent with what I measured earlier with the 5370B when I > didn't have the reference and the inputs in coherence. It appears that > the test below, where I used the same reference for *everything* > triggered the problem that Poul-Henning warned about, so those results > should be disregarded. > > While I haven't done any testing to validate this, I think the complaint > about the 74HC390 dividers isn't so much their jitter in normal use, but > the tempco problems the cascaded stages can cause. If you can do it, it > would be interesting to measure the phase change over temperature -- > I've done a preliminary experiment on that for the TADD-2, but plan to > rerun it with much better measurement technique. > > I'm also hoping to do a jitter and tempco test of the Wenzel input > conditioning circuit by itself. I really like that circuit for its wide > input amplitude range. > > John > ---- > Brian Kirby said the following on 04/04/2009 04:18 PM: > >> I will report some results on a asynchronous divider, which I basically >> copied from Dr. Thomas Clark's designs, which everybody likes to report >> as a bad design. >> >> The 10 MHz input signal is coupled thru a resistor and capacitor. On >> the other side of the capacitor is the resistive divider that is tied to >> Vcc and ground - it biases the signal to 2.5 volts, which is feed to the >> input of the 74HC132. The output of the 74HC132 feeds several 74HC390s >> until it becomes a buffered 1 pulse per second signal. I also have >> buffered 5 MHz and 1 MHz outputs. The other 3/4 of the 74HC132 are used >> to externally synchronize the 74HC390s. >> >> I used the Thunderbolt as the source of 10 MHz and it was feed to the >> divider, and the stop input on the HP5370B. The 5370B was run on >> internal clock. The 1 PPS from the divider feed the start input on the >> 5370B. >> >> 100 seconds TI 79.865 nS MIN 79.80 nS MAX 79.98 nS STD 36.4 pS. >> 1000 seconds TI 79.831 nS MIN 79.71 nS MAX 80.00 nS STD 49.9 pS >> 10K seconds TI 80.1552 nS MIN 79.79 nS MAX 80.88 nS STD 271 pS >> 100K planned >> >> Also a second test, using the Thunderbolt as a source of 10 MHz and it >> was feed to the divider, the stop input on the 5370B and the external >> clock of the 5370B. The 1 PPS from the divider feed the start input on >> the 5370B. >> >> 100 seconds TI 75.002 nS MIN 74.96 nS MAX 75.04 nS STD 22.5 pS >> 1000 seconds TI 74.931 nS MIN 74.80 nS MAX 75.04 nS STD 56.8 pS >> 10K seconds TI 77.5135 nS MIN 77.40 nS MAX 77.62 nS STD 35.9 pS >> 100K measurement in progress. >> >> I believe having STD in parts of 10-14th is fairly respectable for >> amateur designs.. >> >> Brian KD4FM >> >> John Ackermann N8UR wrote: >> >>> I just finished a jitter test of the first TADD-2 built on the >>> production circuit board. >>> >>> The configuration was somewhat optimized from what I used for the >>> earlier tests. >>> >>> A single 10 MHz source was daisy-chained to the TADD-2 input, to the >>> 5370B external reference input, and to the 5370B STOP channel. The 1 >>> PPS output from the TADD-2 was connected to the 5370B START channel. >>> Thus any reference jitter shouldn't be common-mode, and using the >>> reference clock on the STOP channel avoids the need for a second >>> divider, and ensures that the time interval is small (always less than >>> 100 ns; in this case, about 90 ns). >>> >>> For a 10,000 sample run, the standard deviation was 12.1 picoseconds, >>> and the peak-to-peak variation was 70 picoseconds. Based on experiments >>> I ran a few years ago, I think this is pretty much the noise floor of >>> the 5370B and the divider could be better than this. >>> >>> John >>> >>> _______________________________________________ >>> time-nuts mailing list -- time-nuts at febo.com >>> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >>> and follow the instructions there. >>> >>> >>> >> _______________________________________________ >> time-nuts mailing list -- time-nuts at febo.com >> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. >> > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > From bruce.griffiths at xtra.co.nz Sat Apr 4 21:37:18 2009 From: bruce.griffiths at xtra.co.nz (Bruce Griffiths) Date: Sun, 05 Apr 2009 09:37:18 +1200 Subject: [time-nuts] Updated Divider Jitter Results - 74HC390 In-Reply-To: <49D7C6B7.1090801@febo.com> References: <49D68734.3020900@febo.com> <49D7C0AA.6060708@gmail.com> <49D7C6B7.1090801@febo.com> Message-ID: <49D7D30E.40208@xtra.co.nz> John With a slow slew rate input signal like a 10MHz sinewave the Wavecrest jitter due to the noise of its wideband input amplifiers may be quite high. So it may be better to measure the relative jitter of 2 dividers. Bruce John Ackermann N8UR wrote: > Hi Brian -- > > It's good to collect this data; thanks. It's interesting that your std > dev in the first test seems to increase significantly with the number of > samples; I haven't seen that kind of scaling here (1K sample and 10k > sample turned in very similar std dev). From what Poul-Henning said > earlier, your first run may suffer the same distortion as my data at the > bottom of this thread. > > I just finished rerunning the TADD-2 test using a Wavecrest DTS-2075 > (the first real use I've had for that box!) and with 1 PPS input on the > start channel, 10 MHz from the same source on the stop channel, and 10K > samples, I got 22.0 ps of jitter, and a 92 ps min/max range. (As far as > I can determine, the Wavecrest doesn't allow you to use an external > reference, and its internal reference runs at 100 MHz so it probably > wouldn't be useful in this measurement.) > > That's consistent with what I measured earlier with the 5370B when I > didn't have the reference and the inputs in coherence. It appears that > the test below, where I used the same reference for *everything* > triggered the problem that Poul-Henning warned about, so those results > should be disregarded. > > While I haven't done any testing to validate this, I think the complaint > about the 74HC390 dividers isn't so much their jitter in normal use, but > the tempco problems the cascaded stages can cause. If you can do it, it > would be interesting to measure the phase change over temperature -- > I've done a preliminary experiment on that for the TADD-2, but plan to > rerun it with much better measurement technique. > > I'm also hoping to do a jitter and tempco test of the Wenzel input > conditioning circuit by itself. I really like that circuit for its wide > input amplitude range. > > John > ---- > Brian Kirby said the following on 04/04/2009 04:18 PM: > >> I will report some results on a asynchronous divider, which I basically >> copied from Dr. Thomas Clark's designs, which everybody likes to report >> as a bad design. >> >> The 10 MHz input signal is coupled thru a resistor and capacitor. On >> the other side of the capacitor is the resistive divider that is tied to >> Vcc and ground - it biases the signal to 2.5 volts, which is feed to the >> input of the 74HC132. The output of the 74HC132 feeds several 74HC390s >> until it becomes a buffered 1 pulse per second signal. I also have >> buffered 5 MHz and 1 MHz outputs. The other 3/4 of the 74HC132 are used >> to externally synchronize the 74HC390s. >> >> I used the Thunderbolt as the source of 10 MHz and it was feed to the >> divider, and the stop input on the HP5370B. The 5370B was run on >> internal clock. The 1 PPS from the divider feed the start input on the >> 5370B. >> >> 100 seconds TI 79.865 nS MIN 79.80 nS MAX 79.98 nS STD 36.4 pS. >> 1000 seconds TI 79.831 nS MIN 79.71 nS MAX 80.00 nS STD 49.9 pS >> 10K seconds TI 80.1552 nS MIN 79.79 nS MAX 80.88 nS STD 271 pS >> 100K planned >> >> Also a second test, using the Thunderbolt as a source of 10 MHz and it >> was feed to the divider, the stop input on the 5370B and the external >> clock of the 5370B. The 1 PPS from the divider feed the start input on >> the 5370B. >> >> 100 seconds TI 75.002 nS MIN 74.96 nS MAX 75.04 nS STD 22.5 pS >> 1000 seconds TI 74.931 nS MIN 74.80 nS MAX 75.04 nS STD 56.8 pS >> 10K seconds TI 77.5135 nS MIN 77.40 nS MAX 77.62 nS STD 35.9 pS >> 100K measurement in progress. >> >> I believe having STD in parts of 10-14th is fairly respectable for >> amateur designs.. >> >> Brian KD4FM >> >> John Ackermann N8UR wrote: >> >>> I just finished a jitter test of the first TADD-2 built on the >>> production circuit board. >>> >>> The configuration was somewhat optimized from what I used for the >>> earlier tests. >>> >>> A single 10 MHz source was daisy-chained to the TADD-2 input, to the >>> 5370B external reference input, and to the 5370B STOP channel. The 1 >>> PPS output from the TADD-2 was connected to the 5370B START channel. >>> Thus any reference jitter shouldn't be common-mode, and using the >>> reference clock on the STOP channel avoids the need for a second >>> divider, and ensures that the time interval is small (always less than >>> 100 ns; in this case, about 90 ns). >>> >>> For a 10,000 sample run, the standard deviation was 12.1 picoseconds, >>> and the peak-to-peak variation was 70 picoseconds. Based on experiments >>> I ran a few years ago, I think this is pretty much the noise floor of >>> the 5370B and the divider could be better than this. >>> >>> John >>> >>> _______________________________________________ >>> time-nuts mailing list -- time-nuts at febo.com >>> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >>> and follow the instructions there. >>> >>> >>> >> _______________________________________________ >> time-nuts mailing list -- time-nuts at febo.com >> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. >> > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > From jra at febo.com Sat Apr 4 23:04:38 2009 From: jra at febo.com (John Ackermann N8UR) Date: Sat, 04 Apr 2009 19:04:38 -0400 Subject: [time-nuts] Updated Divider Jitter Results - 74HC390 In-Reply-To: <49D7D30E.40208@xtra.co.nz> References: <49D68734.3020900@febo.com> <49D7C0AA.6060708@gmail.com> <49D7C6B7.1090801@febo.com> <49D7D30E.40208@xtra.co.nz> Message-ID: <49D7E786.3060903@febo.com> I can do that, but was hoping to isolate the performance of the Wenzel waveform conversion circuit. An initial test showed jitter of about 25 ps -- which is about the same as for the whole divider chain, so you may be correct that the input amplifiers are limiting. But also, I was doing a quick and dirty setup without paying much attention to how the signal was coupled. I'll be able to improve on that in tomorrow's experiments. John ---- Bruce Griffiths said the following on 04/04/2009 05:37 PM: > John > > With a slow slew rate input signal like a 10MHz sinewave the Wavecrest > jitter due to the noise of its wideband input amplifiers may be quite high. > > So it may be better to measure the relative jitter of 2 dividers. > > Bruce > > John Ackermann N8UR wrote: >> Hi Brian -- >> >> It's good to collect this data; thanks. It's interesting that your std >> dev in the first test seems to increase significantly with the number of >> samples; I haven't seen that kind of scaling here (1K sample and 10k >> sample turned in very similar std dev). From what Poul-Henning said >> earlier, your first run may suffer the same distortion as my data at the >> bottom of this thread. >> >> I just finished rerunning the TADD-2 test using a Wavecrest DTS-2075 >> (the first real use I've had for that box!) and with 1 PPS input on the >> start channel, 10 MHz from the same source on the stop channel, and 10K >> samples, I got 22.0 ps of jitter, and a 92 ps min/max range. (As far as >> I can determine, the Wavecrest doesn't allow you to use an external >> reference, and its internal reference runs at 100 MHz so it probably >> wouldn't be useful in this measurement.) >> >> That's consistent with what I measured earlier with the 5370B when I >> didn't have the reference and the inputs in coherence. It appears that >> the test below, where I used the same reference for *everything* >> triggered the problem that Poul-Henning warned about, so those results >> should be disregarded. >> >> While I haven't done any testing to validate this, I think the complaint >> about the 74HC390 dividers isn't so much their jitter in normal use, but >> the tempco problems the cascaded stages can cause. If you can do it, it >> would be interesting to measure the phase change over temperature -- >> I've done a preliminary experiment on that for the TADD-2, but plan to >> rerun it with much better measurement technique. >> >> I'm also hoping to do a jitter and tempco test of the Wenzel input >> conditioning circuit by itself. I really like that circuit for its wide >> input amplitude range. >> >> John >> ---- >> Brian Kirby said the following on 04/04/2009 04:18 PM: >> >>> I will report some results on a asynchronous divider, which I basically >>> copied from Dr. Thomas Clark's designs, which everybody likes to report >>> as a bad design. >>> >>> The 10 MHz input signal is coupled thru a resistor and capacitor. On >>> the other side of the capacitor is the resistive divider that is tied to >>> Vcc and ground - it biases the signal to 2.5 volts, which is feed to the >>> input of the 74HC132. The output of the 74HC132 feeds several 74HC390s >>> until it becomes a buffered 1 pulse per second signal. I also have >>> buffered 5 MHz and 1 MHz outputs. The other 3/4 of the 74HC132 are used >>> to externally synchronize the 74HC390s. >>> >>> I used the Thunderbolt as the source of 10 MHz and it was feed to the >>> divider, and the stop input on the HP5370B. The 5370B was run on >>> internal clock. The 1 PPS from the divider feed the start input on the >>> 5370B. >>> >>> 100 seconds TI 79.865 nS MIN 79.80 nS MAX 79.98 nS STD 36.4 pS. >>> 1000 seconds TI 79.831 nS MIN 79.71 nS MAX 80.00 nS STD 49.9 pS >>> 10K seconds TI 80.1552 nS MIN 79.79 nS MAX 80.88 nS STD 271 pS >>> 100K planned >>> >>> Also a second test, using the Thunderbolt as a source of 10 MHz and it >>> was feed to the divider, the stop input on the 5370B and the external >>> clock of the 5370B. The 1 PPS from the divider feed the start input on >>> the 5370B. >>> >>> 100 seconds TI 75.002 nS MIN 74.96 nS MAX 75.04 nS STD 22.5 pS >>> 1000 seconds TI 74.931 nS MIN 74.80 nS MAX 75.04 nS STD 56.8 pS >>> 10K seconds TI 77.5135 nS MIN 77.40 nS MAX 77.62 nS STD 35.9 pS >>> 100K measurement in progress. >>> >>> I believe having STD in parts of 10-14th is fairly respectable for >>> amateur designs.. >>> >>> Brian KD4FM >>> >>> John Ackermann N8UR wrote: >>> >>>> I just finished a jitter test of the first TADD-2 built on the >>>> production circuit board. >>>> >>>> The configuration was somewhat optimized from what I used for the >>>> earlier tests. >>>> >>>> A single 10 MHz source was daisy-chained to the TADD-2 input, to the >>>> 5370B external reference input, and to the 5370B STOP channel. The 1 >>>> PPS output from the TADD-2 was connected to the 5370B START channel. >>>> Thus any reference jitter shouldn't be common-mode, and using the >>>> reference clock on the STOP channel avoids the need for a second >>>> divider, and ensures that the time interval is small (always less than >>>> 100 ns; in this case, about 90 ns). >>>> >>>> For a 10,000 sample run, the standard deviation was 12.1 picoseconds, >>>> and the peak-to-peak variation was 70 picoseconds. Based on experiments >>>> I ran a few years ago, I think this is pretty much the noise floor of >>>> the 5370B and the divider could be better than this. >>>> >>>> John >>>> >>>> _______________________________________________ >>>> time-nuts mailing list -- time-nuts at febo.com >>>> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >>>> and follow the instructions there. >>>> >>>> >>>> >>> _______________________________________________ >>> time-nuts mailing list -- time-nuts at febo.com >>> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >>> and follow the instructions there. >>> >> >> _______________________________________________ >> time-nuts mailing list -- time-nuts at febo.com >> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. >> >> > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. From bruce.griffiths at xtra.co.nz Sat Apr 4 23:07:57 2009 From: bruce.griffiths at xtra.co.nz (Bruce Griffiths) Date: Sun, 05 Apr 2009 11:07:57 +1200 Subject: [time-nuts] time-nuts Frequency Divider In-Reply-To: References: Message-ID: <49D7E84D.7000601@xtra.co.nz> Bert Unless you can provide a set of specifications it isn't possible to recommend any particular design as being fit for the application. For the purposes of comparing a divider generated PPS signal against a GPS derived PPS output almost any input clock shaper should have adequate performance. For such applications achieving a sufficiently low jitter PPS output can be achieved using almost any divider chain. However ensuring a low clock to output propagation delay tempco is entirely another matter and either requires a fully synchronous divider or using an output retiming synchroniser. If multiple ripple clocking is used in the divider then a 3 stage synchroniser that first resynchronises to 1MHz, then 2MHz and finally to 10MHz may be required. If the lower frequency dividers in the cascade use something as slow as 4000 series CMOS then even more synchroniser stages will be required. If we consider minimising the trigger jitter of an SR620 driven from say a 2V pp 10MHz sine wave, then a single stage limiter with a slope gain of about 5x and a bandwidth of about 50MHz will ensure that the trigger circuit jitter due to its linter and trigger circuit input noise is reduced to below 2ps rms with a low noise input source. If a 2 stage limiter cascade with the same slope gain is used the jitter due to limiter and trigger circuit input noise can be reduced to below 1.3ps rms with a low noise source if the low pass filter time constant at the output of each stage is chosen appropriately. If the output of a divider is to be used as a low phase noise source then picosecond or even subpicosecond jitter is desirable. For the ultimate performance in such applications a regenerative divider can have a much lower output phase noise than a digital divider. Injection locked dividers are one form of regenerative divider complete with integrated mixer and filter, however conjugate regenerative dividers using a diode mixer and low phase noise amplifier etc will have lower phase noise. Bruce EWKehren at aol.com wrote: > Bruce, thank you for the info. I have never had the need or desire to get 1 > ps accuracy however in designing low noise signal sources I have always had to > battle reference oscillator noise and was often nor sure if it was the > oscillator or the input circuit. However I would like to see a recommendation as > to an attainable design. Thanks again Bert > > > In a message dated 4/4/2009 4:35:09 P.M. Eastern Daylight Time, > bruce.griffiths at xtra.co.nz writes: > > Bert > > Neither the HP5370 nor the SR620 have low enough internal jitter to > accurately characterise the intrinisic output jitter of either a 74HC04 > (~4ps) or a 74AC04 (~1ps). > Rather than just tossing together a divider from various parts though to > produce an output with low jitter its better to be able to characterise > the jitter properties (intrinsic as well as that due to logic device > input noise with a finite input signal slew rate) of various logic > families. > It is then possible to actually design a sine to logic level converter > that achieves the lowest possible output jitter for a given complexity > and specified input frequency and amplitude. > > The real problem is that one needs to accurately measure jitter of 1ps > or so. > There are few time interval counters that allow this. > One can also measure the change in noise floor when such a device is > placed in the clock input path of a high frequency ADC and thence derive > the jitter. > In principle, the output jitter of a divider can also be calculated from > the phase noise spectrum of its output. > > Bruce > > > > EWKehren at aol.com wrote: > >> Having built eight of Brooks units, my experience was that the problem was >> > > >> not with the amplifier but the way the RS F/F in the phase comparator II >> > was > >> working in some of the devices. For me they all worked in the oscillator >> > input > >> but some brands did not work properly with the GPS input. With all the >> > dialog > >> on the divider subject, is it not time to develop one design that >> > combines > >> KISS and all the collective know how? Bert Kehren WB5MZJ >> >> >> In a message dated 4/3/2009 5:17:18 P.M. Eastern Daylight Time, >> bruce.griffiths at xtra.co.nz writes: >> >> Correction: >> >> I forgot to include the intrinsic jitter of the gate in the calculations. >> See underlined corrections below. >> >> >> Bruce >> >> Bruce Griffiths wrote: >> >> >> >> >>> Magnus >>> >>> The input noise of a logic inverter or other trigger device used as a >>> clock shaper is important. >>> If we have a logic inverter device with the following characteristics: >>> >>> Input noise: 100uV rms >>> Intrinsic jitter: 1ps rms >>> >>> Then the input signal slew rate at the threshold crossing has to be >>> greater than >>> >>> 3x1E-4/1E-12 = 3E8 V/s or 300 V/us >>> >>> to ensure that the output jitter isnt increased by more than 5% from the >>> intrinsic jitter. >>> >>> With a 1.4V pk 10MHz sinewave input the maximum slew rate is ~89V/us (at >>> the zero crossing). >>> For such an input signal the output jitter will be about _1.5 ps_. >>> This increases to about _1.72ps_ if there is a threshold offset of 1V. >>> This can be reduced to about 1.05ps by amplifying the slope of the input >>> signal by ~ 3.4x. >>> >>> The intrinsic jitter (RJ. DDJ isn't important when the input signal is a >>> low distortion sinewave) of a 74AC04 inverter is about 1ps. >>> However the equivalent input noise is unknown. >>> The noise could, in principle, be determined by measuring the output >>> jitter as a function of the input signal slew rate. >>> >>> Whilst AM and other noise associated with the source can be reduced by >>> filtering, the input noise of a trigger circuit cannot (except perhaps >>> for the trigger circuits input current noise). >>> >>> Magnus Danielson wrote: >>> >>> >>> >>>> Bruce Griffiths skrev: >>>> >>>> >>>> >>>> >>>>> Ulrich >>>>> >>>>> Your experience with the SR620 illustrates the point I was making >>>>> > quite > >>>>> well. >>>>> It really does matter what you do in front of the limiter circuit built >>>>> into the counter. >>>>> A bandpass or any other filter by itself is ineffective unless the >>>>> signal is exceptionally noisy. >>>>> >>>>> By using the inverter in the 74HCT4046 you have added a low gain >>>>> > limiter > >>>>> stage the bandwidth of which is smaller than that of the SR620 input >>>>> circuit. >>>>> This has the effect of increasing the slew rate of the input signal >>>>> whilst producing an output with less jitter than the SR620 input >>>>> > circuit > >>>>> would without this low pass filtered limiter circuit (the inverter from >>>>> the 74HCT4046). The slew rate at the 74HCT4046 inverter output is >>>>> greater than that of the input signal which means that the jitter due >>>>> the counter input circuit noise is smaller than when this low gain low >>>>> bandwidth limiter isn't used. >>>>> The input circuit of the SR620 has a wide noise bandwidth (~ 470MHz >>>>> assuming a single pole response with a 300MHz 3dB high frequency >>>>> > cutoff) > >>>>> and a correspondingly high total input noise (~350uV rms). >>>>> If the slew rate of the SR 620 input signal at the trigger point the >>>>> jitter due to this noise dominates the trigger circuit output jitter. >>>>> The HP5370 time interval counter input circuit has a lower noise >>>>> bandwidth (~160MHz??) and is quieter (~ 100uV rms) than the input >>>>> circuit of the SR620 and thus the HP5370 jitter (without the 74HCT4046 >>>>> limiter) for the same 10MHz signal should be less than that of the >>>>> > SR620 > >>>>> (without the 74HCT4046 limiter). >>>>> >>>>> >>>>> >>>>> >>>> As a curiosity, there are various variants of the original 4046 which >>>> has different sensitivity on the input side... one of them has several >>>> inverters in a row to get the needed gain where as the other variant >>>> does not. This difference made a huge difference in some applications. >>>> >>>> >>>> >>>> >>>> >>> The appropriate device (one that will have the least output jitter) to >>> use will vary with the input signal zero crossing slew rate. >>> That is it depends on both the input signal frequency and amplitude. >>> >>> >>> >>> >>>>> If one uses a state of the art trigger circuit with a noise bandwidth >>>>> > of > >>>>> 1GHz or more then the total input noise will be even larger so it >>>>> becomes even more important to use an optimised cascade of limiter+ low >>>>> output pass filter stages to increase the slew rate of the counter >>>>> input trigger circuit at the trigger threshold. >>>>> Careful optimisation of the gain of each stage and the corresponding >>>>> output filter cutoff frequency for each stage is necessary to minimise >>>>> the output jitter of the counter trigger circuit. >>>>> There is also an optimum number of such stages that minimises the >>>>> trigger jitter. >>>>> >>>>> The optimisation problem for Limiter stages with gaussian wideband >>>>> > input > >>>>> noise was solved in the 1990's. >>>>> Unfortunately the optimum number of stages, associated gains and output >>>>> filter bandwidths depends on the input signal frequency and amplitude >>>>> > so > >>>>> that in general it isn't possible to use the same limiter cascade for a >>>>> wide range of signal amplitudes and frequencies and minimise the jitter >>>>> for each frequency and amplitude. >>>>> >>>>> >>>>> >>>>> >>>> Actually, you can make a cascade setup which is approaching optimum and >>>> insert signal at the stage where the signals slewrate matches the range >>>> > > >>>> for each stage. Since the gain steps is larger later in a slew rate >>>> amplifier chain, the last stages may have a little coarse slew rate >>>> range, but additional mid-range amplifiers that can act as alternative >>>> input amps could curcumvent that such that a wide range but and fairly >>>> good trigger jitter could be achieved. >>>> >>>> The comparator level is fed to whatever stage is the first stage. >>>> >>>> Such an approach could lead to much improved jitter values for lower >>>> frequency signals with associated gain in measurement accuracy. >>>> >>>> It is easy to make a pre-amplifier set that achieves this, but you want >>>> to integrate the control algorithms for automatic use. >>>> >>>> >>>> >>>> >>>> >>> That would constitute an interesting design challenge. >>> >>> >>> >>>>> Thus such circuits aren't usually employed in general purpose >>>>> > frequency > >>>>> >>>>> >> counters. >> >> >>>>> >>>>> >>>>> >>>>> >>>> Certainly true. A generic counter is usually equipped with triggers >>>> > such > >>>> that they can measure slewrate without too much difficulty. >>>> >>>> >>>> >>>> >>>> >>>>> However if the input signal frequency and amplitude are known and >>>>> > stable > >>>>> then using such a limiter filter cascade is feasible. >>>>> >>>>> >>>>> >>>>> >>>> Indeed. >>>> >>>> Cheers, >>>> Magnus >>>> >>>> _______________________________________________ >>>> time-nuts mailing list -- time-nuts at febo.com >>>> To unsubscribe, go to >>>> >>>> >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> >> >>>> and follow the instructions there. >>>> >>>> >>>> >>>> >>>> >>> Bruce >>> >>> _______________________________________________ >>> time-nuts mailing list -- time-nuts at febo.com >>> To unsubscribe, go to >>> >>> >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> >> >>> and follow the instructions there. >>> >>> >>> >>> >> _______________________________________________ >> time-nuts mailing list -- time-nuts at febo.com >> To unsubscribe, go to >> > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > >> and follow the instructions there. >> >> >> **************Worried about job security? Check out the 5 safest jobs in a >> recession. >> >> > (http://jobs.aol.com/gallery/growing-job-industries?ncid=emlcntuscare00000003) > >> _______________________________________________ >> time-nuts mailing list -- time-nuts at febo.com >> To unsubscribe, go to >> > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > >> and follow the instructions there. >> >> >> > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > > **************Worried about job security? Check out the 5 safest jobs in a > recession. > (http://jobs.aol.com/gallery/growing-job-industries?ncid=emlcntuscare00000003) > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > From jmiles at pop.net Sat Apr 4 23:10:19 2009 From: jmiles at pop.net (John Miles) Date: Sat, 4 Apr 2009 16:10:19 -0700 Subject: [time-nuts] Updated Divider Jitter Results - 74HC390 In-Reply-To: <49D7C6B7.1090801@febo.com> Message-ID: > > I believe having STD in parts of 10-14th is fairly respectable for > > amateur designs.. It depends on whether it's due to the counter or the DUT. Keep in mind the 5370's own jitter is about 15-20 ps for a best-case unit (and they all seem to be a bit different). For an application like an ADC sampling clock, SNR is 20*log(1/(2*pi*freq*jitter)). In this case the jitter floor is around 10 ps, and you would like to think the device itself is cleaner. Using that equation, 10 ps of jitter at 10 MHz puts the SNR at about 64 dB. That's about the same SNR floor that you'd see if you used a traditional microwave spectrum analyzer to observe the integrated noise on the same 10 MHz source. You would never try to use a conventional SA to measure phase noise on a 10 MHz source, unless you knew from the outset that you had a really, seriously awful 10 MHz source. Likewise, you can't use a conventional time-interval counter to characterize the jitter in the time domain. You need a specialized test set, either a very clean direct-sampling ADC/FFT or another type of baseband PN analyzer. > >> For a 10,000 sample run, the standard deviation was 12.1 picoseconds, > >> and the peak-to-peak variation was 70 picoseconds. Based on > experiments > >> I ran a few years ago, I think this is pretty much the noise floor of > >> the 5370B and the divider could be better than this. Exactly. The divider had better be *much* better than that, or it is not useful for a large number of applications. The TSC5120 can do residual noise measurements, right...? That's the better tool for the job. -- john, KE5FX From bruce.griffiths at xtra.co.nz Sat Apr 4 23:16:11 2009 From: bruce.griffiths at xtra.co.nz (Bruce Griffiths) Date: Sun, 05 Apr 2009 11:16:11 +1200 Subject: [time-nuts] Updated Divider Jitter Results - 74HC390 In-Reply-To: <49D7E786.3060903@febo.com> References: <49D68734.3020900@febo.com> <49D7C0AA.6060708@gmail.com> <49D7C6B7.1090801@febo.com> <49D7D30E.40208@xtra.co.nz> <49D7E786.3060903@febo.com> Message-ID: <49D7EA3B.7080502@xtra.co.nz> John The jitter of the Wenzel waveform conversion circuit will vary with the input signal amplitude. Thus one could probably measure the jitter as a function of input signal amplitude and derive the waveform conversion circuit jitter performance from that data. Bruce John Ackermann N8UR wrote: > I can do that, but was hoping to isolate the performance of the Wenzel > waveform conversion circuit. An initial test showed jitter of about 25 > ps -- which is about the same as for the whole divider chain, so you may > be correct that the input amplifiers are limiting. But also, I was > doing a quick and dirty setup without paying much attention to how the > signal was coupled. I'll be able to improve on that in tomorrow's > experiments. > > John > ---- > > Bruce Griffiths said the following on 04/04/2009 05:37 PM: > >> John >> >> With a slow slew rate input signal like a 10MHz sinewave the Wavecrest >> jitter due to the noise of its wideband input amplifiers may be quite high. >> >> So it may be better to measure the relative jitter of 2 dividers. >> >> Bruce >> >> John Ackermann N8UR wrote: >> >>> Hi Brian -- >>> >>> It's good to collect this data; thanks. It's interesting that your std >>> dev in the first test seems to increase significantly with the number of >>> samples; I haven't seen that kind of scaling here (1K sample and 10k >>> sample turned in very similar std dev). From what Poul-Henning said >>> earlier, your first run may suffer the same distortion as my data at the >>> bottom of this thread. >>> >>> I just finished rerunning the TADD-2 test using a Wavecrest DTS-2075 >>> (the first real use I've had for that box!) and with 1 PPS input on the >>> start channel, 10 MHz from the same source on the stop channel, and 10K >>> samples, I got 22.0 ps of jitter, and a 92 ps min/max range. (As far as >>> I can determine, the Wavecrest doesn't allow you to use an external >>> reference, and its internal reference runs at 100 MHz so it probably >>> wouldn't be useful in this measurement.) >>> >>> That's consistent with what I measured earlier with the 5370B when I >>> didn't have the reference and the inputs in coherence. It appears that >>> the test below, where I used the same reference for *everything* >>> triggered the problem that Poul-Henning warned about, so those results >>> should be disregarded. >>> >>> While I haven't done any testing to validate this, I think the complaint >>> about the 74HC390 dividers isn't so much their jitter in normal use, but >>> the tempco problems the cascaded stages can cause. If you can do it, it >>> would be interesting to measure the phase change over temperature -- >>> I've done a preliminary experiment on that for the TADD-2, but plan to >>> rerun it with much better measurement technique. >>> >>> I'm also hoping to do a jitter and tempco test of the Wenzel input >>> conditioning circuit by itself. I really like that circuit for its wide >>> input amplitude range. >>> >>> John >>> ---- >>> Brian Kirby said the following on 04/04/2009 04:18 PM: >>> >>> >>>> I will report some results on a asynchronous divider, which I basically >>>> copied from Dr. Thomas Clark's designs, which everybody likes to report >>>> as a bad design. >>>> >>>> The 10 MHz input signal is coupled thru a resistor and capacitor. On >>>> the other side of the capacitor is the resistive divider that is tied to >>>> Vcc and ground - it biases the signal to 2.5 volts, which is feed to the >>>> input of the 74HC132. The output of the 74HC132 feeds several 74HC390s >>>> until it becomes a buffered 1 pulse per second signal. I also have >>>> buffered 5 MHz and 1 MHz outputs. The other 3/4 of the 74HC132 are used >>>> to externally synchronize the 74HC390s. >>>> >>>> I used the Thunderbolt as the source of 10 MHz and it was feed to the >>>> divider, and the stop input on the HP5370B. The 5370B was run on >>>> internal clock. The 1 PPS from the divider feed the start input on the >>>> 5370B. >>>> >>>> 100 seconds TI 79.865 nS MIN 79.80 nS MAX 79.98 nS STD 36.4 pS. >>>> 1000 seconds TI 79.831 nS MIN 79.71 nS MAX 80.00 nS STD 49.9 pS >>>> 10K seconds TI 80.1552 nS MIN 79.79 nS MAX 80.88 nS STD 271 pS >>>> 100K planned >>>> >>>> Also a second test, using the Thunderbolt as a source of 10 MHz and it >>>> was feed to the divider, the stop input on the 5370B and the external >>>> clock of the 5370B. The 1 PPS from the divider feed the start input on >>>> the 5370B. >>>> >>>> 100 seconds TI 75.002 nS MIN 74.96 nS MAX 75.04 nS STD 22.5 pS >>>> 1000 seconds TI 74.931 nS MIN 74.80 nS MAX 75.04 nS STD 56.8 pS >>>> 10K seconds TI 77.5135 nS MIN 77.40 nS MAX 77.62 nS STD 35.9 pS >>>> 100K measurement in progress. >>>> >>>> I believe having STD in parts of 10-14th is fairly respectable for >>>> amateur designs.. >>>> >>>> Brian KD4FM >>>> >>>> John Ackermann N8UR wrote: >>>> >>>> >>>>> I just finished a jitter test of the first TADD-2 built on the >>>>> production circuit board. >>>>> >>>>> The configuration was somewhat optimized from what I used for the >>>>> earlier tests. >>>>> >>>>> A single 10 MHz source was daisy-chained to the TADD-2 input, to the >>>>> 5370B external reference input, and to the 5370B STOP channel. The 1 >>>>> PPS output from the TADD-2 was connected to the 5370B START channel. >>>>> Thus any reference jitter shouldn't be common-mode, and using the >>>>> reference clock on the STOP channel avoids the need for a second >>>>> divider, and ensures that the time interval is small (always less than >>>>> 100 ns; in this case, about 90 ns). >>>>> >>>>> For a 10,000 sample run, the standard deviation was 12.1 picoseconds, >>>>> and the peak-to-peak variation was 70 picoseconds. Based on experiments >>>>> I ran a few years ago, I think this is pretty much the noise floor of >>>>> the 5370B and the divider could be better than this. >>>>> >>>>> John >>>>> >>>>> _______________________________________________ >>>>> time-nuts mailing list -- time-nuts at febo.com >>>>> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >>>>> and follow the instructions there. >>>>> >>>>> >>>>> >>>>> >>>> _______________________________________________ >>>> time-nuts mailing list -- time-nuts at febo.com >>>> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >>>> and follow the instructions there. >>>> >>>> >>> _______________________________________________ >>> time-nuts mailing list -- time-nuts at febo.com >>> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >>> and follow the instructions there. >>> >>> >>> >> _______________________________________________ >> time-nuts mailing list -- time-nuts at febo.com >> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. >> > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > From bruce.griffiths at xtra.co.nz Sat Apr 4 23:30:28 2009 From: bruce.griffiths at xtra.co.nz (Bruce Griffiths) Date: Sun, 05 Apr 2009 11:30:28 +1200 Subject: [time-nuts] Updated Divider Jitter Results - 74HC390 In-Reply-To: <49D7E786.3060903@febo.com> References: <49D68734.3020900@febo.com> <49D7C0AA.6060708@gmail.com> <49D7C6B7.1090801@febo.com> <49D7D30E.40208@xtra.co.nz> <49D7E786.3060903@febo.com> Message-ID: <49D7ED94.6080304@xtra.co.nz> John I can't find a spec for the Wavecrest 2075 input amplifier/trigger circuit noise but it could be as high as 1mV rms given its 800MHz+ input bandwidth. If the noise is 1mV rms: Then an input signal slew rate of 1V/ns is required to keep the jitter contribution of the amplifier input noise below 1ps rms. A 3 stage limiter cascade with an overall slope gain of about 12x can be used to increase the slew rate of a 10MHz 2V pp input signal to 1V/ns. With an appropriate distribution of limiter stage gain and bandwidth, the jitter contribution due to limiter noise and Wavecrest input noise can be held below1.2ps rms. The jitter contribution due to amplifier input noise with such an input signal connected directly to the Wavecrest input would be about 16ps rms. Bruce John Ackermann N8UR wrote: > I can do that, but was hoping to isolate the performance of the Wenzel > waveform conversion circuit. An initial test showed jitter of about 25 > ps -- which is about the same as for the whole divider chain, so you may > be correct that the input amplifiers are limiting. But also, I was > doing a quick and dirty setup without paying much attention to how the > signal was coupled. I'll be able to improve on that in tomorrow's > experiments. > > John > ---- > > Bruce Griffiths said the following on 04/04/2009 05:37 PM: > >> John >> >> With a slow slew rate input signal like a 10MHz sinewave the Wavecrest >> jitter due to the noise of its wideband input amplifiers may be quite high. >> >> So it may be better to measure the relative jitter of 2 dividers. >> >> Bruce >> >> John Ackermann N8UR wrote: >> >>> Hi Brian -- >>> >>> It's good to collect this data; thanks. It's interesting that your std >>> dev in the first test seems to increase significantly with the number of >>> samples; I haven't seen that kind of scaling here (1K sample and 10k >>> sample turned in very similar std dev). From what Poul-Henning said >>> earlier, your first run may suffer the same distortion as my data at the >>> bottom of this thread. >>> >>> I just finished rerunning the TADD-2 test using a Wavecrest DTS-2075 >>> (the first real use I've had for that box!) and with 1 PPS input on the >>> start channel, 10 MHz from the same source on the stop channel, and 10K >>> samples, I got 22.0 ps of jitter, and a 92 ps min/max range. (As far as >>> I can determine, the Wavecrest doesn't allow you to use an external >>> reference, and its internal reference runs at 100 MHz so it probably >>> wouldn't be useful in this measurement.) >>> >>> That's consistent with what I measured earlier with the 5370B when I >>> didn't have the reference and the inputs in coherence. It appears that >>> the test below, where I used the same reference for *everything* >>> triggered the problem that Poul-Henning warned about, so those results >>> should be disregarded. >>> >>> While I haven't done any testing to validate this, I think the complaint >>> about the 74HC390 dividers isn't so much their jitter in normal use, but >>> the tempco problems the cascaded stages can cause. If you can do it, it >>> would be interesting to measure the phase change over temperature -- >>> I've done a preliminary experiment on that for the TADD-2, but plan to >>> rerun it with much better measurement technique. >>> >>> I'm also hoping to do a jitter and tempco test of the Wenzel input >>> conditioning circuit by itself. I really like that circuit for its wide >>> input amplitude range. >>> >>> John >>> ---- >>> Brian Kirby said the following on 04/04/2009 04:18 PM: >>> >>> >>>> I will report some results on a asynchronous divider, which I basically >>>> copied from Dr. Thomas Clark's designs, which everybody likes to report >>>> as a bad design. >>>> >>>> The 10 MHz input signal is coupled thru a resistor and capacitor. On >>>> the other side of the capacitor is the resistive divider that is tied to >>>> Vcc and ground - it biases the signal to 2.5 volts, which is feed to the >>>> input of the 74HC132. The output of the 74HC132 feeds several 74HC390s >>>> until it becomes a buffered 1 pulse per second signal. I also have >>>> buffered 5 MHz and 1 MHz outputs. The other 3/4 of the 74HC132 are used >>>> to externally synchronize the 74HC390s. >>>> >>>> I used the Thunderbolt as the source of 10 MHz and it was feed to the >>>> divider, and the stop input on the HP5370B. The 5370B was run on >>>> internal clock. The 1 PPS from the divider feed the start input on the >>>> 5370B. >>>> >>>> 100 seconds TI 79.865 nS MIN 79.80 nS MAX 79.98 nS STD 36.4 pS. >>>> 1000 seconds TI 79.831 nS MIN 79.71 nS MAX 80.00 nS STD 49.9 pS >>>> 10K seconds TI 80.1552 nS MIN 79.79 nS MAX 80.88 nS STD 271 pS >>>> 100K planned >>>> >>>> Also a second test, using the Thunderbolt as a source of 10 MHz and it >>>> was feed to the divider, the stop input on the 5370B and the external >>>> clock of the 5370B. The 1 PPS from the divider feed the start input on >>>> the 5370B. >>>> >>>> 100 seconds TI 75.002 nS MIN 74.96 nS MAX 75.04 nS STD 22.5 pS >>>> 1000 seconds TI 74.931 nS MIN 74.80 nS MAX 75.04 nS STD 56.8 pS >>>> 10K seconds TI 77.5135 nS MIN 77.40 nS MAX 77.62 nS STD 35.9 pS >>>> 100K measurement in progress. >>>> >>>> I believe having STD in parts of 10-14th is fairly respectable for >>>> amateur designs.. >>>> >>>> Brian KD4FM >>>> >>>> John Ackermann N8UR wrote: >>>> >>>> >>>>> I just finished a jitter test of the first TADD-2 built on the >>>>> production circuit board. >>>>> >>>>> The configuration was somewhat optimized from what I used for the >>>>> earlier tests. >>>>> >>>>> A single 10 MHz source was daisy-chained to the TADD-2 input, to the >>>>> 5370B external reference input, and to the 5370B STOP channel. The 1 >>>>> PPS output from the TADD-2 was connected to the 5370B START channel. >>>>> Thus any reference jitter shouldn't be common-mode, and using the >>>>> reference clock on the STOP channel avoids the need for a second >>>>> divider, and ensures that the time interval is small (always less than >>>>> 100 ns; in this case, about 90 ns). >>>>> >>>>> For a 10,000 sample run, the standard deviation was 12.1 picoseconds, >>>>> and the peak-to-peak variation was 70 picoseconds. Based on experiments >>>>> I ran a few years ago, I think this is pretty much the noise floor of >>>>> the 5370B and the divider could be better than this. >>>>> >>>>> John >>>>> >>>>> _______________________________________________ >>>>> time-nuts mailing list -- time-nuts at febo.com >>>>> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >>>>> and follow the instructions there. >>>>> >>>>> >>>>> >>>>> >>>> _______________________________________________ >>>> time-nuts mailing list -- time-nuts at febo.com >>>> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >>>> and follow the instructions there. >>>> >>>> >>> _______________________________________________ >>> time-nuts mailing list -- time-nuts at febo.com >>> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >>> and follow the instructions there. >>> >>> >>> >> _______________________________________________ >> time-nuts mailing list -- time-nuts at febo.com >> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. >> > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > From jra at febo.com Sun Apr 5 00:09:28 2009 From: jra at febo.com (John Ackermann N8UR) Date: Sat, 04 Apr 2009 20:09:28 -0400 Subject: [time-nuts] Updated Divider Jitter Results - 74HC390 In-Reply-To: <49D7ED94.6080304@xtra.co.nz> References: <49D68734.3020900@febo.com> <49D7C0AA.6060708@gmail.com> <49D7C6B7.1090801@febo.com> <49D7D30E.40208@xtra.co.nz> <49D7E786.3060903@febo.com> <49D7ED94.6080304@xtra.co.nz> Message-ID: <49D7F6B8.6000701@febo.com> Bruce Griffiths said the following on 04/04/2009 07:30 PM: > John > > I can't find a spec for the Wavecrest 2075 input amplifier/trigger > circuit noise but it could be as high as 1mV rms given its 800MHz+ input > bandwidth. > > If the noise is 1mV rms: > Then an input signal slew rate of 1V/ns is required to keep the jitter > contribution of the amplifier input noise below 1ps rms. > A 3 stage limiter cascade with an overall slope gain of about 12x can be > used to increase the slew rate of a 10MHz 2V pp input signal to 1V/ns. > With an appropriate distribution of limiter stage gain and bandwidth, > the jitter contribution due to limiter noise and Wavecrest input noise > can be held below1.2ps rms. > The jitter contribution due to amplifier input noise with such an input > signal connected directly to the Wavecrest input would be about 16ps rms. Bruce -- A simple experiment just verified your hunch that input amp noise is a limiting factor. Using the Wavecrest in time interval ("total propagation delay") mode with signal going into channel 1, then through a 4 foot cable into channel 2 to generate about 6 ns of delay (with a tee at channel 2 providing a 50 ohm load): A 10 MHz sine wave at 1.0V P-P shows a 100K sample jitter of 23 ps. A 10 MHz pulse train at 1.0V P-P from a 5359A Time Synthesizer (with < 5 ns transition time) shows a 100K sample jitter of 4 ps. I think I missed the point of your suggestion a couple of messages ago, but I get it now -- to measure the input circuit performance, I probably need to use two input circuits, one fed to start and the other to stop, so the Wavecrest can get a better slew rate to deal with, then divide by sqrt(2). That'll be part of tomorrow's experiments... John From bruce.griffiths at xtra.co.nz Sun Apr 5 00:42:28 2009 From: bruce.griffiths at xtra.co.nz (Bruce Griffiths) Date: Sun, 05 Apr 2009 12:42:28 +1200 Subject: [time-nuts] Updated Divider Jitter Results - 74HC390 In-Reply-To: <49D7F6B8.6000701@febo.com> References: <49D68734.3020900@febo.com> <49D7C0AA.6060708@gmail.com> <49D7C6B7.1090801@febo.com> <49D7D30E.40208@xtra.co.nz> <49D7E786.3060903@febo.com> <49D7ED94.6080304@xtra.co.nz> <49D7F6B8.6000701@febo.com> Message-ID: <49D7FE74.5030708@xtra.co.nz> John The parameters for a simple model for the Wavecrest input jitter can be derived from your measurements as For each channel: Jitter = SQRT[8E-24 + 2.53E-7/(S*S)] Where S is the input signal slew rate at the trigger threshold Input noise ~ 503 uV rms. (2.53E-7 = square of input rms noise) 8E-24 = square of Wavecrest input channel intrinsic jitter (2.8ps rms). Bruce John Ackermann N8UR wrote: > Bruce Griffiths said the following on 04/04/2009 07:30 PM: > >> John >> >> I can't find a spec for the Wavecrest 2075 input amplifier/trigger >> circuit noise but it could be as high as 1mV rms given its 800MHz+ input >> bandwidth. >> >> If the noise is 1mV rms: >> Then an input signal slew rate of 1V/ns is required to keep the jitter >> contribution of the amplifier input noise below 1ps rms. >> A 3 stage limiter cascade with an overall slope gain of about 12x can be >> used to increase the slew rate of a 10MHz 2V pp input signal to 1V/ns. >> With an appropriate distribution of limiter stage gain and bandwidth, >> the jitter contribution due to limiter noise and Wavecrest input noise >> can be held below1.2ps rms. >> The jitter contribution due to amplifier input noise with such an input >> signal connected directly to the Wavecrest input would be about 16ps rms. >> > > Bruce -- > > A simple experiment just verified your hunch that input amp noise is a > limiting factor. Using the Wavecrest in time interval ("total > propagation delay") mode with signal going into channel 1, then through > a 4 foot cable into channel 2 to generate about 6 ns of delay (with a > tee at channel 2 providing a 50 ohm load): > > A 10 MHz sine wave at 1.0V P-P shows a 100K sample jitter of 23 ps. > > A 10 MHz pulse train at 1.0V P-P from a 5359A Time Synthesizer (with < 5 > ns transition time) shows a 100K sample jitter of 4 ps. > > I think I missed the point of your suggestion a couple of messages ago, > but I get it now -- to measure the input circuit performance, I probably > need to use two input circuits, one fed to start and the other to stop, > so the Wavecrest can get a better slew rate to deal with, then divide by > sqrt(2). That'll be part of tomorrow's experiments... > > John > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > From peterawson at earthlink.net Sun Apr 5 00:42:39 2009 From: peterawson at earthlink.net (Pete) Date: Sat, 4 Apr 2009 18:42:39 -0600 Subject: [time-nuts] Updated Divider Jitter Results - 74HC390 References: <49D68734.3020900@febo.com> <49D7C0AA.6060708@gmail.com> <49D7C6B7.1090801@febo.com> <49D7D30E.40208@xtra.co.nz><49D7E786.3060903@febo.com> <49D7ED94.6080304@xtra.co.nz> Message-ID: <90C98A701B1C4CC4B7B61642EE8AEAC2@BASE1> Bruce, Your analysis conforms closely to measured results on my DTS-2075. With the cleanest 10MHz source I have, at 2Vp-p, the DTS-2075 jitter reading is 11.4ps rms. Running this number back into equivalent input noise yields 716uV rms. The DTS-2075 input spec (assumed to be for -3dB response) is 700MHz, which should be nearly 900MHz equivalent noise bandwidth. These numbers are all reasonable & serve to demonstrate the need for low noise signal conditioning. Pete Rawson From bruce.griffiths at xtra.co.nz Sun Apr 5 01:09:35 2009 From: bruce.griffiths at xtra.co.nz (Bruce Griffiths) Date: Sun, 05 Apr 2009 13:09:35 +1200 Subject: [time-nuts] Updated Divider Jitter Results - 74HC390 In-Reply-To: <49D7FE74.5030708@xtra.co.nz> References: <49D68734.3020900@febo.com> <49D7C0AA.6060708@gmail.com> <49D7C6B7.1090801@febo.com> <49D7D30E.40208@xtra.co.nz> <49D7E786.3060903@febo.com> <49D7ED94.6080304@xtra.co.nz> <49D7F6B8.6000701@febo.com> <49D7FE74.5030708@xtra.co.nz> Message-ID: <49D804CF.3080106@xtra.co.nz> For start stop measurements with the same slew rate signal at each input channel Total jitter = SQRT [16E-24 + 5.06E-7/(S*S)] where the effective (combined) input noise is 711 uV rms. and the intrinsic jitter is 4ps rms. Bruce Bruce Griffiths wrote: > John > > The parameters for a simple model for the Wavecrest input jitter can be > derived from your measurements as > > For each channel: > Jitter = SQRT[8E-24 + 2.53E-7/(S*S)] > Where S is the input signal slew rate at the trigger threshold > > Input noise ~ 503 uV rms. (2.53E-7 = square of input rms noise) > 8E-24 = square of Wavecrest input channel intrinsic jitter (2.8ps rms). > > Bruce > > John Ackermann N8UR wrote: > >> Bruce Griffiths said the following on 04/04/2009 07:30 PM: >> >> >>> John >>> >>> I can't find a spec for the Wavecrest 2075 input amplifier/trigger >>> circuit noise but it could be as high as 1mV rms given its 800MHz+ input >>> bandwidth. >>> >>> If the noise is 1mV rms: >>> Then an input signal slew rate of 1V/ns is required to keep the jitter >>> contribution of the amplifier input noise below 1ps rms. >>> A 3 stage limiter cascade with an overall slope gain of about 12x can be >>> used to increase the slew rate of a 10MHz 2V pp input signal to 1V/ns. >>> With an appropriate distribution of limiter stage gain and bandwidth, >>> the jitter contribution due to limiter noise and Wavecrest input noise >>> can be held below1.2ps rms. >>> The jitter contribution due to amplifier input noise with such an input >>> signal connected directly to the Wavecrest input would be about 16ps rms. >>> >>> >> Bruce -- >> >> A simple experiment just verified your hunch that input amp noise is a >> limiting factor. Using the Wavecrest in time interval ("total >> propagation delay") mode with signal going into channel 1, then through >> a 4 foot cable into channel 2 to generate about 6 ns of delay (with a >> tee at channel 2 providing a 50 ohm load): >> >> A 10 MHz sine wave at 1.0V P-P shows a 100K sample jitter of 23 ps. >> >> A 10 MHz pulse train at 1.0V P-P from a 5359A Time Synthesizer (with < 5 >> ns transition time) shows a 100K sample jitter of 4 ps. >> >> I think I missed the point of your suggestion a couple of messages ago, >> but I get it now -- to measure the input circuit performance, I probably >> need to use two input circuits, one fed to start and the other to stop, >> so the Wavecrest can get a better slew rate to deal with, then divide by >> sqrt(2). That'll be part of tomorrow's experiments... >> >> John >> >> >> _______________________________________________ >> time-nuts mailing list -- time-nuts at febo.com >> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. >> >> >> > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > From SAIDJACK at aol.com Sun Apr 5 03:37:59 2009 From: SAIDJACK at aol.com (SAIDJACK at aol.com) Date: Sat, 4 Apr 2009 23:37:59 EDT Subject: [time-nuts] Updated Divider Jitter Results - 74HC390 Message-ID: Hello Pete, Bruce, I can confirm that the Wavecrest is sensitive to edge rise-time. It was not designed to measure sine waves. With a 10MHz sine wave from a Fury GPSDO as the source I get 8 - 10ps rms jitter. That exact same signal run through an NC7SZ04 buffer prior to feeding it into the DTS-2075, then scaled to the +/-1.1Vpeak input of the DTS-2075 yields jitter below the units' noise floor (~3.2ps rms) on a good OCXO. I also have a DTS-2070C that performs slightly better - about 2.9ps rms. bye, Said In a message dated 4/4/2009 17:43:23 Pacific Daylight Time, peterawson at earthlink.net writes: Bruce, Your analysis conforms closely to measured results on my DTS-2075. With the cleanest 10MHz source I have, at 2Vp-p, the DTS-2075 jitter reading is 11.4ps rms. Running this number back into equivalent input noise yields 716uV rms. The DTS-2075 input spec (assumed to be for -3dB response) is 700MHz, which should be nearly 900MHz equivalent noise bandwidth. These numbers are all reasonable & serve to demonstrate the need for low noise signal conditioning. Pete Rawson From EWKehren at aol.com Sun Apr 5 14:25:50 2009 From: EWKehren at aol.com (EWKehren at aol.com) Date: Sun, 5 Apr 2009 10:25:50 EDT Subject: [time-nuts] time-nuts Frequency Divider Message-ID: Thank you Bruce for your valuable insight. In the past I did spend time on Cesium Standards and with valuable inputs from Corby concerning the FTS tube interface I converted a HP 5062C to a Standard using a FTS tube. I also made other changes like changing to a 10 MHz 10811, the Master Clock 1 PPS assembly and the 1 PPS Advance Generator assembly. It has served me well over the last ten years. Only recently did I get back into the game with more focus on oscillators, mainly because of the vast accumulation of units and with Corby's help am looking at oscillators and try to get good short term as well as long term performance. This is all part of a downsizing effort. Way to much stuff. I only recently joined time-nuts and follow the dialog. It is clear that there is a vast knowledge base that could and probably is used to develop solutions in this arena and a candidate could be a general purpose divider chain that addresses most if not all the issues. Over forty years ago in my college years I did a counter using Motorola MC 790 series and presented a student paper on that subject at IEEE. Did some more work at home at TI that you can find in old TI Opto Electronics Catalogs. In this case my contribution would be limited to laying out a PC board. Bert In a message dated 4/4/2009 7:09:00 P.M. Eastern Daylight Time, bruce.griffiths at xtra.co.nz writes: Bert Unless you can provide a set of specifications it isn't possible to recommend any particular design as being fit for the application. For the purposes of comparing a divider generated PPS signal against a GPS derived PPS output almost any input clock shaper should have adequate performance. For such applications achieving a sufficiently low jitter PPS output can be achieved using almost any divider chain. However ensuring a low clock to output propagation delay tempco is entirely another matter and either requires a fully synchronous divider or using an output retiming synchroniser. If multiple ripple clocking is used in the divider then a 3 stage synchroniser that first resynchronises to 1MHz, then 2MHz and finally to 10MHz may be required. If the lower frequency dividers in the cascade use something as slow as 4000 series CMOS then even more synchroniser stages will be required. If we consider minimising the trigger jitter of an SR620 driven from say a 2V pp 10MHz sine wave, then a single stage limiter with a slope gain of about 5x and a bandwidth of about 50MHz will ensure that the trigger circuit jitter due to its linter and trigger circuit input noise is reduced to below 2ps rms with a low noise input source. If a 2 stage limiter cascade with the same slope gain is used the jitter due to limiter and trigger circuit input noise can be reduced to below 1.3ps rms with a low noise source if the low pass filter time constant at the output of each stage is chosen appropriately. If the output of a divider is to be used as a low phase noise source then picosecond or even subpicosecond jitter is desirable. For the ultimate performance in such applications a regenerative divider can have a much lower output phase noise than a digital divider. Injection locked dividers are one form of regenerative divider complete with integrated mixer and filter, however conjugate regenerative dividers using a diode mixer and low phase noise amplifier etc will have lower phase noise. Bruce EWKehren at aol.com wrote: > Bruce, thank you for the info. I have never had the need or desire to get 1 > ps accuracy however in designing low noise signal sources I have always had to > battle reference oscillator noise and was often nor sure if it was the > oscillator or the input circuit. However I would like to see a recommendation as > to an attainable design. Thanks again Bert > > > In a message dated 4/4/2009 4:35:09 P.M. Eastern Daylight Time, > bruce.griffiths at xtra.co.nz writes: > > Bert > > Neither the HP5370 nor the SR620 have low enough internal jitter to > accurately characterise the intrinisic output jitter of either a 74HC04 > (~4ps) or a 74AC04 (~1ps). > Rather than just tossing together a divider from various parts though to > produce an output with low jitter its better to be able to characterise > the jitter properties (intrinsic as well as that due to logic device > input noise with a finite input signal slew rate) of various logic > families. > It is then possible to actually design a sine to logic level converter > that achieves the lowest possible output jitter for a given complexity > and specified input frequency and amplitude. > > The real problem is that one needs to accurately measure jitter of 1ps > or so. > There are few time interval counters that allow this. > One can also measure the change in noise floor when such a device is > placed in the clock input path of a high frequency ADC and thence derive > the jitter. > In principle, the output jitter of a divider can also be calculated from > the phase noise spectrum of its output. > > Bruce > > > > EWKehren at aol.com wrote: > >> Having built eight of Brooks units, my experience was that the problem was >> > > >> not with the amplifier but the way the RS F/F in the phase comparator II >> > was > >> working in some of the devices. For me they all worked in the oscillator >> > input > >> but some brands did not work properly with the GPS input. With all the >> > dialog > >> on the divider subject, is it not time to develop one design that >> > combines > >> KISS and all the collective know how? Bert Kehren WB5MZJ >> >> >> In a message dated 4/3/2009 5:17:18 P.M. Eastern Daylight Time, >> bruce.griffiths at xtra.co.nz writes: >> >> Correction: >> >> I forgot to include the intrinsic jitter of the gate in the calculations. >> See underlined corrections below. >> >> >> Bruce >> >> Bruce Griffiths wrote: >> >> >> >> >>> Magnus >>> >>> The input noise of a logic inverter or other trigger device used as a >>> clock shaper is important. >>> If we have a logic inverter device with the following characteristics: >>> >>> Input noise: 100uV rms >>> Intrinsic jitter: 1ps rms >>> >>> Then the input signal slew rate at the threshold crossing has to be >>> greater than >>> >>> 3x1E-4/1E-12 = 3E8 V/s or 300 V/us >>> >>> to ensure that the output jitter isnt increased by more than 5% from the >>> intrinsic jitter. >>> >>> With a 1.4V pk 10MHz sinewave input the maximum slew rate is ~89V/us (at >>> the zero crossing). >>> For such an input signal the output jitter will be about _1.5 ps_. >>> This increases to about _1.72ps_ if there is a threshold offset of 1V. >>> This can be reduced to about 1.05ps by amplifying the slope of the input >>> signal by ~ 3.4x. >>> >>> The intrinsic jitter (RJ. DDJ isn't important when the input signal is a >>> low distortion sinewave) of a 74AC04 inverter is about 1ps. >>> However the equivalent input noise is unknown. >>> The noise could, in principle, be determined by measuring the output >>> jitter as a function of the input signal slew rate. >>> >>> Whilst AM and other noise associated with the source can be reduced by >>> filtering, the input noise of a trigger circuit cannot (except perhaps >>> for the trigger circuits input current noise). >>> >>> Magnus Danielson wrote: >>> >>> >>> >>>> Bruce Griffiths skrev: >>>> >>>> >>>> >>>> >>>>> Ulrich >>>>> >>>>> Your experience with the SR620 illustrates the point I was making >>>>> > quite > >>>>> well. >>>>> It really does matter what you do in front of the limiter circuit built >>>>> into the counter. >>>>> A bandpass or any other filter by itself is ineffective unless the >>>>> signal is exceptionally noisy. >>>>> >>>>> By using the inverter in the 74HCT4046 you have added a low gain >>>>> > limiter > >>>>> stage the bandwidth of which is smaller than that of the SR620 input >>>>> circuit. >>>>> This has the effect of increasing the slew rate of the input signal >>>>> whilst producing an output with less jitter than the SR620 input >>>>> > circuit > >>>>> would without this low pass filtered limiter circuit (the inverter from >>>>> the 74HCT4046). The slew rate at the 74HCT4046 inverter output is >>>>> greater than that of the input signal which means that the jitter due >>>>> the counter input circuit noise is smaller than when this low gain low >>>>> bandwidth limiter isn't used. >>>>> The input circuit of the SR620 has a wide noise bandwidth (~ 470MHz >>>>> assuming a single pole response with a 300MHz 3dB high frequency >>>>> > cutoff) > >>>>> and a correspondingly high total input noise (~350uV rms). >>>>> If the slew rate of the SR 620 input signal at the trigger point the >>>>> jitter due to this noise dominates the trigger circuit output jitter. >>>>> The HP5370 time interval counter input circuit has a lower noise >>>>> bandwidth (~160MHz??) and is quieter (~ 100uV rms) than the input >>>>> circuit of the SR620 and thus the HP5370 jitter (without the 74HCT4046 >>>>> limiter) for the same 10MHz signal should be less than that of the >>>>> > SR620 > >>>>> (without the 74HCT4046 limiter). >>>>> >>>>> >>>>> >>>>> >>>> As a curiosity, there are various variants of the original 4046 which >>>> has different sensitivity on the input side... one of them has several >>>> inverters in a row to get the needed gain where as the other variant >>>> does not. This difference made a huge difference in some applications. >>>> >>>> >>>> >>>> >>>> >>> The appropriate device (one that will have the least output jitter) to >>> use will vary with the input signal zero crossing slew rate. >>> That is it depends on both the input signal frequency and amplitude. >>> >>> >>> >>> >>>>> If one uses a state of the art trigger circuit with a noise bandwidth >>>>> > of > >>>>> 1GHz or more then the total input noise will be even larger so it >>>>> becomes even more important to use an optimised cascade of limiter+ low >>>>> output pass filter stages to increase the slew rate of the counter >>>>> input trigger circuit at the trigger threshold. >>>>> Careful optimisation of the gain of each stage and the corresponding >>>>> output filter cutoff frequency for each stage is necessary to minimise >>>>> the output jitter of the counter trigger circuit. >>>>> There is also an optimum number of such stages that minimises the >>>>> trigger jitter. >>>>> >>>>> The optimisation problem for Limiter stages with gaussian wideband >>>>> > input > >>>>> noise was solved in the 1990's. >>>>> Unfortunately the optimum number of stages, associated gains and output >>>>> filter bandwidths depends on the input signal frequency and amplitude >>>>> > so > >>>>> that in general it isn't possible to use the same limiter cascade for a >>>>> wide range of signal amplitudes and frequencies and minimise the jitter >>>>> for each frequency and amplitude. >>>>> >>>>> >>>>> >>>>> >>>> Actually, you can make a cascade setup which is approaching optimum and >>>> insert signal at the stage where the signals slewrate matches the range >>>> > > >>>> for each stage. Since the gain steps is larger later in a slew rate >>>> amplifier chain, the last stages may have a little coarse slew rate >>>> range, but additional mid-range amplifiers that can act as alternative >>>> input amps could curcumvent that such that a wide range but and fairly >>>> good trigger jitter could be achieved. >>>> >>>> The comparator level is fed to whatever stage is the first stage. >>>> >>>> Such an approach could lead to much improved jitter values for lower >>>> frequency signals with associated gain in measurement accuracy. >>>> >>>> It is easy to make a pre-amplifier set that achieves this, but you want >>>> to integrate the control algorithms for automatic use. >>>> >>>> >>>> >>>> >>>> >>> That would constitute an interesting design challenge. >>> >>> >>> >>>>> Thus such circuits aren't usually employed in general purpose >>>>> > frequency > >>>>> >>>>> >> counters. >> >> >>>>> >>>>> >>>>> >>>>> >>>> Certainly true. A generic counter is usually equipped with triggers >>>> > such > >>>> that they can measure slewrate without too much difficulty. >>>> >>>> >>>> >>>> >>>> >>>>> However if the input signal frequency and amplitude are known and >>>>> > stable > >>>>> then using such a limiter filter cascade is feasible. >>>>> >>>>> >>>>> >>>>> >>>> Indeed. >>>> >>>> Cheers, >>>> Magnus >>>> >>>> _______________________________________________ >>>> time-nuts mailing list -- time-nuts at febo.com >>>> To unsubscribe, go to >>>> >>>> >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> >> >>>> and follow the instructions there. >>>> >>>> >>>> >>>> >>>> >>> Bruce >>> >>> _______________________________________________ >>> time-nuts mailing list -- time-nuts at febo.com >>> To unsubscribe, go to >>> >>> >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> >> >>> and follow the instructions there. >>> >>> >>> >>> >> _______________________________________________ >> time-nuts mailing list -- time-nuts at febo.com >> To unsubscribe, go to >> > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > >> and follow the instructions there. >> >> >> **************Worried about job security? Check out the 5 safest jobs in a >> recession. >> >> > (http://jobs.aol.com/gallery/growing-job-industries?ncid=emlcntuscare00000003) > >> _______________________________________________ >> time-nuts mailing list -- time-nuts at febo.com >> To unsubscribe, go to >> > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > >> and follow the instructions there. >> >> >> > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > > **************Worried about job security? Check out the 5 safest jobs in a > recession. > (http://jobs.aol.com/gallery/growing-job-industries?ncid=emlcntuscare00000003) > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > _______________________________________________ time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. **************Worried about job security? Check out the 5 safest jobs in a recession. (http://jobs.aol.com/gallery/growing-job-industries?ncid=emlcntuscare00000003) From david.partridge at dsl.pipex.com Sun Apr 5 15:56:01 2009 From: david.partridge at dsl.pipex.com (David C. Partridge) Date: Sun, 5 Apr 2009 16:56:01 +0100 Subject: [time-nuts] time-nuts Frequency Divider In-Reply-To: References: Message-ID: Just another reminder - this job has been done, at least no-one has come back to me and said "Dave, your divider isn't up to scratch". Cheers Dave -----Original Message----- From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On Behalf Of EWKehren at aol.com Sent: 05 April 2009 15:26 To: time-nuts at febo.com Subject: Re: [time-nuts] time-nuts Frequency Divider Thank you Bruce for your valuable insight. In the past I did spend time on Cesium Standards and with valuable inputs from Corby concerning the FTS tube interface I converted a HP 5062C to a Standard using a FTS tube. I also made other changes like changing to a 10 MHz 10811, the Master Clock 1 PPS assembly and the 1 PPS Advance Generator assembly. It has served me well over the last ten years. Only recently did I get back into the game with more focus on oscillators, mainly because of the vast accumulation of units and with Corby's help am looking at oscillators and try to get good short term as well as long term performance. This is all part of a downsizing effort. Way to much stuff. I only recently joined time-nuts and follow the dialog. It is clear that there is a vast knowledge base that could and probably is used to develop solutions in this arena and a candidate could be a general purpose divider chain that addresses most if not all the issues. Over forty years ago in my college years I did a counter using Motorola MC 790 series and presented a student paper on that subject at IEEE. Did some more work at home at TI that you can find in old TI Opto Electronics Catalogs. In this case my contribution would be limited to laying out a PC board. Bert In a message dated 4/4/2009 7:09:00 P.M. Eastern Daylight Time, bruce.griffiths at xtra.co.nz writes: Bert Unless you can provide a set of specifications it isn't possible to recommend any particular design as being fit for the application. For the purposes of comparing a divider generated PPS signal against a GPS derived PPS output almost any input clock shaper should have adequate performance. For such applications achieving a sufficiently low jitter PPS output can be achieved using almost any divider chain. However ensuring a low clock to output propagation delay tempco is entirely another matter and either requires a fully synchronous divider or using an output retiming synchroniser. If multiple ripple clocking is used in the divider then a 3 stage synchroniser that first resynchronises to 1MHz, then 2MHz and finally to 10MHz may be required. If the lower frequency dividers in the cascade use something as slow as 4000 series CMOS then even more synchroniser stages will be required. If we consider minimising the trigger jitter of an SR620 driven from say a 2V pp 10MHz sine wave, then a single stage limiter with a slope gain of about 5x and a bandwidth of about 50MHz will ensure that the trigger circuit jitter due to its linter and trigger circuit input noise is reduced to below 2ps rms with a low noise input source. If a 2 stage limiter cascade with the same slope gain is used the jitter due to limiter and trigger circuit input noise can be reduced to below 1.3ps rms with a low noise source if the low pass filter time constant at the output of each stage is chosen appropriately. If the output of a divider is to be used as a low phase noise source then picosecond or even subpicosecond jitter is desirable. For the ultimate performance in such applications a regenerative divider can have a much lower output phase noise than a digital divider. Injection locked dividers are one form of regenerative divider complete with integrated mixer and filter, however conjugate regenerative dividers using a diode mixer and low phase noise amplifier etc will have lower phase noise. Bruce EWKehren at aol.com wrote: > Bruce, thank you for the info. I have never had the need or desire to > get 1 > ps accuracy however in designing low noise signal sources I have > always had to > battle reference oscillator noise and was often nor sure if it was > the oscillator or the input circuit. However I would like to see a recommendation as > to an attainable design. Thanks again Bert > > > In a message dated 4/4/2009 4:35:09 P.M. Eastern Daylight Time, > bruce.griffiths at xtra.co.nz writes: > > Bert > > Neither the HP5370 nor the SR620 have low enough internal jitter to > accurately characterise the intrinisic output jitter of either a > 74HC04 > (~4ps) or a 74AC04 (~1ps). > Rather than just tossing together a divider from various parts > though to produce an output with low jitter its better to be able to characterise > the jitter properties (intrinsic as well as that due to logic device > input noise with a finite input signal slew rate) of various logic > families. > It is then possible to actually design a sine to logic level > converter that achieves the lowest possible output jitter for a given complexity > and specified input frequency and amplitude. > > The real problem is that one needs to accurately measure jitter of > 1ps or so. > There are few time interval counters that allow this. > One can also measure the change in noise floor when such a device is > placed in the clock input path of a high frequency ADC and thence > derive the jitter. > In principle, the output jitter of a divider can also be calculated > from the phase noise spectrum of its output. > > Bruce > > > > EWKehren at aol.com wrote: > >> Having built eight of Brooks units, my experience was that the >> problem was >> > > >> not with the amplifier but the way the RS F/F in the phase >> comparator II >> > was > >> working in some of the devices. For me they all worked in the >> oscillator >> > input > >> but some brands did not work properly with the GPS input. With all >> the >> > dialog > >> on the divider subject, is it not time to develop one design that >> > combines > >> KISS and all the collective know how? Bert Kehren WB5MZJ >> >> >> In a message dated 4/3/2009 5:17:18 P.M. Eastern Daylight Time, >> bruce.griffiths at xtra.co.nz writes: >> >> Correction: >> >> I forgot to include the intrinsic jitter of the gate in the calculations. >> See underlined corrections below. >> >> >> Bruce >> >> Bruce Griffiths wrote: >> >> >> >> >>> Magnus >>> >>> The input noise of a logic inverter or other trigger device used >>> as a clock shaper is important. >>> If we have a logic inverter device with the following characteristics: >>> >>> Input noise: 100uV rms >>> Intrinsic jitter: 1ps rms >>> >>> Then the input signal slew rate at the threshold crossing has to be >>> greater than >>> >>> 3x1E-4/1E-12 = 3E8 V/s or 300 V/us >>> >>> to ensure that the output jitter isnt increased by more than 5% >>> from the >>> intrinsic jitter. >>> >>> With a 1.4V pk 10MHz sinewave input the maximum slew rate is ~89V/us (at >>> the zero crossing). >>> For such an input signal the output jitter will be about _1.5 ps_. >>> This increases to about _1.72ps_ if there is a threshold offset of 1V. >>> This can be reduced to about 1.05ps by amplifying the slope of >>> the input >>> signal by ~ 3.4x. >>> >>> The intrinsic jitter (RJ. DDJ isn't important when the input signal is a >>> low distortion sinewave) of a 74AC04 inverter is about 1ps. >>> However the equivalent input noise is unknown. >>> The noise could, in principle, be determined by measuring the >>> output jitter as a function of the input signal slew rate. >>> >>> Whilst AM and other noise associated with the source can be >>> reduced by filtering, the input noise of a trigger circuit cannot (except perhaps >>> for the trigger circuits input current noise). >>> >>> Magnus Danielson wrote: >>> >>> >>> >>>> Bruce Griffiths skrev: >>>> >>>> >>>> >>>> >>>>> Ulrich >>>>> >>>>> Your experience with the SR620 illustrates the point I was making >>>>> > quite > >>>>> well. >>>>> It really does matter what you do in front of the limiter >>>>> circuit built >>>>> into the counter. >>>>> A bandpass or any other filter by itself is ineffective unless the >>>>> signal is exceptionally noisy. >>>>> >>>>> By using the inverter in the 74HCT4046 you have added a low >>>>> gain >>>>> > limiter > >>>>> stage the bandwidth of which is smaller than that of the SR620 input >>>>> circuit. >>>>> This has the effect of increasing the slew rate of the input signal >>>>> whilst producing an output with less jitter than the SR620 input >>>>> > circuit > >>>>> would without this low pass filtered limiter circuit (the >>>>> inverter from >>>>> the 74HCT4046). The slew rate at the 74HCT4046 inverter output is >>>>> greater than that of the input signal which means that the jitter due >>>>> the counter input circuit noise is smaller than when this low gain low >>>>> bandwidth limiter isn't used. >>>>> The input circuit of the SR620 has a wide noise bandwidth (~ 470MHz >>>>> assuming a single pole response with a 300MHz 3dB high frequency >>>>> > cutoff) > >>>>> and a correspondingly high total input noise (~350uV rms). >>>>> If the slew rate of the SR 620 input signal at the trigger point the >>>>> jitter due to this noise dominates the trigger circuit output jitter. >>>>> The HP5370 time interval counter input circuit has a lower noise >>>>> bandwidth (~160MHz??) and is quieter (~ 100uV rms) than the input >>>>> circuit of the SR620 and thus the HP5370 jitter (without the 74HCT4046 >>>>> limiter) for the same 10MHz signal should be less than that of the >>>>> > SR620 > >>>>> (without the 74HCT4046 limiter). >>>>> >>>>> >>>>> >>>>> >>>> As a curiosity, there are various variants of the original 4046 which >>>> has different sensitivity on the input side... one of them has several >>>> inverters in a row to get the needed gain where as the other variant >>>> does not. This difference made a huge difference in some applications. >>>> >>>> >>>> >>>> >>>> >>> The appropriate device (one that will have the least output jitter) to >>> use will vary with the input signal zero crossing slew rate. >>> That is it depends on both the input signal frequency and amplitude. >>> >>> >>> >>> >>>>> If one uses a state of the art trigger circuit with a noise bandwidth >>>>> > of > >>>>> 1GHz or more then the total input noise will be even larger so >>>>> it becomes even more important to use an optimised cascade of >>>>> limiter+ low >>>>> output pass filter stages to increase the slew rate of the counter >>>>> input trigger circuit at the trigger threshold. >>>>> Careful optimisation of the gain of each stage and the corresponding >>>>> output filter cutoff frequency for each stage is necessary to minimise >>>>> the output jitter of the counter trigger circuit. >>>>> There is also an optimum number of such stages that minimises the >>>>> trigger jitter. >>>>> >>>>> The optimisation problem for Limiter stages with gaussian >>>>> wideband >>>>> > input > >>>>> noise was solved in the 1990's. >>>>> Unfortunately the optimum number of stages, associated gains >>>>> and output >>>>> filter bandwidths depends on the input signal frequency and amplitude >>>>> > so > >>>>> that in general it isn't possible to use the same limiter >>>>> cascade for a >>>>> wide range of signal amplitudes and frequencies and minimise the jitter >>>>> for each frequency and amplitude. >>>>> >>>>> >>>>> >>>>> >>>> Actually, you can make a cascade setup which is approaching optimum and >>>> insert signal at the stage where the signals slewrate matches >>>> the range >>>> > > >>>> for each stage. Since the gain steps is larger later in a slew rate >>>> amplifier chain, the last stages may have a little coarse slew rate >>>> range, but additional mid-range amplifiers that can act as alternative >>>> input amps could curcumvent that such that a wide range but and fairly >>>> good trigger jitter could be achieved. >>>> >>>> The comparator level is fed to whatever stage is the first stage. >>>> >>>> Such an approach could lead to much improved jitter values for lower >>>> frequency signals with associated gain in measurement accuracy. >>>> >>>> It is easy to make a pre-amplifier set that achieves this, but >>>> you want >>>> to integrate the control algorithms for automatic use. >>>> >>>> >>>> >>>> >>>> >>> That would constitute an interesting design challenge. >>> >>> >>> >>>>> Thus such circuits aren't usually employed in general purpose >>>>> > frequency > >>>>> >>>>> >> counters. >> >> >>>>> >>>>> >>>>> >>>>> >>>> Certainly true. A generic counter is usually equipped with >>>> triggers >>>> > such > >>>> that they can measure slewrate without too much difficulty. >>>> >>>> >>>> >>>> >>>> >>>>> However if the input signal frequency and amplitude are known and >>>>> > stable > >>>>> then using such a limiter filter cascade is feasible. >>>>> >>>>> >>>>> >>>>> >>>> Indeed. >>>> >>>> Cheers, >>>> Magnus >>>> >>>> _______________________________________________ >>>> time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go >>>> to >>>> >>>> >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> >> >>>> and follow the instructions there. >>>> >>>> >>>> >>>> >>>> >>> Bruce >>> >>> _______________________________________________ >>> time-nuts mailing list -- time-nuts at febo.com >>> To unsubscribe, go to >>> >>> >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> >> >>> and follow the instructions there. >>> >>> >>> >>> >> _______________________________________________ >> time-nuts mailing list -- time-nuts at febo.com >> To unsubscribe, go to >> > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > >> and follow the instructions there. >> >> >> **************Worried about job security? Check out the 5 safest >> jobs in a >> recession. >> >> > (http://jobs.aol.com/gallery/growing-job-industries?ncid=emlcntuscare0000000 3) > >> _______________________________________________ >> time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to >> > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > >> and follow the instructions there. >> >> >> > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > > **************Worried about job security? Check out the 5 safest jobs > in a recession. > (http://jobs.aol.com/gallery/growing-job-industries?ncid=emlcntuscare0000000 3) > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > _______________________________________________ time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. **************Worried about job security? Check out the 5 safest jobs in a recession. (http://jobs.aol.com/gallery/growing-job-industries?ncid=emlcntuscare0000000 3) _______________________________________________ time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. From EWKehren at aol.com Sun Apr 5 17:10:24 2009 From: EWKehren at aol.com (EWKehren at aol.com) Date: Sun, 5 Apr 2009 13:10:24 EDT Subject: [time-nuts] time-nuts Frequency Divider Message-ID: Sorry Dave, as I said I am new to the site and am not aware of your work. Would you please supply me with the link so I can take a look. If the job is done why all the conversation? Bert In a message dated 4/5/2009 11:57:33 A.M. Eastern Daylight Time, david.partridge at dsl.pipex.com writes: Just another reminder - this job has been done, at least no-one has come back to me and said "Dave, your divider isn't up to scratch". Cheers Dave -----Original Message----- From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On Behalf Of EWKehren at aol.com Sent: 05 April 2009 15:26 To: time-nuts at febo.com Subject: Re: [time-nuts] time-nuts Frequency Divider Thank you Bruce for your valuable insight. In the past I did spend time on Cesium Standards and with valuable inputs from Corby concerning the FTS tube interface I converted a HP 5062C to a Standard using a FTS tube. I also made other changes like changing to a 10 MHz 10811, the Master Clock 1 PPS assembly and the 1 PPS Advance Generator assembly. It has served me well over the last ten years. Only recently did I get back into the game with more focus on oscillators, mainly because of the vast accumulation of units and with Corby's help am looking at oscillators and try to get good short term as well as long term performance. This is all part of a downsizing effort. Way to much stuff. I only recently joined time-nuts and follow the dialog. It is clear that there is a vast knowledge base that could and probably is used to develop solutions in this arena and a candidate could be a general purpose divider chain that addresses most if not all the issues. Over forty years ago in my college years I did a counter using Motorola MC 790 series and presented a student paper on that subject at IEEE. Did some more work at home at TI that you can find in old TI Opto Electronics Catalogs. In this case my contribution would be limited to laying out a PC board. Bert In a message dated 4/4/2009 7:09:00 P.M. Eastern Daylight Time, bruce.griffiths at xtra.co.nz writes: Bert Unless you can provide a set of specifications it isn't possible to recommend any particular design as being fit for the application. For the purposes of comparing a divider generated PPS signal against a GPS derived PPS output almost any input clock shaper should have adequate performance. For such applications achieving a sufficiently low jitter PPS output can be achieved using almost any divider chain. However ensuring a low clock to output propagation delay tempco is entirely another matter and either requires a fully synchronous divider or using an output retiming synchroniser. If multiple ripple clocking is used in the divider then a 3 stage synchroniser that first resynchronises to 1MHz, then 2MHz and finally to 10MHz may be required. If the lower frequency dividers in the cascade use something as slow as 4000 series CMOS then even more synchroniser stages will be required. If we consider minimising the trigger jitter of an SR620 driven from say a 2V pp 10MHz sine wave, then a single stage limiter with a slope gain of about 5x and a bandwidth of about 50MHz will ensure that the trigger circuit jitter due to its linter and trigger circuit input noise is reduced to below 2ps rms with a low noise input source. If a 2 stage limiter cascade with the same slope gain is used the jitter due to limiter and trigger circuit input noise can be reduced to below 1.3ps rms with a low noise source if the low pass filter time constant at the output of each stage is chosen appropriately. If the output of a divider is to be used as a low phase noise source then picosecond or even subpicosecond jitter is desirable. For the ultimate performance in such applications a regenerative divider can have a much lower output phase noise than a digital divider. Injection locked dividers are one form of regenerative divider complete with integrated mixer and filter, however conjugate regenerative dividers using a diode mixer and low phase noise amplifier etc will have lower phase noise. Bruce EWKehren at aol.com wrote: > Bruce, thank you for the info. I have never had the need or desire to > get 1 > ps accuracy however in designing low noise signal sources I have > always had to > battle reference oscillator noise and was often nor sure if it was > the oscillator or the input circuit. However I would like to see a recommendation as > to an attainable design. Thanks again Bert > > > In a message dated 4/4/2009 4:35:09 P.M. Eastern Daylight Time, > bruce.griffiths at xtra.co.nz writes: > > Bert > > Neither the HP5370 nor the SR620 have low enough internal jitter to > accurately characterise the intrinisic output jitter of either a > 74HC04 > (~4ps) or a 74AC04 (~1ps). > Rather than just tossing together a divider from various parts > though to produce an output with low jitter its better to be able to characterise > the jitter properties (intrinsic as well as that due to logic device > input noise with a finite input signal slew rate) of various logic > families. > It is then possible to actually design a sine to logic level > converter that achieves the lowest possible output jitter for a given complexity > and specified input frequency and amplitude. > > The real problem is that one needs to accurately measure jitter of > 1ps or so. > There are few time interval counters that allow this. > One can also measure the change in noise floor when such a device is > placed in the clock input path of a high frequency ADC and thence > derive the jitter. > In principle, the output jitter of a divider can also be calculated > from the phase noise spectrum of its output. > > Bruce > > > > EWKehren at aol.com wrote: > >> Having built eight of Brooks units, my experience was that the >> problem was >> > > >> not with the amplifier but the way the RS F/F in the phase >> comparator II >> > was > >> working in some of the devices. For me they all worked in the >> oscillator >> > input > >> but some brands did not work properly with the GPS input. With all >> the >> > dialog > >> on the divider subject, is it not time to develop one design that >> > combines > >> KISS and all the collective know how? Bert Kehren WB5MZJ >> >> >> In a message dated 4/3/2009 5:17:18 P.M. Eastern Daylight Time, >> bruce.griffiths at xtra.co.nz writes: >> >> Correction: >> >> I forgot to include the intrinsic jitter of the gate in the calculations. >> See underlined corrections below. >> >> >> Bruce >> >> Bruce Griffiths wrote: >> >> >> >> >>> Magnus >>> >>> The input noise of a logic inverter or other trigger device used >>> as a clock shaper is important. >>> If we have a logic inverter device with the following characteristics: >>> >>> Input noise: 100uV rms >>> Intrinsic jitter: 1ps rms >>> >>> Then the input signal slew rate at the threshold crossing has to be >>> greater than >>> >>> 3x1E-4/1E-12 = 3E8 V/s or 300 V/us >>> >>> to ensure that the output jitter isnt increased by more than 5% >>> from the >>> intrinsic jitter. >>> >>> With a 1.4V pk 10MHz sinewave input the maximum slew rate is ~89V/us (at >>> the zero crossing). >>> For such an input signal the output jitter will be about _1.5 ps_. >>> This increases to about _1.72ps_ if there is a threshold offset of 1V. >>> This can be reduced to about 1.05ps by amplifying the slope of >>> the input >>> signal by ~ 3.4x. >>> >>> The intrinsic jitter (RJ. DDJ isn't important when the input signal is a >>> low distortion sinewave) of a 74AC04 inverter is about 1ps. >>> However the equivalent input noise is unknown. >>> The noise could, in principle, be determined by measuring the >>> output jitter as a function of the input signal slew rate. >>> >>> Whilst AM and other noise associated with the source can be >>> reduced by filtering, the input noise of a trigger circuit cannot (except perhaps >>> for the trigger circuits input current noise). >>> >>> Magnus Danielson wrote: >>> >>> >>> >>>> Bruce Griffiths skrev: >>>> >>>> >>>> >>>> >>>>> Ulrich >>>>> >>>>> Your experience with the SR620 illustrates the point I was making >>>>> > quite > >>>>> well. >>>>> It really does matter what you do in front of the limiter >>>>> circuit built >>>>> into the counter. >>>>> A bandpass or any other filter by itself is ineffective unless the >>>>> signal is exceptionally noisy. >>>>> >>>>> By using the inverter in the 74HCT4046 you have added a low >>>>> gain >>>>> > limiter > >>>>> stage the bandwidth of which is smaller than that of the SR620 input >>>>> circuit. >>>>> This has the effect of increasing the slew rate of the input signal >>>>> whilst producing an output with less jitter than the SR620 input >>>>> > circuit > >>>>> would without this low pass filtered limiter circuit (the >>>>> inverter from >>>>> the 74HCT4046). The slew rate at the 74HCT4046 inverter output is >>>>> greater than that of the input signal which means that the jitter due >>>>> the counter input circuit noise is smaller than when this low gain low >>>>> bandwidth limiter isn't used. >>>>> The input circuit of the SR620 has a wide noise bandwidth (~ 470MHz >>>>> assuming a single pole response with a 300MHz 3dB high frequency >>>>> > cutoff) > >>>>> and a correspondingly high total input noise (~350uV rms). >>>>> If the slew rate of the SR 620 input signal at the trigger point the >>>>> jitter due to this noise dominates the trigger circuit output jitter. >>>>> The HP5370 time interval counter input circuit has a lower noise >>>>> bandwidth (~160MHz??) and is quieter (~ 100uV rms) than the input >>>>> circuit of the SR620 and thus the HP5370 jitter (without the 74HCT4046 >>>>> limiter) for the same 10MHz signal should be less than that of the >>>>> > SR620 > >>>>> (without the 74HCT4046 limiter). >>>>> >>>>> >>>>> >>>>> >>>> As a curiosity, there are various variants of the original 4046 which >>>> has different sensitivity on the input side... one of them has several >>>> inverters in a row to get the needed gain where as the other variant >>>> does not. This difference made a huge difference in some applications. >>>> >>>> >>>> >>>> >>>> >>> The appropriate device (one that will have the least output jitter) to >>> use will vary with the input signal zero crossing slew rate. >>> That is it depends on both the input signal frequency and amplitude. >>> >>> >>> >>> >>>>> If one uses a state of the art trigger circuit with a noise bandwidth >>>>> > of > >>>>> 1GHz or more then the total input noise will be even larger so >>>>> it becomes even more important to use an optimised cascade of >>>>> limiter+ low >>>>> output pass filter stages to increase the slew rate of the counter >>>>> input trigger circuit at the trigger threshold. >>>>> Careful optimisation of the gain of each stage and the corresponding >>>>> output filter cutoff frequency for each stage is necessary to minimise >>>>> the output jitter of the counter trigger circuit. >>>>> There is also an optimum number of such stages that minimises the >>>>> trigger jitter. >>>>> >>>>> The optimisation problem for Limiter stages with gaussian >>>>> wideband >>>>> > input > >>>>> noise was solved in the 1990's. >>>>> Unfortunately the optimum number of stages, associated gains >>>>> and output >>>>> filter bandwidths depends on the input signal frequency and amplitude >>>>> > so > >>>>> that in general it isn't possible to use the same limiter >>>>> cascade for a >>>>> wide range of signal amplitudes and frequencies and minimise the jitter >>>>> for each frequency and amplitude. >>>>> >>>>> >>>>> >>>>> >>>> Actually, you can make a cascade setup which is approaching optimum and >>>> insert signal at the stage where the signals slewrate matches >>>> the range >>>> > > >>>> for each stage. Since the gain steps is larger later in a slew rate >>>> amplifier chain, the last stages may have a little coarse slew rate >>>> range, but additional mid-range amplifiers that can act as alternative >>>> input amps could curcumvent that such that a wide range but and fairly >>>> good trigger jitter could be achieved. >>>> >>>> The comparator level is fed to whatever stage is the first stage. >>>> >>>> Such an approach could lead to much improved jitter values for lower >>>> frequency signals with associated gain in measurement accuracy. >>>> >>>> It is easy to make a pre-amplifier set that achieves this, but >>>> you want >>>> to integrate the control algorithms for automatic use. >>>> >>>> >>>> >>>> >>>> >>> That would constitute an interesting design challenge. >>> >>> >>> >>>>> Thus such circuits aren't usually employed in general purpose >>>>> > frequency > >>>>> >>>>> >> counters. >> >> >>>>> >>>>> >>>>> >>>>> >>>> Certainly true. A generic counter is usually equipped with >>>> triggers >>>> > such > >>>> that they can measure slewrate without too much difficulty. >>>> >>>> >>>> >>>> >>>> >>>>> However if the input signal frequency and amplitude are known and >>>>> > stable > >>>>> then using such a limiter filter cascade is feasible. >>>>> >>>>> >>>>> >>>>> >>>> Indeed. >>>> >>>> Cheers, >>>> Magnus >>>> >>>> _______________________________________________ >>>> time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go >>>> to >>>> >>>> >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> >> >>>> and follow the instructions there. >>>> >>>> >>>> >>>> >>>> >>> Bruce >>> >>> _______________________________________________ >>> time-nuts mailing list -- time-nuts at febo.com >>> To unsubscribe, go to >>> >>> >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> >> >>> and follow the instructions there. >>> >>> >>> >>> >> _______________________________________________ >> time-nuts mailing list -- time-nuts at febo.com >> To unsubscribe, go to >> > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > >> and follow the instructions there. >> >> >> **************Worried about job security? Check out the 5 safest >> jobs in a >> recession. >> >> > (http://jobs.aol.com/gallery/growing-job-industries?ncid=emlcntuscare0000000 3) > >> _______________________________________________ >> time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to >> > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > >> and follow the instructions there. >> >> >> > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > > **************Worried about job security? Check out the 5 safest jobs > in a recession. > (http://jobs.aol.com/gallery/growing-job-industries?ncid=emlcntuscare0000000 3) > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > _______________________________________________ time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. **************Worried about job security? Check out the 5 safest jobs in a recession. (http://jobs.aol.com/gallery/growing-job-industries?ncid=emlcntuscare0000000 3) _______________________________________________ time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. _______________________________________________ time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. **************Worried about job security? Check out the 5 safest jobs in a recession. (http://jobs.aol.com/gallery/growing-job-industries?ncid=emlcntuscare00000003) From sam at canardpc.com Mon Apr 6 13:59:49 2009 From: sam at canardpc.com (Samuel D. [x86/CPC]) Date: Mon, 6 Apr 2009 15:59:49 +0200 Subject: [time-nuts] Replacement High-Speed AOP for Distribution Amplifier Message-ID: <00b101c9b6bf$f36103c0$da230b40$@com> Hi there, I'm working on a new GPS-Disciplined Rubidium Frequency Standard and I'm now designing the distribution amplifier stage. There is many schematics everywhere on the Internet, the most famous is the TADD-1 reviewed by the not-less-famous TVB. Almost all of them use high-speed Op Amps originally designed for video processing. The most common AOP are the MAX477 (used in TADD-1) and the MAX4135. Unfortunately, both of them are now obsolete and will be discontinued soon. I checked Digikey and Farnell, but those parts are not available anymore, so, I'm looking for an equivalent (or better!) replacement. Any hints ? PS : A French member of that list, Daniel, contacted me some weeks ago. Due to a corrupted Outlook file, I lost your contact and wasn't able to keep in touch with you. Please send me an email if you read this ;) --------------------- Samuel DEMEULEMEESTER Presse Non Stop - Canard PC http://www.canardpc.com Tel : +33.6.13.73.4003 MSN : sam at x86.fr From lasse.moell at swipnet.se Mon Apr 6 15:23:18 2009 From: lasse.moell at swipnet.se (Lasse) Date: Mon, 06 Apr 2009 17:23:18 +0200 Subject: [time-nuts] Update: Datum/Trimble 9390 PROM Message-ID: Just received my new PROMS ver. DT103E and everything appears to work. My reader did not support the 28F010N chips so have no dump... I suggest you contact the local Symmmetricom rep for a free chip! /Lasse From yuri at ostry.ru Mon Apr 6 15:29:17 2009 From: yuri at ostry.ru (Yuri Ostry) Date: Mon, 6 Apr 2009 19:29:17 +0400 Subject: [time-nuts] Replacement High-Speed AOP for Distribution Amplifier In-Reply-To: <00b101c9b6bf$f36103c0$da230b40$@com> References: <00b101c9b6bf$f36103c0$da230b40$@com> Message-ID: <828755970.20090406192917@ostry.ru> Hello, Monday, April 6, 2009, 17:59:49, Samuel D. wrote: S> Hi there, S> I'm working on a new GPS-Disciplined Rubidium Frequency Standard and I'm now S> designing the distribution amplifier stage. There is many schematics S> everywhere on the Internet, the most famous is the TADD-1 reviewed by the S> not-less-famous TVB. Almost all of them use high-speed Op Amps originally S> designed for video processing. The most common AOP are the MAX477 (used in S> TADD-1) and the MAX4135. Unfortunately, both of them are now obsolete and S> will be discontinued soon. I checked Digikey and Farnell, but those parts S> are not available anymore, so, I'm looking for an equivalent (or better!) S> replacement. S> Any hints ? Check current Analog Devices opamps offers. There is some pin to pin replacement for MAX477. If memory serves me corectly, it is AD8047 (I may be wrong, though, check datasheets). -- Best regards, Yuri mailto:yuri at ostry.ru From sam at canardpc.com Mon Apr 6 16:21:39 2009 From: sam at canardpc.com (Samuel D. [x86/CPC]) Date: Mon, 6 Apr 2009 18:21:39 +0200 Subject: [time-nuts] Replacement High-Speed AOP for Distribution Amplifier In-Reply-To: <828755970.20090406192917@ostry.ru> References: <00b101c9b6bf$f36103c0$da230b40$@com> <828755970.20090406192917@ostry.ru> Message-ID: <00e501c9b6d3$c411b7e0$4c3527a0$@com> The slew rate seems a bit slow on AD8047 (750 V/?s VS 1100 V/?s). A great (but expensive) AOP with really nice specs is the LT1227 from Linear. But I'm not a time guru and perhaps there is some tricks that I'm not aware of. For a distribution amplifier designed to share an accurate 10 MHz sine wave (and perhaps a 5 Mhz square wave), what are the most important specs to look at ? -----Message d'origine----- De?: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] De la part de Yuri Ostry Envoy??: lundi 6 avril 2009 17:29 ??: Discussion of precise time and frequency measurement Objet?: Re: [time-nuts] Replacement High-Speed AOP for Distribution Amplifier Hello, Monday, April 6, 2009, 17:59:49, Samuel D. wrote: S> Hi there, S> I'm working on a new GPS-Disciplined Rubidium Frequency Standard and I'm now S> designing the distribution amplifier stage. There is many schematics S> everywhere on the Internet, the most famous is the TADD-1 reviewed by the S> not-less-famous TVB. Almost all of them use high-speed Op Amps originally S> designed for video processing. The most common AOP are the MAX477 (used in S> TADD-1) and the MAX4135. Unfortunately, both of them are now obsolete and S> will be discontinued soon. I checked Digikey and Farnell, but those parts S> are not available anymore, so, I'm looking for an equivalent (or better!) S> replacement. S> Any hints ? Check current Analog Devices opamps offers. There is some pin to pin replacement for MAX477. If memory serves me corectly, it is AD8047 (I may be wrong, though, check datasheets). -- Best regards, Yuri mailto:yuri at ostry.ru _______________________________________________ time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. From paul at greenrover.demon.co.uk Mon Apr 6 17:06:11 2009 From: paul at greenrover.demon.co.uk (paul at greenrover.demon.co.uk) Date: Mon, 06 Apr 2009 18:06:11 +0100 Subject: [time-nuts] Hand Held GPS In-Reply-To: <49D0642E.3010904@greenrover.demon.co.uk> References: <49CC93C9.4010908@greenrover.demon.co.uk> <1197.SVVXXVxVQkI=.1238164282.squirrel@webmail.securepacific.net> <36802.80.251.207.129.1238271578.squirrel@webmail.lysator.liu.se> <49D0642E.3010904@greenrover.demon.co.uk> Message-ID: <49DA3683.80604@greenrover.demon.co.uk> paul at greenrover.demon.co.uk wrote: To follow up on my previous request for help, I ordered a Garmin GPSmap60 which delivers an unloaded 3.2V to the MCX connector with fresh batteries. Tried it on a couple of Symetricom and Motorola site antennas on the end of 100 feet of cable and it works just fine. So thanks for all the pointers and help - job done! Regards Paul -- 73 de Paul GW8IZR IO73TI http://www.gw8izr.com From Arnold.Tibus at gmx.de Mon Apr 6 17:09:14 2009 From: Arnold.Tibus at gmx.de (Arnold Tibus) Date: Mon, 06 Apr 2009 19:09:14 +0200 Subject: [time-nuts] RF mixers for oscillator characterization, some questions Message-ID: Hello the Time Nuts, I am looking for some good mixers for oscillator phase/ noise measurements, so I would be happy if somebody would assist in giving helpful answers to my ordinary questions: What mixers have to be applied/ are recommendable? What has to be observed? Can I use just ordinary dbm as they are in use in modern hf receivers? What about the hp models as the 10514A? I saw mentioned 'series' on such models, are they selected ore is it just the normal serie no, different for each unit? Is it risky to buy used ones and what are nominal prices for these items? Many tia, regards, Arnold From KE9H at austin.rr.com Mon Apr 6 17:47:53 2009 From: KE9H at austin.rr.com (Graham / KE9H) Date: Mon, 06 Apr 2009 12:47:53 -0500 Subject: [time-nuts] Sawtooth correction in UT+ receiver In-Reply-To: References: Message-ID: <49DA4049.6000308@austin.rr.com> All: I have several Motorola UT+ receivers, hardware version R5, version 3.1 software. Will these receivers provide a sawtooth correction message that can be used for external correction? If so, can you provide or point me at the documentation for the messages? Thanks, --- Graham / KE9H == From peterawson at earthlink.net Mon Apr 6 19:57:40 2009 From: peterawson at earthlink.net (Pete) Date: Mon, 6 Apr 2009 13:57:40 -0600 Subject: [time-nuts] RF mixers for oscillator characterization, some questions References: Message-ID: Arnold, I have had good experience with the SYPD series from Mini-circuits. I have not seen any used, but their new cost is reasonable. They do several things well e.g. the DC offset on the units I received is <1mV & they produce >2V p-p when driven @ +7dBm. Pete Rawson From bruce.griffiths at xtra.co.nz Mon Apr 6 21:46:47 2009 From: bruce.griffiths at xtra.co.nz (Bruce Griffiths) Date: Tue, 07 Apr 2009 09:46:47 +1200 Subject: [time-nuts] RF mixers for oscillator characterization, some questions In-Reply-To: References: Message-ID: <49DA7847.5010905@xtra.co.nz> Pete wrote: > Arnold, > > I have had good experience with the SYPD series > from Mini-circuits. I have not seen any used, but > their new cost is reasonable. They do several things > well e.g. the DC offset on the units I received is > <1mV & they produce >2V p-p when driven @ > +7dBm. > > Pete Rawson > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > Pete These are OK except when one needs to isolate the IF ground from the RF grounds to avoid low frequency ground loop problems. The RPD and MPD through hole series are better in this regard as they allow the IF ground to be isolated from the RF grounds. The flicker phase noise characteristics of the mixer/phase detector should be measured as some mixers/phase detectors have lower flicker phase noise than others. The termination of the IF port will affect the mixer phase noise. For offset frequencies < 100kHz a capacitive termination of the IF port which reflects the sum frequency back into the mixer reduces the mixer phase noise. The tradeoff is that the mixer output at higher offset frequencies is attenuated by the IF port termination. Terminating the IF port in a capacitor reduces the RF port impedance, so that a low value series resistor (22 to 39 ohms - select for lowest VSWR) is then required to improve the RF port VSWR. Terminating the IF port with a capacitor also alters the mixer gain (as a phase detector) so this needs to be measured in conjunction with the noise 10514 and 10534 mixers using discrete diodes supposedly have lower flicker noise than mixers using integrated quad diodes. Bruce From bruce.griffiths at xtra.co.nz Mon Apr 6 22:29:24 2009 From: bruce.griffiths at xtra.co.nz (Bruce Griffiths) Date: Tue, 07 Apr 2009 10:29:24 +1200 Subject: [time-nuts] Replacement High-Speed AOP for Distribution Amplifier In-Reply-To: <00b101c9b6bf$f36103c0$da230b40$@com> References: <00b101c9b6bf$f36103c0$da230b40$@com> Message-ID: <49DA8244.7010906@xtra.co.nz> Samuel Wideband oapmps should only used in distribution amplifiers when their inferior flicker phase noise and phase noise floor characteristics are acceptable. One can easily achieve a far lower flicker and broadband phase noise floor using discrete components rather than opamps. Even the simple discrete component buffers used in some Austron frequency standards will have better phase noise characteristics than an opamp based distribution amplifier. If you decide to use opamps you need to look at: 1) Slew rate 2) Distortion at the anticipated output level and frequency. 3) Opamp input noise both in the flicker region as well as at high frequency. Using an input step up transformer can be helpful in reducing the phase noise of an opamp based distribution amplifier. It is also advisable to use a very low noise power supply as power supply noise will modulate the opamp RF phase shift thereby increasing the flicker phase noise level. Bruce Samuel D. [x86/CPC] wrote: > Hi there, > > I'm working on a new GPS-Disciplined Rubidium Frequency Standard and I'm now > designing the distribution amplifier stage. There is many schematics > everywhere on the Internet, the most famous is the TADD-1 reviewed by the > not-less-famous TVB. Almost all of them use high-speed Op Amps originally > designed for video processing. The most common AOP are the MAX477 (used in > TADD-1) and the MAX4135. Unfortunately, both of them are now obsolete and > will be discontinued soon. I checked Digikey and Farnell, but those parts > are not available anymore, so, I'm looking for an equivalent (or better!) > replacement. > > Any hints ? > > PS : A French member of that list, Daniel, contacted me some weeks ago. Due > to a corrupted Outlook file, I lost your contact and wasn't able to keep in > touch with you. Please send me an email if you read this ;) > > --------------------- > Samuel DEMEULEMEESTER > Presse Non Stop - Canard PC > http://www.canardpc.com > Tel : +33.6.13.73.4003 > MSN : sam at x86.fr > > > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > From magnus at rubidium.dyndns.org Mon Apr 6 22:58:56 2009 From: magnus at rubidium.dyndns.org (Magnus Danielson) Date: Tue, 07 Apr 2009 00:58:56 +0200 Subject: [time-nuts] RF mixers for oscillator characterization, some questions In-Reply-To: <49DA7847.5010905@xtra.co.nz> References: <49DA7847.5010905@xtra.co.nz> Message-ID: <49DA8930.9000208@rubidium.dyndns.org> Bruce Griffiths skrev: > Pete wrote: >> Arnold, >> >> I have had good experience with the SYPD series >> from Mini-circuits. I have not seen any used, but >> their new cost is reasonable. They do several things >> well e.g. the DC offset on the units I received is >> <1mV & they produce >2V p-p when driven @ >> +7dBm. >> >> Pete Rawson >> >> _______________________________________________ >> time-nuts mailing list -- time-nuts at febo.com >> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. >> >> > Pete > > These are OK except when one needs to isolate the IF ground from the RF > grounds to avoid low frequency ground loop problems. > The RPD and MPD through hole series are better in this regard as they > allow the IF ground to be isolated from the RF grounds. It should be noted that several of their SMB mixers have separated grounds, but it is not documented in their datasheets. > The flicker phase noise characteristics of the mixer/phase detector > should be measured as some mixers/phase detectors have lower flicker > phase noise than others. > The termination of the IF port will affect the mixer phase noise. For > offset frequencies < 100kHz a capacitive termination of the IF port > which reflects the sum frequency back into the mixer reduces the mixer > phase noise. It essentially sees a very low impedance at those frequencies. My experiments with capacitive loading of mixers basically indicates that the actual low-frequency slope of an unloaded mixer does not change, but the capacitor load filters the sum-frequency (with overtones) while a resistive 50 ohm load just loads the amplitude down and gives no significant change to performance. Optimum performance out of a mixer in my experience comes from fairly high-impedance load at low frequencies with a direct capacitive loading for filtering effects. A non-filtered response is quite interesting to see with a fairly slow beating frequency occuring. Kind of soothing waveforms floating slowly as waves over the scope. > The tradeoff is that the mixer output at higher offset > frequencies is attenuated by the IF port termination. > Terminating the IF port in a capacitor reduces the RF port impedance, so > that a low value series resistor (22 to 39 ohms - select for lowest > VSWR) is then required to improve the RF port VSWR. Which in improves phase-stability as reflected waves has less impact. -3 dB pads have also been used by the good folks over at NIST at one time. > Terminating the IF port with a capacitor also alters the mixer gain (as > a phase detector) so this needs to be measured in conjunction with the noise Well... the normal 50 Ohm loading alters the mixer gain... not the cap. But since the normation is towards 50 Ohm... ah well... > 10514 and 10534 mixers using discrete diodes supposedly have lower > flicker noise than mixers using integrated quad diodes. They however has common ground in their every day laboratory variants. There exist variants meant for production. However, they are not made out of that exquisite components, so their performance should be replicable, as have been pointed out before. Cheers, Magnus From bruce.griffiths at xtra.co.nz Mon Apr 6 23:40:41 2009 From: bruce.griffiths at xtra.co.nz (Bruce Griffiths) Date: Tue, 07 Apr 2009 11:40:41 +1200 Subject: [time-nuts] RF mixers for oscillator characterization, some questions In-Reply-To: <49DA8930.9000208@rubidium.dyndns.org> References: <49DA7847.5010905@xtra.co.nz> <49DA8930.9000208@rubidium.dyndns.org> Message-ID: <49DA92F9.8080100@xtra.co.nz> Magnus Magnus Danielson wrote: > Bruce Griffiths skrev: > >> Pete wrote: >> >>> Arnold, >>> >>> I have had good experience with the SYPD series >>> from Mini-circuits. I have not seen any used, but >>> their new cost is reasonable. They do several things >>> well e.g. the DC offset on the units I received is >>> <1mV & they produce >2V p-p when driven @ >>> +7dBm. >>> >>> Pete Rawson >>> >>> _______________________________________________ >>> time-nuts mailing list -- time-nuts at febo.com >>> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >>> and follow the instructions there. >>> >>> >>> >> Pete >> >> These are OK except when one needs to isolate the IF ground from the RF >> grounds to avoid low frequency ground loop problems. >> The RPD and MPD through hole series are better in this regard as they >> allow the IF ground to be isolated from the RF grounds. >> > > It should be noted that several of their SMB mixers have separated > grounds, but it is not documented in their datasheets. > > >> The flicker phase noise characteristics of the mixer/phase detector >> should be measured as some mixers/phase detectors have lower flicker >> phase noise than others. >> The termination of the IF port will affect the mixer phase noise. For >> offset frequencies < 100kHz a capacitive termination of the IF port >> which reflects the sum frequency back into the mixer reduces the mixer >> phase noise. >> > > It essentially sees a very low impedance at those frequencies. > > My experiments with capacitive loading of mixers basically indicates > that the actual low-frequency slope of an unloaded mixer does not > change, but the capacitor load filters the sum-frequency (with > overtones) while a resistive 50 ohm load just loads the amplitude down > and gives no significant change to performance. Optimum performance out > of a mixer in my experience comes from fairly high-impedance load at low > frequencies with a direct capacitive loading for filtering effects. > > A non-filtered response is quite interesting to see with a fairly slow > beating frequency occuring. Kind of soothing waveforms floating slowly > as waves over the scope. > > The effect of reflecting the sum frequency back into the mixer is documented in some Watkins Johnson and HP/Agilent appliction notes. It can be very effective even at microwave frequencies. >> The tradeoff is that the mixer output at higher offset >> frequencies is attenuated by the IF port termination. >> Terminating the IF port in a capacitor reduces the RF port impedance, so >> that a low value series resistor (22 to 39 ohms - select for lowest >> VSWR) is then required to improve the RF port VSWR. >> > > Which in improves phase-stability as reflected waves has less impact. > -3 dB pads have also been used by the good folks over at NIST at one time. > > The best combination is a series resistor plus an attenuator pad. >> Terminating the IF port with a capacitor also alters the mixer gain (as >> a phase detector) so this needs to be measured in conjunction with the noise >> > > Well... the normal 50 Ohm loading alters the mixer gain... not the cap. > But since the normation is towards 50 Ohm... ah well... > > >> 10514 and 10534 mixers using discrete diodes supposedly have lower >> flicker noise than mixers using integrated quad diodes. >> > > They however has common ground in their every day laboratory variants. > There exist variants meant for production. However, they are not made > out of that exquisite components, so their performance should be > replicable, as have been pointed out before. > > The B versions intended for through hole PCB mount have separate grounds for all ports. These don't seem to be as widely available as they once were although I have an HP10534B one. > Cheers, > Magnus > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > Bruce From df6jb at ulrich-bangert.de Tue Apr 7 06:46:37 2009 From: df6jb at ulrich-bangert.de (Ulrich Bangert) Date: Tue, 7 Apr 2009 08:46:37 +0200 Subject: [time-nuts] Replacement High-Speed AOP for Distribution Amplifier In-Reply-To: <00b101c9b6bf$f36103c0$da230b40$@com> Message-ID: <153CF70722B84B95A94BECC671029B2C@athlon> Samuel, from the "high isolation" point of view an AD8007 may be a good choice if you are out for a chip based design. If you consider a discrete design, follow Bruce's "low noise pages". Best regards Ulrich > -----Ursprungliche Nachricht----- > Von: time-nuts-bounces at febo.com > [mailto:time-nuts-bounces at febo.com] Im Auftrag von Samuel D. [x86/CPC] > Gesendet: Montag, 6. April 2009 16:00 > An: time-nuts at febo.com > Betreff: [time-nuts] Replacement High-Speed AOP for > Distribution Amplifier > > > Hi there, > > I'm working on a new GPS-Disciplined Rubidium Frequency > Standard and I'm now designing the distribution amplifier > stage. There is many schematics everywhere on the Internet, > the most famous is the TADD-1 reviewed by the not-less-famous > TVB. Almost all of them use high-speed Op Amps originally > designed for video processing. The most common AOP are the > MAX477 (used in > TADD-1) and the MAX4135. Unfortunately, both of them are now > obsolete and will be discontinued soon. I checked Digikey and > Farnell, but those parts are not available anymore, so, I'm > looking for an equivalent (or better!) replacement. > > Any hints ? > > PS : A French member of that list, Daniel, contacted me some > weeks ago. Due to a corrupted Outlook file, I lost your > contact and wasn't able to keep in touch with you. Please > send me an email if you read this ;) > > --------------------- > Samuel DEMEULEMEESTER > Presse Non Stop - Canard PC > http://www.canardpc.com > Tel : +33.6.13.73.4003 > MSN : sam at x86.fr > > > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. From df6jb at ulrich-bangert.de Tue Apr 7 07:00:49 2009 From: df6jb at ulrich-bangert.de (Ulrich Bangert) Date: Tue, 7 Apr 2009 09:00:49 +0200 Subject: [time-nuts] Sawtooth correction in UT+ receiver In-Reply-To: <49DA4049.6000308@austin.rr.com> Message-ID: Graham, I just sent the command description to your private mail address. 73s de Ulrich, DF6JB > -----Ursprungliche Nachricht----- > Von: time-nuts-bounces at febo.com > [mailto:time-nuts-bounces at febo.com] Im Auftrag von Graham / KE9H > Gesendet: Montag, 6. April 2009 19:48 > An: Discussion of precise time and frequency measurement > Betreff: [time-nuts] Sawtooth correction in UT+ receiver > > > All: > > I have several Motorola UT+ receivers, hardware version R5, > version 3.1 software. Will these receivers provide a > sawtooth correction message that can be used for external correction? > > If so, can you provide or point me at the documentation for > the messages? > > Thanks, > --- Graham / KE9H > > == > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. From rexa at sonic.net Tue Apr 7 09:25:36 2009 From: rexa at sonic.net (Rex) Date: Tue, 07 Apr 2009 02:25:36 -0700 Subject: [time-nuts] CTS oscillator info? Message-ID: <49DB1C10.6020101@sonic.net> I just bought an oscillator on ebay. Here's the basic description from the listing, "This is an auction for one CTS Knights 970-2162-0 (WP 93216-L1) 5MHz OCXO oscillator." It is a double oven and actually has a frequency of 5.000055 MHz on the label, so 55 Hz above 5 MHz. I'm hoping it is a very clean source and will be good for beating against other 5 MHz sources to measure them, but I haven't found any more info on this one with searches. Does anyone on the list have any guess what it might have been used with? I'm guessing it may be for some piece of measurement test equipment. Or does anyone have a lead on specs for the quality of its output signal? The auction was 130297655960, if anyone wants to look at the pictures. thanks, Rex From sar10538 at gmail.com Tue Apr 7 11:16:30 2009 From: sar10538 at gmail.com (Steve Rooke) Date: Tue, 7 Apr 2009 23:16:30 +1200 Subject: [time-nuts] Cabling GPS antennas Message-ID: <1231b6a80904070416j14adc226vb3e8994709acd8f8@mail.gmail.com> I'm installing a Lucent KS-24019L112A connected to a Z3805A with the two located about 15m apart from each other. Both items connect via a 50Ohm N connector so I'm cabling for that impedance. Ideally I'd like to buy RG213 or LMR-400 but that is rare'ish down here in NZ and the price reflects that. I won't consider RG58 as there will be hardly anything coming out of the end of the cable with the loss it has at these frequencies. I was thinking outside the square and see that dual/quad screened RG6 is cheap and plentiful now but of course it's 75Ohm and there would be a big fat impedance mismatch using this. I thought about looking at fitting impedance matching baluns at each end but that is not cheap and there are losses involved with this approach anyway. Is it just down to bighting the bullet or has anyone had a way round this? 73, Steve -- Steve Rooke - ZL3TUV & G8KVD & JAKDTTNW Omnium finis imminet From sar10538 at gmail.com Tue Apr 7 11:18:30 2009 From: sar10538 at gmail.com (Steve Rooke) Date: Tue, 7 Apr 2009 23:18:30 +1200 Subject: [time-nuts] Cabling GPS antennas In-Reply-To: <1231b6a80904070416j14adc226vb3e8994709acd8f8@mail.gmail.com> References: <1231b6a80904070416j14adc226vb3e8994709acd8f8@mail.gmail.com> Message-ID: <1231b6a80904070418x7e27eb76gc08dba3c1cfe6eca@mail.gmail.com> BTW, has anyone got a spare mount for this antenna they would be prepared to sell me? 2009/4/7 Steve Rooke : > I'm installing a Lucent KS-24019L112A connected to a Z3805A with the > two located about 15m apart from each other. Both items connect via a > 50Ohm N connector so I'm cabling for that impedance. Ideally I'd like > to buy RG213 or LMR-400 but that is rare'ish down here in NZ and the > price reflects that. I won't consider RG58 as there will be hardly > anything coming out of the end of the cable with the loss it has at > these frequencies. I was thinking outside the square and see that > dual/quad screened RG6 is cheap and plentiful now but of course it's > 75Ohm and there would be a big fat impedance mismatch using this. I > thought about looking at fitting impedance matching baluns at each end > but that is not cheap and there are losses involved with this approach > anyway. > > Is it just down to bighting the bullet or has anyone had a way round this? > > 73, > Steve > -- > Steve Rooke - ZL3TUV & G8KVD & JAKDTTNW > Omnium finis imminet > -- Steve Rooke - ZL3TUV & G8KVD & JAKDTTNW Omnium finis imminet From sar10538 at gmail.com Tue Apr 7 12:09:38 2009 From: sar10538 at gmail.com (Steve Rooke) Date: Wed, 8 Apr 2009 00:09:38 +1200 Subject: [time-nuts] Characterising frequency standards Message-ID: <1231b6a80904070509m5b8bb638gbc088500444254c3@mail.gmail.com> A while back when we were discussing the performance of the Shortt free pendulum clock a reference was made to tvb's paper on allen deviation, http://www.leapsecond.com/hsn2006/ch2.pdf, which I found to be an excellent primer on the subject. It was interesting to see that with only a subset of the data, the allen deviations up to about the total of the data collection period could be calculated with reasonable accuracy. This had me thinking that if just a proportion of the data covering up to a specific averaging time gave good results, would disconnected data amounting to the same period give the same results. To me it seems that accuracy of the results is not related to the need to capture every event consecutively, it is more a case of collecting the same size data set even though samples were not consecutive. My reasoning behind this is that any set of data for a DUT should give the same results even though the data sets are not related time wise. OK, there are affects caused by different environmental conditions and drift but these can be calculated out. The only think that would shoot a big hole in this is if there was a repeatable difference between alternate cycles. So why am I saying this, well from what I have read on this group and on the web, I have been left with a feeling that it was vital to capture every event over a samplig period to ensure an accurate measurement. This requires equipment capable of time-stamping each event or employing such techniques as picket-fence. This is due to the limitations of most counters being unable to reset in time to measure the next time period of an input. At this stage I cannot see why it is not possible to just measure a cycle, let the counter/timer reset and then let it measure the next full cycle that follows. Agreed this would mean that alternate cycles were lost (assuming the counter/timer can reset within the space of one cycle) but the measurement could still collect the same amount of data points, it would just take twice as long. In fact, it could be possible to make the counter/timer measure alternate cycles on the opposite transitions, thereby reducing the total measurement time to just one and a half times the 'normal' time. With respect to any problem related to alternate cycles, the measurement system could be made to collect two data sets with single cycle skipped between each set. The difference will be that the data set would consist of measurements of each individual non-sequential cycle as opposed to a history of the start times of each cycle. So the short story is, does the data stream really have to consist of sequential samples or is it just a statistical thing so for the same size of data set, the results should be similar. 73, Steve -- Steve Rooke - ZL3TUV & G8KVD & JAKDTTNW Omnium finis imminet From bruce.griffiths at xtra.co.nz Tue Apr 7 12:39:10 2009 From: bruce.griffiths at xtra.co.nz (Bruce Griffiths) Date: Wed, 08 Apr 2009 00:39:10 +1200 Subject: [time-nuts] Characterising frequency standards In-Reply-To: <1231b6a80904070509m5b8bb638gbc088500444254c3@mail.gmail.com> References: <1231b6a80904070509m5b8bb638gbc088500444254c3@mail.gmail.com> Message-ID: <49DB496E.6030602@xtra.co.nz> Steve Rooke wrote: > A while back when we were discussing the performance of the Shortt > free pendulum clock a reference was made to tvb's paper on allen > deviation, http://www.leapsecond.com/hsn2006/ch2.pdf, which I found to > be an excellent primer on the subject. It was interesting to see that > with only a subset of the data, the allen deviations up to about the > total of the data collection period could be calculated with > reasonable accuracy. This had me thinking that if just a proportion of > the data covering up to a specific averaging time gave good results, > would disconnected data amounting to the same period give the same > results. To me it seems that accuracy of the results is not related to > the need to capture every event consecutively, it is more a case of > collecting the same size data set even though samples were not > consecutive. My reasoning behind this is that any set of data for a > DUT should give the same results even though the data sets are not > related time wise. OK, there are affects caused by different > environmental conditions and drift but these can be calculated out. > The only think that would shoot a big hole in this is if there was a > repeatable difference between alternate cycles. > > So why am I saying this, well from what I have read on this group and > on the web, I have been left with a feeling that it was vital to > capture every event over a samplig period to ensure an accurate > measurement. This requires equipment capable of time-stamping each > event or employing such techniques as picket-fence. This is due to the > limitations of most counters being unable to reset in time to measure > the next time period of an input. At this stage I cannot see why it is > not possible to just measure a cycle, let the counter/timer reset and > then let it measure the next full cycle that follows. Agreed this > would mean that alternate cycles were lost (assuming the counter/timer > can reset within the space of one cycle) but the measurement could > still collect the same amount of data points, it would just take twice > as long. In fact, it could be possible to make the counter/timer > measure alternate cycles on the opposite transitions, thereby reducing > the total measurement time to just one and a half times the 'normal' > time. With respect to any problem related to alternate cycles, the > measurement system could be made to collect two data sets with single > cycle skipped between each set. > > The difference will be that the data set would consist of measurements > of each individual non-sequential cycle as opposed to a history of the > start times of each cycle. > > So the short story is, does the data stream really have to consist of > sequential samples or is it just a statistical thing so for the same > size of data set, the results should be similar. > > 73, > Steve > Steve It is essential to measure the phase differences between every Nth zero crossing without missing any such cycles. You don't have to time stamp every zero crossing every Nth one will suffice but one then has no information for shorter time intervals than N periods. More accurate estimation of the Allan deviation is possible if the time interval between time stamps is shorter. The reason that you can't omit one of the time stamps in the sequence (if you wish to accurately characterise the frequency stability of the source under test) is that the process isn't stationary. Estimates of classical measures such as the mean and standard deviation from the samples diverge as the number of samples increase. Whilst attempts have been made to estimate the error due to deadtime, the corrections require that the phase noise characteristics of the 2 (or more) sources being compared are accurately known. Avoiding deadtime problems is fairly easy if you use an instrument that can timestamp events on the fly. It is almost trivial to build such an instrument within a single FPGA or CPLD. Bruce From vogelchr at vogel.cx Tue Apr 7 12:40:31 2009 From: vogelchr at vogel.cx (Christian Vogel) Date: Tue, 07 Apr 2009 14:40:31 +0200 Subject: [time-nuts] Cabling GPS antennas In-Reply-To: <1231b6a80904070416j14adc226vb3e8994709acd8f8@mail.gmail.com> References: <1231b6a80904070416j14adc226vb3e8994709acd8f8@mail.gmail.com> Message-ID: <20090407144031.69xl3jdog0skww4w@webmail.df.eu> Hi Steve, > these frequencies. I was thinking outside the square and see that > dual/quad screened RG6 is cheap and plentiful now but of course it's > 75Ohm and there would be a big fat impedance mismatch using this. I > thought about looking at fitting impedance matching baluns at each end > but that is not cheap and there are losses involved with this approach > anyway. the manual of the Trimble Thunderbolt GPSDO recommends doing exactly that. 75Ohm cable obviously is cheaper, due to it being ubiquitously used for TV and video installations and has lower loss due to the higher impedance (impedance/resistance ratio). They (Trimble) claim that reflections will not introduce any problems. One can argue that, to cause interference effects, a wave has to travel back from the GPSO to the antenna and back to the GPDO (where it interferes with the direct signal). This will be attenuated by the SWR twice, and dampened by the cable loss twice. The issue at hand has been discussed at length one (two?) year(s) ago and included a link to an article that analytically analyzed the effect of multipath (of which the reflections are a specific case) on GPS accurady, if I remember correctly. Chris --- Quote from the Trimble manual (ThunderboltBook2003.pdf), Page "3-5" --- Note ? RG-59 is a 75 ohm coaxial cable. The ThunderBolt and the Bullet antenna are compatible with either 50-ohm or 75-ohm cable. Compared to most 50 ohm cable, 75 ohm cable provides superior transmissibility for the 1.5 GHz GPS signal and a better quality cable for the price. Mismatched impedance is not a problem. Note ? The input impedance of the ThunderBolt RF input & its antenna is 50 ohms. From bruce.griffiths at xtra.co.nz Tue Apr 7 12:47:09 2009 From: bruce.griffiths at xtra.co.nz (Bruce Griffiths) Date: Wed, 08 Apr 2009 00:47:09 +1200 Subject: [time-nuts] Cabling GPS antennas In-Reply-To: <20090407144031.69xl3jdog0skww4w@webmail.df.eu> References: <1231b6a80904070416j14adc226vb3e8994709acd8f8@mail.gmail.com> <20090407144031.69xl3jdog0skww4w@webmail.df.eu> Message-ID: <49DB4B4D.2070705@xtra.co.nz> The reason that such cable mismatch isnt a problem is that the VSWR of the Thunderbolt input is relatively high. Bruce Christian Vogel wrote: > Hi Steve, > > >> these frequencies. I was thinking outside the square and see that >> dual/quad screened RG6 is cheap and plentiful now but of course it's >> 75Ohm and there would be a big fat impedance mismatch using this. I >> thought about looking at fitting impedance matching baluns at each end >> but that is not cheap and there are losses involved with this approach >> anyway. >> > > the manual of the Trimble Thunderbolt GPSDO recommends doing exactly > that. 75Ohm cable obviously is cheaper, due to it being ubiquitously > used for TV and video installations and has lower loss due to the > higher impedance (impedance/resistance ratio). They (Trimble) claim > that reflections will not introduce any problems. > > One can argue that, to cause interference effects, a wave has to > travel back from the GPSO to the antenna and back to the GPDO (where > it interferes with the direct signal). This will be attenuated by the > SWR twice, and dampened by the cable loss twice. > > The issue at hand has been discussed at length one (two?) year(s) ago > and included a link to an article that analytically analyzed the > effect of multipath (of which the reflections are a specific case) on > GPS accurady, if I remember correctly. > > Chris > > --- Quote from the Trimble manual (ThunderboltBook2003.pdf), Page "3-5" --- > Note ? RG-59 is a 75 ohm coaxial cable. The ThunderBolt and the Bullet > antenna are > compatible with either 50-ohm or 75-ohm cable. Compared to most 50 ohm > cable, 75 > ohm cable provides superior transmissibility for the 1.5 GHz GPS signal and a > better quality cable for the price. Mismatched impedance is not a problem. > > Note ? The input impedance of the ThunderBolt RF input & its antenna > is 50 ohms. > > > > > > > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > From phk at phk.freebsd.dk Tue Apr 7 16:22:06 2009 From: phk at phk.freebsd.dk (Poul-Henning Kamp) Date: Tue, 07 Apr 2009 16:22:06 +0000 Subject: [time-nuts] Characterising frequency standards In-Reply-To: Your message of "Wed, 08 Apr 2009 00:09:38 +1200." <1231b6a80904070509m5b8bb638gbc088500444254c3@mail.gmail.com> Message-ID: <35851.1239121326@critter.freebsd.dk> In message <1231b6a80904070509m5b8bb638gbc088500444254c3 at mail.gmail.com>, Steve Rooke writes: >So why am I saying this, well from what I have read on this group and >on the web, I have been left with a feeling that it was vital to >capture every event over a samplig period to ensure an accurate >measurement. It is vital only to simplify the calculation of the uncertainties on the result more than the result itself. If you skip every other time interval, you have no information about noise of the obvious 1/p frequency, just like Nyquist says. Dividing a 10MHz signal to 1PPS, and measuring the adev on that, therefore gives us no right to talk about what happens on the fast side of tau=1sec. Aperiodic sampling can be an incredible powerfull tool to use instead: Comparing the two 10MHz signals by measuring the difference i duration between ramdomly chosen sequences of thousand samples, gives very detailed information, as long as you know the exact relative placement of your 1k sample runs relative to each other. The mathmatical handling is nasty though. -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 phk at FreeBSD.ORG | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. From phk at phk.freebsd.dk Tue Apr 7 16:22:47 2009 From: phk at phk.freebsd.dk (Poul-Henning Kamp) Date: Tue, 07 Apr 2009 16:22:47 +0000 Subject: [time-nuts] Characterising frequency standards In-Reply-To: Your message of "Wed, 08 Apr 2009 00:39:10 +1200." <49DB496E.6030602@xtra.co.nz> Message-ID: <35862.1239121367@critter.freebsd.dk> In message <49DB496E.6030602 at xtra.co.nz>, Bruce Griffiths writes: >Steve Rooke wrote: >It is essential to measure the phase differences between every Nth zero >crossing without missing any such cycles. And he does, except it is only every 2N instead of 1N. -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 phk at FreeBSD.ORG | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. From david at endor.com Tue Apr 7 17:15:54 2009 From: david at endor.com (David McGaw) Date: Tue, 07 Apr 2009 13:15:54 -0400 Subject: [time-nuts] Cabling GPS antennas In-Reply-To: <49DB4B4D.2070705@xtra.co.nz> References: <1231b6a80904070416j14adc226vb3e8994709acd8f8@mail.gmail.com> <20090407144031.69xl3jdog0skww4w@webmail.df.eu> <49DB4B4D.2070705@xtra.co.nz> Message-ID: <200904071715.n37HFiQp023687@mailhub24.dartmouth.edu> Hi Steve, I find it hard to believe myself, but the numbers don't lie. A 1.5:1 SWR junction gives 0.177dB transmission loss and a -13.98 dB reflection. If you have a true 50 ohm antenna and receiver and use 75 ohm LOSS-LESS cable, the transmission loss will be only 0.35dB and the doubly reflected wave will be 28dB down. Any line loss makes things rapidly better still. 15m of TV foam-type RG-6/U will have ~3.7dB cable loss or ~4dB total loss, and a reflection 35dB down. BTW, return loss of the cable itself is rated at -15dB @ 1500MHz! And, as has been pointed out, the SWR of the receiver and antenna will not be 1:1 either. Good luck, David At 08:47 AM 4/7/2009, you wrote: >The reason that such cable mismatch isnt a problem is that the VSWR of >the Thunderbolt input is relatively high. > >Bruce > >Christian Vogel wrote: > > Hi Steve, > > > > > >> these frequencies. I was thinking outside the square and see that > >> dual/quad screened RG6 is cheap and plentiful now but of course it's > >> 75Ohm and there would be a big fat impedance mismatch using this. I > >> thought about looking at fitting impedance matching baluns at each end > >> but that is not cheap and there are losses involved with this approach > >> anyway. > >> > > > > the manual of the Trimble Thunderbolt GPSDO recommends doing exactly > > that. 75Ohm cable obviously is cheaper, due to it being ubiquitously > > used for TV and video installations and has lower loss due to the > > higher impedance (impedance/resistance ratio). They (Trimble) claim > > that reflections will not introduce any problems. > > > > One can argue that, to cause interference effects, a wave has to > > travel back from the GPSO to the antenna and back to the GPDO (where > > it interferes with the direct signal). This will be attenuated by the > > SWR twice, and dampened by the cable loss twice. > > > > The issue at hand has been discussed at length one (two?) year(s) ago > > and included a link to an article that analytically analyzed the > > effect of multipath (of which the reflections are a specific case) on > > GPS accurady, if I remember correctly. > > > > Chris > > > > --- Quote from the Trimble manual (ThunderboltBook2003.pdf), Page "3-5" --- > > Note ? RG-59 is a 75 ohm coaxial cable. The ThunderBolt and the Bullet > > antenna are > > compatible with either 50-ohm or 75-ohm cable. Compared to most 50 ohm > > cable, 75 > > ohm cable provides superior transmissibility for the 1.5 GHz GPS > signal and a > > better quality cable for the price. Mismatched impedance is not a problem. > > > > Note ? The input impedance of the ThunderBolt RF input & its antenna > > is 50 ohms. > > > > > > > > > > > > > > > > > > _______________________________________________ > > time-nuts mailing list -- time-nuts at febo.com > > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > > and follow the instructions there. > > > > > > >_______________________________________________ >time-nuts mailing list -- time-nuts at febo.com >To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >and follow the instructions there. From peterl at standingwave.org Tue Apr 7 20:10:26 2009 From: peterl at standingwave.org (Peter Loron) Date: Tue, 7 Apr 2009 13:10:26 -0700 Subject: [time-nuts] CTS oscillator info? Message-ID: <8E78B99F-D366-44EB-B20A-58271758635C@standingwave.org> > I just bought an oscillator on ebay. Here's the basic description from > the listing, > "This is an auction for one CTS Knights 970-2162-0 (WP 93216-L1) 5MHz > OCXO oscillator." > > It is a double oven and actually has a frequency of 5.000055 MHz on > the > label, so 55 Hz above > 5 MHz. I'm hoping it is a very clean source and will be good for > beating > against other 5 MHz > sources to measure them, but I haven't found any more info on this one > with searches. > > Does anyone on the list have any guess what it might have been used > with? I'm guessing it may be > for some piece of measurement test equipment. Or does anyone have a > lead > on specs for the > quality of its output signal? > > The auction was 130297655960, if anyone wants to look at the pictures. > > thanks, > Rex Hello, group. The item Rex is referring to is one I sold to him. When I acquired the lot of OCXOs, I sent a mail to CTS, asking them for any information on them. They were able to supply me with the mechanical drawings, but the specs are proprietary as they were custom built for Lucent...likely embedded in some sort of comms equipment. I'm guessing that if they went to the expense of buying double-oven oscillators, they chose good specs for them. I'm thinking of desoldering the adjustment screws on one of them to see if I can tune it to 5.000000 MHz, although that is probably in noise floor of my equipment. For somebody (like me) who does not have a background in metrology and lacks any serious measuring equipment, is there a way to characterize items like this short of sending them to a lab? Thanks. -Pete From tvb at LeapSecond.com Tue Apr 7 20:16:14 2009 From: tvb at LeapSecond.com (Tom Van Baak) Date: Tue, 7 Apr 2009 13:16:14 -0700 Subject: [time-nuts] Characterising frequency standards References: <1231b6a80904070509m5b8bb638gbc088500444254c3@mail.gmail.com> Message-ID: Steve, You've asked a couple of questions. Let me start with this. It is true that if one were only interested in the performance of a pendulum (or quartz or atomic) clock for averaging times of one day that all you would need is a series of time error (aka phase) measurements made about the same time once a day (doesn't have to be that exact). After one week, you'd have 7 error measurements (=6 frequency =5 stability points) and this is adequate to calculate the ADEV for tau 1 day. This alone allows you to rank your clock among all the other pendulum clocks out there. Note also you get time error and rate error from these few data points too. As another example, suppose you have a nice HP 10811A oscillator and want to measure its drift rate. In this case you could spend just 100 seconds and measure its frequency once a day, or even once every couple of days. Do this for a month and you'd have several dozen points. If you plot these frequency measurements you will likely see that they approximately fall on a line; the slope of the is the frequency drift rate of the 10811. The general shape of the points, or the fit of the line is a rough indication of how consistent the drift rate is or if it's increasing or decreasing. Neither of these examples require a lot of data. Both of these are real-world examples. OK so far? /tvb From rexa at sonic.net Tue Apr 7 20:56:11 2009 From: rexa at sonic.net (Rex) Date: Tue, 07 Apr 2009 13:56:11 -0700 Subject: [time-nuts] CTS oscillator info? In-Reply-To: <8E78B99F-D366-44EB-B20A-58271758635C@standingwave.org> References: <8E78B99F-D366-44EB-B20A-58271758635C@standingwave.org> Message-ID: <49DBBDEB.4020507@sonic.net> Peter Loron wrote: >> I just bought an oscillator on ebay. Here's the basic description from >> the listing, >> "This is an auction for one CTS Knights 970-2162-0 (WP 93216-L1) 5MHz >> OCXO oscillator." >> >> It is a double oven and actually has a frequency of 5.000055 MHz on >> the >> label, so 55 Hz above >> 5 MHz. I'm hoping it is a very clean source and will be good for >> beating >> against other 5 MHz >> sources to measure them, but I haven't found any more info on this one >> with searches. >> >> Does anyone on the list have any guess what it might have been used >> with? I'm guessing it may be >> for some piece of measurement test equipment. Or does anyone have a >> lead >> on specs for the >> quality of its output signal? >> >> The auction was 130297655960, if anyone wants to look at the pictures. >> >> thanks, >> Rex >> > > Hello, group. The item Rex is referring to is one I sold to him. When > I acquired the lot of OCXOs, I sent a mail to CTS, asking them for any > information on them. They were able to supply me with the mechanical > drawings, but the specs are proprietary as they were custom built for > Lucent...likely embedded in some sort of comms equipment. I'm guessing > that if they went to the expense of buying double-oven oscillators, > they chose good specs for them. > > I'm thinking of desoldering the adjustment screws on one of them to > see if I can tune it to 5.000000 MHz, although that is probably in > noise floor of my equipment. > > For somebody (like me) who does not have a background in metrology and > lacks any serious measuring equipment, is there a way to characterize > items like this short of sending them to a lab? > > Thanks. > > -Pete > > > A list member sent me a brief CTS datasheet. Looks like the oscillator is probably a version of JKSC-142. The info is brief and does not mention noise but the main feature is long term and temperature stability. STABILITY: +/-1x10^-7 for 20 yrs without any adjustment. I can't guess why Lucent would want them 55 Hz above 5 MHz unless it was some kind of measurement application, but I don't know much about telephone stuff. -Rex From rexa at sonic.net Tue Apr 7 21:32:15 2009 From: rexa at sonic.net (Rex) Date: Tue, 07 Apr 2009 14:32:15 -0700 Subject: [time-nuts] CTS oscillator info? In-Reply-To: <49DBBDEB.4020507@sonic.net> References: <8E78B99F-D366-44EB-B20A-58271758635C@standingwave.org> <49DBBDEB.4020507@sonic.net> Message-ID: <49DBC65F.1070606@sonic.net> Rex wrote: > A list member sent me a brief CTS datasheet. Looks like the oscillator > is probably a version of JKSC-142. The info is brief and does not > mention noise but the main feature is long term and temperature > stability. STABILITY: +/-1x10^-7 for 20 yrs without any adjustment. > > I can't guess why Lucent would want them 55 Hz above 5 MHz unless it was > some kind of measurement application, but I don't know much about > telephone stuff. > > -Rex > I think small attachments are ok. I cut out and shrunk the portion of the datasheet that seems to apply to this oscillator. Attached as a gif file. -------------- next part -------------- A non-text attachment was scrubbed... Name: jksc-142.gif Type: image/gif Size: 81999 bytes Desc: not available Url : http://www.febo.com/pipermail/time-nuts/attachments/20090407/b78b57c4/attachment-0001.gif From peterl at standingwave.org Tue Apr 7 21:38:38 2009 From: peterl at standingwave.org (Peter Loron) Date: Tue, 7 Apr 2009 14:38:38 -0700 Subject: [time-nuts] CTS oscillator info? In-Reply-To: <49DBC65F.1070606@sonic.net> (sfid-20090407_143023_462755_DED4CB6F) References: <8E78B99F-D366-44EB-B20A-58271758635C@standingwave.org> <49DBBDEB.4020507@sonic.net> <49DBC65F.1070606@sonic.net> (sfid-20090407_143023_462755_DED4CB6F) Message-ID: <08686AAF-4253-46AA-A99F-DEBFF7FDF519@standingwave.org> On Apr 7, 2009, at 2:32 PM, Rex wrote: > Rex wrote: >> A list member sent me a brief CTS datasheet. Looks like the >> oscillator is probably a version of JKSC-142. The info is brief and >> does not mention noise but the main feature is long term and >> temperature stability. STABILITY: +/-1x10^-7 for 20 yrs without any >> adjustment. >> >> I can't guess why Lucent would want them 55 Hz above 5 MHz unless >> it was some kind of measurement application, but I don't know much >> about telephone stuff. >> >> -Rex >> > > I think small attachments are ok. I cut out and shrunk the portion > of the datasheet that seems to apply to this oscillator. > > Attached as a gif file. > > > Rex, thanks for posting that information! -Pete From sar10538 at gmail.com Wed Apr 8 11:41:26 2009 From: sar10538 at gmail.com (Steve Rooke) Date: Wed, 8 Apr 2009 23:41:26 +1200 Subject: [time-nuts] Characterising frequency standards In-Reply-To: References: <1231b6a80904070509m5b8bb638gbc088500444254c3@mail.gmail.com> Message-ID: <1231b6a80904080441p7a747a3h1f73bf8a2df30350@mail.gmail.com> Tom, I understand fully the points that you have made but I have obviously not made my point clear to all and i apologise for my poor communication skills. This is what I'm getting at: Using your adev1.exe from http://www.leapsecond.com/tools/adev1.htm and processing various forms of gps.dat from http://www.leapsecond.com/pages/gpsdo-sim/gps.dat.gz. C:\Documents and Settings\Steve Rooke\Desktop>adev1.exe 1 gps1.dat) C:\Documents and Settings\Steve Rooke\Desktop>adev1.exe 1 gps2.dat) C:\Documents and Settings\Steve Rooke\Desktop>adev1.exe 1 : > Steve, > > You've asked a couple of questions. Let me start with this. > > It is true that if one were only interested in the performance > of a pendulum (or quartz or atomic) clock for averaging times > of one day that all you would need is a series of time error > (aka phase) measurements made about the same time once > a day (doesn't have to be that exact). After one week, you'd > have 7 error measurements (=6 frequency =5 stability points) > and this is adequate to calculate the ADEV for tau 1 day. > This alone allows you to rank your clock among all the other > pendulum clocks out there. Note also you get time error and > rate error from these few data points too. > > As another example, suppose you have a nice HP 10811A > oscillator and want to measure its drift rate. In this case you > could spend just 100 seconds and measure its frequency > once a day, or even once every couple of days. Do this for > a month and you'd have several dozen points. If you plot > these frequency measurements you will likely see that they > approximately fall on a line; the slope of the is the frequency > drift rate of the 10811. The general shape of the points, or > the fit of the line is a rough indication of how consistent the > drift rate is or if it's increasing or decreasing. > > Neither of these examples require a lot of data. Both of these > are real-world examples. > > OK so far? > > /tvb > > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > -- Steve Rooke - ZL3TUV & G8KVD & JAKDTTNW Omnium finis imminet From bruce.griffiths at xtra.co.nz Wed Apr 8 11:59:53 2009 From: bruce.griffiths at xtra.co.nz (Bruce Griffiths) Date: Wed, 08 Apr 2009 23:59:53 +1200 Subject: [time-nuts] Characterising frequency standards In-Reply-To: <1231b6a80904080441p7a747a3h1f73bf8a2df30350@mail.gmail.com> References: <1231b6a80904070509m5b8bb638gbc088500444254c3@mail.gmail.com> <1231b6a80904080441p7a747a3h1f73bf8a2df30350@mail.gmail.com> Message-ID: <49DC91B9.6090004@xtra.co.nz> Steve If you delete every second measurement then your effective minimum sampling time is now 2s and you can no longer calculate ADEV for tau< 2s. You can still calculate ADEV for tau = 100,000 sec. If you delete all but the first 200,000 lines then you can calculated ADEV for tau=1sec and up to tau= 25,000 sec with reasonable accuracy. You shouldn't lose sight of the fact that ADEV and OADEV are both estimates of the Allan deviation. Bruce Steve Rooke wrote: > Tom, > > I understand fully the points that you have made but I have obviously > not made my point clear to all and i apologise for my poor > communication skills. > > This is what I'm getting at: > > Using your adev1.exe from http://www.leapsecond.com/tools/adev1.htm > and processing various forms of gps.dat from > http://www.leapsecond.com/pages/gpsdo-sim/gps.dat.gz. > > C:\Documents and Settings\Steve Rooke\Desktop>adev1.exe 1 > ** Sampling period: 1 s > ** Phase data scale factor: 1.000e+000 > ** Total phase samples: 400000 > ** Normal and Overlapping Allan deviation: > > 1 tau, 3.0127e-009 adev(n=399998), 3.0127e-009 oadev(n=399998) > 2 tau, 1.5110e-009 adev(n=199998), 1.5119e-009 oadev(n=399996) > 5 tau, 6.2107e-010 adev(n=79998), 6.1983e-010 oadev(n=399990) > 10 tau, 3.1578e-010 adev(n=39998), 3.1549e-010 oadev(n=399980) > 20 tau, 1.6531e-010 adev(n=19998), 1.6534e-010 oadev(n=399960) > 50 tau, 7.2513e-011 adev(n=7998), 7.3531e-011 oadev(n=399900) > 100 tau, 4.0029e-011 adev(n=3998), 4.0618e-011 oadev(n=399800) > 200 tau, 2.1512e-011 adev(n=1998), 2.1633e-011 oadev(n=399600) > 500 tau, 9.2193e-012 adev(n=798), 9.1630e-012 oadev(n=399000) > 1000 tau, 4.9719e-012 adev(n=398), 4.7750e-012 oadev(n=398000) > 2000 tau, 2.6742e-012 adev(n=198), 2.5214e-012 oadev(n=396000) > 5000 tau, 1.0010e-012 adev(n=78), 1.1032e-012 oadev(n=390000) > 10000 tau, 6.1333e-013 adev(n=38), 6.1039e-013 oadev(n=380000) > 20000 tau, 3.8162e-013 adev(n=18), 3.2913e-013 oadev(n=360000) > 50000 tau, 1.0228e-013 adev(n=6), 1.5074e-013 oadev(n=300000) > 100000 tau, 5.8577e-014 adev(n=2), 6.7597e-014 oadev(n=200000) > > So far, so good. Now I delete every even line in the file which leaves > me with 200000 lines of data (400000 lines in original gps.dat file). > (awk 'and(NR, 1) == 0 {print}' gps1.dat) > > C:\Documents and Settings\Steve Rooke\Desktop>adev1.exe 1 > ** Sampling period: 1 s > ** Phase data scale factor: 1.000e+000 > ** Total phase samples: 200000 > ** Normal and Overlapping Allan deviation: > > 1 tau, 3.0257e-009 adev(n=199998), 3.0257e-009 oadev(n=199998) > 2 tau, 1.5373e-009 adev(n=99998), 1.5345e-009 oadev(n=199996) > 5 tau, 6.3147e-010 adev(n=39998), 6.3057e-010 oadev(n=199990) > 10 tau, 3.3140e-010 adev(n=19998), 3.3067e-010 oadev(n=199980) > 20 tau, 1.7872e-010 adev(n=9998), 1.7810e-010 oadev(n=199960) > 50 tau, 7.9428e-011 adev(n=3998), 8.1216e-011 oadev(n=199900) > 100 tau, 4.2352e-011 adev(n=1998), 4.3265e-011 oadev(n=199800) > 200 tau, 2.2001e-011 adev(n=998), 2.2593e-011 oadev(n=199600) > 500 tau, 9.6853e-012 adev(n=398), 9.5441e-012 oadev(n=199000) > 1000 tau, 5.0139e-012 adev(n=198), 5.0387e-012 oadev(n=198000) > 2000 tau, 2.7994e-012 adev(n=98), 2.7090e-012 oadev(n=196000) > 5000 tau, 1.4280e-012 adev(n=38), 1.2214e-012 oadev(n=190000) > 10000 tau, 7.4881e-013 adev(n=18), 6.5814e-013 oadev(n=180000) > 20000 tau, 7.6518e-013 adev(n=8), 3.7253e-013 oadev(n=160000) > 50000 tau, 2.4698e-014 adev(n=2), 1.3539e-013 oadev(n=100000) > > Obviously we don't have enough data now for a measurement of 100000 > tau but the results for the other tau are quite close, especially when > there are sufficient data points. Now this is discontinuous data, > exactly what I was trying to allude to. > > OK, so now I take only the top 200000 lines of the gps.dat file (head > -200000 gps.dat >gps2.dat) > > C:\Documents and Settings\Steve Rooke\Desktop>adev1.exe 1 > ** Sampling period: 1 s > ** Phase data scale factor: 1.000e+000 > ** Total phase samples: 200000 > ** Normal and Overlapping Allan deviation: > > 1 tau, 3.0411e-009 adev(n=199998), 3.0411e-009 oadev(n=199998) > 2 tau, 1.4985e-009 adev(n=99998), 1.4999e-009 oadev(n=199996) > 5 tau, 6.1964e-010 adev(n=39998), 6.2010e-010 oadev(n=199990) > 10 tau, 3.1315e-010 adev(n=19998), 3.1339e-010 oadev(n=199980) > 20 tau, 1.6499e-010 adev(n=9998), 1.6495e-010 oadev(n=199960) > 50 tau, 7.1425e-011 adev(n=3998), 7.3416e-011 oadev(n=199900) > 100 tau, 3.9940e-011 adev(n=1998), 4.0730e-011 oadev(n=199800) > 200 tau, 2.1488e-011 adev(n=998), 2.1558e-011 oadev(n=199600) > 500 tau, 8.4809e-012 adev(n=398), 9.0886e-012 oadev(n=199000) > 1000 tau, 4.9223e-012 adev(n=198), 4.7104e-012 oadev(n=198000) > 2000 tau, 2.4335e-012 adev(n=98), 2.4515e-012 oadev(n=196000) > 5000 tau, 1.0308e-012 adev(n=38), 1.0861e-012 oadev(n=190000) > 10000 tau, 5.9504e-013 adev(n=18), 6.1031e-013 oadev(n=180000) > 20000 tau, 3.6277e-013 adev(n=8), 3.1994e-013 oadev(n=160000) > 50000 tau, 1.0630e-013 adev(n=2), 1.6715e-013 oadev(n=100000) > > Is there any Linux tools for calculating adev as I'm having to run > Windows in a VMware session? > > 73, > Steve > > 2009/4/8 Tom Van Baak : > >> Steve, >> >> You've asked a couple of questions. Let me start with this. >> >> It is true that if one were only interested in the performance >> of a pendulum (or quartz or atomic) clock for averaging times >> of one day that all you would need is a series of time error >> (aka phase) measurements made about the same time once >> a day (doesn't have to be that exact). After one week, you'd >> have 7 error measurements (=6 frequency =5 stability points) >> and this is adequate to calculate the ADEV for tau 1 day. >> This alone allows you to rank your clock among all the other >> pendulum clocks out there. Note also you get time error and >> rate error from these few data points too. >> >> As another example, suppose you have a nice HP 10811A >> oscillator and want to measure its drift rate. In this case you >> could spend just 100 seconds and measure its frequency >> once a day, or even once every couple of days. Do this for >> a month and you'd have several dozen points. If you plot >> these frequency measurements you will likely see that they >> approximately fall on a line; the slope of the is the frequency >> drift rate of the 10811. The general shape of the points, or >> the fit of the line is a rough indication of how consistent the >> drift rate is or if it's increasing or decreasing. >> >> Neither of these examples require a lot of data. Both of these >> are real-world examples. >> >> OK so far? >> >> /tvb >> >> >> >> _______________________________________________ >> time-nuts mailing list -- time-nuts at febo.com >> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. >> >> > > > > From sar10538 at gmail.com Wed Apr 8 12:04:14 2009 From: sar10538 at gmail.com (Steve Rooke) Date: Thu, 9 Apr 2009 00:04:14 +1200 Subject: [time-nuts] Characterising frequency standards In-Reply-To: <49DC91B9.6090004@xtra.co.nz> References: <1231b6a80904070509m5b8bb638gbc088500444254c3@mail.gmail.com> <1231b6a80904080441p7a747a3h1f73bf8a2df30350@mail.gmail.com> <49DC91B9.6090004@xtra.co.nz> Message-ID: <1231b6a80904080504n4a3a22dcr247fae5df39ed840@mail.gmail.com> Bruce, But how does that explain the output of Tom's adev1 program which still seems to give a a good measurement at tau = 1s? 73, Steve 2009/4/8 Bruce Griffiths : > Steve > > If you delete every second measurement then your effective minimum > sampling time is now 2s and you can no longer calculate ADEV for tau< 2s. > You can still calculate ADEV for tau = 100,000 sec. > > If you delete all but the first 200,000 lines then you can calculated > ADEV for tau=1sec and up to tau= 25,000 sec with reasonable accuracy. > > You shouldn't lose sight of the fact that ADEV and OADEV are both > estimates of the Allan deviation. > > > Bruce > > Steve Rooke wrote: >> Tom, >> >> I understand fully the points that you have made but I have obviously >> not made my point clear to all and i apologise for my poor >> communication skills. >> >> This is what I'm getting at: >> >> Using your adev1.exe from http://www.leapsecond.com/tools/adev1.htm >> and processing various forms of gps.dat from >> http://www.leapsecond.com/pages/gpsdo-sim/gps.dat.gz. >> >> C:\Documents and Settings\Steve Rooke\Desktop>adev1.exe 1 > >> ** Sampling period: 1 s >> ** Phase data scale factor: 1.000e+000 >> ** Total phase samples: 400000 >> ** Normal and Overlapping Allan deviation: >> >> ? ? ? ?1 tau, 3.0127e-009 adev(n=399998), ? 3.0127e-009 oadev(n=399998) >> ? ? ? ?2 tau, 1.5110e-009 adev(n=199998), ? 1.5119e-009 oadev(n=399996) >> ? ? ? ?5 tau, 6.2107e-010 adev(n=79998), ? ?6.1983e-010 oadev(n=399990) >> ? ? ? 10 tau, 3.1578e-010 adev(n=39998), ? ?3.1549e-010 oadev(n=399980) >> ? ? ? 20 tau, 1.6531e-010 adev(n=19998), ? ?1.6534e-010 oadev(n=399960) >> ? ? ? 50 tau, 7.2513e-011 adev(n=7998), ? ? 7.3531e-011 oadev(n=399900) >> ? ? ?100 tau, 4.0029e-011 adev(n=3998), ? ? 4.0618e-011 oadev(n=399800) >> ? ? ?200 tau, 2.1512e-011 adev(n=1998), ? ? 2.1633e-011 oadev(n=399600) >> ? ? ?500 tau, 9.2193e-012 adev(n=798), ? ? ?9.1630e-012 oadev(n=399000) >> ? ? 1000 tau, 4.9719e-012 adev(n=398), ? ? ?4.7750e-012 oadev(n=398000) >> ? ? 2000 tau, 2.6742e-012 adev(n=198), ? ? ?2.5214e-012 oadev(n=396000) >> ? ? 5000 tau, 1.0010e-012 adev(n=78), ? ? ? 1.1032e-012 oadev(n=390000) >> ? ?10000 tau, 6.1333e-013 adev(n=38), ? ? ? 6.1039e-013 oadev(n=380000) >> ? ?20000 tau, 3.8162e-013 adev(n=18), ? ? ? 3.2913e-013 oadev(n=360000) >> ? ?50000 tau, 1.0228e-013 adev(n=6), ? ? ? ?1.5074e-013 oadev(n=300000) >> ? 100000 tau, 5.8577e-014 adev(n=2), ? ? ? ?6.7597e-014 oadev(n=200000) >> >> So far, so good. Now I delete every even line in the file which leaves >> me with 200000 lines of data (400000 lines in original gps.dat file). >> (awk 'and(NR, 1) == 0 {print}' gps1.dat) >> >> C:\Documents and Settings\Steve Rooke\Desktop>adev1.exe 1 > >> ** Sampling period: 1 s >> ** Phase data scale factor: 1.000e+000 >> ** Total phase samples: 200000 >> ** Normal and Overlapping Allan deviation: >> >> ? ? ? ?1 tau, 3.0257e-009 adev(n=199998), ? 3.0257e-009 oadev(n=199998) >> ? ? ? ?2 tau, 1.5373e-009 adev(n=99998), ? ?1.5345e-009 oadev(n=199996) >> ? ? ? ?5 tau, 6.3147e-010 adev(n=39998), ? ?6.3057e-010 oadev(n=199990) >> ? ? ? 10 tau, 3.3140e-010 adev(n=19998), ? ?3.3067e-010 oadev(n=199980) >> ? ? ? 20 tau, 1.7872e-010 adev(n=9998), ? ? 1.7810e-010 oadev(n=199960) >> ? ? ? 50 tau, 7.9428e-011 adev(n=3998), ? ? 8.1216e-011 oadev(n=199900) >> ? ? ?100 tau, 4.2352e-011 adev(n=1998), ? ? 4.3265e-011 oadev(n=199800) >> ? ? ?200 tau, 2.2001e-011 adev(n=998), ? ? ?2.2593e-011 oadev(n=199600) >> ? ? ?500 tau, 9.6853e-012 adev(n=398), ? ? ?9.5441e-012 oadev(n=199000) >> ? ? 1000 tau, 5.0139e-012 adev(n=198), ? ? ?5.0387e-012 oadev(n=198000) >> ? ? 2000 tau, 2.7994e-012 adev(n=98), ? ? ? 2.7090e-012 oadev(n=196000) >> ? ? 5000 tau, 1.4280e-012 adev(n=38), ? ? ? 1.2214e-012 oadev(n=190000) >> ? ?10000 tau, 7.4881e-013 adev(n=18), ? ? ? 6.5814e-013 oadev(n=180000) >> ? ?20000 tau, 7.6518e-013 adev(n=8), ? ? ? ?3.7253e-013 oadev(n=160000) >> ? ?50000 tau, 2.4698e-014 adev(n=2), ? ? ? ?1.3539e-013 oadev(n=100000) >> >> Obviously we don't have enough data now for a measurement of 100000 >> tau but the results for the other tau are quite close, especially when >> there are sufficient data points. Now this is discontinuous data, >> exactly what I was trying to allude to. >> >> OK, so now I take only the top 200000 lines of the gps.dat file (head >> -200000 gps.dat >gps2.dat) >> >> C:\Documents and Settings\Steve Rooke\Desktop>adev1.exe 1 > >> ** Sampling period: 1 s >> ** Phase data scale factor: 1.000e+000 >> ** Total phase samples: 200000 >> ** Normal and Overlapping Allan deviation: >> >> ? ? ? ?1 tau, 3.0411e-009 adev(n=199998), ? 3.0411e-009 oadev(n=199998) >> ? ? ? ?2 tau, 1.4985e-009 adev(n=99998), ? ?1.4999e-009 oadev(n=199996) >> ? ? ? ?5 tau, 6.1964e-010 adev(n=39998), ? ?6.2010e-010 oadev(n=199990) >> ? ? ? 10 tau, 3.1315e-010 adev(n=19998), ? ?3.1339e-010 oadev(n=199980) >> ? ? ? 20 tau, 1.6499e-010 adev(n=9998), ? ? 1.6495e-010 oadev(n=199960) >> ? ? ? 50 tau, 7.1425e-011 adev(n=3998), ? ? 7.3416e-011 oadev(n=199900) >> ? ? ?100 tau, 3.9940e-011 adev(n=1998), ? ? 4.0730e-011 oadev(n=199800) >> ? ? ?200 tau, 2.1488e-011 adev(n=998), ? ? ?2.1558e-011 oadev(n=199600) >> ? ? ?500 tau, 8.4809e-012 adev(n=398), ? ? ?9.0886e-012 oadev(n=199000) >> ? ? 1000 tau, 4.9223e-012 adev(n=198), ? ? ?4.7104e-012 oadev(n=198000) >> ? ? 2000 tau, 2.4335e-012 adev(n=98), ? ? ? 2.4515e-012 oadev(n=196000) >> ? ? 5000 tau, 1.0308e-012 adev(n=38), ? ? ? 1.0861e-012 oadev(n=190000) >> ? ?10000 tau, 5.9504e-013 adev(n=18), ? ? ? 6.1031e-013 oadev(n=180000) >> ? ?20000 tau, 3.6277e-013 adev(n=8), ? ? ? ?3.1994e-013 oadev(n=160000) >> ? ?50000 tau, 1.0630e-013 adev(n=2), ? ? ? ?1.6715e-013 oadev(n=100000) >> >> Is there any Linux tools for calculating adev as I'm having to run >> Windows in a VMware session? >> >> 73, >> Steve >> >> 2009/4/8 Tom Van Baak : >> >>> Steve, >>> >>> You've asked a couple of questions. Let me start with this. >>> >>> It is true that if one were only interested in the performance >>> of a pendulum (or quartz or atomic) clock for averaging times >>> of one day that all you would need is a series of time error >>> (aka phase) measurements made about the same time once >>> a day (doesn't have to be that exact). After one week, you'd >>> have 7 error measurements (=6 frequency =5 stability points) >>> and this is adequate to calculate the ADEV for tau 1 day. >>> This alone allows you to rank your clock among all the other >>> pendulum clocks out there. Note also you get time error and >>> rate error from these few data points too. >>> >>> As another example, suppose you have a nice HP 10811A >>> oscillator and want to measure its drift rate. In this case you >>> could spend just 100 seconds and measure its frequency >>> once a day, or even once every couple of days. Do this for >>> a month and you'd have several dozen points. If you plot >>> these frequency measurements you will likely see that they >>> approximately fall on a line; the slope of the is the frequency >>> drift rate of the 10811. The general shape of the points, or >>> the fit of the line is a rough indication of how consistent the >>> drift rate is or if it's increasing or decreasing. >>> >>> Neither of these examples require a lot of data. Both of these >>> are real-world examples. >>> >>> OK so far? >>> >>> /tvb >>> >>> >>> >>> _______________________________________________ >>> time-nuts mailing list -- time-nuts at febo.com >>> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >>> and follow the instructions there. >>> >>> >> >> >> >> > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > -- Steve Rooke - ZL3TUV & G8KVD & JAKDTTNW Omnium finis imminet From bruce.griffiths at xtra.co.nz Wed Apr 8 12:11:17 2009 From: bruce.griffiths at xtra.co.nz (Bruce Griffiths) Date: Thu, 09 Apr 2009 00:11:17 +1200 Subject: [time-nuts] Characterising frequency standards In-Reply-To: <1231b6a80904080504n4a3a22dcr247fae5df39ed840@mail.gmail.com> References: <1231b6a80904070509m5b8bb638gbc088500444254c3@mail.gmail.com> <1231b6a80904080441p7a747a3h1f73bf8a2df30350@mail.gmail.com> <49DC91B9.6090004@xtra.co.nz> <1231b6a80904080504n4a3a22dcr247fae5df39ed840@mail.gmail.com> Message-ID: <49DC9465.7070109@xtra.co.nz> Steve It cant, it must be a matter of interpretation. Perhaps it means something like: 1 tau means tau = 1x the interval between consecutive measurements. 2 tau means tau = 2x the interval between consecutive measurements 100000 tau means tau = 100,000 x the interval between consecutive measurements Bruce Steve Rooke wrote: > Bruce, > > But how does that explain the output of Tom's adev1 program which > still seems to give a a good measurement at tau = 1s? > > 73, > Steve > > 2009/4/8 Bruce Griffiths : > >> Steve >> >> If you delete every second measurement then your effective minimum >> sampling time is now 2s and you can no longer calculate ADEV for tau< 2s. >> You can still calculate ADEV for tau = 100,000 sec. >> >> If you delete all but the first 200,000 lines then you can calculated >> ADEV for tau=1sec and up to tau= 25,000 sec with reasonable accuracy. >> >> You shouldn't lose sight of the fact that ADEV and OADEV are both >> estimates of the Allan deviation. >> >> >> Bruce >> >> Steve Rooke wrote: >> >>> Tom, >>> >>> I understand fully the points that you have made but I have obviously >>> not made my point clear to all and i apologise for my poor >>> communication skills. >>> >>> This is what I'm getting at: >>> >>> Using your adev1.exe from http://www.leapsecond.com/tools/adev1.htm >>> and processing various forms of gps.dat from >>> http://www.leapsecond.com/pages/gpsdo-sim/gps.dat.gz. >>> >>> C:\Documents and Settings\Steve Rooke\Desktop>adev1.exe 1 >> >>> ** Sampling period: 1 s >>> ** Phase data scale factor: 1.000e+000 >>> ** Total phase samples: 400000 >>> ** Normal and Overlapping Allan deviation: >>> >>> 1 tau, 3.0127e-009 adev(n=399998), 3.0127e-009 oadev(n=399998) >>> 2 tau, 1.5110e-009 adev(n=199998), 1.5119e-009 oadev(n=399996) >>> 5 tau, 6.2107e-010 adev(n=79998), 6.1983e-010 oadev(n=399990) >>> 10 tau, 3.1578e-010 adev(n=39998), 3.1549e-010 oadev(n=399980) >>> 20 tau, 1.6531e-010 adev(n=19998), 1.6534e-010 oadev(n=399960) >>> 50 tau, 7.2513e-011 adev(n=7998), 7.3531e-011 oadev(n=399900) >>> 100 tau, 4.0029e-011 adev(n=3998), 4.0618e-011 oadev(n=399800) >>> 200 tau, 2.1512e-011 adev(n=1998), 2.1633e-011 oadev(n=399600) >>> 500 tau, 9.2193e-012 adev(n=798), 9.1630e-012 oadev(n=399000) >>> 1000 tau, 4.9719e-012 adev(n=398), 4.7750e-012 oadev(n=398000) >>> 2000 tau, 2.6742e-012 adev(n=198), 2.5214e-012 oadev(n=396000) >>> 5000 tau, 1.0010e-012 adev(n=78), 1.1032e-012 oadev(n=390000) >>> 10000 tau, 6.1333e-013 adev(n=38), 6.1039e-013 oadev(n=380000) >>> 20000 tau, 3.8162e-013 adev(n=18), 3.2913e-013 oadev(n=360000) >>> 50000 tau, 1.0228e-013 adev(n=6), 1.5074e-013 oadev(n=300000) >>> 100000 tau, 5.8577e-014 adev(n=2), 6.7597e-014 oadev(n=200000) >>> >>> So far, so good. Now I delete every even line in the file which leaves >>> me with 200000 lines of data (400000 lines in original gps.dat file). >>> (awk 'and(NR, 1) == 0 {print}' gps1.dat) >>> >>> C:\Documents and Settings\Steve Rooke\Desktop>adev1.exe 1 >> >>> ** Sampling period: 1 s >>> ** Phase data scale factor: 1.000e+000 >>> ** Total phase samples: 200000 >>> ** Normal and Overlapping Allan deviation: >>> >>> 1 tau, 3.0257e-009 adev(n=199998), 3.0257e-009 oadev(n=199998) >>> 2 tau, 1.5373e-009 adev(n=99998), 1.5345e-009 oadev(n=199996) >>> 5 tau, 6.3147e-010 adev(n=39998), 6.3057e-010 oadev(n=199990) >>> 10 tau, 3.3140e-010 adev(n=19998), 3.3067e-010 oadev(n=199980) >>> 20 tau, 1.7872e-010 adev(n=9998), 1.7810e-010 oadev(n=199960) >>> 50 tau, 7.9428e-011 adev(n=3998), 8.1216e-011 oadev(n=199900) >>> 100 tau, 4.2352e-011 adev(n=1998), 4.3265e-011 oadev(n=199800) >>> 200 tau, 2.2001e-011 adev(n=998), 2.2593e-011 oadev(n=199600) >>> 500 tau, 9.6853e-012 adev(n=398), 9.5441e-012 oadev(n=199000) >>> 1000 tau, 5.0139e-012 adev(n=198), 5.0387e-012 oadev(n=198000) >>> 2000 tau, 2.7994e-012 adev(n=98), 2.7090e-012 oadev(n=196000) >>> 5000 tau, 1.4280e-012 adev(n=38), 1.2214e-012 oadev(n=190000) >>> 10000 tau, 7.4881e-013 adev(n=18), 6.5814e-013 oadev(n=180000) >>> 20000 tau, 7.6518e-013 adev(n=8), 3.7253e-013 oadev(n=160000) >>> 50000 tau, 2.4698e-014 adev(n=2), 1.3539e-013 oadev(n=100000) >>> >>> Obviously we don't have enough data now for a measurement of 100000 >>> tau but the results for the other tau are quite close, especially when >>> there are sufficient data points. Now this is discontinuous data, >>> exactly what I was trying to allude to. >>> >>> OK, so now I take only the top 200000 lines of the gps.dat file (head >>> -200000 gps.dat >gps2.dat) >>> >>> C:\Documents and Settings\Steve Rooke\Desktop>adev1.exe 1 >> >>> ** Sampling period: 1 s >>> ** Phase data scale factor: 1.000e+000 >>> ** Total phase samples: 200000 >>> ** Normal and Overlapping Allan deviation: >>> >>> 1 tau, 3.0411e-009 adev(n=199998), 3.0411e-009 oadev(n=199998) >>> 2 tau, 1.4985e-009 adev(n=99998), 1.4999e-009 oadev(n=199996) >>> 5 tau, 6.1964e-010 adev(n=39998), 6.2010e-010 oadev(n=199990) >>> 10 tau, 3.1315e-010 adev(n=19998), 3.1339e-010 oadev(n=199980) >>> 20 tau, 1.6499e-010 adev(n=9998), 1.6495e-010 oadev(n=199960) >>> 50 tau, 7.1425e-011 adev(n=3998), 7.3416e-011 oadev(n=199900) >>> 100 tau, 3.9940e-011 adev(n=1998), 4.0730e-011 oadev(n=199800) >>> 200 tau, 2.1488e-011 adev(n=998), 2.1558e-011 oadev(n=199600) >>> 500 tau, 8.4809e-012 adev(n=398), 9.0886e-012 oadev(n=199000) >>> 1000 tau, 4.9223e-012 adev(n=198), 4.7104e-012 oadev(n=198000) >>> 2000 tau, 2.4335e-012 adev(n=98), 2.4515e-012 oadev(n=196000) >>> 5000 tau, 1.0308e-012 adev(n=38), 1.0861e-012 oadev(n=190000) >>> 10000 tau, 5.9504e-013 adev(n=18), 6.1031e-013 oadev(n=180000) >>> 20000 tau, 3.6277e-013 adev(n=8), 3.1994e-013 oadev(n=160000) >>> 50000 tau, 1.0630e-013 adev(n=2), 1.6715e-013 oadev(n=100000) >>> >>> Is there any Linux tools for calculating adev as I'm having to run >>> Windows in a VMware session? >>> >>> 73, >>> Steve >>> >>> 2009/4/8 Tom Van Baak : >>> >>> >>>> Steve, >>>> >>>> You've asked a couple of questions. Let me start with this. >>>> >>>> It is true that if one were only interested in the performance >>>> of a pendulum (or quartz or atomic) clock for averaging times >>>> of one day that all you would need is a series of time error >>>> (aka phase) measurements made about the same time once >>>> a day (doesn't have to be that exact). After one week, you'd >>>> have 7 error measurements (=6 frequency =5 stability points) >>>> and this is adequate to calculate the ADEV for tau 1 day. >>>> This alone allows you to rank your clock among all the other >>>> pendulum clocks out there. Note also you get time error and >>>> rate error from these few data points too. >>>> >>>> As another example, suppose you have a nice HP 10811A >>>> oscillator and want to measure its drift rate. In this case you >>>> could spend just 100 seconds and measure its frequency >>>> once a day, or even once every couple of days. Do this for >>>> a month and you'd have several dozen points. If you plot >>>> these frequency measurements you will likely see that they >>>> approximately fall on a line; the slope of the is the frequency >>>> drift rate of the 10811. The general shape of the points, or >>>> the fit of the line is a rough indication of how consistent the >>>> drift rate is or if it's increasing or decreasing. >>>> >>>> Neither of these examples require a lot of data. Both of these >>>> are real-world examples. >>>> >>>> OK so far? >>>> >>>> /tvb >>>> >>>> >>>> >>>> _______________________________________________ >>>> time-nuts mailing list -- time-nuts at febo.com >>>> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >>>> and follow the instructions there. >>>> >>>> >>>> >>> >>> >>> >> _______________________________________________ >> time-nuts mailing list -- time-nuts at febo.com >> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. >> >> > > > > From sar10538 at gmail.com Wed Apr 8 12:27:28 2009 From: sar10538 at gmail.com (Steve Rooke) Date: Thu, 9 Apr 2009 00:27:28 +1200 Subject: [time-nuts] Characterising frequency standards In-Reply-To: <49DC9465.7070109@xtra.co.nz> References: <1231b6a80904070509m5b8bb638gbc088500444254c3@mail.gmail.com> <1231b6a80904080441p7a747a3h1f73bf8a2df30350@mail.gmail.com> <49DC91B9.6090004@xtra.co.nz> <1231b6a80904080504n4a3a22dcr247fae5df39ed840@mail.gmail.com> <49DC9465.7070109@xtra.co.nz> Message-ID: <1231b6a80904080527m182f0f74h70f8a3eda5693382@mail.gmail.com> Bruce, I hear what you say but the results seem to correlate quite well:- 1 tau, 3.0127e-009 adev(n=399998), 3.0127e-009 oadev(n=399998) 1 tau, 3.0257e-009 adev(n=199998), 3.0257e-009 oadev(n=199998) And using the first half of the data:- 1 tau, 3.0411e-009 adev(n=199998), 3.0411e-009 oadev(n=199998) So I'm trying to understand why this won't work. 73, Steve 2009/4/9 Bruce Griffiths : > Steve > > It cant, it must be a matter of interpretation. > Perhaps it means something like: > > 1 tau means tau = 1x the interval between consecutive measurements. > 2 tau means tau = 2x the interval between consecutive measurements > > 100000 tau means ?tau = 100,000 x the interval between ?consecutive > measurements > > Bruce > > Steve Rooke wrote: >> Bruce, >> >> But how does that explain the output of Tom's adev1 program which >> still seems to give a a good measurement at tau = 1s? >> >> 73, >> Steve >> >> 2009/4/8 Bruce Griffiths : >> >>> Steve >>> >>> If you delete every second measurement then your effective minimum >>> sampling time is now 2s and you can no longer calculate ADEV for tau< 2s. >>> You can still calculate ADEV for tau = 100,000 sec. >>> >>> If you delete all but the first 200,000 lines then you can calculated >>> ADEV for tau=1sec and up to tau= 25,000 sec with reasonable accuracy. >>> >>> You shouldn't lose sight of the fact that ADEV and OADEV are both >>> estimates of the Allan deviation. >>> >>> >>> Bruce >>> >>> Steve Rooke wrote: >>> >>>> Tom, >>>> >>>> I understand fully the points that you have made but I have obviously >>>> not made my point clear to all and i apologise for my poor >>>> communication skills. >>>> >>>> This is what I'm getting at: >>>> >>>> Using your adev1.exe from http://www.leapsecond.com/tools/adev1.htm >>>> and processing various forms of gps.dat from >>>> http://www.leapsecond.com/pages/gpsdo-sim/gps.dat.gz. >>>> >>>> C:\Documents and Settings\Steve Rooke\Desktop>adev1.exe 1 >>> >>>> ** Sampling period: 1 s >>>> ** Phase data scale factor: 1.000e+000 >>>> ** Total phase samples: 400000 >>>> ** Normal and Overlapping Allan deviation: >>>> >>>> ? ? ? ?1 tau, 3.0127e-009 adev(n=399998), ? 3.0127e-009 oadev(n=399998) >>>> ? ? ? ?2 tau, 1.5110e-009 adev(n=199998), ? 1.5119e-009 oadev(n=399996) >>>> ? ? ? ?5 tau, 6.2107e-010 adev(n=79998), ? ?6.1983e-010 oadev(n=399990) >>>> ? ? ? 10 tau, 3.1578e-010 adev(n=39998), ? ?3.1549e-010 oadev(n=399980) >>>> ? ? ? 20 tau, 1.6531e-010 adev(n=19998), ? ?1.6534e-010 oadev(n=399960) >>>> ? ? ? 50 tau, 7.2513e-011 adev(n=7998), ? ? 7.3531e-011 oadev(n=399900) >>>> ? ? ?100 tau, 4.0029e-011 adev(n=3998), ? ? 4.0618e-011 oadev(n=399800) >>>> ? ? ?200 tau, 2.1512e-011 adev(n=1998), ? ? 2.1633e-011 oadev(n=399600) >>>> ? ? ?500 tau, 9.2193e-012 adev(n=798), ? ? ?9.1630e-012 oadev(n=399000) >>>> ? ? 1000 tau, 4.9719e-012 adev(n=398), ? ? ?4.7750e-012 oadev(n=398000) >>>> ? ? 2000 tau, 2.6742e-012 adev(n=198), ? ? ?2.5214e-012 oadev(n=396000) >>>> ? ? 5000 tau, 1.0010e-012 adev(n=78), ? ? ? 1.1032e-012 oadev(n=390000) >>>> ? ?10000 tau, 6.1333e-013 adev(n=38), ? ? ? 6.1039e-013 oadev(n=380000) >>>> ? ?20000 tau, 3.8162e-013 adev(n=18), ? ? ? 3.2913e-013 oadev(n=360000) >>>> ? ?50000 tau, 1.0228e-013 adev(n=6), ? ? ? ?1.5074e-013 oadev(n=300000) >>>> ? 100000 tau, 5.8577e-014 adev(n=2), ? ? ? ?6.7597e-014 oadev(n=200000) >>>> >>>> So far, so good. Now I delete every even line in the file which leaves >>>> me with 200000 lines of data (400000 lines in original gps.dat file). >>>> (awk 'and(NR, 1) == 0 {print}' gps1.dat) >>>> >>>> C:\Documents and Settings\Steve Rooke\Desktop>adev1.exe 1 >>> >>>> ** Sampling period: 1 s >>>> ** Phase data scale factor: 1.000e+000 >>>> ** Total phase samples: 200000 >>>> ** Normal and Overlapping Allan deviation: >>>> >>>> ? ? ? ?1 tau, 3.0257e-009 adev(n=199998), ? 3.0257e-009 oadev(n=199998) >>>> ? ? ? ?2 tau, 1.5373e-009 adev(n=99998), ? ?1.5345e-009 oadev(n=199996) >>>> ? ? ? ?5 tau, 6.3147e-010 adev(n=39998), ? ?6.3057e-010 oadev(n=199990) >>>> ? ? ? 10 tau, 3.3140e-010 adev(n=19998), ? ?3.3067e-010 oadev(n=199980) >>>> ? ? ? 20 tau, 1.7872e-010 adev(n=9998), ? ? 1.7810e-010 oadev(n=199960) >>>> ? ? ? 50 tau, 7.9428e-011 adev(n=3998), ? ? 8.1216e-011 oadev(n=199900) >>>> ? ? ?100 tau, 4.2352e-011 adev(n=1998), ? ? 4.3265e-011 oadev(n=199800) >>>> ? ? ?200 tau, 2.2001e-011 adev(n=998), ? ? ?2.2593e-011 oadev(n=199600) >>>> ? ? ?500 tau, 9.6853e-012 adev(n=398), ? ? ?9.5441e-012 oadev(n=199000) >>>> ? ? 1000 tau, 5.0139e-012 adev(n=198), ? ? ?5.0387e-012 oadev(n=198000) >>>> ? ? 2000 tau, 2.7994e-012 adev(n=98), ? ? ? 2.7090e-012 oadev(n=196000) >>>> ? ? 5000 tau, 1.4280e-012 adev(n=38), ? ? ? 1.2214e-012 oadev(n=190000) >>>> ? ?10000 tau, 7.4881e-013 adev(n=18), ? ? ? 6.5814e-013 oadev(n=180000) >>>> ? ?20000 tau, 7.6518e-013 adev(n=8), ? ? ? ?3.7253e-013 oadev(n=160000) >>>> ? ?50000 tau, 2.4698e-014 adev(n=2), ? ? ? ?1.3539e-013 oadev(n=100000) >>>> >>>> Obviously we don't have enough data now for a measurement of 100000 >>>> tau but the results for the other tau are quite close, especially when >>>> there are sufficient data points. Now this is discontinuous data, >>>> exactly what I was trying to allude to. >>>> >>>> OK, so now I take only the top 200000 lines of the gps.dat file (head >>>> -200000 gps.dat >gps2.dat) >>>> >>>> C:\Documents and Settings\Steve Rooke\Desktop>adev1.exe 1 >>> >>>> ** Sampling period: 1 s >>>> ** Phase data scale factor: 1.000e+000 >>>> ** Total phase samples: 200000 >>>> ** Normal and Overlapping Allan deviation: >>>> >>>> ? ? ? ?1 tau, 3.0411e-009 adev(n=199998), ? 3.0411e-009 oadev(n=199998) >>>> ? ? ? ?2 tau, 1.4985e-009 adev(n=99998), ? ?1.4999e-009 oadev(n=199996) >>>> ? ? ? ?5 tau, 6.1964e-010 adev(n=39998), ? ?6.2010e-010 oadev(n=199990) >>>> ? ? ? 10 tau, 3.1315e-010 adev(n=19998), ? ?3.1339e-010 oadev(n=199980) >>>> ? ? ? 20 tau, 1.6499e-010 adev(n=9998), ? ? 1.6495e-010 oadev(n=199960) >>>> ? ? ? 50 tau, 7.1425e-011 adev(n=3998), ? ? 7.3416e-011 oadev(n=199900) >>>> ? ? ?100 tau, 3.9940e-011 adev(n=1998), ? ? 4.0730e-011 oadev(n=199800) >>>> ? ? ?200 tau, 2.1488e-011 adev(n=998), ? ? ?2.1558e-011 oadev(n=199600) >>>> ? ? ?500 tau, 8.4809e-012 adev(n=398), ? ? ?9.0886e-012 oadev(n=199000) >>>> ? ? 1000 tau, 4.9223e-012 adev(n=198), ? ? ?4.7104e-012 oadev(n=198000) >>>> ? ? 2000 tau, 2.4335e-012 adev(n=98), ? ? ? 2.4515e-012 oadev(n=196000) >>>> ? ? 5000 tau, 1.0308e-012 adev(n=38), ? ? ? 1.0861e-012 oadev(n=190000) >>>> ? ?10000 tau, 5.9504e-013 adev(n=18), ? ? ? 6.1031e-013 oadev(n=180000) >>>> ? ?20000 tau, 3.6277e-013 adev(n=8), ? ? ? ?3.1994e-013 oadev(n=160000) >>>> ? ?50000 tau, 1.0630e-013 adev(n=2), ? ? ? ?1.6715e-013 oadev(n=100000) >>>> >>>> Is there any Linux tools for calculating adev as I'm having to run >>>> Windows in a VMware session? >>>> >>>> 73, >>>> Steve >>>> >>>> 2009/4/8 Tom Van Baak : >>>> >>>> >>>>> Steve, >>>>> >>>>> You've asked a couple of questions. Let me start with this. >>>>> >>>>> It is true that if one were only interested in the performance >>>>> of a pendulum (or quartz or atomic) clock for averaging times >>>>> of one day that all you would need is a series of time error >>>>> (aka phase) measurements made about the same time once >>>>> a day (doesn't have to be that exact). After one week, you'd >>>>> have 7 error measurements (=6 frequency =5 stability points) >>>>> and this is adequate to calculate the ADEV for tau 1 day. >>>>> This alone allows you to rank your clock among all the other >>>>> pendulum clocks out there. Note also you get time error and >>>>> rate error from these few data points too. >>>>> >>>>> As another example, suppose you have a nice HP 10811A >>>>> oscillator and want to measure its drift rate. In this case you >>>>> could spend just 100 seconds and measure its frequency >>>>> once a day, or even once every couple of days. Do this for >>>>> a month and you'd have several dozen points. If you plot >>>>> these frequency measurements you will likely see that they >>>>> approximately fall on a line; the slope of the is the frequency >>>>> drift rate of the 10811. The general shape of the points, or >>>>> the fit of the line is a rough indication of how consistent the >>>>> drift rate is or if it's increasing or decreasing. >>>>> >>>>> Neither of these examples require a lot of data. Both of these >>>>> are real-world examples. >>>>> >>>>> OK so far? >>>>> >>>>> /tvb >>>>> >>>>> >>>>> >>>>> _______________________________________________ >>>>> time-nuts mailing list -- time-nuts at febo.com >>>>> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >>>>> and follow the instructions there. >>>>> >>>>> >>>>> >>>> >>>> >>>> >>> _______________________________________________ >>> time-nuts mailing list -- time-nuts at febo.com >>> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >>> and follow the instructions there. >>> >>> >> >> >> >> > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > -- Steve Rooke - ZL3TUV & G8KVD & JAKDTTNW Omnium finis imminet From bruce.griffiths at xtra.co.nz Wed Apr 8 12:27:54 2009 From: bruce.griffiths at xtra.co.nz (Bruce Griffiths) Date: Thu, 09 Apr 2009 00:27:54 +1200 Subject: [time-nuts] Characterising frequency standards In-Reply-To: <1231b6a80904080504n4a3a22dcr247fae5df39ed840@mail.gmail.com> References: <1231b6a80904070509m5b8bb638gbc088500444254c3@mail.gmail.com> <1231b6a80904080441p7a747a3h1f73bf8a2df30350@mail.gmail.com> <49DC91B9.6090004@xtra.co.nz> <1231b6a80904080504n4a3a22dcr247fae5df39ed840@mail.gmail.com> Message-ID: <49DC984A.2010509@xtra.co.nz> Steve The data file doesn't include the time interval between samples so do you set this in some way? If so you need to set it to 1s for the unaltered data, to 2s when you take every 2nd sample, and 1s when you take the first 200,000 samples. In principle you could use CANVAS (available on request from USNO - however you may have to wait a few days while they decide whether to grant your request.) for such analysis in Linux but you would then need the Linux version of Matlab. Or you could request that it be compiled for Linux - a fairly simple task if one has the Linux version of Matlab. In principle you should be able to port the m source files to Scilab, but there are some subtle differences between Scilab and Matlab so this may take a while. Bruce Steve Rooke wrote: > Bruce, > > But how does that explain the output of Tom's adev1 program which > still seems to give a a good measurement at tau = 1s? > > 73, > Steve > > 2009/4/8 Bruce Griffiths : > >> Steve >> >> If you delete every second measurement then your effective minimum >> sampling time is now 2s and you can no longer calculate ADEV for tau< 2s. >> You can still calculate ADEV for tau = 100,000 sec. >> >> If you delete all but the first 200,000 lines then you can calculated >> ADEV for tau=1sec and up to tau= 25,000 sec with reasonable accuracy. >> >> You shouldn't lose sight of the fact that ADEV and OADEV are both >> estimates of the Allan deviation. >> >> >> Bruce >> >> Steve Rooke wrote: >> >>> Tom, >>> >>> I understand fully the points that you have made but I have obviously >>> not made my point clear to all and i apologise for my poor >>> communication skills. >>> >>> This is what I'm getting at: >>> >>> Using your adev1.exe from http://www.leapsecond.com/tools/adev1.htm >>> and processing various forms of gps.dat from >>> http://www.leapsecond.com/pages/gpsdo-sim/gps.dat.gz. >>> >>> C:\Documents and Settings\Steve Rooke\Desktop>adev1.exe 1 >> >>> ** Sampling period: 1 s >>> ** Phase data scale factor: 1.000e+000 >>> ** Total phase samples: 400000 >>> ** Normal and Overlapping Allan deviation: >>> >>> 1 tau, 3.0127e-009 adev(n=399998), 3.0127e-009 oadev(n=399998) >>> 2 tau, 1.5110e-009 adev(n=199998), 1.5119e-009 oadev(n=399996) >>> 5 tau, 6.2107e-010 adev(n=79998), 6.1983e-010 oadev(n=399990) >>> 10 tau, 3.1578e-010 adev(n=39998), 3.1549e-010 oadev(n=399980) >>> 20 tau, 1.6531e-010 adev(n=19998), 1.6534e-010 oadev(n=399960) >>> 50 tau, 7.2513e-011 adev(n=7998), 7.3531e-011 oadev(n=399900) >>> 100 tau, 4.0029e-011 adev(n=3998), 4.0618e-011 oadev(n=399800) >>> 200 tau, 2.1512e-011 adev(n=1998), 2.1633e-011 oadev(n=399600) >>> 500 tau, 9.2193e-012 adev(n=798), 9.1630e-012 oadev(n=399000) >>> 1000 tau, 4.9719e-012 adev(n=398), 4.7750e-012 oadev(n=398000) >>> 2000 tau, 2.6742e-012 adev(n=198), 2.5214e-012 oadev(n=396000) >>> 5000 tau, 1.0010e-012 adev(n=78), 1.1032e-012 oadev(n=390000) >>> 10000 tau, 6.1333e-013 adev(n=38), 6.1039e-013 oadev(n=380000) >>> 20000 tau, 3.8162e-013 adev(n=18), 3.2913e-013 oadev(n=360000) >>> 50000 tau, 1.0228e-013 adev(n=6), 1.5074e-013 oadev(n=300000) >>> 100000 tau, 5.8577e-014 adev(n=2), 6.7597e-014 oadev(n=200000) >>> >>> So far, so good. Now I delete every even line in the file which leaves >>> me with 200000 lines of data (400000 lines in original gps.dat file). >>> (awk 'and(NR, 1) == 0 {print}' gps1.dat) >>> >>> C:\Documents and Settings\Steve Rooke\Desktop>adev1.exe 1 >> >>> ** Sampling period: 1 s >>> INCORRECT!! sampling period is now 2s. >>> ** Phase data scale factor: 1.000e+000 >>> ** Total phase samples: 200000 >>> ** Normal and Overlapping Allan deviation: >>> >>> 1 tau, 3.0257e-009 adev(n=199998), 3.0257e-009 oadev(n=199998) >>> 2 tau, 1.5373e-009 adev(n=99998), 1.5345e-009 oadev(n=199996) >>> 5 tau, 6.3147e-010 adev(n=39998), 6.3057e-010 oadev(n=199990) >>> 10 tau, 3.3140e-010 adev(n=19998), 3.3067e-010 oadev(n=199980) >>> 20 tau, 1.7872e-010 adev(n=9998), 1.7810e-010 oadev(n=199960) >>> 50 tau, 7.9428e-011 adev(n=3998), 8.1216e-011 oadev(n=199900) >>> 100 tau, 4.2352e-011 adev(n=1998), 4.3265e-011 oadev(n=199800) >>> 200 tau, 2.2001e-011 adev(n=998), 2.2593e-011 oadev(n=199600) >>> 500 tau, 9.6853e-012 adev(n=398), 9.5441e-012 oadev(n=199000) >>> 1000 tau, 5.0139e-012 adev(n=198), 5.0387e-012 oadev(n=198000) >>> 2000 tau, 2.7994e-012 adev(n=98), 2.7090e-012 oadev(n=196000) >>> 5000 tau, 1.4280e-012 adev(n=38), 1.2214e-012 oadev(n=190000) >>> 10000 tau, 7.4881e-013 adev(n=18), 6.5814e-013 oadev(n=180000) >>> 20000 tau, 7.6518e-013 adev(n=8), 3.7253e-013 oadev(n=160000) >>> 50000 tau, 2.4698e-014 adev(n=2), 1.3539e-013 oadev(n=100000) >>> >>> Obviously we don't have enough data now for a measurement of 100000 >>> tau but the results for the other tau are quite close, especially when >>> there are sufficient data points. Now this is discontinuous data, >>> exactly what I was trying to allude to. >>> >>> OK, so now I take only the top 200000 lines of the gps.dat file (head >>> -200000 gps.dat >gps2.dat) >>> >>> C:\Documents and Settings\Steve Rooke\Desktop>adev1.exe 1 >> >>> ** Sampling period: 1 s >>> ** Phase data scale factor: 1.000e+000 >>> ** Total phase samples: 200000 >>> ** Normal and Overlapping Allan deviation: >>> >>> 1 tau, 3.0411e-009 adev(n=199998), 3.0411e-009 oadev(n=199998) >>> 2 tau, 1.4985e-009 adev(n=99998), 1.4999e-009 oadev(n=199996) >>> 5 tau, 6.1964e-010 adev(n=39998), 6.2010e-010 oadev(n=199990) >>> 10 tau, 3.1315e-010 adev(n=19998), 3.1339e-010 oadev(n=199980) >>> 20 tau, 1.6499e-010 adev(n=9998), 1.6495e-010 oadev(n=199960) >>> 50 tau, 7.1425e-011 adev(n=3998), 7.3416e-011 oadev(n=199900) >>> 100 tau, 3.9940e-011 adev(n=1998), 4.0730e-011 oadev(n=199800) >>> 200 tau, 2.1488e-011 adev(n=998), 2.1558e-011 oadev(n=199600) >>> 500 tau, 8.4809e-012 adev(n=398), 9.0886e-012 oadev(n=199000) >>> 1000 tau, 4.9223e-012 adev(n=198), 4.7104e-012 oadev(n=198000) >>> 2000 tau, 2.4335e-012 adev(n=98), 2.4515e-012 oadev(n=196000) >>> 5000 tau, 1.0308e-012 adev(n=38), 1.0861e-012 oadev(n=190000) >>> 10000 tau, 5.9504e-013 adev(n=18), 6.1031e-013 oadev(n=180000) >>> 20000 tau, 3.6277e-013 adev(n=8), 3.1994e-013 oadev(n=160000) >>> 50000 tau, 1.0630e-013 adev(n=2), 1.6715e-013 oadev(n=100000) >>> >>> Is there any Linux tools for calculating adev as I'm having to run >>> Windows in a VMware session? >>> >>> 73, >>> Steve >>> >>> 2009/4/8 Tom Van Baak : >>> >>> >>>> Steve, >>>> >>>> You've asked a couple of questions. Let me start with this. >>>> >>>> It is true that if one were only interested in the performance >>>> of a pendulum (or quartz or atomic) clock for averaging times >>>> of one day that all you would need is a series of time error >>>> (aka phase) measurements made about the same time once >>>> a day (doesn't have to be that exact). After one week, you'd >>>> have 7 error measurements (=6 frequency =5 stability points) >>>> and this is adequate to calculate the ADEV for tau 1 day. >>>> This alone allows you to rank your clock among all the other >>>> pendulum clocks out there. Note also you get time error and >>>> rate error from these few data points too. >>>> >>>> As another example, suppose you have a nice HP 10811A >>>> oscillator and want to measure its drift rate. In this case you >>>> could spend just 100 seconds and measure its frequency >>>> once a day, or even once every couple of days. Do this for >>>> a month and you'd have several dozen points. If you plot >>>> these frequency measurements you will likely see that they >>>> approximately fall on a line; the slope of the is the frequency >>>> drift rate of the 10811. The general shape of the points, or >>>> the fit of the line is a rough indication of how consistent the >>>> drift rate is or if it's increasing or decreasing. >>>> >>>> Neither of these examples require a lot of data. Both of these >>>> are real-world examples. >>>> >>>> OK so far? >>>> >>>> /tvb >>>> >>>> >>>> >>>> _______________________________________________ >>>> time-nuts mailing list -- time-nuts at febo.com >>>> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >>>> and follow the instructions there. >>>> >>>> >>>> >>> >>> >>> >> _______________________________________________ >> time-nuts mailing list -- time-nuts at febo.com >> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. >> >> > > > > From sar10538 at gmail.com Wed Apr 8 12:37:57 2009 From: sar10538 at gmail.com (Steve Rooke) Date: Thu, 9 Apr 2009 00:37:57 +1200 Subject: [time-nuts] Characterising frequency standards In-Reply-To: <49DC984A.2010509@xtra.co.nz> References: <1231b6a80904070509m5b8bb638gbc088500444254c3@mail.gmail.com> <1231b6a80904080441p7a747a3h1f73bf8a2df30350@mail.gmail.com> <49DC91B9.6090004@xtra.co.nz> <1231b6a80904080504n4a3a22dcr247fae5df39ed840@mail.gmail.com> <49DC984A.2010509@xtra.co.nz> Message-ID: <1231b6a80904080537r2944092bsbc9e31ba0de7f6c8@mail.gmail.com> Bruce, I set nothing, as indicated in my text, I just delete data points, IE. a file of 400000 records now becomes 200000. I'm trying to get my head round this as the absolute requirement for continuous data seems unneeded. What you have to remember here is that the data set I'm working with consists of discrete measurements of the period of each pulse. If it was timestamps, then there would be problems. I don't know how much MATLAB costs but I would guess it is way out of my budget. 73, Steve 2009/4/9 Bruce Griffiths : > Steve > > The data file doesn't include the time interval between samples so do > you set this in some way? > If so you need to set it to 1s for the unaltered data, to 2s when you > take every 2nd sample, and 1s when you take the first 200,000 samples. > > In principle you could use CANVAS (available on request from USNO - > however you may have to wait a few days while they decide whether to > grant your request.) for such analysis in Linux but you would then need > the Linux version of Matlab. > Or you could request that it be compiled for Linux - a fairly simple > task if one has the Linux version of Matlab. > > In principle you should be able to port the m source files to Scilab, > but there are some subtle differences between Scilab and Matlab so this > may take a while. > > Bruce > > Steve Rooke wrote: >> Bruce, >> >> But how does that explain the output of Tom's adev1 program which >> still seems to give a a good measurement at tau = 1s? >> >> 73, >> Steve >> >> 2009/4/8 Bruce Griffiths : >> >>> Steve >>> >>> If you delete every second measurement then your effective minimum >>> sampling time is now 2s and you can no longer calculate ADEV for tau< 2s. >>> You can still calculate ADEV for tau = 100,000 sec. >>> >>> If you delete all but the first 200,000 lines then you can calculated >>> ADEV for tau=1sec and up to tau= 25,000 sec with reasonable accuracy. >>> >>> You shouldn't lose sight of the fact that ADEV and OADEV are both >>> estimates of the Allan deviation. >>> >>> >>> Bruce >>> >>> Steve Rooke wrote: >>> >>>> Tom, >>>> >>>> I understand fully the points that you have made but I have obviously >>>> not made my point clear to all and i apologise for my poor >>>> communication skills. >>>> >>>> This is what I'm getting at: >>>> >>>> Using your adev1.exe from http://www.leapsecond.com/tools/adev1.htm >>>> and processing various forms of gps.dat from >>>> http://www.leapsecond.com/pages/gpsdo-sim/gps.dat.gz. >>>> >>>> C:\Documents and Settings\Steve Rooke\Desktop>adev1.exe 1 >>> >>>> ** Sampling period: 1 s >>>> ** Phase data scale factor: 1.000e+000 >>>> ** Total phase samples: 400000 >>>> ** Normal and Overlapping Allan deviation: >>>> >>>> ? ? ? ?1 tau, 3.0127e-009 adev(n=399998), ? 3.0127e-009 oadev(n=399998) >>>> ? ? ? ?2 tau, 1.5110e-009 adev(n=199998), ? 1.5119e-009 oadev(n=399996) >>>> ? ? ? ?5 tau, 6.2107e-010 adev(n=79998), ? ?6.1983e-010 oadev(n=399990) >>>> ? ? ? 10 tau, 3.1578e-010 adev(n=39998), ? ?3.1549e-010 oadev(n=399980) >>>> ? ? ? 20 tau, 1.6531e-010 adev(n=19998), ? ?1.6534e-010 oadev(n=399960) >>>> ? ? ? 50 tau, 7.2513e-011 adev(n=7998), ? ? 7.3531e-011 oadev(n=399900) >>>> ? ? ?100 tau, 4.0029e-011 adev(n=3998), ? ? 4.0618e-011 oadev(n=399800) >>>> ? ? ?200 tau, 2.1512e-011 adev(n=1998), ? ? 2.1633e-011 oadev(n=399600) >>>> ? ? ?500 tau, 9.2193e-012 adev(n=798), ? ? ?9.1630e-012 oadev(n=399000) >>>> ? ? 1000 tau, 4.9719e-012 adev(n=398), ? ? ?4.7750e-012 oadev(n=398000) >>>> ? ? 2000 tau, 2.6742e-012 adev(n=198), ? ? ?2.5214e-012 oadev(n=396000) >>>> ? ? 5000 tau, 1.0010e-012 adev(n=78), ? ? ? 1.1032e-012 oadev(n=390000) >>>> ? ?10000 tau, 6.1333e-013 adev(n=38), ? ? ? 6.1039e-013 oadev(n=380000) >>>> ? ?20000 tau, 3.8162e-013 adev(n=18), ? ? ? 3.2913e-013 oadev(n=360000) >>>> ? ?50000 tau, 1.0228e-013 adev(n=6), ? ? ? ?1.5074e-013 oadev(n=300000) >>>> ? 100000 tau, 5.8577e-014 adev(n=2), ? ? ? ?6.7597e-014 oadev(n=200000) >>>> >>>> So far, so good. Now I delete every even line in the file which leaves >>>> me with 200000 lines of data (400000 lines in original gps.dat file). >>>> (awk 'and(NR, 1) == 0 {print}' gps1.dat) >>>> >>>> C:\Documents and Settings\Steve Rooke\Desktop>adev1.exe 1 >>> >>>> ** Sampling period: 1 s >>>> > INCORRECT!! > sampling period is now 2s. >>>> ** Phase data scale factor: 1.000e+000 >>>> ** Total phase samples: 200000 >>>> ** Normal and Overlapping Allan deviation: >>>> >>>> ? ? ? ?1 tau, 3.0257e-009 adev(n=199998), ? 3.0257e-009 oadev(n=199998) >>>> ? ? ? ?2 tau, 1.5373e-009 adev(n=99998), ? ?1.5345e-009 oadev(n=199996) >>>> ? ? ? ?5 tau, 6.3147e-010 adev(n=39998), ? ?6.3057e-010 oadev(n=199990) >>>> ? ? ? 10 tau, 3.3140e-010 adev(n=19998), ? ?3.3067e-010 oadev(n=199980) >>>> ? ? ? 20 tau, 1.7872e-010 adev(n=9998), ? ? 1.7810e-010 oadev(n=199960) >>>> ? ? ? 50 tau, 7.9428e-011 adev(n=3998), ? ? 8.1216e-011 oadev(n=199900) >>>> ? ? ?100 tau, 4.2352e-011 adev(n=1998), ? ? 4.3265e-011 oadev(n=199800) >>>> ? ? ?200 tau, 2.2001e-011 adev(n=998), ? ? ?2.2593e-011 oadev(n=199600) >>>> ? ? ?500 tau, 9.6853e-012 adev(n=398), ? ? ?9.5441e-012 oadev(n=199000) >>>> ? ? 1000 tau, 5.0139e-012 adev(n=198), ? ? ?5.0387e-012 oadev(n=198000) >>>> ? ? 2000 tau, 2.7994e-012 adev(n=98), ? ? ? 2.7090e-012 oadev(n=196000) >>>> ? ? 5000 tau, 1.4280e-012 adev(n=38), ? ? ? 1.2214e-012 oadev(n=190000) >>>> ? ?10000 tau, 7.4881e-013 adev(n=18), ? ? ? 6.5814e-013 oadev(n=180000) >>>> ? ?20000 tau, 7.6518e-013 adev(n=8), ? ? ? ?3.7253e-013 oadev(n=160000) >>>> ? ?50000 tau, 2.4698e-014 adev(n=2), ? ? ? ?1.3539e-013 oadev(n=100000) >>>> >>>> Obviously we don't have enough data now for a measurement of 100000 >>>> tau but the results for the other tau are quite close, especially when >>>> there are sufficient data points. Now this is discontinuous data, >>>> exactly what I was trying to allude to. >>>> >>>> OK, so now I take only the top 200000 lines of the gps.dat file (head >>>> -200000 gps.dat >gps2.dat) >>>> >>>> C:\Documents and Settings\Steve Rooke\Desktop>adev1.exe 1 >>> >>>> ** Sampling period: 1 s >>>> ** Phase data scale factor: 1.000e+000 >>>> ** Total phase samples: 200000 >>>> ** Normal and Overlapping Allan deviation: >>>> >>>> ? ? ? ?1 tau, 3.0411e-009 adev(n=199998), ? 3.0411e-009 oadev(n=199998) >>>> ? ? ? ?2 tau, 1.4985e-009 adev(n=99998), ? ?1.4999e-009 oadev(n=199996) >>>> ? ? ? ?5 tau, 6.1964e-010 adev(n=39998), ? ?6.2010e-010 oadev(n=199990) >>>> ? ? ? 10 tau, 3.1315e-010 adev(n=19998), ? ?3.1339e-010 oadev(n=199980) >>>> ? ? ? 20 tau, 1.6499e-010 adev(n=9998), ? ? 1.6495e-010 oadev(n=199960) >>>> ? ? ? 50 tau, 7.1425e-011 adev(n=3998), ? ? 7.3416e-011 oadev(n=199900) >>>> ? ? ?100 tau, 3.9940e-011 adev(n=1998), ? ? 4.0730e-011 oadev(n=199800) >>>> ? ? ?200 tau, 2.1488e-011 adev(n=998), ? ? ?2.1558e-011 oadev(n=199600) >>>> ? ? ?500 tau, 8.4809e-012 adev(n=398), ? ? ?9.0886e-012 oadev(n=199000) >>>> ? ? 1000 tau, 4.9223e-012 adev(n=198), ? ? ?4.7104e-012 oadev(n=198000) >>>> ? ? 2000 tau, 2.4335e-012 adev(n=98), ? ? ? 2.4515e-012 oadev(n=196000) >>>> ? ? 5000 tau, 1.0308e-012 adev(n=38), ? ? ? 1.0861e-012 oadev(n=190000) >>>> ? ?10000 tau, 5.9504e-013 adev(n=18), ? ? ? 6.1031e-013 oadev(n=180000) >>>> ? ?20000 tau, 3.6277e-013 adev(n=8), ? ? ? ?3.1994e-013 oadev(n=160000) >>>> ? ?50000 tau, 1.0630e-013 adev(n=2), ? ? ? ?1.6715e-013 oadev(n=100000) >>>> >>>> Is there any Linux tools for calculating adev as I'm having to run >>>> Windows in a VMware session? >>>> >>>> 73, >>>> Steve >>>> >>>> 2009/4/8 Tom Van Baak : >>>> >>>> >>>>> Steve, >>>>> >>>>> You've asked a couple of questions. Let me start with this. >>>>> >>>>> It is true that if one were only interested in the performance >>>>> of a pendulum (or quartz or atomic) clock for averaging times >>>>> of one day that all you would need is a series of time error >>>>> (aka phase) measurements made about the same time once >>>>> a day (doesn't have to be that exact). After one week, you'd >>>>> have 7 error measurements (=6 frequency =5 stability points) >>>>> and this is adequate to calculate the ADEV for tau 1 day. >>>>> This alone allows you to rank your clock among all the other >>>>> pendulum clocks out there. Note also you get time error and >>>>> rate error from these few data points too. >>>>> >>>>> As another example, suppose you have a nice HP 10811A >>>>> oscillator and want to measure its drift rate. In this case you >>>>> could spend just 100 seconds and measure its frequency >>>>> once a day, or even once every couple of days. Do this for >>>>> a month and you'd have several dozen points. If you plot >>>>> these frequency measurements you will likely see that they >>>>> approximately fall on a line; the slope of the is the frequency >>>>> drift rate of the 10811. The general shape of the points, or >>>>> the fit of the line is a rough indication of how consistent the >>>>> drift rate is or if it's increasing or decreasing. >>>>> >>>>> Neither of these examples require a lot of data. Both of these >>>>> are real-world examples. >>>>> >>>>> OK so far? >>>>> >>>>> /tvb >>>>> >>>>> >>>>> >>>>> _______________________________________________ >>>>> time-nuts mailing list -- time-nuts at febo.com >>>>> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >>>>> and follow the instructions there. >>>>> >>>>> >>>>> >>>> >>>> >>>> >>> _______________________________________________ >>> time-nuts mailing list -- time-nuts at febo.com >>> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >>> and follow the instructions there. >>> >>> >> >> >> >> > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > -- Steve Rooke - ZL3TUV & G8KVD & JAKDTTNW Omnium finis imminet From bruce.griffiths at xtra.co.nz Wed Apr 8 12:55:18 2009 From: bruce.griffiths at xtra.co.nz (Bruce Griffiths) Date: Thu, 09 Apr 2009 00:55:18 +1200 Subject: [time-nuts] Characterising frequency standards In-Reply-To: <1231b6a80904080537r2944092bsbc9e31ba0de7f6c8@mail.gmail.com> References: <1231b6a80904070509m5b8bb638gbc088500444254c3@mail.gmail.com> <1231b6a80904080441p7a747a3h1f73bf8a2df30350@mail.gmail.com> <49DC91B9.6090004@xtra.co.nz> <1231b6a80904080504n4a3a22dcr247fae5df39ed840@mail.gmail.com> <49DC984A.2010509@xtra.co.nz> <1231b6a80904080537r2944092bsbc9e31ba0de7f6c8@mail.gmail.com> Message-ID: <49DC9EB6.1040806@xtra.co.nz> Steve Therein lies your problem. adev1 defaults to a sampling interval of 1 sec. (read the C source code). TvB's documentation explicitly states that you should supply the sampling interval. (its a command line argument for adev1.c). adev1.c is a simple command line program that uses stdin and stdout so porting it to a linux command line (non graphical) program should be straightforward. You can even use redirection and pipes should you need them. You can try porting it to Scilab which is free courtesy of the French Government. Bruce Steve Rooke wrote: > Bruce, > > I set nothing, as indicated in my text, I just delete data points, IE. > a file of 400000 records now becomes 200000. I'm trying to get my head > round this as the absolute requirement for continuous data seems > unneeded. What you have to remember here is that the data set I'm > working with consists of discrete measurements of the period of each > pulse. If it was timestamps, then there would be problems. > > I don't know how much MATLAB costs but I would guess it is way out of my budget. > > 73, > Steve > > 2009/4/9 Bruce Griffiths : > >> Steve >> >> The data file doesn't include the time interval between samples so do >> you set this in some way? >> If so you need to set it to 1s for the unaltered data, to 2s when you >> take every 2nd sample, and 1s when you take the first 200,000 samples. >> >> In principle you could use CANVAS (available on request from USNO - >> however you may have to wait a few days while they decide whether to >> grant your request.) for such analysis in Linux but you would then need >> the Linux version of Matlab. >> Or you could request that it be compiled for Linux - a fairly simple >> task if one has the Linux version of Matlab. >> >> In principle you should be able to port the m source files to Scilab, >> but there are some subtle differences between Scilab and Matlab so this >> may take a while. >> >> Bruce >> >> Steve Rooke wrote: >> >>> Bruce, >>> >>> But how does that explain the output of Tom's adev1 program which >>> still seems to give a a good measurement at tau = 1s? >>> >>> 73, >>> Steve >>> >>> 2009/4/8 Bruce Griffiths : >>> >>> >>>> Steve >>>> >>>> If you delete every second measurement then your effective minimum >>>> sampling time is now 2s and you can no longer calculate ADEV for tau< 2s. >>>> You can still calculate ADEV for tau = 100,000 sec. >>>> >>>> If you delete all but the first 200,000 lines then you can calculated >>>> ADEV for tau=1sec and up to tau= 25,000 sec with reasonable accuracy. >>>> >>>> You shouldn't lose sight of the fact that ADEV and OADEV are both >>>> estimates of the Allan deviation. >>>> >>>> >>>> Bruce >>>> >>>> Steve Rooke wrote: >>>> >>>> >>>>> Tom, >>>>> >>>>> I understand fully the points that you have made but I have obviously >>>>> not made my point clear to all and i apologise for my poor >>>>> communication skills. >>>>> >>>>> This is what I'm getting at: >>>>> >>>>> Using your adev1.exe from http://www.leapsecond.com/tools/adev1.htm >>>>> and processing various forms of gps.dat from >>>>> http://www.leapsecond.com/pages/gpsdo-sim/gps.dat.gz. >>>>> >>>>> C:\Documents and Settings\Steve Rooke\Desktop>adev1.exe 1 >>>> >>>>> ** Sampling period: 1 s >>>>> ** Phase data scale factor: 1.000e+000 >>>>> ** Total phase samples: 400000 >>>>> ** Normal and Overlapping Allan deviation: >>>>> >>>>> 1 tau, 3.0127e-009 adev(n=399998), 3.0127e-009 oadev(n=399998) >>>>> 2 tau, 1.5110e-009 adev(n=199998), 1.5119e-009 oadev(n=399996) >>>>> 5 tau, 6.2107e-010 adev(n=79998), 6.1983e-010 oadev(n=399990) >>>>> 10 tau, 3.1578e-010 adev(n=39998), 3.1549e-010 oadev(n=399980) >>>>> 20 tau, 1.6531e-010 adev(n=19998), 1.6534e-010 oadev(n=399960) >>>>> 50 tau, 7.2513e-011 adev(n=7998), 7.3531e-011 oadev(n=399900) >>>>> 100 tau, 4.0029e-011 adev(n=3998), 4.0618e-011 oadev(n=399800) >>>>> 200 tau, 2.1512e-011 adev(n=1998), 2.1633e-011 oadev(n=399600) >>>>> 500 tau, 9.2193e-012 adev(n=798), 9.1630e-012 oadev(n=399000) >>>>> 1000 tau, 4.9719e-012 adev(n=398), 4.7750e-012 oadev(n=398000) >>>>> 2000 tau, 2.6742e-012 adev(n=198), 2.5214e-012 oadev(n=396000) >>>>> 5000 tau, 1.0010e-012 adev(n=78), 1.1032e-012 oadev(n=390000) >>>>> 10000 tau, 6.1333e-013 adev(n=38), 6.1039e-013 oadev(n=380000) >>>>> 20000 tau, 3.8162e-013 adev(n=18), 3.2913e-013 oadev(n=360000) >>>>> 50000 tau, 1.0228e-013 adev(n=6), 1.5074e-013 oadev(n=300000) >>>>> 100000 tau, 5.8577e-014 adev(n=2), 6.7597e-014 oadev(n=200000) >>>>> >>>>> So far, so good. Now I delete every even line in the file which leaves >>>>> me with 200000 lines of data (400000 lines in original gps.dat file). >>>>> (awk 'and(NR, 1) == 0 {print}' gps1.dat) >>>>> >>>>> C:\Documents and Settings\Steve Rooke\Desktop>adev1.exe 1 >>>> >>>>> ** Sampling period: 1 s >>>>> >>>>> >> INCORRECT!! >> sampling period is now 2s. >> >>>>> ** Phase data scale factor: 1.000e+000 >>>>> ** Total phase samples: 200000 >>>>> ** Normal and Overlapping Allan deviation: >>>>> >>>>> 1 tau, 3.0257e-009 adev(n=199998), 3.0257e-009 oadev(n=199998) >>>>> 2 tau, 1.5373e-009 adev(n=99998), 1.5345e-009 oadev(n=199996) >>>>> 5 tau, 6.3147e-010 adev(n=39998), 6.3057e-010 oadev(n=199990) >>>>> 10 tau, 3.3140e-010 adev(n=19998), 3.3067e-010 oadev(n=199980) >>>>> 20 tau, 1.7872e-010 adev(n=9998), 1.7810e-010 oadev(n=199960) >>>>> 50 tau, 7.9428e-011 adev(n=3998), 8.1216e-011 oadev(n=199900) >>>>> 100 tau, 4.2352e-011 adev(n=1998), 4.3265e-011 oadev(n=199800) >>>>> 200 tau, 2.2001e-011 adev(n=998), 2.2593e-011 oadev(n=199600) >>>>> 500 tau, 9.6853e-012 adev(n=398), 9.5441e-012 oadev(n=199000) >>>>> 1000 tau, 5.0139e-012 adev(n=198), 5.0387e-012 oadev(n=198000) >>>>> 2000 tau, 2.7994e-012 adev(n=98), 2.7090e-012 oadev(n=196000) >>>>> 5000 tau, 1.4280e-012 adev(n=38), 1.2214e-012 oadev(n=190000) >>>>> 10000 tau, 7.4881e-013 adev(n=18), 6.5814e-013 oadev(n=180000) >>>>> 20000 tau, 7.6518e-013 adev(n=8), 3.7253e-013 oadev(n=160000) >>>>> 50000 tau, 2.4698e-014 adev(n=2), 1.3539e-013 oadev(n=100000) >>>>> >>>>> Obviously we don't have enough data now for a measurement of 100000 >>>>> tau but the results for the other tau are quite close, especially when >>>>> there are sufficient data points. Now this is discontinuous data, >>>>> exactly what I was trying to allude to. >>>>> >>>>> OK, so now I take only the top 200000 lines of the gps.dat file (head >>>>> -200000 gps.dat >gps2.dat) >>>>> >>>>> C:\Documents and Settings\Steve Rooke\Desktop>adev1.exe 1 >>>> >>>>> ** Sampling period: 1 s >>>>> ** Phase data scale factor: 1.000e+000 >>>>> ** Total phase samples: 200000 >>>>> ** Normal and Overlapping Allan deviation: >>>>> >>>>> 1 tau, 3.0411e-009 adev(n=199998), 3.0411e-009 oadev(n=199998) >>>>> 2 tau, 1.4985e-009 adev(n=99998), 1.4999e-009 oadev(n=199996) >>>>> 5 tau, 6.1964e-010 adev(n=39998), 6.2010e-010 oadev(n=199990) >>>>> 10 tau, 3.1315e-010 adev(n=19998), 3.1339e-010 oadev(n=199980) >>>>> 20 tau, 1.6499e-010 adev(n=9998), 1.6495e-010 oadev(n=199960) >>>>> 50 tau, 7.1425e-011 adev(n=3998), 7.3416e-011 oadev(n=199900) >>>>> 100 tau, 3.9940e-011 adev(n=1998), 4.0730e-011 oadev(n=199800) >>>>> 200 tau, 2.1488e-011 adev(n=998), 2.1558e-011 oadev(n=199600) >>>>> 500 tau, 8.4809e-012 adev(n=398), 9.0886e-012 oadev(n=199000) >>>>> 1000 tau, 4.9223e-012 adev(n=198), 4.7104e-012 oadev(n=198000) >>>>> 2000 tau, 2.4335e-012 adev(n=98), 2.4515e-012 oadev(n=196000) >>>>> 5000 tau, 1.0308e-012 adev(n=38), 1.0861e-012 oadev(n=190000) >>>>> 10000 tau, 5.9504e-013 adev(n=18), 6.1031e-013 oadev(n=180000) >>>>> 20000 tau, 3.6277e-013 adev(n=8), 3.1994e-013 oadev(n=160000) >>>>> 50000 tau, 1.0630e-013 adev(n=2), 1.6715e-013 oadev(n=100000) >>>>> >>>>> Is there any Linux tools for calculating adev as I'm having to run >>>>> Windows in a VMware session? >>>>> >>>>> 73, >>>>> Steve >>>>> >>>>> 2009/4/8 Tom Van Baak : >>>>> >>>>> >>>>> >>>>>> Steve, >>>>>> >>>>>> You've asked a couple of questions. Let me start with this. >>>>>> >>>>>> It is true that if one were only interested in the performance >>>>>> of a pendulum (or quartz or atomic) clock for averaging times >>>>>> of one day that all you would need is a series of time error >>>>>> (aka phase) measurements made about the same time once >>>>>> a day (doesn't have to be that exact). After one week, you'd >>>>>> have 7 error measurements (=6 frequency =5 stability points) >>>>>> and this is adequate to calculate the ADEV for tau 1 day. >>>>>> This alone allows you to rank your clock among all the other >>>>>> pendulum clocks out there. Note also you get time error and >>>>>> rate error from these few data points too. >>>>>> >>>>>> As another example, suppose you have a nice HP 10811A >>>>>> oscillator and want to measure its drift rate. In this case you >>>>>> could spend just 100 seconds and measure its frequency >>>>>> once a day, or even once every couple of days. Do this for >>>>>> a month and you'd have several dozen points. If you plot >>>>>> these frequency measurements you will likely see that they >>>>>> approximately fall on a line; the slope of the is the frequency >>>>>> drift rate of the 10811. The general shape of the points, or >>>>>> the fit of the line is a rough indication of how consistent the >>>>>> drift rate is or if it's increasing or decreasing. >>>>>> >>>>>> Neither of these examples require a lot of data. Both of these >>>>>> are real-world examples. >>>>>> >>>>>> OK so far? >>>>>> >>>>>> /tvb >>>>>> >>>>>> >>>>>> >>>>>> _______________________________________________ >>>>>> time-nuts mailing list -- time-nuts at febo.com >>>>>> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >>>>>> and follow the instructions there. >>>>>> >>>>>> >>>>>> >>>>>> >>>>> >>>>> >>>> _______________________________________________ >>>> time-nuts mailing list -- time-nuts at febo.com >>>> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >>>> and follow the instructions there. >>>> >>>> >>>> >>> >>> >>> >> _______________________________________________ >> time-nuts mailing list -- time-nuts at febo.com >> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. >> >> > > > > From sar10538 at gmail.com Wed Apr 8 12:59:36 2009 From: sar10538 at gmail.com (Steve Rooke) Date: Thu, 9 Apr 2009 00:59:36 +1200 Subject: [time-nuts] Hadamard variance Message-ID: <1231b6a80904080559o7a4cf618r49276df9d7599820@mail.gmail.com> According to Wikipedia, this is insensitive to drift and so seems like a better tool for measuring oscillators, like ocxo. I don't think I've seen this being used by anyone on the list and wonder why? 73, Steve -- Steve Rooke - ZL3TUV & G8KVD & JAKDTTNW Omnium finis imminet From jra at febo.com Wed Apr 8 13:01:43 2009 From: jra at febo.com (John Ackermann N8UR) Date: Wed, 08 Apr 2009 09:01:43 -0400 Subject: [time-nuts] Characterising frequency standards In-Reply-To: <49DC9EB6.1040806@xtra.co.nz> References: <1231b6a80904070509m5b8bb638gbc088500444254c3@mail.gmail.com> <1231b6a80904080441p7a747a3h1f73bf8a2df30350@mail.gmail.com> <49DC91B9.6090004@xtra.co.nz> <1231b6a80904080504n4a3a22dcr247fae5df39ed840@mail.gmail.com> <49DC984A.2010509@xtra.co.nz> <1231b6a80904080537r2944092bsbc9e31ba0de7f6c8@mail.gmail.com> <49DC9EB6.1040806@xtra.co.nz> Message-ID: <49DCA037.3070706@febo.com> I've compiled adev1 under Linux with no changes required; don't recall the exact gcc line I used but it was pretty much the obvious one. Steve, one other point -- your results with every sample versus every-other-sample aren't hugely different because ADEV doesn't usually change dramatically over very short differences in tau (unless there's some sort of periodicity in the noise). So, it would not be unusual to see that the result for tau=2 seconds (what you got when you removed every other sample) will be only slightly different than for tau=1 second. John ---- Bruce Griffiths wrote: > Steve > > Therein lies your problem. > adev1 defaults to a sampling interval of 1 sec. (read the C source code). > TvB's documentation explicitly states that you should supply the > sampling interval. (its a command line argument for adev1.c). > > adev1.c is a simple command line program that uses stdin and stdout so > porting it to a linux command line (non graphical) program should be > straightforward. > You can even use redirection and pipes should you need them. > > You can try porting it to Scilab which is free courtesy of the French > Government. > > > Bruce > > Steve Rooke wrote: >> Bruce, >> >> I set nothing, as indicated in my text, I just delete data points, IE. >> a file of 400000 records now becomes 200000. I'm trying to get my head >> round this as the absolute requirement for continuous data seems >> unneeded. What you have to remember here is that the data set I'm >> working with consists of discrete measurements of the period of each >> pulse. If it was timestamps, then there would be problems. >> >> I don't know how much MATLAB costs but I would guess it is way out of my budget. >> >> 73, >> Steve >> >> 2009/4/9 Bruce Griffiths : >> >>> Steve >>> >>> The data file doesn't include the time interval between samples so do >>> you set this in some way? >>> If so you need to set it to 1s for the unaltered data, to 2s when you >>> take every 2nd sample, and 1s when you take the first 200,000 samples. >>> >>> In principle you could use CANVAS (available on request from USNO - >>> however you may have to wait a few days while they decide whether to >>> grant your request.) for such analysis in Linux but you would then need >>> the Linux version of Matlab. >>> Or you could request that it be compiled for Linux - a fairly simple >>> task if one has the Linux version of Matlab. >>> >>> In principle you should be able to port the m source files to Scilab, >>> but there are some subtle differences between Scilab and Matlab so this >>> may take a while. >>> >>> Bruce >>> >>> Steve Rooke wrote: >>> >>>> Bruce, >>>> >>>> But how does that explain the output of Tom's adev1 program which >>>> still seems to give a a good measurement at tau = 1s? >>>> >>>> 73, >>>> Steve >>>> >>>> 2009/4/8 Bruce Griffiths : >>>> >>>> >>>>> Steve >>>>> >>>>> If you delete every second measurement then your effective minimum >>>>> sampling time is now 2s and you can no longer calculate ADEV for tau< 2s. >>>>> You can still calculate ADEV for tau = 100,000 sec. >>>>> >>>>> If you delete all but the first 200,000 lines then you can calculated >>>>> ADEV for tau=1sec and up to tau= 25,000 sec with reasonable accuracy. >>>>> >>>>> You shouldn't lose sight of the fact that ADEV and OADEV are both >>>>> estimates of the Allan deviation. >>>>> >>>>> >>>>> Bruce >>>>> >>>>> Steve Rooke wrote: >>>>> >>>>> >>>>>> Tom, >>>>>> >>>>>> I understand fully the points that you have made but I have obviously >>>>>> not made my point clear to all and i apologise for my poor >>>>>> communication skills. >>>>>> >>>>>> This is what I'm getting at: >>>>>> >>>>>> Using your adev1.exe from http://www.leapsecond.com/tools/adev1.htm >>>>>> and processing various forms of gps.dat from >>>>>> http://www.leapsecond.com/pages/gpsdo-sim/gps.dat.gz. >>>>>> >>>>>> C:\Documents and Settings\Steve Rooke\Desktop>adev1.exe 1 >>>>> >>>>>> ** Sampling period: 1 s >>>>>> ** Phase data scale factor: 1.000e+000 >>>>>> ** Total phase samples: 400000 >>>>>> ** Normal and Overlapping Allan deviation: >>>>>> >>>>>> 1 tau, 3.0127e-009 adev(n=399998), 3.0127e-009 oadev(n=399998) >>>>>> 2 tau, 1.5110e-009 adev(n=199998), 1.5119e-009 oadev(n=399996) >>>>>> 5 tau, 6.2107e-010 adev(n=79998), 6.1983e-010 oadev(n=399990) >>>>>> 10 tau, 3.1578e-010 adev(n=39998), 3.1549e-010 oadev(n=399980) >>>>>> 20 tau, 1.6531e-010 adev(n=19998), 1.6534e-010 oadev(n=399960) >>>>>> 50 tau, 7.2513e-011 adev(n=7998), 7.3531e-011 oadev(n=399900) >>>>>> 100 tau, 4.0029e-011 adev(n=3998), 4.0618e-011 oadev(n=399800) >>>>>> 200 tau, 2.1512e-011 adev(n=1998), 2.1633e-011 oadev(n=399600) >>>>>> 500 tau, 9.2193e-012 adev(n=798), 9.1630e-012 oadev(n=399000) >>>>>> 1000 tau, 4.9719e-012 adev(n=398), 4.7750e-012 oadev(n=398000) >>>>>> 2000 tau, 2.6742e-012 adev(n=198), 2.5214e-012 oadev(n=396000) >>>>>> 5000 tau, 1.0010e-012 adev(n=78), 1.1032e-012 oadev(n=390000) >>>>>> 10000 tau, 6.1333e-013 adev(n=38), 6.1039e-013 oadev(n=380000) >>>>>> 20000 tau, 3.8162e-013 adev(n=18), 3.2913e-013 oadev(n=360000) >>>>>> 50000 tau, 1.0228e-013 adev(n=6), 1.5074e-013 oadev(n=300000) >>>>>> 100000 tau, 5.8577e-014 adev(n=2), 6.7597e-014 oadev(n=200000) >>>>>> >>>>>> So far, so good. Now I delete every even line in the file which leaves >>>>>> me with 200000 lines of data (400000 lines in original gps.dat file). >>>>>> (awk 'and(NR, 1) == 0 {print}' gps1.dat) >>>>>> >>>>>> C:\Documents and Settings\Steve Rooke\Desktop>adev1.exe 1 >>>>> >>>>>> ** Sampling period: 1 s >>>>>> >>>>>> >>> INCORRECT!! >>> sampling period is now 2s. >>> >>>>>> ** Phase data scale factor: 1.000e+000 >>>>>> ** Total phase samples: 200000 >>>>>> ** Normal and Overlapping Allan deviation: >>>>>> >>>>>> 1 tau, 3.0257e-009 adev(n=199998), 3.0257e-009 oadev(n=199998) >>>>>> 2 tau, 1.5373e-009 adev(n=99998), 1.5345e-009 oadev(n=199996) >>>>>> 5 tau, 6.3147e-010 adev(n=39998), 6.3057e-010 oadev(n=199990) >>>>>> 10 tau, 3.3140e-010 adev(n=19998), 3.3067e-010 oadev(n=199980) >>>>>> 20 tau, 1.7872e-010 adev(n=9998), 1.7810e-010 oadev(n=199960) >>>>>> 50 tau, 7.9428e-011 adev(n=3998), 8.1216e-011 oadev(n=199900) >>>>>> 100 tau, 4.2352e-011 adev(n=1998), 4.3265e-011 oadev(n=199800) >>>>>> 200 tau, 2.2001e-011 adev(n=998), 2.2593e-011 oadev(n=199600) >>>>>> 500 tau, 9.6853e-012 adev(n=398), 9.5441e-012 oadev(n=199000) >>>>>> 1000 tau, 5.0139e-012 adev(n=198), 5.0387e-012 oadev(n=198000) >>>>>> 2000 tau, 2.7994e-012 adev(n=98), 2.7090e-012 oadev(n=196000) >>>>>> 5000 tau, 1.4280e-012 adev(n=38), 1.2214e-012 oadev(n=190000) >>>>>> 10000 tau, 7.4881e-013 adev(n=18), 6.5814e-013 oadev(n=180000) >>>>>> 20000 tau, 7.6518e-013 adev(n=8), 3.7253e-013 oadev(n=160000) >>>>>> 50000 tau, 2.4698e-014 adev(n=2), 1.3539e-013 oadev(n=100000) >>>>>> >>>>>> Obviously we don't have enough data now for a measurement of 100000 >>>>>> tau but the results for the other tau are quite close, especially when >>>>>> there are sufficient data points. Now this is discontinuous data, >>>>>> exactly what I was trying to allude to. >>>>>> >>>>>> OK, so now I take only the top 200000 lines of the gps.dat file (head >>>>>> -200000 gps.dat >gps2.dat) >>>>>> >>>>>> C:\Documents and Settings\Steve Rooke\Desktop>adev1.exe 1 >>>>> >>>>>> ** Sampling period: 1 s >>>>>> ** Phase data scale factor: 1.000e+000 >>>>>> ** Total phase samples: 200000 >>>>>> ** Normal and Overlapping Allan deviation: >>>>>> >>>>>> 1 tau, 3.0411e-009 adev(n=199998), 3.0411e-009 oadev(n=199998) >>>>>> 2 tau, 1.4985e-009 adev(n=99998), 1.4999e-009 oadev(n=199996) >>>>>> 5 tau, 6.1964e-010 adev(n=39998), 6.2010e-010 oadev(n=199990) >>>>>> 10 tau, 3.1315e-010 adev(n=19998), 3.1339e-010 oadev(n=199980) >>>>>> 20 tau, 1.6499e-010 adev(n=9998), 1.6495e-010 oadev(n=199960) >>>>>> 50 tau, 7.1425e-011 adev(n=3998), 7.3416e-011 oadev(n=199900) >>>>>> 100 tau, 3.9940e-011 adev(n=1998), 4.0730e-011 oadev(n=199800) >>>>>> 200 tau, 2.1488e-011 adev(n=998), 2.1558e-011 oadev(n=199600) >>>>>> 500 tau, 8.4809e-012 adev(n=398), 9.0886e-012 oadev(n=199000) >>>>>> 1000 tau, 4.9223e-012 adev(n=198), 4.7104e-012 oadev(n=198000) >>>>>> 2000 tau, 2.4335e-012 adev(n=98), 2.4515e-012 oadev(n=196000) >>>>>> 5000 tau, 1.0308e-012 adev(n=38), 1.0861e-012 oadev(n=190000) >>>>>> 10000 tau, 5.9504e-013 adev(n=18), 6.1031e-013 oadev(n=180000) >>>>>> 20000 tau, 3.6277e-013 adev(n=8), 3.1994e-013 oadev(n=160000) >>>>>> 50000 tau, 1.0630e-013 adev(n=2), 1.6715e-013 oadev(n=100000) >>>>>> >>>>>> Is there any Linux tools for calculating adev as I'm having to run >>>>>> Windows in a VMware session? >>>>>> >>>>>> 73, >>>>>> Steve >>>>>> >>>>>> 2009/4/8 Tom Van Baak : >>>>>> >>>>>> >>>>>> >>>>>>> Steve, >>>>>>> >>>>>>> You've asked a couple of questions. Let me start with this. >>>>>>> >>>>>>> It is true that if one were only interested in the performance >>>>>>> of a pendulum (or quartz or atomic) clock for averaging times >>>>>>> of one day that all you would need is a series of time error >>>>>>> (aka phase) measurements made about the same time once >>>>>>> a day (doesn't have to be that exact). After one week, you'd >>>>>>> have 7 error measurements (=6 frequency =5 stability points) >>>>>>> and this is adequate to calculate the ADEV for tau 1 day. >>>>>>> This alone allows you to rank your clock among all the other >>>>>>> pendulum clocks out there. Note also you get time error and >>>>>>> rate error from these few data points too. >>>>>>> >>>>>>> As another example, suppose you have a nice HP 10811A >>>>>>> oscillator and want to measure its drift rate. In this case you >>>>>>> could spend just 100 seconds and measure its frequency >>>>>>> once a day, or even once every couple of days. Do this for >>>>>>> a month and you'd have several dozen points. If you plot >>>>>>> these frequency measurements you will likely see that they >>>>>>> approximately fall on a line; the slope of the is the frequency >>>>>>> drift rate of the 10811. The general shape of the points, or >>>>>>> the fit of the line is a rough indication of how consistent the >>>>>>> drift rate is or if it's increasing or decreasing. >>>>>>> >>>>>>> Neither of these examples require a lot of data. Both of these >>>>>>> are real-world examples. >>>>>>> >>>>>>> OK so far? >>>>>>> >>>>>>> /tvb >>>>>>> >>>>>>> >>>>>>> >>>>>>> _______________________________________________ >>>>>>> time-nuts mailing list -- time-nuts at febo.com >>>>>>> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >>>>>>> and follow the instructions there. >>>>>>> >>>>>>> >>>>>>> >>>>>>> >>>>>> >>>>> _______________________________________________ >>>>> time-nuts mailing list -- time-nuts at febo.com >>>>> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >>>>> and follow the instructions there. >>>>> >>>>> >>>>> >>>> >>>> >>> _______________________________________________ >>> time-nuts mailing list -- time-nuts at febo.com >>> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >>> and follow the instructions there. >>> >>> >> >> >> > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. From sar10538 at gmail.com Wed Apr 8 13:02:43 2009 From: sar10538 at gmail.com (Steve Rooke) Date: Thu, 9 Apr 2009 01:02:43 +1200 Subject: [time-nuts] Characterising frequency standards In-Reply-To: <49DC9EB6.1040806@xtra.co.nz> References: <1231b6a80904070509m5b8bb638gbc088500444254c3@mail.gmail.com> <1231b6a80904080441p7a747a3h1f73bf8a2df30350@mail.gmail.com> <49DC91B9.6090004@xtra.co.nz> <1231b6a80904080504n4a3a22dcr247fae5df39ed840@mail.gmail.com> <49DC984A.2010509@xtra.co.nz> <1231b6a80904080537r2944092bsbc9e31ba0de7f6c8@mail.gmail.com> <49DC9EB6.1040806@xtra.co.nz> Message-ID: <1231b6a80904080602w58ea54c4tdb56bc160e56b4ae@mail.gmail.com> Bruce, But the sampling interval is still 1 sec and you can see by my notes that I explicitly give this on the command line for adev1.exe. OK, I'll have a go at compiling it as it is just a command line program. 73, Steve 2009/4/9 Bruce Griffiths : > Steve > > Therein lies your problem. > adev1 ?defaults to a sampling interval of 1 sec. (read the C source code). > TvB's documentation explicitly states that you should supply the > sampling interval. (its a command line argument for adev1.c). > > adev1.c is a simple command line program that uses stdin and stdout so > porting it to a linux command line (non graphical) program should be > straightforward. > You can even use redirection and pipes should you need them. > > You can try porting it to Scilab which is free courtesy of the French > Government. > > > Bruce > > Steve Rooke wrote: >> Bruce, >> >> I set nothing, as indicated in my text, I just delete data points, IE. >> a file of 400000 records now becomes 200000. I'm trying to get my head >> round this as the absolute requirement for continuous data seems >> unneeded. What you have to remember here is that the data set I'm >> working with consists of discrete measurements of the period of each >> pulse. If it was timestamps, then there would be problems. >> >> I don't know how much MATLAB costs but I would guess it is way out of my budget. >> >> 73, >> Steve >> >> 2009/4/9 Bruce Griffiths : >> >>> Steve >>> >>> The data file doesn't include the time interval between samples so do >>> you set this in some way? >>> If so you need to set it to 1s for the unaltered data, to 2s when you >>> take every 2nd sample, and 1s when you take the first 200,000 samples. >>> >>> In principle you could use CANVAS (available on request from USNO - >>> however you may have to wait a few days while they decide whether to >>> grant your request.) for such analysis in Linux but you would then need >>> the Linux version of Matlab. >>> Or you could request that it be compiled for Linux - a fairly simple >>> task if one has the Linux version of Matlab. >>> >>> In principle you should be able to port the m source files to Scilab, >>> but there are some subtle differences between Scilab and Matlab so this >>> may take a while. >>> >>> Bruce >>> >>> Steve Rooke wrote: >>> >>>> Bruce, >>>> >>>> But how does that explain the output of Tom's adev1 program which >>>> still seems to give a a good measurement at tau = 1s? >>>> >>>> 73, >>>> Steve >>>> >>>> 2009/4/8 Bruce Griffiths : >>>> >>>> >>>>> Steve >>>>> >>>>> If you delete every second measurement then your effective minimum >>>>> sampling time is now 2s and you can no longer calculate ADEV for tau< 2s. >>>>> You can still calculate ADEV for tau = 100,000 sec. >>>>> >>>>> If you delete all but the first 200,000 lines then you can calculated >>>>> ADEV for tau=1sec and up to tau= 25,000 sec with reasonable accuracy. >>>>> >>>>> You shouldn't lose sight of the fact that ADEV and OADEV are both >>>>> estimates of the Allan deviation. >>>>> >>>>> >>>>> Bruce >>>>> >>>>> Steve Rooke wrote: >>>>> >>>>> >>>>>> Tom, >>>>>> >>>>>> I understand fully the points that you have made but I have obviously >>>>>> not made my point clear to all and i apologise for my poor >>>>>> communication skills. >>>>>> >>>>>> This is what I'm getting at: >>>>>> >>>>>> Using your adev1.exe from http://www.leapsecond.com/tools/adev1.htm >>>>>> and processing various forms of gps.dat from >>>>>> http://www.leapsecond.com/pages/gpsdo-sim/gps.dat.gz. >>>>>> >>>>>> C:\Documents and Settings\Steve Rooke\Desktop>adev1.exe 1 >>>>> >>>>>> ** Sampling period: 1 s >>>>>> ** Phase data scale factor: 1.000e+000 >>>>>> ** Total phase samples: 400000 >>>>>> ** Normal and Overlapping Allan deviation: >>>>>> >>>>>> ? ? ? ?1 tau, 3.0127e-009 adev(n=399998), ? 3.0127e-009 oadev(n=399998) >>>>>> ? ? ? ?2 tau, 1.5110e-009 adev(n=199998), ? 1.5119e-009 oadev(n=399996) >>>>>> ? ? ? ?5 tau, 6.2107e-010 adev(n=79998), ? ?6.1983e-010 oadev(n=399990) >>>>>> ? ? ? 10 tau, 3.1578e-010 adev(n=39998), ? ?3.1549e-010 oadev(n=399980) >>>>>> ? ? ? 20 tau, 1.6531e-010 adev(n=19998), ? ?1.6534e-010 oadev(n=399960) >>>>>> ? ? ? 50 tau, 7.2513e-011 adev(n=7998), ? ? 7.3531e-011 oadev(n=399900) >>>>>> ? ? ?100 tau, 4.0029e-011 adev(n=3998), ? ? 4.0618e-011 oadev(n=399800) >>>>>> ? ? ?200 tau, 2.1512e-011 adev(n=1998), ? ? 2.1633e-011 oadev(n=399600) >>>>>> ? ? ?500 tau, 9.2193e-012 adev(n=798), ? ? ?9.1630e-012 oadev(n=399000) >>>>>> ? ? 1000 tau, 4.9719e-012 adev(n=398), ? ? ?4.7750e-012 oadev(n=398000) >>>>>> ? ? 2000 tau, 2.6742e-012 adev(n=198), ? ? ?2.5214e-012 oadev(n=396000) >>>>>> ? ? 5000 tau, 1.0010e-012 adev(n=78), ? ? ? 1.1032e-012 oadev(n=390000) >>>>>> ? ?10000 tau, 6.1333e-013 adev(n=38), ? ? ? 6.1039e-013 oadev(n=380000) >>>>>> ? ?20000 tau, 3.8162e-013 adev(n=18), ? ? ? 3.2913e-013 oadev(n=360000) >>>>>> ? ?50000 tau, 1.0228e-013 adev(n=6), ? ? ? ?1.5074e-013 oadev(n=300000) >>>>>> ? 100000 tau, 5.8577e-014 adev(n=2), ? ? ? ?6.7597e-014 oadev(n=200000) >>>>>> >>>>>> So far, so good. Now I delete every even line in the file which leaves >>>>>> me with 200000 lines of data (400000 lines in original gps.dat file). >>>>>> (awk 'and(NR, 1) == 0 {print}' gps1.dat) >>>>>> >>>>>> C:\Documents and Settings\Steve Rooke\Desktop>adev1.exe 1 >>>>> >>>>>> ** Sampling period: 1 s >>>>>> >>>>>> >>> INCORRECT!! >>> sampling period is now 2s. >>> >>>>>> ** Phase data scale factor: 1.000e+000 >>>>>> ** Total phase samples: 200000 >>>>>> ** Normal and Overlapping Allan deviation: >>>>>> >>>>>> ? ? ? ?1 tau, 3.0257e-009 adev(n=199998), ? 3.0257e-009 oadev(n=199998) >>>>>> ? ? ? ?2 tau, 1.5373e-009 adev(n=99998), ? ?1.5345e-009 oadev(n=199996) >>>>>> ? ? ? ?5 tau, 6.3147e-010 adev(n=39998), ? ?6.3057e-010 oadev(n=199990) >>>>>> ? ? ? 10 tau, 3.3140e-010 adev(n=19998), ? ?3.3067e-010 oadev(n=199980) >>>>>> ? ? ? 20 tau, 1.7872e-010 adev(n=9998), ? ? 1.7810e-010 oadev(n=199960) >>>>>> ? ? ? 50 tau, 7.9428e-011 adev(n=3998), ? ? 8.1216e-011 oadev(n=199900) >>>>>> ? ? ?100 tau, 4.2352e-011 adev(n=1998), ? ? 4.3265e-011 oadev(n=199800) >>>>>> ? ? ?200 tau, 2.2001e-011 adev(n=998), ? ? ?2.2593e-011 oadev(n=199600) >>>>>> ? ? ?500 tau, 9.6853e-012 adev(n=398), ? ? ?9.5441e-012 oadev(n=199000) >>>>>> ? ? 1000 tau, 5.0139e-012 adev(n=198), ? ? ?5.0387e-012 oadev(n=198000) >>>>>> ? ? 2000 tau, 2.7994e-012 adev(n=98), ? ? ? 2.7090e-012 oadev(n=196000) >>>>>> ? ? 5000 tau, 1.4280e-012 adev(n=38), ? ? ? 1.2214e-012 oadev(n=190000) >>>>>> ? ?10000 tau, 7.4881e-013 adev(n=18), ? ? ? 6.5814e-013 oadev(n=180000) >>>>>> ? ?20000 tau, 7.6518e-013 adev(n=8), ? ? ? ?3.7253e-013 oadev(n=160000) >>>>>> ? ?50000 tau, 2.4698e-014 adev(n=2), ? ? ? ?1.3539e-013 oadev(n=100000) >>>>>> >>>>>> Obviously we don't have enough data now for a measurement of 100000 >>>>>> tau but the results for the other tau are quite close, especially when >>>>>> there are sufficient data points. Now this is discontinuous data, >>>>>> exactly what I was trying to allude to. >>>>>> >>>>>> OK, so now I take only the top 200000 lines of the gps.dat file (head >>>>>> -200000 gps.dat >gps2.dat) >>>>>> >>>>>> C:\Documents and Settings\Steve Rooke\Desktop>adev1.exe 1 >>>>> >>>>>> ** Sampling period: 1 s >>>>>> ** Phase data scale factor: 1.000e+000 >>>>>> ** Total phase samples: 200000 >>>>>> ** Normal and Overlapping Allan deviation: >>>>>> >>>>>> ? ? ? ?1 tau, 3.0411e-009 adev(n=199998), ? 3.0411e-009 oadev(n=199998) >>>>>> ? ? ? ?2 tau, 1.4985e-009 adev(n=99998), ? ?1.4999e-009 oadev(n=199996) >>>>>> ? ? ? ?5 tau, 6.1964e-010 adev(n=39998), ? ?6.2010e-010 oadev(n=199990) >>>>>> ? ? ? 10 tau, 3.1315e-010 adev(n=19998), ? ?3.1339e-010 oadev(n=199980) >>>>>> ? ? ? 20 tau, 1.6499e-010 adev(n=9998), ? ? 1.6495e-010 oadev(n=199960) >>>>>> ? ? ? 50 tau, 7.1425e-011 adev(n=3998), ? ? 7.3416e-011 oadev(n=199900) >>>>>> ? ? ?100 tau, 3.9940e-011 adev(n=1998), ? ? 4.0730e-011 oadev(n=199800) >>>>>> ? ? ?200 tau, 2.1488e-011 adev(n=998), ? ? ?2.1558e-011 oadev(n=199600) >>>>>> ? ? ?500 tau, 8.4809e-012 adev(n=398), ? ? ?9.0886e-012 oadev(n=199000) >>>>>> ? ? 1000 tau, 4.9223e-012 adev(n=198), ? ? ?4.7104e-012 oadev(n=198000) >>>>>> ? ? 2000 tau, 2.4335e-012 adev(n=98), ? ? ? 2.4515e-012 oadev(n=196000) >>>>>> ? ? 5000 tau, 1.0308e-012 adev(n=38), ? ? ? 1.0861e-012 oadev(n=190000) >>>>>> ? ?10000 tau, 5.9504e-013 adev(n=18), ? ? ? 6.1031e-013 oadev(n=180000) >>>>>> ? ?20000 tau, 3.6277e-013 adev(n=8), ? ? ? ?3.1994e-013 oadev(n=160000) >>>>>> ? ?50000 tau, 1.0630e-013 adev(n=2), ? ? ? ?1.6715e-013 oadev(n=100000) >>>>>> >>>>>> Is there any Linux tools for calculating adev as I'm having to run >>>>>> Windows in a VMware session? >>>>>> >>>>>> 73, >>>>>> Steve >>>>>> >>>>>> 2009/4/8 Tom Van Baak : >>>>>> >>>>>> >>>>>> >>>>>>> Steve, >>>>>>> >>>>>>> You've asked a couple of questions. Let me start with this. >>>>>>> >>>>>>> It is true that if one were only interested in the performance >>>>>>> of a pendulum (or quartz or atomic) clock for averaging times >>>>>>> of one day that all you would need is a series of time error >>>>>>> (aka phase) measurements made about the same time once >>>>>>> a day (doesn't have to be that exact). After one week, you'd >>>>>>> have 7 error measurements (=6 frequency =5 stability points) >>>>>>> and this is adequate to calculate the ADEV for tau 1 day. >>>>>>> This alone allows you to rank your clock among all the other >>>>>>> pendulum clocks out there. Note also you get time error and >>>>>>> rate error from these few data points too. >>>>>>> >>>>>>> As another example, suppose you have a nice HP 10811A >>>>>>> oscillator and want to measure its drift rate. In this case you >>>>>>> could spend just 100 seconds and measure its frequency >>>>>>> once a day, or even once every couple of days. Do this for >>>>>>> a month and you'd have several dozen points. If you plot >>>>>>> these frequency measurements you will likely see that they >>>>>>> approximately fall on a line; the slope of the is the frequency >>>>>>> drift rate of the 10811. The general shape of the points, or >>>>>>> the fit of the line is a rough indication of how consistent the >>>>>>> drift rate is or if it's increasing or decreasing. >>>>>>> >>>>>>> Neither of these examples require a lot of data. Both of these >>>>>>> are real-world examples. >>>>>>> >>>>>>> OK so far? >>>>>>> >>>>>>> /tvb >>>>>>> >>>>>>> >>>>>>> >>>>>>> _______________________________________________ >>>>>>> time-nuts mailing list -- time-nuts at febo.com >>>>>>> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >>>>>>> and follow the instructions there. >>>>>>> >>>>>>> >>>>>>> >>>>>>> >>>>>> >>>>>> >>>>> _______________________________________________ >>>>> time-nuts mailing list -- time-nuts at febo.com >>>>> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >>>>> and follow the instructions there. >>>>> >>>>> >>>>> >>>> >>>> >>>> >>> _______________________________________________ >>> time-nuts mailing list -- time-nuts at febo.com >>> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >>> and follow the instructions there. >>> >>> >> >> >> >> > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > -- Steve Rooke - ZL3TUV & G8KVD & JAKDTTNW Omnium finis imminet From bruce.griffiths at xtra.co.nz Wed Apr 8 13:05:39 2009 From: bruce.griffiths at xtra.co.nz (Bruce Griffiths) Date: Thu, 09 Apr 2009 01:05:39 +1200 Subject: [time-nuts] Hadamard variance In-Reply-To: <1231b6a80904080559o7a4cf618r49276df9d7599820@mail.gmail.com> References: <1231b6a80904080559o7a4cf618r49276df9d7599820@mail.gmail.com> Message-ID: <49DCA123.2020607@xtra.co.nz> Steve Rooke wrote: > According to Wikipedia, this is insensitive to drift and so seems like > a better tool for measuring oscillators, like ocxo. I don't think I've > seen this being used by anyone on the list and wonder why? > > 73, > Steve > Steve But at least some of us do use it. Ulrich includes estimators (both the non overlapping and overlapping estimators) for it in Plotter. Plotter is a Windows program so you will have to use VMware, Wine or another Virtual machine to run it in Linux. Bruce From sar10538 at gmail.com Wed Apr 8 13:09:03 2009 From: sar10538 at gmail.com (Steve Rooke) Date: Thu, 9 Apr 2009 01:09:03 +1200 Subject: [time-nuts] Characterising frequency standards In-Reply-To: <49DCA037.3070706@febo.com> References: <1231b6a80904070509m5b8bb638gbc088500444254c3@mail.gmail.com> <1231b6a80904080441p7a747a3h1f73bf8a2df30350@mail.gmail.com> <49DC91B9.6090004@xtra.co.nz> <1231b6a80904080504n4a3a22dcr247fae5df39ed840@mail.gmail.com> <49DC984A.2010509@xtra.co.nz> <1231b6a80904080537r2944092bsbc9e31ba0de7f6c8@mail.gmail.com> <49DC9EB6.1040806@xtra.co.nz> <49DCA037.3070706@febo.com> Message-ID: <1231b6a80904080609h46c4c9b0te5fe63b78da5d0a2@mail.gmail.com> John, OK, I see what you mean if I re-run with a 2 second period:- C:\Documents and Settings\Steve Rooke\Desktop>adev1.exe 2 : > I've compiled adev1 under Linux with no changes required; don't recall > the exact gcc line I used but it was pretty much the obvious one. > > Steve, one other point -- your results with every sample versus > every-other-sample aren't hugely different because ADEV doesn't usually > change dramatically over very short differences in tau (unless there's > some sort of periodicity in the noise). ?So, it would not be unusual to > see that the result for tau=2 seconds (what you got when you removed > every other sample) will be only slightly different than for tau=1 second. > > John > ---- > Bruce Griffiths wrote: >> Steve >> >> Therein lies your problem. >> adev1 ?defaults to a sampling interval of 1 sec. (read the C source code). >> TvB's documentation explicitly states that you should supply the >> sampling interval. (its a command line argument for adev1.c). >> >> adev1.c is a simple command line program that uses stdin and stdout so >> porting it to a linux command line (non graphical) program should be >> straightforward. >> You can even use redirection and pipes should you need them. >> >> You can try porting it to Scilab which is free courtesy of the French >> Government. >> >> >> Bruce >> >> Steve Rooke wrote: >>> Bruce, >>> >>> I set nothing, as indicated in my text, I just delete data points, IE. >>> a file of 400000 records now becomes 200000. I'm trying to get my head >>> round this as the absolute requirement for continuous data seems >>> unneeded. What you have to remember here is that the data set I'm >>> working with consists of discrete measurements of the period of each >>> pulse. If it was timestamps, then there would be problems. >>> >>> I don't know how much MATLAB costs but I would guess it is way out of my budget. >>> >>> 73, >>> Steve >>> >>> 2009/4/9 Bruce Griffiths : >>> >>>> Steve >>>> >>>> The data file doesn't include the time interval between samples so do >>>> you set this in some way? >>>> If so you need to set it to 1s for the unaltered data, to 2s when you >>>> take every 2nd sample, and 1s when you take the first 200,000 samples. >>>> >>>> In principle you could use CANVAS (available on request from USNO - >>>> however you may have to wait a few days while they decide whether to >>>> grant your request.) for such analysis in Linux but you would then need >>>> the Linux version of Matlab. >>>> Or you could request that it be compiled for Linux - a fairly simple >>>> task if one has the Linux version of Matlab. >>>> >>>> In principle you should be able to port the m source files to Scilab, >>>> but there are some subtle differences between Scilab and Matlab so this >>>> may take a while. >>>> >>>> Bruce >>>> >>>> Steve Rooke wrote: >>>> >>>>> Bruce, >>>>> >>>>> But how does that explain the output of Tom's adev1 program which >>>>> still seems to give a a good measurement at tau = 1s? >>>>> >>>>> 73, >>>>> Steve >>>>> >>>>> 2009/4/8 Bruce Griffiths : >>>>> >>>>> >>>>>> Steve >>>>>> >>>>>> If you delete every second measurement then your effective minimum >>>>>> sampling time is now 2s and you can no longer calculate ADEV for tau< 2s. >>>>>> You can still calculate ADEV for tau = 100,000 sec. >>>>>> >>>>>> If you delete all but the first 200,000 lines then you can calculated >>>>>> ADEV for tau=1sec and up to tau= 25,000 sec with reasonable accuracy. >>>>>> >>>>>> You shouldn't lose sight of the fact that ADEV and OADEV are both >>>>>> estimates of the Allan deviation. >>>>>> >>>>>> >>>>>> Bruce >>>>>> >>>>>> Steve Rooke wrote: >>>>>> >>>>>> >>>>>>> Tom, >>>>>>> >>>>>>> I understand fully the points that you have made but I have obviously >>>>>>> not made my point clear to all and i apologise for my poor >>>>>>> communication skills. >>>>>>> >>>>>>> This is what I'm getting at: >>>>>>> >>>>>>> Using your adev1.exe from http://www.leapsecond.com/tools/adev1.htm >>>>>>> and processing various forms of gps.dat from >>>>>>> http://www.leapsecond.com/pages/gpsdo-sim/gps.dat.gz. >>>>>>> >>>>>>> C:\Documents and Settings\Steve Rooke\Desktop>adev1.exe 1 >>>>>> >>>>>>> ** Sampling period: 1 s >>>>>>> ** Phase data scale factor: 1.000e+000 >>>>>>> ** Total phase samples: 400000 >>>>>>> ** Normal and Overlapping Allan deviation: >>>>>>> >>>>>>> ? ? ? ?1 tau, 3.0127e-009 adev(n=399998), ? 3.0127e-009 oadev(n=399998) >>>>>>> ? ? ? ?2 tau, 1.5110e-009 adev(n=199998), ? 1.5119e-009 oadev(n=399996) >>>>>>> ? ? ? ?5 tau, 6.2107e-010 adev(n=79998), ? ?6.1983e-010 oadev(n=399990) >>>>>>> ? ? ? 10 tau, 3.1578e-010 adev(n=39998), ? ?3.1549e-010 oadev(n=399980) >>>>>>> ? ? ? 20 tau, 1.6531e-010 adev(n=19998), ? ?1.6534e-010 oadev(n=399960) >>>>>>> ? ? ? 50 tau, 7.2513e-011 adev(n=7998), ? ? 7.3531e-011 oadev(n=399900) >>>>>>> ? ? ?100 tau, 4.0029e-011 adev(n=3998), ? ? 4.0618e-011 oadev(n=399800) >>>>>>> ? ? ?200 tau, 2.1512e-011 adev(n=1998), ? ? 2.1633e-011 oadev(n=399600) >>>>>>> ? ? ?500 tau, 9.2193e-012 adev(n=798), ? ? ?9.1630e-012 oadev(n=399000) >>>>>>> ? ? 1000 tau, 4.9719e-012 adev(n=398), ? ? ?4.7750e-012 oadev(n=398000) >>>>>>> ? ? 2000 tau, 2.6742e-012 adev(n=198), ? ? ?2.5214e-012 oadev(n=396000) >>>>>>> ? ? 5000 tau, 1.0010e-012 adev(n=78), ? ? ? 1.1032e-012 oadev(n=390000) >>>>>>> ? ?10000 tau, 6.1333e-013 adev(n=38), ? ? ? 6.1039e-013 oadev(n=380000) >>>>>>> ? ?20000 tau, 3.8162e-013 adev(n=18), ? ? ? 3.2913e-013 oadev(n=360000) >>>>>>> ? ?50000 tau, 1.0228e-013 adev(n=6), ? ? ? ?1.5074e-013 oadev(n=300000) >>>>>>> ? 100000 tau, 5.8577e-014 adev(n=2), ? ? ? ?6.7597e-014 oadev(n=200000) >>>>>>> >>>>>>> So far, so good. Now I delete every even line in the file which leaves >>>>>>> me with 200000 lines of data (400000 lines in original gps.dat file). >>>>>>> (awk 'and(NR, 1) == 0 {print}' gps1.dat) >>>>>>> >>>>>>> C:\Documents and Settings\Steve Rooke\Desktop>adev1.exe 1 >>>>>> >>>>>>> ** Sampling period: 1 s >>>>>>> >>>>>>> >>>> INCORRECT!! >>>> sampling period is now 2s. >>>> >>>>>>> ** Phase data scale factor: 1.000e+000 >>>>>>> ** Total phase samples: 200000 >>>>>>> ** Normal and Overlapping Allan deviation: >>>>>>> >>>>>>> ? ? ? ?1 tau, 3.0257e-009 adev(n=199998), ? 3.0257e-009 oadev(n=199998) >>>>>>> ? ? ? ?2 tau, 1.5373e-009 adev(n=99998), ? ?1.5345e-009 oadev(n=199996) >>>>>>> ? ? ? ?5 tau, 6.3147e-010 adev(n=39998), ? ?6.3057e-010 oadev(n=199990) >>>>>>> ? ? ? 10 tau, 3.3140e-010 adev(n=19998), ? ?3.3067e-010 oadev(n=199980) >>>>>>> ? ? ? 20 tau, 1.7872e-010 adev(n=9998), ? ? 1.7810e-010 oadev(n=199960) >>>>>>> ? ? ? 50 tau, 7.9428e-011 adev(n=3998), ? ? 8.1216e-011 oadev(n=199900) >>>>>>> ? ? ?100 tau, 4.2352e-011 adev(n=1998), ? ? 4.3265e-011 oadev(n=199800) >>>>>>> ? ? ?200 tau, 2.2001e-011 adev(n=998), ? ? ?2.2593e-011 oadev(n=199600) >>>>>>> ? ? ?500 tau, 9.6853e-012 adev(n=398), ? ? ?9.5441e-012 oadev(n=199000) >>>>>>> ? ? 1000 tau, 5.0139e-012 adev(n=198), ? ? ?5.0387e-012 oadev(n=198000) >>>>>>> ? ? 2000 tau, 2.7994e-012 adev(n=98), ? ? ? 2.7090e-012 oadev(n=196000) >>>>>>> ? ? 5000 tau, 1.4280e-012 adev(n=38), ? ? ? 1.2214e-012 oadev(n=190000) >>>>>>> ? ?10000 tau, 7.4881e-013 adev(n=18), ? ? ? 6.5814e-013 oadev(n=180000) >>>>>>> ? ?20000 tau, 7.6518e-013 adev(n=8), ? ? ? ?3.7253e-013 oadev(n=160000) >>>>>>> ? ?50000 tau, 2.4698e-014 adev(n=2), ? ? ? ?1.3539e-013 oadev(n=100000) >>>>>>> >>>>>>> Obviously we don't have enough data now for a measurement of 100000 >>>>>>> tau but the results for the other tau are quite close, especially when >>>>>>> there are sufficient data points. Now this is discontinuous data, >>>>>>> exactly what I was trying to allude to. >>>>>>> >>>>>>> OK, so now I take only the top 200000 lines of the gps.dat file (head >>>>>>> -200000 gps.dat >gps2.dat) >>>>>>> >>>>>>> C:\Documents and Settings\Steve Rooke\Desktop>adev1.exe 1 >>>>>> >>>>>>> ** Sampling period: 1 s >>>>>>> ** Phase data scale factor: 1.000e+000 >>>>>>> ** Total phase samples: 200000 >>>>>>> ** Normal and Overlapping Allan deviation: >>>>>>> >>>>>>> ? ? ? ?1 tau, 3.0411e-009 adev(n=199998), ? 3.0411e-009 oadev(n=199998) >>>>>>> ? ? ? ?2 tau, 1.4985e-009 adev(n=99998), ? ?1.4999e-009 oadev(n=199996) >>>>>>> ? ? ? ?5 tau, 6.1964e-010 adev(n=39998), ? ?6.2010e-010 oadev(n=199990) >>>>>>> ? ? ? 10 tau, 3.1315e-010 adev(n=19998), ? ?3.1339e-010 oadev(n=199980) >>>>>>> ? ? ? 20 tau, 1.6499e-010 adev(n=9998), ? ? 1.6495e-010 oadev(n=199960) >>>>>>> ? ? ? 50 tau, 7.1425e-011 adev(n=3998), ? ? 7.3416e-011 oadev(n=199900) >>>>>>> ? ? ?100 tau, 3.9940e-011 adev(n=1998), ? ? 4.0730e-011 oadev(n=199800) >>>>>>> ? ? ?200 tau, 2.1488e-011 adev(n=998), ? ? ?2.1558e-011 oadev(n=199600) >>>>>>> ? ? ?500 tau, 8.4809e-012 adev(n=398), ? ? ?9.0886e-012 oadev(n=199000) >>>>>>> ? ? 1000 tau, 4.9223e-012 adev(n=198), ? ? ?4.7104e-012 oadev(n=198000) >>>>>>> ? ? 2000 tau, 2.4335e-012 adev(n=98), ? ? ? 2.4515e-012 oadev(n=196000) >>>>>>> ? ? 5000 tau, 1.0308e-012 adev(n=38), ? ? ? 1.0861e-012 oadev(n=190000) >>>>>>> ? ?10000 tau, 5.9504e-013 adev(n=18), ? ? ? 6.1031e-013 oadev(n=180000) >>>>>>> ? ?20000 tau, 3.6277e-013 adev(n=8), ? ? ? ?3.1994e-013 oadev(n=160000) >>>>>>> ? ?50000 tau, 1.0630e-013 adev(n=2), ? ? ? ?1.6715e-013 oadev(n=100000) >>>>>>> >>>>>>> Is there any Linux tools for calculating adev as I'm having to run >>>>>>> Windows in a VMware session? >>>>>>> >>>>>>> 73, >>>>>>> Steve >>>>>>> >>>>>>> 2009/4/8 Tom Van Baak : >>>>>>> >>>>>>> >>>>>>> >>>>>>>> Steve, >>>>>>>> >>>>>>>> You've asked a couple of questions. Let me start with this. >>>>>>>> >>>>>>>> It is true that if one were only interested in the performance >>>>>>>> of a pendulum (or quartz or atomic) clock for averaging times >>>>>>>> of one day that all you would need is a series of time error >>>>>>>> (aka phase) measurements made about the same time once >>>>>>>> a day (doesn't have to be that exact). After one week, you'd >>>>>>>> have 7 error measurements (=6 frequency =5 stability points) >>>>>>>> and this is adequate to calculate the ADEV for tau 1 day. >>>>>>>> This alone allows you to rank your clock among all the other >>>>>>>> pendulum clocks out there. Note also you get time error and >>>>>>>> rate error from these few data points too. >>>>>>>> >>>>>>>> As another example, suppose you have a nice HP 10811A >>>>>>>> oscillator and want to measure its drift rate. In this case you >>>>>>>> could spend just 100 seconds and measure its frequency >>>>>>>> once a day, or even once every couple of days. Do this for >>>>>>>> a month and you'd have several dozen points. If you plot >>>>>>>> these frequency measurements you will likely see that they >>>>>>>> approximately fall on a line; the slope of the is the frequency >>>>>>>> drift rate of the 10811. The general shape of the points, or >>>>>>>> the fit of the line is a rough indication of how consistent the >>>>>>>> drift rate is or if it's increasing or decreasing. >>>>>>>> >>>>>>>> Neither of these examples require a lot of data. Both of these >>>>>>>> are real-world examples. >>>>>>>> >>>>>>>> OK so far? >>>>>>>> >>>>>>>> /tvb >>>>>>>> >>>>>>>> >>>>>>>> >>>>>>>> _______________________________________________ >>>>>>>> time-nuts mailing list -- time-nuts at febo.com >>>>>>>> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >>>>>>>> and follow the instructions there. >>>>>>>> >>>>>>>> >>>>>>>> >>>>>>>> >>>>>>> >>>>>> _______________________________________________ >>>>>> time-nuts mailing list -- time-nuts at febo.com >>>>>> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >>>>>> and follow the instructions there. >>>>>> >>>>>> >>>>>> >>>>> >>>>> >>>> _______________________________________________ >>>> time-nuts mailing list -- time-nuts at febo.com >>>> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >>>> and follow the instructions there. >>>> >>>> >>> >>> >>> >> >> >> _______________________________________________ >> time-nuts mailing list -- time-nuts at febo.com >> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > -- Steve Rooke - ZL3TUV & G8KVD & JAKDTTNW Omnium finis imminet From bruce.griffiths at xtra.co.nz Wed Apr 8 13:10:27 2009 From: bruce.griffiths at xtra.co.nz (Bruce Griffiths) Date: Thu, 09 Apr 2009 01:10:27 +1200 Subject: [time-nuts] Characterising frequency standards In-Reply-To: <1231b6a80904080602w58ea54c4tdb56bc160e56b4ae@mail.gmail.com> References: <1231b6a80904070509m5b8bb638gbc088500444254c3@mail.gmail.com> <1231b6a80904080441p7a747a3h1f73bf8a2df30350@mail.gmail.com> <49DC91B9.6090004@xtra.co.nz> <1231b6a80904080504n4a3a22dcr247fae5df39ed840@mail.gmail.com> <49DC984A.2010509@xtra.co.nz> <1231b6a80904080537r2944092bsbc9e31ba0de7f6c8@mail.gmail.com> <49DC9EB6.1040806@xtra.co.nz> <1231b6a80904080602w58ea54c4tdb56bc160e56b4ae@mail.gmail.com> Message-ID: <49DCA243.4020906@xtra.co.nz> Steve Rooke wrote: > Bruce, > > But the sampling interval is still 1 sec and you can see by my notes > that I explicitly give this on the command line for adev1.exe. > > The sampling interval is indeed 1sec in the original data. However, if you delete every second sample the sampling interval in the resultant data is then 2 sec. > OK, I'll have a go at compiling it as it is just a command line program. > > 73, > Steve > > 2009/4/9 Bruce Griffiths : > >> Steve >> >> Therein lies your problem. >> adev1 defaults to a sampling interval of 1 sec. (read the C source code). >> TvB's documentation explicitly states that you should supply the >> sampling interval. (its a command line argument for adev1.c). >> >> adev1.c is a simple command line program that uses stdin and stdout so >> porting it to a linux command line (non graphical) program should be >> straightforward. >> You can even use redirection and pipes should you need them. >> >> You can try porting it to Scilab which is free courtesy of the French >> Government. >> >> >> Bruce >> >> Steve Rooke wrote: >> >>> Bruce, >>> >>> I set nothing, as indicated in my text, I just delete data points, IE. >>> a file of 400000 records now becomes 200000. I'm trying to get my head >>> round this as the absolute requirement for continuous data seems >>> unneeded. What you have to remember here is that the data set I'm >>> working with consists of discrete measurements of the period of each >>> pulse. If it was timestamps, then there would be problems. >>> >>> I don't know how much MATLAB costs but I would guess it is way out of my budget. >>> >>> 73, >>> Steve >>> >>> 2009/4/9 Bruce Griffiths : >>> >>> >>>> Steve >>>> >>>> The data file doesn't include the time interval between samples so do >>>> you set this in some way? >>>> If so you need to set it to 1s for the unaltered data, to 2s when you >>>> take every 2nd sample, and 1s when you take the first 200,000 samples. >>>> >>>> In principle you could use CANVAS (available on request from USNO - >>>> however you may have to wait a few days while they decide whether to >>>> grant your request.) for such analysis in Linux but you would then need >>>> the Linux version of Matlab. >>>> Or you could request that it be compiled for Linux - a fairly simple >>>> task if one has the Linux version of Matlab. >>>> >>>> In principle you should be able to port the m source files to Scilab, >>>> but there are some subtle differences between Scilab and Matlab so this >>>> may take a while. >>>> >>>> Bruce >>>> >>>> Steve Rooke wrote: >>>> >>>> >>>>> Bruce, >>>>> >>>>> But how does that explain the output of Tom's adev1 program which >>>>> still seems to give a a good measurement at tau = 1s? >>>>> >>>>> 73, >>>>> Steve >>>>> >>>>> 2009/4/8 Bruce Griffiths : >>>>> >>>>> >>>>> >>>>>> Steve >>>>>> >>>>>> If you delete every second measurement then your effective minimum >>>>>> sampling time is now 2s and you can no longer calculate ADEV for tau< 2s. >>>>>> You can still calculate ADEV for tau = 100,000 sec. >>>>>> >>>>>> If you delete all but the first 200,000 lines then you can calculated >>>>>> ADEV for tau=1sec and up to tau= 25,000 sec with reasonable accuracy. >>>>>> >>>>>> You shouldn't lose sight of the fact that ADEV and OADEV are both >>>>>> estimates of the Allan deviation. >>>>>> >>>>>> >>>>>> Bruce >>>>>> >>>>>> Steve Rooke wrote: >>>>>> >>>>>> >>>>>> >>>>>>> Tom, >>>>>>> >>>>>>> I understand fully the points that you have made but I have obviously >>>>>>> not made my point clear to all and i apologise for my poor >>>>>>> communication skills. >>>>>>> >>>>>>> This is what I'm getting at: >>>>>>> >>>>>>> Using your adev1.exe from http://www.leapsecond.com/tools/adev1.htm >>>>>>> and processing various forms of gps.dat from >>>>>>> http://www.leapsecond.com/pages/gpsdo-sim/gps.dat.gz. >>>>>>> >>>>>>> C:\Documents and Settings\Steve Rooke\Desktop>adev1.exe 1 >>>>>> >>>>>>> ** Sampling period: 1 s >>>>>>> ** Phase data scale factor: 1.000e+000 >>>>>>> ** Total phase samples: 400000 >>>>>>> ** Normal and Overlapping Allan deviation: >>>>>>> >>>>>>> 1 tau, 3.0127e-009 adev(n=399998), 3.0127e-009 oadev(n=399998) >>>>>>> 2 tau, 1.5110e-009 adev(n=199998), 1.5119e-009 oadev(n=399996) >>>>>>> 5 tau, 6.2107e-010 adev(n=79998), 6.1983e-010 oadev(n=399990) >>>>>>> 10 tau, 3.1578e-010 adev(n=39998), 3.1549e-010 oadev(n=399980) >>>>>>> 20 tau, 1.6531e-010 adev(n=19998), 1.6534e-010 oadev(n=399960) >>>>>>> 50 tau, 7.2513e-011 adev(n=7998), 7.3531e-011 oadev(n=399900) >>>>>>> 100 tau, 4.0029e-011 adev(n=3998), 4.0618e-011 oadev(n=399800) >>>>>>> 200 tau, 2.1512e-011 adev(n=1998), 2.1633e-011 oadev(n=399600) >>>>>>> 500 tau, 9.2193e-012 adev(n=798), 9.1630e-012 oadev(n=399000) >>>>>>> 1000 tau, 4.9719e-012 adev(n=398), 4.7750e-012 oadev(n=398000) >>>>>>> 2000 tau, 2.6742e-012 adev(n=198), 2.5214e-012 oadev(n=396000) >>>>>>> 5000 tau, 1.0010e-012 adev(n=78), 1.1032e-012 oadev(n=390000) >>>>>>> 10000 tau, 6.1333e-013 adev(n=38), 6.1039e-013 oadev(n=380000) >>>>>>> 20000 tau, 3.8162e-013 adev(n=18), 3.2913e-013 oadev(n=360000) >>>>>>> 50000 tau, 1.0228e-013 adev(n=6), 1.5074e-013 oadev(n=300000) >>>>>>> 100000 tau, 5.8577e-014 adev(n=2), 6.7597e-014 oadev(n=200000) >>>>>>> >>>>>>> So far, so good. Now I delete every even line in the file which leaves >>>>>>> me with 200000 lines of data (400000 lines in original gps.dat file). >>>>>>> (awk 'and(NR, 1) == 0 {print}' gps1.dat) >>>>>>> >>>>>>> C:\Documents and Settings\Steve Rooke\Desktop>adev1.exe 1 >>>>>> >>>>>>> ** Sampling period: 1 s >>>>>>> >>>>>>> >>>>>>> >>>> INCORRECT!! >>>> sampling period is now 2s. >>>> >>>> >>>>>>> ** Phase data scale factor: 1.000e+000 >>>>>>> ** Total phase samples: 200000 >>>>>>> ** Normal and Overlapping Allan deviation: >>>>>>> >>>>>>> 1 tau, 3.0257e-009 adev(n=199998), 3.0257e-009 oadev(n=199998) >>>>>>> 2 tau, 1.5373e-009 adev(n=99998), 1.5345e-009 oadev(n=199996) >>>>>>> 5 tau, 6.3147e-010 adev(n=39998), 6.3057e-010 oadev(n=199990) >>>>>>> 10 tau, 3.3140e-010 adev(n=19998), 3.3067e-010 oadev(n=199980) >>>>>>> 20 tau, 1.7872e-010 adev(n=9998), 1.7810e-010 oadev(n=199960) >>>>>>> 50 tau, 7.9428e-011 adev(n=3998), 8.1216e-011 oadev(n=199900) >>>>>>> 100 tau, 4.2352e-011 adev(n=1998), 4.3265e-011 oadev(n=199800) >>>>>>> 200 tau, 2.2001e-011 adev(n=998), 2.2593e-011 oadev(n=199600) >>>>>>> 500 tau, 9.6853e-012 adev(n=398), 9.5441e-012 oadev(n=199000) >>>>>>> 1000 tau, 5.0139e-012 adev(n=198), 5.0387e-012 oadev(n=198000) >>>>>>> 2000 tau, 2.7994e-012 adev(n=98), 2.7090e-012 oadev(n=196000) >>>>>>> 5000 tau, 1.4280e-012 adev(n=38), 1.2214e-012 oadev(n=190000) >>>>>>> 10000 tau, 7.4881e-013 adev(n=18), 6.5814e-013 oadev(n=180000) >>>>>>> 20000 tau, 7.6518e-013 adev(n=8), 3.7253e-013 oadev(n=160000) >>>>>>> 50000 tau, 2.4698e-014 adev(n=2), 1.3539e-013 oadev(n=100000) >>>>>>> >>>>>>> Obviously we don't have enough data now for a measurement of 100000 >>>>>>> tau but the results for the other tau are quite close, especially when >>>>>>> there are sufficient data points. Now this is discontinuous data, >>>>>>> exactly what I was trying to allude to. >>>>>>> >>>>>>> OK, so now I take only the top 200000 lines of the gps.dat file (head >>>>>>> -200000 gps.dat >gps2.dat) >>>>>>> >>>>>>> C:\Documents and Settings\Steve Rooke\Desktop>adev1.exe 1 >>>>>> >>>>>>> ** Sampling period: 1 s >>>>>>> ** Phase data scale factor: 1.000e+000 >>>>>>> ** Total phase samples: 200000 >>>>>>> ** Normal and Overlapping Allan deviation: >>>>>>> >>>>>>> 1 tau, 3.0411e-009 adev(n=199998), 3.0411e-009 oadev(n=199998) >>>>>>> 2 tau, 1.4985e-009 adev(n=99998), 1.4999e-009 oadev(n=199996) >>>>>>> 5 tau, 6.1964e-010 adev(n=39998), 6.2010e-010 oadev(n=199990) >>>>>>> 10 tau, 3.1315e-010 adev(n=19998), 3.1339e-010 oadev(n=199980) >>>>>>> 20 tau, 1.6499e-010 adev(n=9998), 1.6495e-010 oadev(n=199960) >>>>>>> 50 tau, 7.1425e-011 adev(n=3998), 7.3416e-011 oadev(n=199900) >>>>>>> 100 tau, 3.9940e-011 adev(n=1998), 4.0730e-011 oadev(n=199800) >>>>>>> 200 tau, 2.1488e-011 adev(n=998), 2.1558e-011 oadev(n=199600) >>>>>>> 500 tau, 8.4809e-012 adev(n=398), 9.0886e-012 oadev(n=199000) >>>>>>> 1000 tau, 4.9223e-012 adev(n=198), 4.7104e-012 oadev(n=198000) >>>>>>> 2000 tau, 2.4335e-012 adev(n=98), 2.4515e-012 oadev(n=196000) >>>>>>> 5000 tau, 1.0308e-012 adev(n=38), 1.0861e-012 oadev(n=190000) >>>>>>> 10000 tau, 5.9504e-013 adev(n=18), 6.1031e-013 oadev(n=180000) >>>>>>> 20000 tau, 3.6277e-013 adev(n=8), 3.1994e-013 oadev(n=160000) >>>>>>> 50000 tau, 1.0630e-013 adev(n=2), 1.6715e-013 oadev(n=100000) >>>>>>> >>>>>>> Is there any Linux tools for calculating adev as I'm having to run >>>>>>> Windows in a VMware session? >>>>>>> >>>>>>> 73, >>>>>>> Steve >>>>>>> >>>>>>> 2009/4/8 Tom Van Baak : >>>>>>> >>>>>>> >>>>>>> >>>>>>> >>>>>>>> Steve, >>>>>>>> >>>>>>>> You've asked a couple of questions. Let me start with this. >>>>>>>> >>>>>>>> It is true that if one were only interested in the performance >>>>>>>> of a pendulum (or quartz or atomic) clock for averaging times >>>>>>>> of one day that all you would need is a series of time error >>>>>>>> (aka phase) measurements made about the same time once >>>>>>>> a day (doesn't have to be that exact). After one week, you'd >>>>>>>> have 7 error measurements (=6 frequency =5 stability points) >>>>>>>> and this is adequate to calculate the ADEV for tau 1 day. >>>>>>>> This alone allows you to rank your clock among all the other >>>>>>>> pendulum clocks out there. Note also you get time error and >>>>>>>> rate error from these few data points too. >>>>>>>> >>>>>>>> As another example, suppose you have a nice HP 10811A >>>>>>>> oscillator and want to measure its drift rate. In this case you >>>>>>>> could spend just 100 seconds and measure its frequency >>>>>>>> once a day, or even once every couple of days. Do this for >>>>>>>> a month and you'd have several dozen points. If you plot >>>>>>>> these frequency measurements you will likely see that they >>>>>>>> approximately fall on a line; the slope of the is the frequency >>>>>>>> drift rate of the 10811. The general shape of the points, or >>>>>>>> the fit of the line is a rough indication of how consistent the >>>>>>>> drift rate is or if it's increasing or decreasing. >>>>>>>> >>>>>>>> Neither of these examples require a lot of data. Both of these >>>>>>>> are real-world examples. >>>>>>>> >>>>>>>> OK so far? >>>>>>>> >>>>>>>> /tvb >>>>>>>> >>>>>>>> >>>>>>>> >>>>>>>> _______________________________________________ >>>>>>>> time-nuts mailing list -- time-nuts at febo.com >>>>>>>> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >>>>>>>> and follow the instructions there. >>>>>>>> >>>>>>>> >>>>>>>> >>>>>>>> >>>>>>>> >>>>>>> >>>>>> _______________________________________________ >>>>>> time-nuts mailing list -- time-nuts at febo.com >>>>>> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >>>>>> and follow the instructions there. >>>>>> >>>>>> >>>>>> >>>>>> >>>>> >>>>> >>>> _______________________________________________ >>>> time-nuts mailing list -- time-nuts at febo.com >>>> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >>>> and follow the instructions there. >>>> >>>> >>>> >>> >>> >>> >> _______________________________________________ >> time-nuts mailing list -- time-nuts at febo.com >> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. >> >> > > > > From sar10538 at gmail.com Wed Apr 8 13:16:16 2009 From: sar10538 at gmail.com (Steve Rooke) Date: Thu, 9 Apr 2009 01:16:16 +1200 Subject: [time-nuts] Characterising frequency standards In-Reply-To: <49DCA037.3070706@febo.com> References: <1231b6a80904070509m5b8bb638gbc088500444254c3@mail.gmail.com> <1231b6a80904080441p7a747a3h1f73bf8a2df30350@mail.gmail.com> <49DC91B9.6090004@xtra.co.nz> <1231b6a80904080504n4a3a22dcr247fae5df39ed840@mail.gmail.com> <49DC984A.2010509@xtra.co.nz> <1231b6a80904080537r2944092bsbc9e31ba0de7f6c8@mail.gmail.com> <49DC9EB6.1040806@xtra.co.nz> <49DCA037.3070706@febo.com> Message-ID: <1231b6a80904080616j28741be7wf661421298651ed3@mail.gmail.com> Yes, it compiles cleanly with "gcc -o adev1 -lm adev1.c" and works just like a bought one, thanks. 73, Steve 2009/4/9 John Ackermann N8UR : > I've compiled adev1 under Linux with no changes required; don't recall > the exact gcc line I used but it was pretty much the obvious one. > > Steve, one other point -- your results with every sample versus > every-other-sample aren't hugely different because ADEV doesn't usually > change dramatically over very short differences in tau (unless there's > some sort of periodicity in the noise). ?So, it would not be unusual to > see that the result for tau=2 seconds (what you got when you removed > every other sample) will be only slightly different than for tau=1 second. > > John > ---- > Bruce Griffiths wrote: >> Steve >> >> Therein lies your problem. >> adev1 ?defaults to a sampling interval of 1 sec. (read the C source code). >> TvB's documentation explicitly states that you should supply the >> sampling interval. (its a command line argument for adev1.c). >> >> adev1.c is a simple command line program that uses stdin and stdout so >> porting it to a linux command line (non graphical) program should be >> straightforward. >> You can even use redirection and pipes should you need them. >> >> You can try porting it to Scilab which is free courtesy of the French >> Government. >> >> >> Bruce >> >> Steve Rooke wrote: >>> Bruce, >>> >>> I set nothing, as indicated in my text, I just delete data points, IE. >>> a file of 400000 records now becomes 200000. I'm trying to get my head >>> round this as the absolute requirement for continuous data seems >>> unneeded. What you have to remember here is that the data set I'm >>> working with consists of discrete measurements of the period of each >>> pulse. If it was timestamps, then there would be problems. >>> >>> I don't know how much MATLAB costs but I would guess it is way out of my budget. >>> >>> 73, >>> Steve >>> >>> 2009/4/9 Bruce Griffiths : >>> >>>> Steve >>>> >>>> The data file doesn't include the time interval between samples so do >>>> you set this in some way? >>>> If so you need to set it to 1s for the unaltered data, to 2s when you >>>> take every 2nd sample, and 1s when you take the first 200,000 samples. >>>> >>>> In principle you could use CANVAS (available on request from USNO - >>>> however you may have to wait a few days while they decide whether to >>>> grant your request.) for such analysis in Linux but you would then need >>>> the Linux version of Matlab. >>>> Or you could request that it be compiled for Linux - a fairly simple >>>> task if one has the Linux version of Matlab. >>>> >>>> In principle you should be able to port the m source files to Scilab, >>>> but there are some subtle differences between Scilab and Matlab so this >>>> may take a while. >>>> >>>> Bruce >>>> >>>> Steve Rooke wrote: >>>> >>>>> Bruce, >>>>> >>>>> But how does that explain the output of Tom's adev1 program which >>>>> still seems to give a a good measurement at tau = 1s? >>>>> >>>>> 73, >>>>> Steve >>>>> >>>>> 2009/4/8 Bruce Griffiths : >>>>> >>>>> >>>>>> Steve >>>>>> >>>>>> If you delete every second measurement then your effective minimum >>>>>> sampling time is now 2s and you can no longer calculate ADEV for tau< 2s. >>>>>> You can still calculate ADEV for tau = 100,000 sec. >>>>>> >>>>>> If you delete all but the first 200,000 lines then you can calculated >>>>>> ADEV for tau=1sec and up to tau= 25,000 sec with reasonable accuracy. >>>>>> >>>>>> You shouldn't lose sight of the fact that ADEV and OADEV are both >>>>>> estimates of the Allan deviation. >>>>>> >>>>>> >>>>>> Bruce >>>>>> >>>>>> Steve Rooke wrote: >>>>>> >>>>>> >>>>>>> Tom, >>>>>>> >>>>>>> I understand fully the points that you have made but I have obviously >>>>>>> not made my point clear to all and i apologise for my poor >>>>>>> communication skills. >>>>>>> >>>>>>> This is what I'm getting at: >>>>>>> >>>>>>> Using your adev1.exe from http://www.leapsecond.com/tools/adev1.htm >>>>>>> and processing various forms of gps.dat from >>>>>>> http://www.leapsecond.com/pages/gpsdo-sim/gps.dat.gz. >>>>>>> >>>>>>> C:\Documents and Settings\Steve Rooke\Desktop>adev1.exe 1 >>>>>> >>>>>>> ** Sampling period: 1 s >>>>>>> ** Phase data scale factor: 1.000e+000 >>>>>>> ** Total phase samples: 400000 >>>>>>> ** Normal and Overlapping Allan deviation: >>>>>>> >>>>>>> ? ? ? ?1 tau, 3.0127e-009 adev(n=399998), ? 3.0127e-009 oadev(n=399998) >>>>>>> ? ? ? ?2 tau, 1.5110e-009 adev(n=199998), ? 1.5119e-009 oadev(n=399996) >>>>>>> ? ? ? ?5 tau, 6.2107e-010 adev(n=79998), ? ?6.1983e-010 oadev(n=399990) >>>>>>> ? ? ? 10 tau, 3.1578e-010 adev(n=39998), ? ?3.1549e-010 oadev(n=399980) >>>>>>> ? ? ? 20 tau, 1.6531e-010 adev(n=19998), ? ?1.6534e-010 oadev(n=399960) >>>>>>> ? ? ? 50 tau, 7.2513e-011 adev(n=7998), ? ? 7.3531e-011 oadev(n=399900) >>>>>>> ? ? ?100 tau, 4.0029e-011 adev(n=3998), ? ? 4.0618e-011 oadev(n=399800) >>>>>>> ? ? ?200 tau, 2.1512e-011 adev(n=1998), ? ? 2.1633e-011 oadev(n=399600) >>>>>>> ? ? ?500 tau, 9.2193e-012 adev(n=798), ? ? ?9.1630e-012 oadev(n=399000) >>>>>>> ? ? 1000 tau, 4.9719e-012 adev(n=398), ? ? ?4.7750e-012 oadev(n=398000) >>>>>>> ? ? 2000 tau, 2.6742e-012 adev(n=198), ? ? ?2.5214e-012 oadev(n=396000) >>>>>>> ? ? 5000 tau, 1.0010e-012 adev(n=78), ? ? ? 1.1032e-012 oadev(n=390000) >>>>>>> ? ?10000 tau, 6.1333e-013 adev(n=38), ? ? ? 6.1039e-013 oadev(n=380000) >>>>>>> ? ?20000 tau, 3.8162e-013 adev(n=18), ? ? ? 3.2913e-013 oadev(n=360000) >>>>>>> ? ?50000 tau, 1.0228e-013 adev(n=6), ? ? ? ?1.5074e-013 oadev(n=300000) >>>>>>> ? 100000 tau, 5.8577e-014 adev(n=2), ? ? ? ?6.7597e-014 oadev(n=200000) >>>>>>> >>>>>>> So far, so good. Now I delete every even line in the file which leaves >>>>>>> me with 200000 lines of data (400000 lines in original gps.dat file). >>>>>>> (awk 'and(NR, 1) == 0 {print}' gps1.dat) >>>>>>> >>>>>>> C:\Documents and Settings\Steve Rooke\Desktop>adev1.exe 1 >>>>>> >>>>>>> ** Sampling period: 1 s >>>>>>> >>>>>>> >>>> INCORRECT!! >>>> sampling period is now 2s. >>>> >>>>>>> ** Phase data scale factor: 1.000e+000 >>>>>>> ** Total phase samples: 200000 >>>>>>> ** Normal and Overlapping Allan deviation: >>>>>>> >>>>>>> ? ? ? ?1 tau, 3.0257e-009 adev(n=199998), ? 3.0257e-009 oadev(n=199998) >>>>>>> ? ? ? ?2 tau, 1.5373e-009 adev(n=99998), ? ?1.5345e-009 oadev(n=199996) >>>>>>> ? ? ? ?5 tau, 6.3147e-010 adev(n=39998), ? ?6.3057e-010 oadev(n=199990) >>>>>>> ? ? ? 10 tau, 3.3140e-010 adev(n=19998), ? ?3.3067e-010 oadev(n=199980) >>>>>>> ? ? ? 20 tau, 1.7872e-010 adev(n=9998), ? ? 1.7810e-010 oadev(n=199960) >>>>>>> ? ? ? 50 tau, 7.9428e-011 adev(n=3998), ? ? 8.1216e-011 oadev(n=199900) >>>>>>> ? ? ?100 tau, 4.2352e-011 adev(n=1998), ? ? 4.3265e-011 oadev(n=199800) >>>>>>> ? ? ?200 tau, 2.2001e-011 adev(n=998), ? ? ?2.2593e-011 oadev(n=199600) >>>>>>> ? ? ?500 tau, 9.6853e-012 adev(n=398), ? ? ?9.5441e-012 oadev(n=199000) >>>>>>> ? ? 1000 tau, 5.0139e-012 adev(n=198), ? ? ?5.0387e-012 oadev(n=198000) >>>>>>> ? ? 2000 tau, 2.7994e-012 adev(n=98), ? ? ? 2.7090e-012 oadev(n=196000) >>>>>>> ? ? 5000 tau, 1.4280e-012 adev(n=38), ? ? ? 1.2214e-012 oadev(n=190000) >>>>>>> ? ?10000 tau, 7.4881e-013 adev(n=18), ? ? ? 6.5814e-013 oadev(n=180000) >>>>>>> ? ?20000 tau, 7.6518e-013 adev(n=8), ? ? ? ?3.7253e-013 oadev(n=160000) >>>>>>> ? ?50000 tau, 2.4698e-014 adev(n=2), ? ? ? ?1.3539e-013 oadev(n=100000) >>>>>>> >>>>>>> Obviously we don't have enough data now for a measurement of 100000 >>>>>>> tau but the results for the other tau are quite close, especially when >>>>>>> there are sufficient data points. Now this is discontinuous data, >>>>>>> exactly what I was trying to allude to. >>>>>>> >>>>>>> OK, so now I take only the top 200000 lines of the gps.dat file (head >>>>>>> -200000 gps.dat >gps2.dat) >>>>>>> >>>>>>> C:\Documents and Settings\Steve Rooke\Desktop>adev1.exe 1 >>>>>> >>>>>>> ** Sampling period: 1 s >>>>>>> ** Phase data scale factor: 1.000e+000 >>>>>>> ** Total phase samples: 200000 >>>>>>> ** Normal and Overlapping Allan deviation: >>>>>>> >>>>>>> ? ? ? ?1 tau, 3.0411e-009 adev(n=199998), ? 3.0411e-009 oadev(n=199998) >>>>>>> ? ? ? ?2 tau, 1.4985e-009 adev(n=99998), ? ?1.4999e-009 oadev(n=199996) >>>>>>> ? ? ? ?5 tau, 6.1964e-010 adev(n=39998), ? ?6.2010e-010 oadev(n=199990) >>>>>>> ? ? ? 10 tau, 3.1315e-010 adev(n=19998), ? ?3.1339e-010 oadev(n=199980) >>>>>>> ? ? ? 20 tau, 1.6499e-010 adev(n=9998), ? ? 1.6495e-010 oadev(n=199960) >>>>>>> ? ? ? 50 tau, 7.1425e-011 adev(n=3998), ? ? 7.3416e-011 oadev(n=199900) >>>>>>> ? ? ?100 tau, 3.9940e-011 adev(n=1998), ? ? 4.0730e-011 oadev(n=199800) >>>>>>> ? ? ?200 tau, 2.1488e-011 adev(n=998), ? ? ?2.1558e-011 oadev(n=199600) >>>>>>> ? ? ?500 tau, 8.4809e-012 adev(n=398), ? ? ?9.0886e-012 oadev(n=199000) >>>>>>> ? ? 1000 tau, 4.9223e-012 adev(n=198), ? ? ?4.7104e-012 oadev(n=198000) >>>>>>> ? ? 2000 tau, 2.4335e-012 adev(n=98), ? ? ? 2.4515e-012 oadev(n=196000) >>>>>>> ? ? 5000 tau, 1.0308e-012 adev(n=38), ? ? ? 1.0861e-012 oadev(n=190000) >>>>>>> ? ?10000 tau, 5.9504e-013 adev(n=18), ? ? ? 6.1031e-013 oadev(n=180000) >>>>>>> ? ?20000 tau, 3.6277e-013 adev(n=8), ? ? ? ?3.1994e-013 oadev(n=160000) >>>>>>> ? ?50000 tau, 1.0630e-013 adev(n=2), ? ? ? ?1.6715e-013 oadev(n=100000) >>>>>>> >>>>>>> Is there any Linux tools for calculating adev as I'm having to run >>>>>>> Windows in a VMware session? >>>>>>> >>>>>>> 73, >>>>>>> Steve >>>>>>> >>>>>>> 2009/4/8 Tom Van Baak : >>>>>>> >>>>>>> >>>>>>> >>>>>>>> Steve, >>>>>>>> >>>>>>>> You've asked a couple of questions. Let me start with this. >>>>>>>> >>>>>>>> It is true that if one were only interested in the performance >>>>>>>> of a pendulum (or quartz or atomic) clock for averaging times >>>>>>>> of one day that all you would need is a series of time error >>>>>>>> (aka phase) measurements made about the same time once >>>>>>>> a day (doesn't have to be that exact). After one week, you'd >>>>>>>> have 7 error measurements (=6 frequency =5 stability points) >>>>>>>> and this is adequate to calculate the ADEV for tau 1 day. >>>>>>>> This alone allows you to rank your clock among all the other >>>>>>>> pendulum clocks out there. Note also you get time error and >>>>>>>> rate error from these few data points too. >>>>>>>> >>>>>>>> As another example, suppose you have a nice HP 10811A >>>>>>>> oscillator and want to measure its drift rate. In this case you >>>>>>>> could spend just 100 seconds and measure its frequency >>>>>>>> once a day, or even once every couple of days. Do this for >>>>>>>> a month and you'd have several dozen points. If you plot >>>>>>>> these frequency measurements you will likely see that they >>>>>>>> approximately fall on a line; the slope of the is the frequency >>>>>>>> drift rate of the 10811. The general shape of the points, or >>>>>>>> the fit of the line is a rough indication of how consistent the >>>>>>>> drift rate is or if it's increasing or decreasing. >>>>>>>> >>>>>>>> Neither of these examples require a lot of data. Both of these >>>>>>>> are real-world examples. >>>>>>>> >>>>>>>> OK so far? >>>>>>>> >>>>>>>> /tvb >>>>>>>> >>>>>>>> >>>>>>>> >>>>>>>> _______________________________________________ >>>>>>>> time-nuts mailing list -- time-nuts at febo.com >>>>>>>> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >>>>>>>> and follow the instructions there. >>>>>>>> >>>>>>>> >>>>>>>> >>>>>>>> >>>>>>> >>>>>> _______________________________________________ >>>>>> time-nuts mailing list -- time-nuts at febo.com >>>>>> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >>>>>> and follow the instructions there. >>>>>> >>>>>> >>>>>> >>>>> >>>>> >>>> _______________________________________________ >>>> time-nuts mailing list -- time-nuts at febo.com >>>> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >>>> and follow the instructions there. >>>> >>>> >>> >>> >>> >> >> >> _______________________________________________ >> time-nuts mailing list -- time-nuts at febo.com >> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > -- Steve Rooke - ZL3TUV & G8KVD & JAKDTTNW Omnium finis imminet From sar10538 at gmail.com Wed Apr 8 13:19:48 2009 From: sar10538 at gmail.com (Steve Rooke) Date: Thu, 9 Apr 2009 01:19:48 +1200 Subject: [time-nuts] Characterising frequency standards In-Reply-To: <49DCA243.4020906@xtra.co.nz> References: <1231b6a80904070509m5b8bb638gbc088500444254c3@mail.gmail.com> <1231b6a80904080441p7a747a3h1f73bf8a2df30350@mail.gmail.com> <49DC91B9.6090004@xtra.co.nz> <1231b6a80904080504n4a3a22dcr247fae5df39ed840@mail.gmail.com> <49DC984A.2010509@xtra.co.nz> <1231b6a80904080537r2944092bsbc9e31ba0de7f6c8@mail.gmail.com> <49DC9EB6.1040806@xtra.co.nz> <1231b6a80904080602w58ea54c4tdb56bc160e56b4ae@mail.gmail.com> <49DCA243.4020906@xtra.co.nz> Message-ID: <1231b6a80904080619y60199d73h244598262c1de1b9@mail.gmail.com> 2009/4/9 Bruce Griffiths : > The sampling interval is indeed 1sec in the original data. > However, if you delete every second sample the sampling interval in the > resultant data is then 2 sec. Doesn't that imply that the data point should correspond to the whole sampling period and not just half of it? 73, Steve >> OK, I'll have a go at compiling it as it is just a command line program. >> >> 73, >> Steve >> >> 2009/4/9 Bruce Griffiths : >> >>> Steve >>> >>> Therein lies your problem. >>> adev1 ?defaults to a sampling interval of 1 sec. (read the C source code). >>> TvB's documentation explicitly states that you should supply the >>> sampling interval. (its a command line argument for adev1.c). >>> >>> adev1.c is a simple command line program that uses stdin and stdout so >>> porting it to a linux command line (non graphical) program should be >>> straightforward. >>> You can even use redirection and pipes should you need them. >>> >>> You can try porting it to Scilab which is free courtesy of the French >>> Government. >>> >>> >>> Bruce >>> >>> Steve Rooke wrote: >>> >>>> Bruce, >>>> >>>> I set nothing, as indicated in my text, I just delete data points, IE. >>>> a file of 400000 records now becomes 200000. I'm trying to get my head >>>> round this as the absolute requirement for continuous data seems >>>> unneeded. What you have to remember here is that the data set I'm >>>> working with consists of discrete measurements of the period of each >>>> pulse. If it was timestamps, then there would be problems. >>>> >>>> I don't know how much MATLAB costs but I would guess it is way out of my budget. >>>> >>>> 73, >>>> Steve >>>> >>>> 2009/4/9 Bruce Griffiths : >>>> >>>> >>>>> Steve >>>>> >>>>> The data file doesn't include the time interval between samples so do >>>>> you set this in some way? >>>>> If so you need to set it to 1s for the unaltered data, to 2s when you >>>>> take every 2nd sample, and 1s when you take the first 200,000 samples. >>>>> >>>>> In principle you could use CANVAS (available on request from USNO - >>>>> however you may have to wait a few days while they decide whether to >>>>> grant your request.) for such analysis in Linux but you would then need >>>>> the Linux version of Matlab. >>>>> Or you could request that it be compiled for Linux - a fairly simple >>>>> task if one has the Linux version of Matlab. >>>>> >>>>> In principle you should be able to port the m source files to Scilab, >>>>> but there are some subtle differences between Scilab and Matlab so this >>>>> may take a while. >>>>> >>>>> Bruce >>>>> >>>>> Steve Rooke wrote: >>>>> >>>>> >>>>>> Bruce, >>>>>> >>>>>> But how does that explain the output of Tom's adev1 program which >>>>>> still seems to give a a good measurement at tau = 1s? >>>>>> >>>>>> 73, >>>>>> Steve >>>>>> >>>>>> 2009/4/8 Bruce Griffiths : >>>>>> >>>>>> >>>>>> >>>>>>> Steve >>>>>>> >>>>>>> If you delete every second measurement then your effective minimum >>>>>>> sampling time is now 2s and you can no longer calculate ADEV for tau< 2s. >>>>>>> You can still calculate ADEV for tau = 100,000 sec. >>>>>>> >>>>>>> If you delete all but the first 200,000 lines then you can calculated >>>>>>> ADEV for tau=1sec and up to tau= 25,000 sec with reasonable accuracy. >>>>>>> >>>>>>> You shouldn't lose sight of the fact that ADEV and OADEV are both >>>>>>> estimates of the Allan deviation. >>>>>>> >>>>>>> >>>>>>> Bruce >>>>>>> >>>>>>> Steve Rooke wrote: >>>>>>> >>>>>>> >>>>>>> >>>>>>>> Tom, >>>>>>>> >>>>>>>> I understand fully the points that you have made but I have obviously >>>>>>>> not made my point clear to all and i apologise for my poor >>>>>>>> communication skills. >>>>>>>> >>>>>>>> This is what I'm getting at: >>>>>>>> >>>>>>>> Using your adev1.exe from http://www.leapsecond.com/tools/adev1.htm >>>>>>>> and processing various forms of gps.dat from >>>>>>>> http://www.leapsecond.com/pages/gpsdo-sim/gps.dat.gz. >>>>>>>> >>>>>>>> C:\Documents and Settings\Steve Rooke\Desktop>adev1.exe 1 >>>>>>> >>>>>>>> ** Sampling period: 1 s >>>>>>>> ** Phase data scale factor: 1.000e+000 >>>>>>>> ** Total phase samples: 400000 >>>>>>>> ** Normal and Overlapping Allan deviation: >>>>>>>> >>>>>>>> ? ? ? ?1 tau, 3.0127e-009 adev(n=399998), ? 3.0127e-009 oadev(n=399998) >>>>>>>> ? ? ? ?2 tau, 1.5110e-009 adev(n=199998), ? 1.5119e-009 oadev(n=399996) >>>>>>>> ? ? ? ?5 tau, 6.2107e-010 adev(n=79998), ? ?6.1983e-010 oadev(n=399990) >>>>>>>> ? ? ? 10 tau, 3.1578e-010 adev(n=39998), ? ?3.1549e-010 oadev(n=399980) >>>>>>>> ? ? ? 20 tau, 1.6531e-010 adev(n=19998), ? ?1.6534e-010 oadev(n=399960) >>>>>>>> ? ? ? 50 tau, 7.2513e-011 adev(n=7998), ? ? 7.3531e-011 oadev(n=399900) >>>>>>>> ? ? ?100 tau, 4.0029e-011 adev(n=3998), ? ? 4.0618e-011 oadev(n=399800) >>>>>>>> ? ? ?200 tau, 2.1512e-011 adev(n=1998), ? ? 2.1633e-011 oadev(n=399600) >>>>>>>> ? ? ?500 tau, 9.2193e-012 adev(n=798), ? ? ?9.1630e-012 oadev(n=399000) >>>>>>>> ? ? 1000 tau, 4.9719e-012 adev(n=398), ? ? ?4.7750e-012 oadev(n=398000) >>>>>>>> ? ? 2000 tau, 2.6742e-012 adev(n=198), ? ? ?2.5214e-012 oadev(n=396000) >>>>>>>> ? ? 5000 tau, 1.0010e-012 adev(n=78), ? ? ? 1.1032e-012 oadev(n=390000) >>>>>>>> ? ?10000 tau, 6.1333e-013 adev(n=38), ? ? ? 6.1039e-013 oadev(n=380000) >>>>>>>> ? ?20000 tau, 3.8162e-013 adev(n=18), ? ? ? 3.2913e-013 oadev(n=360000) >>>>>>>> ? ?50000 tau, 1.0228e-013 adev(n=6), ? ? ? ?1.5074e-013 oadev(n=300000) >>>>>>>> ? 100000 tau, 5.8577e-014 adev(n=2), ? ? ? ?6.7597e-014 oadev(n=200000) >>>>>>>> >>>>>>>> So far, so good. Now I delete every even line in the file which leaves >>>>>>>> me with 200000 lines of data (400000 lines in original gps.dat file). >>>>>>>> (awk 'and(NR, 1) == 0 {print}' gps1.dat) >>>>>>>> >>>>>>>> C:\Documents and Settings\Steve Rooke\Desktop>adev1.exe 1 >>>>>>> >>>>>>>> ** Sampling period: 1 s >>>>>>>> >>>>>>>> >>>>>>>> >>>>> INCORRECT!! >>>>> sampling period is now 2s. >>>>> >>>>> >>>>>>>> ** Phase data scale factor: 1.000e+000 >>>>>>>> ** Total phase samples: 200000 >>>>>>>> ** Normal and Overlapping Allan deviation: >>>>>>>> >>>>>>>> ? ? ? ?1 tau, 3.0257e-009 adev(n=199998), ? 3.0257e-009 oadev(n=199998) >>>>>>>> ? ? ? ?2 tau, 1.5373e-009 adev(n=99998), ? ?1.5345e-009 oadev(n=199996) >>>>>>>> ? ? ? ?5 tau, 6.3147e-010 adev(n=39998), ? ?6.3057e-010 oadev(n=199990) >>>>>>>> ? ? ? 10 tau, 3.3140e-010 adev(n=19998), ? ?3.3067e-010 oadev(n=199980) >>>>>>>> ? ? ? 20 tau, 1.7872e-010 adev(n=9998), ? ? 1.7810e-010 oadev(n=199960) >>>>>>>> ? ? ? 50 tau, 7.9428e-011 adev(n=3998), ? ? 8.1216e-011 oadev(n=199900) >>>>>>>> ? ? ?100 tau, 4.2352e-011 adev(n=1998), ? ? 4.3265e-011 oadev(n=199800) >>>>>>>> ? ? ?200 tau, 2.2001e-011 adev(n=998), ? ? ?2.2593e-011 oadev(n=199600) >>>>>>>> ? ? ?500 tau, 9.6853e-012 adev(n=398), ? ? ?9.5441e-012 oadev(n=199000) >>>>>>>> ? ? 1000 tau, 5.0139e-012 adev(n=198), ? ? ?5.0387e-012 oadev(n=198000) >>>>>>>> ? ? 2000 tau, 2.7994e-012 adev(n=98), ? ? ? 2.7090e-012 oadev(n=196000) >>>>>>>> ? ? 5000 tau, 1.4280e-012 adev(n=38), ? ? ? 1.2214e-012 oadev(n=190000) >>>>>>>> ? ?10000 tau, 7.4881e-013 adev(n=18), ? ? ? 6.5814e-013 oadev(n=180000) >>>>>>>> ? ?20000 tau, 7.6518e-013 adev(n=8), ? ? ? ?3.7253e-013 oadev(n=160000) >>>>>>>> ? ?50000 tau, 2.4698e-014 adev(n=2), ? ? ? ?1.3539e-013 oadev(n=100000) >>>>>>>> >>>>>>>> Obviously we don't have enough data now for a measurement of 100000 >>>>>>>> tau but the results for the other tau are quite close, especially when >>>>>>>> there are sufficient data points. Now this is discontinuous data, >>>>>>>> exactly what I was trying to allude to. >>>>>>>> >>>>>>>> OK, so now I take only the top 200000 lines of the gps.dat file (head >>>>>>>> -200000 gps.dat >gps2.dat) >>>>>>>> >>>>>>>> C:\Documents and Settings\Steve Rooke\Desktop>adev1.exe 1 >>>>>>> >>>>>>>> ** Sampling period: 1 s >>>>>>>> ** Phase data scale factor: 1.000e+000 >>>>>>>> ** Total phase samples: 200000 >>>>>>>> ** Normal and Overlapping Allan deviation: >>>>>>>> >>>>>>>> ? ? ? ?1 tau, 3.0411e-009 adev(n=199998), ? 3.0411e-009 oadev(n=199998) >>>>>>>> ? ? ? ?2 tau, 1.4985e-009 adev(n=99998), ? ?1.4999e-009 oadev(n=199996) >>>>>>>> ? ? ? ?5 tau, 6.1964e-010 adev(n=39998), ? ?6.2010e-010 oadev(n=199990) >>>>>>>> ? ? ? 10 tau, 3.1315e-010 adev(n=19998), ? ?3.1339e-010 oadev(n=199980) >>>>>>>> ? ? ? 20 tau, 1.6499e-010 adev(n=9998), ? ? 1.6495e-010 oadev(n=199960) >>>>>>>> ? ? ? 50 tau, 7.1425e-011 adev(n=3998), ? ? 7.3416e-011 oadev(n=199900) >>>>>>>> ? ? ?100 tau, 3.9940e-011 adev(n=1998), ? ? 4.0730e-011 oadev(n=199800) >>>>>>>> ? ? ?200 tau, 2.1488e-011 adev(n=998), ? ? ?2.1558e-011 oadev(n=199600) >>>>>>>> ? ? ?500 tau, 8.4809e-012 adev(n=398), ? ? ?9.0886e-012 oadev(n=199000) >>>>>>>> ? ? 1000 tau, 4.9223e-012 adev(n=198), ? ? ?4.7104e-012 oadev(n=198000) >>>>>>>> ? ? 2000 tau, 2.4335e-012 adev(n=98), ? ? ? 2.4515e-012 oadev(n=196000) >>>>>>>> ? ? 5000 tau, 1.0308e-012 adev(n=38), ? ? ? 1.0861e-012 oadev(n=190000) >>>>>>>> ? ?10000 tau, 5.9504e-013 adev(n=18), ? ? ? 6.1031e-013 oadev(n=180000) >>>>>>>> ? ?20000 tau, 3.6277e-013 adev(n=8), ? ? ? ?3.1994e-013 oadev(n=160000) >>>>>>>> ? ?50000 tau, 1.0630e-013 adev(n=2), ? ? ? ?1.6715e-013 oadev(n=100000) >>>>>>>> >>>>>>>> Is there any Linux tools for calculating adev as I'm having to run >>>>>>>> Windows in a VMware session? >>>>>>>> >>>>>>>> 73, >>>>>>>> Steve >>>>>>>> >>>>>>>> 2009/4/8 Tom Van Baak : >>>>>>>> >>>>>>>> >>>>>>>> >>>>>>>> >>>>>>>>> Steve, >>>>>>>>> >>>>>>>>> You've asked a couple of questions. Let me start with this. >>>>>>>>> >>>>>>>>> It is true that if one were only interested in the performance >>>>>>>>> of a pendulum (or quartz or atomic) clock for averaging times >>>>>>>>> of one day that all you would need is a series of time error >>>>>>>>> (aka phase) measurements made about the same time once >>>>>>>>> a day (doesn't have to be that exact). After one week, you'd >>>>>>>>> have 7 error measurements (=6 frequency =5 stability points) >>>>>>>>> and this is adequate to calculate the ADEV for tau 1 day. >>>>>>>>> This alone allows you to rank your clock among all the other >>>>>>>>> pendulum clocks out there. Note also you get time error and >>>>>>>>> rate error from these few data points too. >>>>>>>>> >>>>>>>>> As another example, suppose you have a nice HP 10811A >>>>>>>>> oscillator and want to measure its drift rate. In this case you >>>>>>>>> could spend just 100 seconds and measure its frequency >>>>>>>>> once a day, or even once every couple of days. Do this for >>>>>>>>> a month and you'd have several dozen points. If you plot >>>>>>>>> these frequency measurements you will likely see that they >>>>>>>>> approximately fall on a line; the slope of the is the frequency >>>>>>>>> drift rate of the 10811. The general shape of the points, or >>>>>>>>> the fit of the line is a rough indication of how consistent the >>>>>>>>> drift rate is or if it's increasing or decreasing. >>>>>>>>> >>>>>>>>> Neither of these examples require a lot of data. Both of these >>>>>>>>> are real-world examples. >>>>>>>>> >>>>>>>>> OK so far? >>>>>>>>> >>>>>>>>> /tvb >>>>>>>>> >>>>>>>>> >>>>>>>>> >>>>>>>>> _______________________________________________ >>>>>>>>> time-nuts mailing list -- time-nuts at febo.com >>>>>>>>> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >>>>>>>>> and follow the instructions there. >>>>>>>>> >>>>>>>>> >>>>>>>>> >>>>>>>>> >>>>>>>>> >>>>>>>> >>>>>>> _______________________________________________ >>>>>>> time-nuts mailing list -- time-nuts at febo.com >>>>>>> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >>>>>>> and follow the instructions there. >>>>>>> >>>>>>> >>>>>>> >>>>>>> >>>>>> >>>>>> >>>>> _______________________________________________ >>>>> time-nuts mailing list -- time-nuts at febo.com >>>>> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >>>>> and follow the instructions there. >>>>> >>>>> >>>>> >>>> >>>> >>>> >>> _______________________________________________ >>> time-nuts mailing list -- time-nuts at febo.com >>> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >>> and follow the instructions there. >>> >>> >> >> >> >> > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > -- Steve Rooke - ZL3TUV & G8KVD & JAKDTTNW Omnium finis imminet From sar10538 at gmail.com Wed Apr 8 13:21:42 2009 From: sar10538 at gmail.com (Steve Rooke) Date: Thu, 9 Apr 2009 01:21:42 +1200 Subject: [time-nuts] Hadamard variance In-Reply-To: <49DCA123.2020607@xtra.co.nz> References: <1231b6a80904080559o7a4cf618r49276df9d7599820@mail.gmail.com> <49DCA123.2020607@xtra.co.nz> Message-ID: <1231b6a80904080621pd243d8fh6a5aaba7681e7aac@mail.gmail.com> Bruce, 2009/4/9 Bruce Griffiths : > But at least some of us do use it. > Ulrich includes estimators (both the non overlapping and overlapping > estimators) for it in Plotter. > Plotter is a Windows program so you will have to use VMware, Wine or > another Virtual machine to run it in Linux. Do you have a link to it please? 73, Steve -- Steve Rooke - ZL3TUV & G8KVD & JAKDTTNW Omnium finis imminet From bruce.griffiths at xtra.co.nz Wed Apr 8 13:28:42 2009 From: bruce.griffiths at xtra.co.nz (Bruce Griffiths) Date: Thu, 09 Apr 2009 01:28:42 +1200 Subject: [time-nuts] Characterising frequency standards In-Reply-To: <1231b6a80904080619y60199d73h244598262c1de1b9@mail.gmail.com> References: <1231b6a80904070509m5b8bb638gbc088500444254c3@mail.gmail.com> <1231b6a80904080441p7a747a3h1f73bf8a2df30350@mail.gmail.com> <49DC91B9.6090004@xtra.co.nz> <1231b6a80904080504n4a3a22dcr247fae5df39ed840@mail.gmail.com> <49DC984A.2010509@xtra.co.nz> <1231b6a80904080537r2944092bsbc9e31ba0de7f6c8@mail.gmail.com> <49DC9EB6.1040806@xtra.co.nz> <1231b6a80904080602w58ea54c4tdb56bc160e56b4ae@mail.gmail.com> <49DCA243.4020906@xtra.co.nz> <1231b6a80904080619y60199d73h244598262c1de1b9@mail.gmail.com> Message-ID: <49DCA68A.4040105@xtra.co.nz> Steve Rooke wrote: > 2009/4/9 Bruce Griffiths : > >> The sampling interval is indeed 1sec in the original data. >> However, if you delete every second sample the sampling interval in the >> resultant data is then 2 sec. >> > > Doesn't that imply that the data point should correspond to the whole > sampling period and not just half of it? > > The total measurement time is only deceased by 1 sec at the most if you delete every second line. The resampled data now has a sampling interval of 2 sec for the entire measurment time. The original data samples are phase differences measured on the second every second. The resampled data are phase differences measured every 2 seconds on the corresponding second transition. > 73, > Steve > > >>> OK, I'll have a go at compiling it as it is just a command line program. >>> >>> 73, >>> Steve >>> >>> 2009/4/9 Bruce Griffiths : >>> >>> >>>> Steve >>>> >>>> Therein lies your problem. >>>> adev1 defaults to a sampling interval of 1 sec. (read the C source code). >>>> TvB's documentation explicitly states that you should supply the >>>> sampling interval. (its a command line argument for adev1.c). >>>> >>>> adev1.c is a simple command line program that uses stdin and stdout so >>>> porting it to a linux command line (non graphical) program should be >>>> straightforward. >>>> You can even use redirection and pipes should you need them. >>>> >>>> You can try porting it to Scilab which is free courtesy of the French >>>> Government. >>>> >>>> >>>> Bruce >>>> >>>> Steve Rooke wrote: >>>> >>>> >>>>> Bruce, >>>>> >>>>> I set nothing, as indicated in my text, I just delete data points, IE. >>>>> a file of 400000 records now becomes 200000. I'm trying to get my head >>>>> round this as the absolute requirement for continuous data seems >>>>> unneeded. What you have to remember here is that the data set I'm >>>>> working with consists of discrete measurements of the period of each >>>>> pulse. If it was timestamps, then there would be problems. >>>>> >>>>> I don't know how much MATLAB costs but I would guess it is way out of my budget. >>>>> >>>>> 73, >>>>> Steve >>>>> >>>>> 2009/4/9 Bruce Griffiths : >>>>> >>>>> >>>>> >>>>>> Steve >>>>>> >>>>>> The data file doesn't include the time interval between samples so do >>>>>> you set this in some way? >>>>>> If so you need to set it to 1s for the unaltered data, to 2s when you >>>>>> take every 2nd sample, and 1s when you take the first 200,000 samples. >>>>>> >>>>>> In principle you could use CANVAS (available on request from USNO - >>>>>> however you may have to wait a few days while they decide whether to >>>>>> grant your request.) for such analysis in Linux but you would then need >>>>>> the Linux version of Matlab. >>>>>> Or you could request that it be compiled for Linux - a fairly simple >>>>>> task if one has the Linux version of Matlab. >>>>>> >>>>>> In principle you should be able to port the m source files to Scilab, >>>>>> but there are some subtle differences between Scilab and Matlab so this >>>>>> may take a while. >>>>>> >>>>>> Bruce >>>>>> >>>>>> Steve Rooke wrote: >>>>>> >>>>>> >>>>>> >>>>>>> Bruce, >>>>>>> >>>>>>> But how does that explain the output of Tom's adev1 program which >>>>>>> still seems to give a a good measurement at tau = 1s? >>>>>>> >>>>>>> 73, >>>>>>> Steve >>>>>>> >>>>>>> 2009/4/8 Bruce Griffiths : >>>>>>> >>>>>>> >>>>>>> >>>>>>> >>>>>>>> Steve >>>>>>>> >>>>>>>> If you delete every second measurement then your effective minimum >>>>>>>> sampling time is now 2s and you can no longer calculate ADEV for tau< 2s. >>>>>>>> You can still calculate ADEV for tau = 100,000 sec. >>>>>>>> >>>>>>>> If you delete all but the first 200,000 lines then you can calculated >>>>>>>> ADEV for tau=1sec and up to tau= 25,000 sec with reasonable accuracy. >>>>>>>> >>>>>>>> You shouldn't lose sight of the fact that ADEV and OADEV are both >>>>>>>> estimates of the Allan deviation. >>>>>>>> >>>>>>>> >>>>>>>> Bruce >>>>>>>> >>>>>>>> Steve Rooke wrote: >>>>>>>> >>>>>>>> >>>>>>>> >>>>>>>> >>>>>>>>> Tom, >>>>>>>>> >>>>>>>>> I understand fully the points that you have made but I have obviously >>>>>>>>> not made my point clear to all and i apologise for my poor >>>>>>>>> communication skills. >>>>>>>>> >>>>>>>>> This is what I'm getting at: >>>>>>>>> >>>>>>>>> Using your adev1.exe from http://www.leapsecond.com/tools/adev1.htm >>>>>>>>> and processing various forms of gps.dat from >>>>>>>>> http://www.leapsecond.com/pages/gpsdo-sim/gps.dat.gz. >>>>>>>>> >>>>>>>>> C:\Documents and Settings\Steve Rooke\Desktop>adev1.exe 1 >>>>>>>> >>>>>>>>> ** Sampling period: 1 s >>>>>>>>> ** Phase data scale factor: 1.000e+000 >>>>>>>>> ** Total phase samples: 400000 >>>>>>>>> ** Normal and Overlapping Allan deviation: >>>>>>>>> >>>>>>>>> 1 tau, 3.0127e-009 adev(n=399998), 3.0127e-009 oadev(n=399998) >>>>>>>>> 2 tau, 1.5110e-009 adev(n=199998), 1.5119e-009 oadev(n=399996) >>>>>>>>> 5 tau, 6.2107e-010 adev(n=79998), 6.1983e-010 oadev(n=399990) >>>>>>>>> 10 tau, 3.1578e-010 adev(n=39998), 3.1549e-010 oadev(n=399980) >>>>>>>>> 20 tau, 1.6531e-010 adev(n=19998), 1.6534e-010 oadev(n=399960) >>>>>>>>> 50 tau, 7.2513e-011 adev(n=7998), 7.3531e-011 oadev(n=399900) >>>>>>>>> 100 tau, 4.0029e-011 adev(n=3998), 4.0618e-011 oadev(n=399800) >>>>>>>>> 200 tau, 2.1512e-011 adev(n=1998), 2.1633e-011 oadev(n=399600) >>>>>>>>> 500 tau, 9.2193e-012 adev(n=798), 9.1630e-012 oadev(n=399000) >>>>>>>>> 1000 tau, 4.9719e-012 adev(n=398), 4.7750e-012 oadev(n=398000) >>>>>>>>> 2000 tau, 2.6742e-012 adev(n=198), 2.5214e-012 oadev(n=396000) >>>>>>>>> 5000 tau, 1.0010e-012 adev(n=78), 1.1032e-012 oadev(n=390000) >>>>>>>>> 10000 tau, 6.1333e-013 adev(n=38), 6.1039e-013 oadev(n=380000) >>>>>>>>> 20000 tau, 3.8162e-013 adev(n=18), 3.2913e-013 oadev(n=360000) >>>>>>>>> 50000 tau, 1.0228e-013 adev(n=6), 1.5074e-013 oadev(n=300000) >>>>>>>>> 100000 tau, 5.8577e-014 adev(n=2), 6.7597e-014 oadev(n=200000) >>>>>>>>> >>>>>>>>> So far, so good. Now I delete every even line in the file which leaves >>>>>>>>> me with 200000 lines of data (400000 lines in original gps.dat file). >>>>>>>>> (awk 'and(NR, 1) == 0 {print}' gps1.dat) >>>>>>>>> >>>>>>>>> C:\Documents and Settings\Steve Rooke\Desktop>adev1.exe 1 >>>>>>>> >>>>>>>>> ** Sampling period: 1 s >>>>>>>>> >>>>>>>>> >>>>>>>>> >>>>>>>>> >>>>>> INCORRECT!! >>>>>> sampling period is now 2s. >>>>>> >>>>>> >>>>>> >>>>>>>>> ** Phase data scale factor: 1.000e+000 >>>>>>>>> ** Total phase samples: 200000 >>>>>>>>> ** Normal and Overlapping Allan deviation: >>>>>>>>> >>>>>>>>> 1 tau, 3.0257e-009 adev(n=199998), 3.0257e-009 oadev(n=199998) >>>>>>>>> 2 tau, 1.5373e-009 adev(n=99998), 1.5345e-009 oadev(n=199996) >>>>>>>>> 5 tau, 6.3147e-010 adev(n=39998), 6.3057e-010 oadev(n=199990) >>>>>>>>> 10 tau, 3.3140e-010 adev(n=19998), 3.3067e-010 oadev(n=199980) >>>>>>>>> 20 tau, 1.7872e-010 adev(n=9998), 1.7810e-010 oadev(n=199960) >>>>>>>>> 50 tau, 7.9428e-011 adev(n=3998), 8.1216e-011 oadev(n=199900) >>>>>>>>> 100 tau, 4.2352e-011 adev(n=1998), 4.3265e-011 oadev(n=199800) >>>>>>>>> 200 tau, 2.2001e-011 adev(n=998), 2.2593e-011 oadev(n=199600) >>>>>>>>> 500 tau, 9.6853e-012 adev(n=398), 9.5441e-012 oadev(n=199000) >>>>>>>>> 1000 tau, 5.0139e-012 adev(n=198), 5.0387e-012 oadev(n=198000) >>>>>>>>> 2000 tau, 2.7994e-012 adev(n=98), 2.7090e-012 oadev(n=196000) >>>>>>>>> 5000 tau, 1.4280e-012 adev(n=38), 1.2214e-012 oadev(n=190000) >>>>>>>>> 10000 tau, 7.4881e-013 adev(n=18), 6.5814e-013 oadev(n=180000) >>>>>>>>> 20000 tau, 7.6518e-013 adev(n=8), 3.7253e-013 oadev(n=160000) >>>>>>>>> 50000 tau, 2.4698e-014 adev(n=2), 1.3539e-013 oadev(n=100000) >>>>>>>>> >>>>>>>>> Obviously we don't have enough data now for a measurement of 100000 >>>>>>>>> tau but the results for the other tau are quite close, especially when >>>>>>>>> there are sufficient data points. Now this is discontinuous data, >>>>>>>>> exactly what I was trying to allude to. >>>>>>>>> >>>>>>>>> OK, so now I take only the top 200000 lines of the gps.dat file (head >>>>>>>>> -200000 gps.dat >gps2.dat) >>>>>>>>> >>>>>>>>> C:\Documents and Settings\Steve Rooke\Desktop>adev1.exe 1 >>>>>>>> >>>>>>>>> ** Sampling period: 1 s >>>>>>>>> ** Phase data scale factor: 1.000e+000 >>>>>>>>> ** Total phase samples: 200000 >>>>>>>>> ** Normal and Overlapping Allan deviation: >>>>>>>>> >>>>>>>>> 1 tau, 3.0411e-009 adev(n=199998), 3.0411e-009 oadev(n=199998) >>>>>>>>> 2 tau, 1.4985e-009 adev(n=99998), 1.4999e-009 oadev(n=199996) >>>>>>>>> 5 tau, 6.1964e-010 adev(n=39998), 6.2010e-010 oadev(n=199990) >>>>>>>>> 10 tau, 3.1315e-010 adev(n=19998), 3.1339e-010 oadev(n=199980) >>>>>>>>> 20 tau, 1.6499e-010 adev(n=9998), 1.6495e-010 oadev(n=199960) >>>>>>>>> 50 tau, 7.1425e-011 adev(n=3998), 7.3416e-011 oadev(n=199900) >>>>>>>>> 100 tau, 3.9940e-011 adev(n=1998), 4.0730e-011 oadev(n=199800) >>>>>>>>> 200 tau, 2.1488e-011 adev(n=998), 2.1558e-011 oadev(n=199600) >>>>>>>>> 500 tau, 8.4809e-012 adev(n=398), 9.0886e-012 oadev(n=199000) >>>>>>>>> 1000 tau, 4.9223e-012 adev(n=198), 4.7104e-012 oadev(n=198000) >>>>>>>>> 2000 tau, 2.4335e-012 adev(n=98), 2.4515e-012 oadev(n=196000) >>>>>>>>> 5000 tau, 1.0308e-012 adev(n=38), 1.0861e-012 oadev(n=190000) >>>>>>>>> 10000 tau, 5.9504e-013 adev(n=18), 6.1031e-013 oadev(n=180000) >>>>>>>>> 20000 tau, 3.6277e-013 adev(n=8), 3.1994e-013 oadev(n=160000) >>>>>>>>> 50000 tau, 1.0630e-013 adev(n=2), 1.6715e-013 oadev(n=100000) >>>>>>>>> >>>>>>>>> Is there any Linux tools for calculating adev as I'm having to run >>>>>>>>> Windows in a VMware session? >>>>>>>>> >>>>>>>>> 73, >>>>>>>>> Steve >>>>>>>>> >>>>>>>>> 2009/4/8 Tom Van Baak : >>>>>>>>> >>>>>>>>> >>>>>>>>> >>>>>>>>> >>>>>>>>> >>>>>>>>>> Steve, >>>>>>>>>> >>>>>>>>>> You've asked a couple of questions. Let me start with this. >>>>>>>>>> >>>>>>>>>> It is true that if one were only interested in the performance >>>>>>>>>> of a pendulum (or quartz or atomic) clock for averaging times >>>>>>>>>> of one day that all you would need is a series of time error >>>>>>>>>> (aka phase) measurements made about the same time once >>>>>>>>>> a day (doesn't have to be that exact). After one week, you'd >>>>>>>>>> have 7 error measurements (=6 frequency =5 stability points) >>>>>>>>>> and this is adequate to calculate the ADEV for tau 1 day. >>>>>>>>>> This alone allows you to rank your clock among all the other >>>>>>>>>> pendulum clocks out there. Note also you get time error and >>>>>>>>>> rate error from these few data points too. >>>>>>>>>> >>>>>>>>>> As another example, suppose you have a nice HP 10811A >>>>>>>>>> oscillator and want to measure its drift rate. In this case you >>>>>>>>>> could spend just 100 seconds and measure its frequency >>>>>>>>>> once a day, or even once every couple of days. Do this for >>>>>>>>>> a month and you'd have several dozen points. If you plot >>>>>>>>>> these frequency measurements you will likely see that they >>>>>>>>>> approximately fall on a line; the slope of the is the frequency >>>>>>>>>> drift rate of the 10811. The general shape of the points, or >>>>>>>>>> the fit of the line is a rough indication of how consistent the >>>>>>>>>> drift rate is or if it's increasing or decreasing. >>>>>>>>>> >>>>>>>>>> Neither of these examples require a lot of data. Both of these >>>>>>>>>> are real-world examples. >>>>>>>>>> >>>>>>>>>> OK so far? >>>>>>>>>> >>>>>>>>>> /tvb >>>>>>>>>> >>>>>>>>>> >>>>>>>>>> >>>>>>>>>> _______________________________________________ >>>>>>>>>> time-nuts mailing list -- time-nuts at febo.com >>>>>>>>>> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >>>>>>>>>> and follow the instructions there. >>>>>>>>>> >>>>>>>>>> >>>>>>>>>> >>>>>>>>>> >>>>>>>>>> >>>>>>>>>> >>>>>>>> _______________________________________________ >>>>>>>> time-nuts mailing list -- time-nuts at febo.com >>>>>>>> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >>>>>>>> and follow the instructions there. >>>>>>>> >>>>>>>> >>>>>>>> >>>>>>>> >>>>>>>> >>>>>>> >>>>>> _______________________________________________ >>>>>> time-nuts mailing list -- time-nuts at febo.com >>>>>> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >>>>>> and follow the instructions there. >>>>>> >>>>>> >>>>>> >>>>>> >>>>> >>>>> >>>> _______________________________________________ >>>> time-nuts mailing list -- time-nuts at febo.com >>>> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >>>> and follow the instructions there. >>>> >>>> >>>> >>> >>> >>> >> _______________________________________________ >> time-nuts mailing list -- time-nuts at febo.com >> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. >> >> > > > > From bruce.griffiths at xtra.co.nz Wed Apr 8 13:32:58 2009 From: bruce.griffiths at xtra.co.nz (Bruce Griffiths) Date: Thu, 09 Apr 2009 01:32:58 +1200 Subject: [time-nuts] Hadamard variance In-Reply-To: <1231b6a80904080621pd243d8fh6a5aaba7681e7aac@mail.gmail.com> References: <1231b6a80904080559o7a4cf618r49276df9d7599820@mail.gmail.com> <49DCA123.2020607@xtra.co.nz> <1231b6a80904080621pd243d8fh6a5aaba7681e7aac@mail.gmail.com> Message-ID: <49DCA78A.5070000@xtra.co.nz> Steve Rooke wrote: > Bruce, > > 2009/4/9 Bruce Griffiths : > >> But at least some of us do use it. >> Ulrich includes estimators (both the non overlapping and overlapping >> estimators) for it in Plotter. >> Plotter is a Windows program so you will have to use VMware, Wine or >> another Virtual machine to run it in Linux. >> > > Do you have a link to it please? > > 73, > Steve > Steve Link is: http://www.ulrich-bangert.de/html/downloads.html Ulrich's EZGPIB can also be used for some simulations if you dont have more suitable tools. However it uses a Pascal style syntax. Bruce From sometimesyoufeellikeanut at twentylogten.com Wed Apr 8 14:48:09 2009 From: sometimesyoufeellikeanut at twentylogten.com (Chris Mack / N1SKY) Date: Wed, 8 Apr 2009 10:48:09 -0400 Subject: [time-nuts] femtosecond jitter anyone? Message-ID: <4CCD1C7E-6952-4FB4-8E1A-3B1A02618BC5@twentylogten.com> Hello fellow time nuts, Have a project here with an OCXO from Vectron at 38.88MHz being the "jitter reference" for a DSP based PLL. The Vectron part has a little bit of close-in phase noise below 12kHz of BW. Is there a way to filter this, say by driving an external (temperature stabilized) crystal "backwards" (in the non-traditional sense rather than using the crystal to provide a clock for a system) and recovering the signal? Also the output of the Vectron part is square and it would be ideal to distribute a sine wave.... I cannot find traditional crystal filters that have a direct center at 38.88MHz also with any usable bandwidth (for the close-in skirt) for this application. The DSP PLL has "femtosecond" jitter capabilities depending on how it is applied, e.g., for SONET and the like and also depending upon measurement BW used. Also the jitter reference comes into play here as well.... For the sampling application this is being used for, it would be ideal (by design) to keep the timing uncertainty below 0.45ps or so... Any thoughts? Cheers, -chris N1SKY -- Chris Mack Electrical Engineer / RF Engineer / Software Engineer / Mastering Engineer Temple, NH From slburris at gmail.com Wed Apr 8 15:28:03 2009 From: slburris at gmail.com (Scott Burris) Date: Wed, 08 Apr 2009 08:28:03 -0700 Subject: [time-nuts] looking at creative ways to route GPS signals through a home to a Thunderbolt Message-ID: <49DCC283.4010908@gmail.com> I have a Thunderbolt (thanks TAPR!) located in a second floor room of my house which has only an obstructed view of the sky. There's no easy way to get to that room, short of putting an antenna on the roof and punching a hole in the wall to get inside. For some reason, my wife takes a dim view of that plan. Plan B would be to mount the antenna near an attic vent, run the cabling inside, go through the attic and drill down into one of the inner walls to terminate in an outlet box of some sort. So the dedicated time-nuts may laugh at plan C. This is to mount an antenna on roof near the garage and connect to the RG6 CATV run from the garage to this room. I'd guess it's about 60-70ft of RG6. Can RG6 pass the 1.5Ghz signal successfully? Is the Thunderbolt sensitive enough to be used this way? Has anyone tried this? Scott From ralph at ralphsmith.org Wed Apr 8 15:35:51 2009 From: ralph at ralphsmith.org (Ralph Smith) Date: Wed, 8 Apr 2009 11:35:51 -0400 (EDT) Subject: [time-nuts] looking at creative ways to route GPS signals through a home to a Thunderbolt In-Reply-To: <49DCC283.4010908@gmail.com> References: <49DCC283.4010908@gmail.com> Message-ID: <8ae813d2255e5667b451ec070cb4ad0b.squirrel@ralphsmith.org> This was discussed just yesterday. The short answer is that Plan C is just what Trimble recommends, with RG-59. I have about 110 feet of RG-6 and it works wonderfully. Ralph On Wed, April 8, 2009 11:28 am, Scott Burris wrote: > I have a Thunderbolt (thanks TAPR!) located in a second floor room of my > house which > has only an obstructed view of the sky. There's no easy way to get to > that room, short > of putting an antenna on the roof and punching a hole in the wall to get > inside. For some reason, > my wife takes a dim view of that plan. > > Plan B would be to mount the antenna near an attic vent, run the cabling > inside, go through the > attic and drill down into one of the inner walls to terminate in an > outlet box of some sort. > > So the dedicated time-nuts may laugh at plan C. This is to mount an > antenna on roof near the garage > and connect to the RG6 CATV run from the garage to this room. I'd guess > it's about 60-70ft of RG6. > Can RG6 pass the 1.5Ghz signal successfully? Is the Thunderbolt > sensitive enough to be used this way? > Has anyone tried this? > > Scott > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > -- Ralph Smith ralph at ralphsmith.org From slburris at gmail.com Wed Apr 8 15:43:11 2009 From: slburris at gmail.com (Scott Burris) Date: Wed, 08 Apr 2009 08:43:11 -0700 Subject: [time-nuts] looking at creative ways to route GPS signals through a home to a Thunderbolt In-Reply-To: <8ae813d2255e5667b451ec070cb4ad0b.squirrel@ralphsmith.org> References: <49DCC283.4010908@gmail.com> <8ae813d2255e5667b451ec070cb4ad0b.squirrel@ralphsmith.org> Message-ID: <49DCC60F.6040803@gmail.com> Oh how embarrassing -- I have that exact message sitting in my inbox not yet read! OK, good to know it works, I'll go with Plan C. Scott Ralph Smith wrote: > This was discussed just yesterday. > > > The short answer is that Plan C is just what Trimble recommends, with > RG-59. I have about 110 feet of RG-6 and it works wonderfully. > > Ralph > > On Wed, April 8, 2009 11:28 am, Scott Burris wrote: > >> I have a Thunderbolt (thanks TAPR!) located in a second floor room of my >> house which >> has only an obstructed view of the sky. There's no easy way to get to >> that room, short >> of putting an antenna on the roof and punching a hole in the wall to get >> inside. For some reason, >> my wife takes a dim view of that plan. >> >> Plan B would be to mount the antenna near an attic vent, run the cabling >> inside, go through the >> attic and drill down into one of the inner walls to terminate in an >> outlet box of some sort. >> >> So the dedicated time-nuts may laugh at plan C. This is to mount an >> antenna on roof near the garage >> and connect to the RG6 CATV run from the garage to this room. I'd guess >> it's about 60-70ft of RG6. >> Can RG6 pass the 1.5Ghz signal successfully? Is the Thunderbolt >> sensitive enough to be used this way? >> Has anyone tried this? >> >> Scott >> >> >> _______________________________________________ >> time-nuts mailing list -- time-nuts at febo.com >> To unsubscribe, go to >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. >> >> > > > From phk at phk.freebsd.dk Wed Apr 8 16:21:28 2009 From: phk at phk.freebsd.dk (Poul-Henning Kamp) Date: Wed, 08 Apr 2009 16:21:28 +0000 Subject: [time-nuts] looking at creative ways to route GPS signals through a home to a Thunderbolt In-Reply-To: Your message of "Wed, 08 Apr 2009 08:28:03 MST." <49DCC283.4010908@gmail.com> Message-ID: <46257.1239207688@critter.freebsd.dk> In message <49DCC283.4010908 at gmail.com>, Scott Burris writes: >So the dedicated time-nuts may laugh at plan C. This is to mount an >antenna on roof near the garage >and connect to the RG6 CATV run from the garage to this room. I'd guess >it's about 60-70ft of RG6. >Can RG6 pass the 1.5Ghz signal successfully? Is the Thunderbolt >sensitive enough to be used this way? >Has anyone tried this? Why not put the thunderbolt on the garage and run the disciplined result over the coax ? -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 phk at FreeBSD.ORG | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. From brooke at pacific.net Wed Apr 8 16:59:30 2009 From: brooke at pacific.net (brooke at pacific.net) Date: Wed, 8 Apr 2009 09:59:30 -0700 (PDT) Subject: [time-nuts] looking at creative ways to route GPS signals through a home to a Thunderbolt In-Reply-To: <49DCC283.4010908@gmail.com> References: <49DCC283.4010908@gmail.com> Message-ID: <3441.SVVXXVxVQkI=.1239209970.squirrel@webmail.securepacific.net> Hi Scott Most GPS antennas have some amount of gain and that varies from none to over 50 dB, with about 20 to 30 dB the most common. The idea is for the system noise figure to be established by the antenna and not the coax loss getting to the receiver. To have gain requires DC power to the antenna. It turns out that most GPS antennas run fine on 3 to 5 Volts. For example the Motorola Timing antenna (white inverted ice cream cone)is specified to run over that voltage range. So you're option C can work if you properly manage the RF and DC aspects. If the DC aspects are not handled properly you risk smoking the antenna. One of the potential problems is there may already be DC or AC on the CATV coax that's not compatible with the GPS antenna DC requirements. Do you have a diagram of the CATV system? Have Fun, Brooke Clarke > I have a Thunderbolt (thanks TAPR!) located in a second floor room of my > house which > has only an obstructed view of the sky. There's no easy way to get to > that room, short > of putting an antenna on the roof and punching a hole in the wall to get > inside. For some reason, > my wife takes a dim view of that plan. > > Plan B would be to mount the antenna near an attic vent, run the cabling > inside, go through the > attic and drill down into one of the inner walls to terminate in an > outlet box of some sort. > > So the dedicated time-nuts may laugh at plan C. This is to mount an > antenna on roof near the garage > and connect to the RG6 CATV run from the garage to this room. I'd guess > it's about 60-70ft of RG6. > Can RG6 pass the 1.5Ghz signal successfully? Is the Thunderbolt > sensitive enough to be used this way? > Has anyone tried this? > > Scott > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > From slburris at gmail.com Wed Apr 8 17:21:11 2009 From: slburris at gmail.com (Scott Burris) Date: Wed, 08 Apr 2009 10:21:11 -0700 Subject: [time-nuts] looking at creative ways to route GPS signals through a home to a Thunderbolt In-Reply-To: <3441.SVVXXVxVQkI=.1239209970.squirrel@webmail.securepacific.net> References: <49DCC283.4010908@gmail.com> <3441.SVVXXVxVQkI=.1239209970.squirrel@webmail.securepacific.net> Message-ID: <49DCDD07.6000501@gmail.com> This is an unused coax run, so there's no AC or DC on this line to be a problem. I do carry feeds from 4 security cameras via a 4 channel modulator on other coax runs to elsewhere in the house, but I can't see trying to mix this application with GPS to this room -- I should really just digitize the security cameras and put it on the IP network, a problem for another day. I've got some vague thoughts about splitting the received signal in this room to go to the Thunderbolt, an NTP server, and one of my homebrew GPS clocks (answering phk's question about just pushing the T-bolt output through the coax from the garage). My priority though is to get my T-bolt permanently installed and running 24/7 so it can be my house frequency standard. All the other uses are secondary to this. In any case, it sounds like it's a worthwhile experiment. I'll have to go through my antenna collection and see what works best. Scott brooke at pacific.net wrote: > Hi Scott > > Most GPS antennas have some amount of gain and that varies from none to > over 50 dB, with about 20 to 30 dB the most common. The idea is for the > system noise figure to be established by the antenna and not the coax loss > getting to the receiver. > > To have gain requires DC power to the antenna. It turns out that most GPS > antennas run fine on 3 to 5 Volts. For example the Motorola Timing > antenna (white inverted ice cream cone)is specified to run over that > voltage range. > > So you're option C can work if you properly manage the RF and DC aspects. > If the DC aspects are not handled properly you risk smoking the antenna. > > One of the potential problems is there may already be DC or AC on the CATV > coax that's not compatible with the GPS antenna DC requirements. Do you > have a diagram of the CATV system? > > Have Fun, > > Brooke Clarke > > >> I have a Thunderbolt (thanks TAPR!) located in a second floor room of my >> house which >> has only an obstructed view of the sky. There's no easy way to get to >> that room, short >> of putting an antenna on the roof and punching a hole in the wall to get >> inside. For some reason, >> my wife takes a dim view of that plan. >> >> Plan B would be to mount the antenna near an attic vent, run the cabling >> inside, go through the >> attic and drill down into one of the inner walls to terminate in an >> outlet box of some sort. >> >> So the dedicated time-nuts may laugh at plan C. This is to mount an >> antenna on roof near the garage >> and connect to the RG6 CATV run from the garage to this room. I'd guess >> it's about 60-70ft of RG6. >> Can RG6 pass the 1.5Ghz signal successfully? Is the Thunderbolt >> sensitive enough to be used this way? >> Has anyone tried this? >> >> Scott >> >> >> _______________________________________________ >> time-nuts mailing list -- time-nuts at febo.com >> To unsubscribe, go to >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. >> >> > > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > From g4hup at btinternet.com Wed Apr 8 17:39:19 2009 From: g4hup at btinternet.com (dave powis) Date: Wed, 8 Apr 2009 17:39:19 +0000 (GMT) Subject: [time-nuts] looking at creative ways to route GPS signals through a home to a Thunderbolt References: <49DCC283.4010908@gmail.com> <3441.SVVXXVxVQkI=.1239209970.squirrel@webmail.securepacific.net> <49DCDD07.6000501@gmail.com> Message-ID: <296819.34929.qm@web86303.mail.ird.yahoo.com> Hi Scott, Looking at your proposed implementation below, you may like to look at one of my kit products - a distribution amplifier which will split a GPS antenna signal up to 4 ways, and will act as the power source for the antenna. There is no need to disable the 5v feeds in the receivers, since there are blocking caps in the DA, although if you do have the software control of them, it would be better to disable! Have a look at http://g4hup.com/DA/DA1_4.htm and look for the details of the G version. Hope this may be useful to you. Regards, Dave, G4HUP http://g4hup.com ________________________________ From: Scott Burris To: Discussion of precise time and frequency measurement Sent: Wednesday, 8 April, 2009 6:21:11 PM Subject: Re: [time-nuts] looking at creative ways to route GPS signals through a home to a Thunderbolt This is an unused coax run, so there's no AC or DC on this line to be a problem. I do carry feeds from 4 security cameras via a 4 channel modulator on other coax runs to elsewhere in the house, but I can't see trying to mix this application with GPS to this room -- I should really just digitize the security cameras and put it on the IP network, a problem for another day. I've got some vague thoughts about splitting the received signal in this room to go to the Thunderbolt, an NTP server, and one of my homebrew GPS clocks (answering phk's question about just pushing the T-bolt output through the coax from the garage). My priority though is to get my T-bolt permanently installed and running 24/7 so it can be my house frequency standard. All the other uses are secondary to this. In any case, it sounds like it's a worthwhile experiment. I'll have to go through my antenna collection and see what works best. Scott brooke at pacific.net wrote: > Hi Scott > > Most GPS antennas have some amount of gain and that varies from none to > over 50 dB, with about 20 to 30 dB the most common. The idea is for the > system noise figure to be established by the antenna and not the coax loss > getting to the receiver. > > To have gain requires DC power to the antenna. It turns out that most GPS > antennas run fine on 3 to 5 Volts. For example the Motorola Timing > antenna (white inverted ice cream cone)is specified to run over that > voltage range. > > So you're option C can work if you properly manage the RF and DC aspects. > If the DC aspects are not handled properly you risk smoking the antenna. > > One of the potential problems is there may already be DC or AC on the CATV > coax that's not compatible with the GPS antenna DC requirements. Do you > have a diagram of the CATV system? > > Have Fun, > > Brooke Clarke > > >> I have a Thunderbolt (thanks TAPR!) located in a second floor room of my >> house which >> has only an obstructed view of the sky. There's no easy way to get to >> that room, short >> of putting an antenna on the roof and punching a hole in the wall to get >> inside. For some reason, >> my wife takes a dim view of that plan. >> >> Plan B would be to mount the antenna near an attic vent, run the cabling >> inside, go through the >> attic and drill down into one of the inner walls to terminate in an >> outlet box of some sort. >> >> So the dedicated time-nuts may laugh at plan C. This is to mount an >> antenna on roof near the garage >> and connect to the RG6 CATV run from the garage to this room. I'd guess >> it's about 60-70ft of RG6. >> Can RG6 pass the 1.5Ghz signal successfully? Is the Thunderbolt >> sensitive enough to be used this way? >> Has anyone tried this? >> >> Scott >> >> >> _______________________________________________ >> time-nuts mailing list -- time-nuts at febo.com >> To unsubscribe, go to >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. >> >> > > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > _______________________________________________ time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. From magnus at rubidium.dyndns.org Wed Apr 8 21:09:28 2009 From: magnus at rubidium.dyndns.org (Magnus Danielson) Date: Wed, 08 Apr 2009 23:09:28 +0200 Subject: [time-nuts] femtosecond jitter anyone? In-Reply-To: <4CCD1C7E-6952-4FB4-8E1A-3B1A02618BC5@twentylogten.com> References: <4CCD1C7E-6952-4FB4-8E1A-3B1A02618BC5@twentylogten.com> Message-ID: <49DD1288.4060103@rubidium.dyndns.org> Chris Mack / N1SKY skrev: > Hello fellow time nuts, > > Have a project here with an OCXO from Vectron at 38.88MHz being the > "jitter reference" for a DSP based PLL. > > The Vectron part has a little bit of close-in phase noise below 12kHz > of BW. Is there a way to filter this, say by driving an external > (temperature stabilized) crystal "backwards" (in the non-traditional > sense rather than using the crystal to provide a clock for a system) > and recovering the signal? > > Also the output of the Vectron part is square and it would be ideal > to distribute a sine wave.... > > I cannot find traditional crystal filters that have a direct center > at 38.88MHz also with any usable bandwidth (for the close-in skirt) > for this application. > > The DSP PLL has "femtosecond" jitter capabilities depending on how it > is applied, e.g., for SONET and the like and also depending upon > measurement BW used. Also the jitter reference comes into play here > as well.... > > For the sampling application this is being used for, it would be > ideal (by design) to keep the timing uncertainty below 0.45ps or so... > > Any thoughts? Do you want to apply jitter to the 38,88 MHz clock? In particular, do you want to be able to modulate it with various amounts of sine in order to test jitter tolerance (a common SDH/SONET test).? Essentially you want phase modulations for those purposes. You can apply them on the output signal for smaller amounts, but for larger deviations it is not as convenient. Tolerance modulations may need to be several cycles peak-to-peak. A combination of phase modulation and frequency modulation can be used. One approach is to phase lock the oscillator to a reference and insert the modulation signal into the PLL loop. Cheers, Magnus From tvb at LeapSecond.com Wed Apr 8 21:37:41 2009 From: tvb at LeapSecond.com (Tom Van Baak) Date: Wed, 8 Apr 2009 14:37:41 -0700 Subject: [time-nuts] Characterising frequency standards References: <1231b6a80904070509m5b8bb638gbc088500444254c3@mail.gmail.com><1231b6a80904080441p7a747a3h1f73bf8a2df30350@mail.gmail.com><49DC91B9.6090004@xtra.co.nz> <1231b6a80904080504n4a3a22dcr247fae5df39ed840@mail.gmail.com> Message-ID: <7911976D35924C91A61F679126F77F9E@pc52> > But how does that explain the output of Tom's adev1 program which > still seems to give a a good measurement at tau = 1s? The first argument to the adev1 program is the sampling interval t0. The program doesn't know how far apart the input file samples are taken so it is your job to specify this. The default is 1 second. If you have data taken one second apart then t0 = 1. If you have data taken two seconds apart then t0 = 2. If you have data taken 60 seconds apart then t0 = 60, etc. If, as in your case, you take raw one second data and remove every other sample (a perfectly valid thing to do), then t0 = 2. Make sense now? It's still "continuous data" in the sense that all measurements are a fixed interval apart. But in any ADEV calculation you have to specify the raw data interval. /tvb From sometimesyoufeellikeanut at twentylogten.com Wed Apr 8 21:45:34 2009 From: sometimesyoufeellikeanut at twentylogten.com (Chris Mack / N1SKY) Date: Wed, 8 Apr 2009 17:45:34 -0400 Subject: [time-nuts] femtosecond jitter anyone? In-Reply-To: <49DD1288.4060103@rubidium.dyndns.org> References: <4CCD1C7E-6952-4FB4-8E1A-3B1A02618BC5@twentylogten.com> <49DD1288.4060103@rubidium.dyndns.org> Message-ID: <18D08480-6725-4251-BE78-145797B6DC31@twentylogten.com> Hey Magnus, This is a good idea for testing.. I have Howard Johnson's book for "high speed digital design (a handbook of black magic)" which shows some circuits with varactors on the transmission line with some ECL gates creating a variable delay based on an analogue voltage... maybe that could work before filtering into a sine.... The DSP ultimately has 3 ports where the jitter reference (pins XA and XB differential sine or square) is one port for the digitally controlled oscillator (and also the clock to run the DSP), then the remaining 2 ports for input clock (CLK_IN) and the output (CLK_OUT) generated clock (any frequency really based on PLL coefficients). It is roughly 1:1 jitter transfer from jitter reference (38,88MHz) to output clock, regardless of CLK_IN but for only a certain bandwidth, 12kHz to 20MHz or so; It gets better, slightly, when looking close into the carrier but ultimately this jitter reference is used to clean an input clock on other pins for the outgoing PLL generated output. The same circuit could also be used outside of testing the jitter reference I suppose and be used on the incoming clock to be cleaned signal too.... Yes, it may actually be ideal to put jitter on the incoming clock to be cleaned... With added jitter on the incoming clock to be cleaned, it may keep the PLL out of the dead zone and ultimately force it do some useful work at all times rather than coast/drift in said dead zone.... But what shape of jittter to be introduced (noise shape on the proposed analogue voltage perturbing the varactors)? hmmmmm.... Still trying to figure out crystals for filter purposes though since any documentation I have on crystals shows a typical circuit with logic gates to make a clock to feed a microprocessor (different from what I need it to do of course since I already have an OCXO).... Harrumph.... Cheers, -chris On Apr 8, 2009, at 5:09 PM, Magnus Danielson wrote: > Chris Mack / N1SKY skrev: >> Hello fellow time nuts, >> >> Have a project here with an OCXO from Vectron at 38.88MHz being the >> "jitter reference" for a DSP based PLL. >> >> The Vectron part has a little bit of close-in phase noise below 12kHz >> of BW. Is there a way to filter this, say by driving an external >> (temperature stabilized) crystal "backwards" (in the non-traditional >> sense rather than using the crystal to provide a clock for a system) >> and recovering the signal? >> >> Also the output of the Vectron part is square and it would be ideal >> to distribute a sine wave.... >> >> I cannot find traditional crystal filters that have a direct center >> at 38.88MHz also with any usable bandwidth (for the close-in skirt) >> for this application. >> >> The DSP PLL has "femtosecond" jitter capabilities depending on how it >> is applied, e.g., for SONET and the like and also depending upon >> measurement BW used. Also the jitter reference comes into play here >> as well.... >> >> For the sampling application this is being used for, it would be >> ideal (by design) to keep the timing uncertainty below 0.45ps or >> so... >> >> Any thoughts? > > Do you want to apply jitter to the 38,88 MHz clock? > > In particular, do you want to be able to modulate it with various > amounts of sine in order to test jitter tolerance (a common SDH/SONET > test).? > > Essentially you want phase modulations for those purposes. You can > apply > them on the output signal for smaller amounts, but for larger > deviations > it is not as convenient. Tolerance modulations may need to be several > cycles peak-to-peak. A combination of phase modulation and frequency > modulation can be used. One approach is to phase lock the > oscillator to > a reference and insert the modulation signal into the PLL loop. > > Cheers, > Magnus > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/ > time-nuts > and follow the instructions there. From magnus at rubidium.dyndns.org Wed Apr 8 22:14:45 2009 From: magnus at rubidium.dyndns.org (Magnus Danielson) Date: Thu, 09 Apr 2009 00:14:45 +0200 Subject: [time-nuts] femtosecond jitter anyone? In-Reply-To: <18D08480-6725-4251-BE78-145797B6DC31@twentylogten.com> References: <4CCD1C7E-6952-4FB4-8E1A-3B1A02618BC5@twentylogten.com> <49DD1288.4060103@rubidium.dyndns.org> <18D08480-6725-4251-BE78-145797B6DC31@twentylogten.com> Message-ID: <49DD21D5.6040109@rubidium.dyndns.org> Chris, Chris Mack / N1SKY skrev: > Hey Magnus, > > This is a good idea for testing.. Applying jitter frequencies for jitter tolerance testing is standard stuff and needs to be done. Jitter tolerance curves match up with MTIE tolerance curves very neatly. > I have Howard Johnson's book for > "high speed digital design (a handbook of black magic)" which shows > some circuits with varactors on the transmission line with some ECL > gates creating a variable delay based on an analogue voltage... maybe > that could work before filtering into a sine.... I think a normal LC tank would be more suitable for that task. It's a good introductional level book for digital signals, but isn't very applicable to waveshaping or clock characterisation and testing. > The DSP ultimately has 3 ports where the jitter reference (pins XA > and XB differential sine or square) is one port for the digitally > controlled oscillator (and also the clock to run the DSP), then the > remaining 2 ports for input clock (CLK_IN) and the output (CLK_OUT) > generated clock (any frequency really based on PLL coefficients). I still don't understand what you want it to do... or what it is supposed to do and what jitter reference means in your context, low jitter or know jitter. > It is roughly 1:1 jitter transfer from jitter reference (38,88MHz) to > output clock, regardless of CLK_IN but for only a certain bandwidth, > 12kHz to 20MHz or so; It gets better, slightly, when looking close > into the carrier but ultimately this jitter reference is used to > clean an input clock on other pins for the outgoing PLL generated > output. Sounds like a locked oscillator with PLL bandwidth of 12 kHz. The jitter of the locked oscillator is high-pass filtered by the PLL loop. > The same circuit could also be used outside of testing the jitter > reference I suppose and be used on the incoming clock to be cleaned > signal too.... > > Yes, it may actually be ideal to put jitter on the incoming clock to > be cleaned... With added jitter on the incoming clock to be cleaned, > it may keep the PLL out of the dead zone and ultimately force it do > some useful work at all times rather than coast/drift in said dead > zone.... But what shape of jittter to be introduced (noise shape on > the proposed analogue voltage perturbing the varactors)? hmmmmm.... If you have a dead-zone on your PLL you need to fix it. I have learned the hard way that dead-zone PLLs can cause significant jitter/wander since they will get very abrupt shifts of direction in each end of the dead-zone. When using detectors (every simple ones like SR-FF) which does not have dead-zones it becomes feasible to tune it properly. Continuous detector and active filter for PI regulation should be the standard approach most of the times. Not hard and expensive to achieve by todays standards IMHO. May I stress that when doing SDH/SONET this is of particular importance. > Still trying to figure out crystals for filter purposes though since > any documentation I have on crystals shows a typical circuit with > logic gates to make a clock to feed a microprocessor (different from > what I need it to do of course since I already have an OCXO).... > Harrumph.... It's actually not that hard to figure out. If you model a crystal as an LCR chain in parallel with a C then you have a model for an oscillator and a single mode. several LCR chains in parallel is needed if multiple modes needs to be modeled/simulated. Crystal filters build upon these types of models. I still don't think you need to revert to crystal filters. If you just want to sine up a squarewave, a simple LC tank may be just want you need. A CLC or CRC PI-filter may also suite your needs more than sufficiently. If you need very high Q filters for a fairly fixed frequency, crystal filters may be used, but PLLs may also be part of the solution, as you can see them as a form of self-retuneable bandpass filter. Cheers, Magnus From bruce.griffiths at xtra.co.nz Wed Apr 8 22:43:16 2009 From: bruce.griffiths at xtra.co.nz (Bruce Griffiths) Date: Thu, 09 Apr 2009 10:43:16 +1200 Subject: [time-nuts] femtosecond jitter anyone? In-Reply-To: <49DD21D5.6040109@rubidium.dyndns.org> References: <4CCD1C7E-6952-4FB4-8E1A-3B1A02618BC5@twentylogten.com> <49DD1288.4060103@rubidium.dyndns.org> <18D08480-6725-4251-BE78-145797B6DC31@twentylogten.com> <49DD21D5.6040109@rubidium.dyndns.org> Message-ID: <49DD2884.5040000@xtra.co.nz> Magnus For examples of the use of crystals in filters for cleaning up the output of a crystal oscillator look at the circuit schematics for some of the early crystal frequency standards. Crystal filters were used quite liberally in some of these to clean up the outputs. However it may be necessary to control the temperature of these crystals. Bruce Magnus Danielson wrote: > Chris, > > Chris Mack / N1SKY skrev: > >> Hey Magnus, >> >> This is a good idea for testing.. >> > > Applying jitter frequencies for jitter tolerance testing is standard > stuff and needs to be done. Jitter tolerance curves match up with MTIE > tolerance curves very neatly. > > >> I have Howard Johnson's book for >> "high speed digital design (a handbook of black magic)" which shows >> some circuits with varactors on the transmission line with some ECL >> gates creating a variable delay based on an analogue voltage... maybe >> that could work before filtering into a sine.... >> > > I think a normal LC tank would be more suitable for that task. > > It's a good introductional level book for digital signals, but isn't > very applicable to waveshaping or clock characterisation and testing. > > >> The DSP ultimately has 3 ports where the jitter reference (pins XA >> and XB differential sine or square) is one port for the digitally >> controlled oscillator (and also the clock to run the DSP), then the >> remaining 2 ports for input clock (CLK_IN) and the output (CLK_OUT) >> generated clock (any frequency really based on PLL coefficients). >> > > I still don't understand what you want it to do... or what it is > supposed to do and what jitter reference means in your context, low > jitter or know jitter. > > >> It is roughly 1:1 jitter transfer from jitter reference (38,88MHz) to >> output clock, regardless of CLK_IN but for only a certain bandwidth, >> 12kHz to 20MHz or so; It gets better, slightly, when looking close >> into the carrier but ultimately this jitter reference is used to >> clean an input clock on other pins for the outgoing PLL generated >> output. >> > > Sounds like a locked oscillator with PLL bandwidth of 12 kHz. The jitter > of the locked oscillator is high-pass filtered by the PLL loop. > > >> The same circuit could also be used outside of testing the jitter >> reference I suppose and be used on the incoming clock to be cleaned >> signal too.... >> >> Yes, it may actually be ideal to put jitter on the incoming clock to >> be cleaned... With added jitter on the incoming clock to be cleaned, >> it may keep the PLL out of the dead zone and ultimately force it do >> some useful work at all times rather than coast/drift in said dead >> zone.... But what shape of jittter to be introduced (noise shape on >> the proposed analogue voltage perturbing the varactors)? hmmmmm.... >> > > If you have a dead-zone on your PLL you need to fix it. I have learned > the hard way that dead-zone PLLs can cause significant jitter/wander > since they will get very abrupt shifts of direction in each end of the > dead-zone. When using detectors (every simple ones like SR-FF) which > does not have dead-zones it becomes feasible to tune it properly. > > Continuous detector and active filter for PI regulation should be the > standard approach most of the times. Not hard and expensive to achieve > by todays standards IMHO. > > May I stress that when doing SDH/SONET this is of particular importance. > > >> Still trying to figure out crystals for filter purposes though since >> any documentation I have on crystals shows a typical circuit with >> logic gates to make a clock to feed a microprocessor (different from >> what I need it to do of course since I already have an OCXO).... >> Harrumph.... >> > > It's actually not that hard to figure out. If you model a crystal as an > LCR chain in parallel with a C then you have a model for an oscillator > and a single mode. several LCR chains in parallel is needed if multiple > modes needs to be modeled/simulated. > > Crystal filters build upon these types of models. I still don't think > you need to revert to crystal filters. If you just want to sine up a > squarewave, a simple LC tank may be just want you need. A CLC or CRC > PI-filter may also suite your needs more than sufficiently. > > If you need very high Q filters for a fairly fixed frequency, crystal > filters may be used, but PLLs may also be part of the solution, as you > can see them as a form of self-retuneable bandpass filter. > > Cheers, > Magnus > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > From tvb at LeapSecond.com Wed Apr 8 22:58:12 2009 From: tvb at LeapSecond.com (Tom Van Baak) Date: Wed, 8 Apr 2009 15:58:12 -0700 Subject: [time-nuts] Hadamard variance References: <1231b6a80904080559o7a4cf618r49276df9d7599820@mail.gmail.com> Message-ID: <951FB64B18654ECE97BFC40BBDC1D2B3@pc52> > According to Wikipedia, this is insensitive to drift and so seems like > a better tool for measuring oscillators, like ocxo. I don't think I've > seen this being used by anyone on the list and wonder why? Hi Steve, I use it sometimes when I need to. But note that in most cases you do NOT want to ignore drift. If you measure an OCXO for the purpose of using it in a clock or appliance or radio or test equipment you really do want to know if it has drift or not. ADEV will show this, while HDEV will not. So you have to be careful about using statistics that deliberately and quietly ignore effects that may be important to your application. On the other hand, if you are choosing an OCXO to be used in a smart GPSDO which you know has internal adaptive drift rate calculation and compensation then, yes, HDEV would be a more appropriate statistic than ADEV. But before you run off and use HDEV for everything note that the other practice that is far more common -- simply remove frequency drift from the raw data before computing an ADEV on the residuals. If you look at plots in professional journals you will often find comments to the effect that phase, frequency, or drift offsets have been added or removed prior to making said phase, frequency, or stability plots. Here, to see the difference that HDEV makes (or not) see: http://www.leapsecond.com/pages/hdev The command line program that I use (ADEV3) these days: Tool for ADEV, MDEV, HDEV: http://www.leapsecond.com/tools/adev3.exe Source code (compiles in windows, bsd, or linux) http://www.leapsecond.com/tools/adev3.c /tvb From magnus at rubidium.dyndns.org Wed Apr 8 23:07:07 2009 From: magnus at rubidium.dyndns.org (Magnus Danielson) Date: Thu, 09 Apr 2009 01:07:07 +0200 Subject: [time-nuts] femtosecond jitter anyone? In-Reply-To: <49DD2884.5040000@xtra.co.nz> References: <4CCD1C7E-6952-4FB4-8E1A-3B1A02618BC5@twentylogten.com> <49DD1288.4060103@rubidium.dyndns.org> <18D08480-6725-4251-BE78-145797B6DC31@twentylogten.com> <49DD21D5.6040109@rubidium.dyndns.org> <49DD2884.5040000@xtra.co.nz> Message-ID: <49DD2E1B.30203@rubidium.dyndns.org> Bruce Griffiths skrev: > Magnus > > For examples of the use of crystals in filters for cleaning up the > output of a crystal oscillator look at the circuit schematics for some > of the early crystal frequency standards. > Crystal filters were used quite liberally in some of these to clean up > the outputs. It's used in the step-up chain of the SR620 for instance. The SR620 has a 10 MHz oscillator (TCXO or as in my case a Wenzel OCXO) which is stepped up to 90 MHz using a fairly ordinary odd-order stepup and filtering chain. The ECL logic counter frontend use this as coarse counter frequency. The analog interpolators is a bit interesting in a few peculiarities but nothing really exciting. The crystal filters of that chain is setup in PI-filter style with the crystals in serial mode. > However it may be necessary to control the temperature of these crystals. Indeed. I wonder if he really needs that level of sine purity. An LC tank should be sufficient to get started. Cheers, Magnus From bruce.griffiths at xtra.co.nz Wed Apr 8 23:18:41 2009 From: bruce.griffiths at xtra.co.nz (Bruce Griffiths) Date: Thu, 09 Apr 2009 11:18:41 +1200 Subject: [time-nuts] femtosecond jitter anyone? In-Reply-To: <49DD2E1B.30203@rubidium.dyndns.org> References: <4CCD1C7E-6952-4FB4-8E1A-3B1A02618BC5@twentylogten.com> <49DD1288.4060103@rubidium.dyndns.org> <18D08480-6725-4251-BE78-145797B6DC31@twentylogten.com> <49DD21D5.6040109@rubidium.dyndns.org> <49DD2884.5040000@xtra.co.nz> <49DD2E1B.30203@rubidium.dyndns.org> Message-ID: <49DD30D1.5040704@xtra.co.nz> Magnus Magnus Danielson wrote: > Bruce Griffiths skrev: > >> Magnus >> >> For examples of the use of crystals in filters for cleaning up the >> output of a crystal oscillator look at the circuit schematics for some >> of the early crystal frequency standards. >> Crystal filters were used quite liberally in some of these to clean up >> the outputs. >> > > It's used in the step-up chain of the SR620 for instance. The SR620 has > a 10 MHz oscillator (TCXO or as in my case a Wenzel OCXO) which is > stepped up to 90 MHz using a fairly ordinary odd-order stepup and > filtering chain. The ECL logic counter frontend use this as coarse > counter frequency. The analog interpolators is a bit interesting in a > few peculiarities but nothing really exciting. > > Except if you believe that they actually use a Z5U capacitor (specified in the parts list) for the interpolator TDC ramp capacitor. If so, this would make for some interesting linearity and dielectric absorption compensation software. > The crystal filters of that chain is setup in PI-filter style with the > crystals in serial mode. > > >> However it may be necessary to control the temperature of these crystals. >> > > Indeed. I wonder if he really needs that level of sine purity. An LC > tank should be sufficient to get started. > > The filter phase instability is reduced significantly if one uses LC filter traps tuned to the unwanted harmonics together with a low pass filter rather than using a high Q bandpass filter. > Cheers, > Magnus > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > Bruce From sometimesyoufeellikeanut at twentylogten.com Wed Apr 8 23:32:20 2009 From: sometimesyoufeellikeanut at twentylogten.com (Chris Mack / N1SKY) Date: Wed, 8 Apr 2009 19:32:20 -0400 Subject: [time-nuts] femtosecond jitter anyone? In-Reply-To: <49DD21D5.6040109@rubidium.dyndns.org> References: <4CCD1C7E-6952-4FB4-8E1A-3B1A02618BC5@twentylogten.com> <49DD1288.4060103@rubidium.dyndns.org> <18D08480-6725-4251-BE78-145797B6DC31@twentylogten.com> <49DD21D5.6040109@rubidium.dyndns.org> Message-ID: >> This is a good idea for testing.. > > Applying jitter frequencies for jitter tolerance testing is standard > stuff and needs to be done. Jitter tolerance curves match up with MTIE > tolerance curves very neatly. > Of course, here is the weird part... It's not SONET; but it is a chip that can be used for SONET... This is for a very specific form of audio clocking (not audiophile, nor consumer) for a mastering engineering application. Common input clock frequencies: 44.1kHz to 96kHz or also a 10MHz rubidium. The DSP PLL is this chip (I am still learning the intricacies of this chip): https://www.silabs.com/Support%20Documents/TechnicalDocs/Si5326.pdf The system clock (to drive the DSP and the DSP's DCO) is essentially a jitter reference, pins XA and XB (differential, single ended capable); Jitter is transferred nearly 1:1 from XA,XB to CLK_OUT. This is the 38.88 MHz reference from Vectron with some skirting issues to be filtered before connected to the XA and XB pins. The input (on CLK_IN pins) is the source clock to be cleaned (e.g., 44.1kHz to 96kHz or 10MHz Rb). The output (on CLK_OUT pins) is 11 MHz to 25MHz for 256x oversampling master clock for ADCs and DACs 24-bit accuracy for 40kHz (88.2kHz to 96kHz sample rate encompassing a 45/55 anti-alias filter) shows the need for sub picosecond timing aperture uncertainty. Of course 24-bit in the real world is hard to achieve (even the new "32-bit" converters have a problem with it) with issues internal to the sampling mechanisms in a DAC / ADC, but with some out-of-band dither and thermal management, coupled with low jitter sampling clock, there may be an additional bit or so to be obtained. This is all part of the experiment.... >> I have Howard Johnson's book for >> I think a normal LC tank would be more suitable for that task. > > It's a good introductional level book for digital signals, but isn't > very applicable to waveshaping or clock characterisation and testing Yes, HJ's books leaves me wanting a little more... seems like an analogue / RF book for digital folks. I am looking for sharp Q to get rid of any skirt around the 38,88MHz of the Vectron OCXO. Temperature can be obtained from cooling componentry already in situ, such that a known temperature is established. Cheers, -chris From magnus at rubidium.dyndns.org Wed Apr 8 23:43:29 2009 From: magnus at rubidium.dyndns.org (Magnus Danielson) Date: Thu, 09 Apr 2009 01:43:29 +0200 Subject: [time-nuts] Hadamard variance In-Reply-To: <951FB64B18654ECE97BFC40BBDC1D2B3@pc52> References: <1231b6a80904080559o7a4cf618r49276df9d7599820@mail.gmail.com> <951FB64B18654ECE97BFC40BBDC1D2B3@pc52> Message-ID: <49DD36A1.2070601@rubidium.dyndns.org> Tom Van Baak skrev: >> According to Wikipedia, this is insensitive to drift and so seems like >> a better tool for measuring oscillators, like ocxo. I don't think I've >> seen this being used by anyone on the list and wonder why? > > Hi Steve, > > I use it sometimes when I need to. But note that in most cases > you do NOT want to ignore drift. If you measure an OCXO for > the purpose of using it in a clock or appliance or radio or test > equipment you really do want to know if it has drift or not. True, but using ADEV is not a good method to bring it into the equation. ADEV is meant to measure frequency stability resulting from phase noise of various slopes. It is not meant to give a measure of drift components which is best estimates through other measures. > ADEV will show this, while HDEV will not. So you have to be careful > about using statistics that deliberately and quietly ignore effects > that may be important to your application. You need to understand what the various measures gives you. The ADEV and its various estimators is usually not drift compensating. The drift will limits the ADEV estimators ability to show noise slopes, but if drift compensations is performed then ADEV estimators typically just continues the slopes further down below the drift rate floor. HDEV is another approach that gives very similar properties. Drift and other higher orders of frequency shift, i.e. shifts in frequency that produces DC shifts needs to be combined and the best way of combing them is to estimate phase, frequency and drift rate errors and build their error over time along with the TDEV over the same time. This time error formulation have been provided in several sources, such as the NIST Special Publication 1065. The TDEV measure (a variant of the MDEV measure) is an estimator for time stability rather than frequency stability. Again it is only meant to be used for estimating the contribution from noise processes, not linear time drift components. Drift is a noise component when estimating ADEV, MDEV and TDEV, so it needs to be removed if sufficiently large in amplitude. ADEV without drift compensation is not a good combined measure for noise and drift. > On the other hand, if you are choosing an OCXO to be used > in a smart GPSDO which you know has internal adaptive drift > rate calculation and compensation then, yes, HDEV would be > a more appropriate statistic than ADEV. > > But before you run off and use HDEV for everything note that > the other practice that is far more common -- simply remove > frequency drift from the raw data before computing an ADEV > on the residuals. If you look at plots in professional journals you > will often find comments to the effect that phase, frequency, or > drift offsets have been added or removed prior to making said > phase, frequency, or stability plots. The normal ADEV estimators is insensitive to phase offset and frequency offset in the data series. Phase and Frequency deviations such as jumps, spikes needs to be canceled or avoided. Frequency drift such as that of a frequency slope will affect ADEV estimators, since the core of ADEV estimators is a second difference, squaring and averaging and a frequency ramp will produce a static value after the second difference. HDEV uses a third difference, so that is why the drift insensitivity comes from, but that is still just a theoretical things since many times the drift is not a pure linear frequency ramp but more complex, so some of it will leak in, but first degree cancelation can occur. Estimating the drift rate is straightforward thought, just use the second difference of the time data and average, then subtract that out of the second differences before squaring and averaging. Infact, the assumption that drift can be canceled is part of building the ADEV theory already in Allans original paper in 1966. It's hidden in the early equations if you look carefully. Regardless of which measure one uses, one should spend some time to read up on the peculiarities of them as one can easily confuse oneself with freely compare results from different stability measures, different estimators of these and then know what form of noise sources may obscure the data. Spending quality time with something like NIST SP1065 is adviceable. Using simulated noise and real measurements and processing them through the various variants can be good, as they react differently to different noise slopes and also to non-noise error sources. Length of measurement list vs. longest tau trusted, effects of repetitive signals etc. etc. all comes into it. Some measures depend on measurement bandwidth where as newer measures can cancel that through a combination of algorithmic change in bandwidth and t0 vs lowest tau analyzed margins. So while HDEV is indeed useful, don't expect it to be a drop-in replacement for ADEV but with drift compensation. Cheers, Magnus From bruce.griffiths at xtra.co.nz Thu Apr 9 00:02:48 2009 From: bruce.griffiths at xtra.co.nz (Bruce Griffiths) Date: Thu, 09 Apr 2009 12:02:48 +1200 Subject: [time-nuts] femtosecond jitter anyone? In-Reply-To: References: <4CCD1C7E-6952-4FB4-8E1A-3B1A02618BC5@twentylogten.com> <49DD1288.4060103@rubidium.dyndns.org> <18D08480-6725-4251-BE78-145797B6DC31@twentylogten.com> <49DD21D5.6040109@rubidium.dyndns.org> Message-ID: <49DD3B28.4040704@xtra.co.nz> Chris Chris Mack / N1SKY wrote: >>> This is a good idea for testing.. >>> >> Applying jitter frequencies for jitter tolerance testing is standard >> stuff and needs to be done. Jitter tolerance curves match up with MTIE >> tolerance curves very neatly. >> >> > > Of course, here is the weird part... It's not SONET; but it is a chip > that can be used for SONET... This is for a very specific form of > audio clocking (not audiophile, nor consumer) for a mastering > engineering application. Common input clock frequencies: 44.1kHz to > 96kHz or also a 10MHz rubidium. > > The DSP PLL is this chip (I am still learning the intricacies of this > chip): > > https://www.silabs.com/Support%20Documents/TechnicalDocs/Si5326.pdf > > The system clock (to drive the DSP and the DSP's DCO) is essentially > a jitter reference, pins XA and XB (differential, single ended > capable); Jitter is transferred nearly 1:1 from XA,XB to CLK_OUT. > This is the 38.88 MHz reference from Vectron with some skirting > issues to be filtered before connected to the XA and XB pins. > > The input (on CLK_IN pins) is the source clock to be cleaned (e.g., > 44.1kHz to 96kHz or 10MHz Rb). > > The output (on CLK_OUT pins) is 11 MHz to 25MHz for 256x > oversampling master clock for ADCs and DACs > > 24-bit accuracy for 40kHz (88.2kHz to 96kHz sample rate encompassing > a 45/55 anti-alias filter) shows the need for sub picosecond timing > aperture uncertainty. > > These ADCs probably have internal jitter way above a few femtosec. > Of course 24-bit in the real world is hard to achieve (even the new > "32-bit" converters have a problem with it) with issues internal to > the sampling mechanisms in a DAC / ADC, but with some out-of-band > dither and thermal management, coupled with low jitter sampling > clock, there may be an additional bit or so to be obtained. This is > all part of the experiment.... > > >>> I have Howard Johnson's book for >>> > > >>> I think a normal LC tank would be more suitable for that task. >>> >> It's a good introductional level book for digital signals, but isn't >> very applicable to waveshaping or clock characterisation and testing >> > > Yes, HJ's books leaves me wanting a little more... seems like an > analogue / RF book for digital folks. > > I am looking for sharp Q to get rid of any skirt around the 38,88MHz > of the Vectron OCXO. > > Unless you are prepared to place the crystals in an oven with the temperature regulated tightly and carefully tune the filter periodically then using a crystal filter (or any passive filter with a sufficiently narrow bandwidth to cleanup the skirts) will not be particularly useful. It would be much easier to use a low bandwidth analog PLL with a low noise VCXO to cleanup the 38.88MHz signal. > Temperature can be obtained from cooling componentry already in situ, > such that a known temperature is established. > > probably not much use unless one arranges to use this to tune the crystal filter, even then thermal gradients, thermal transients and aging will make this problematic. > Cheers, > -chris > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > Bruce From peterawson at earthlink.net Thu Apr 9 00:15:51 2009 From: peterawson at earthlink.net (Pete) Date: Wed, 8 Apr 2009 18:15:51 -0600 Subject: [time-nuts] 74HC4046 receiver Message-ID: <58CFF8BB33914D0AAA5E3B998E0F1B8D@NancysPC> A long thread was running on various ways to process a 10MHz (or other) sinewave to reduce measured jitter (presumably limited by slew rate). This note is a quick look at what the 74HC4046 signal input circuit yields; since it was mentioned in 1 post as possibly useful. Jitter was measured on a DTS-2075 with a 0.18uf blocking cap and a 10:1 resistive divider probe. This provided +/- 250mV into the DTS & an AC coupled, 500 ohm load on the 4046 output. The sinewave source was the 10MHz ref-out from a PM6681, it's the quietest +9dBm signal available to me. From magnus at rubidium.dyndns.org Thu Apr 9 00:16:56 2009 From: magnus at rubidium.dyndns.org (Magnus Danielson) Date: Thu, 09 Apr 2009 02:16:56 +0200 Subject: [time-nuts] femtosecond jitter anyone? In-Reply-To: <49DD30D1.5040704@xtra.co.nz> References: <4CCD1C7E-6952-4FB4-8E1A-3B1A02618BC5@twentylogten.com> <49DD1288.4060103@rubidium.dyndns.org> <18D08480-6725-4251-BE78-145797B6DC31@twentylogten.com> <49DD21D5.6040109@rubidium.dyndns.org> <49DD2884.5040000@xtra.co.nz> <49DD2E1B.30203@rubidium.dyndns.org> <49DD30D1.5040704@xtra.co.nz> Message-ID: <49DD3E78.6050303@rubidium.dyndns.org> Hej Bruce, Bruce Griffiths skrev: > Magnus > > Magnus Danielson wrote: >> Bruce Griffiths skrev: >> >>> Magnus >>> >>> For examples of the use of crystals in filters for cleaning up the >>> output of a crystal oscillator look at the circuit schematics for some >>> of the early crystal frequency standards. >>> Crystal filters were used quite liberally in some of these to clean up >>> the outputs. >>> >> It's used in the step-up chain of the SR620 for instance. The SR620 has >> a 10 MHz oscillator (TCXO or as in my case a Wenzel OCXO) which is >> stepped up to 90 MHz using a fairly ordinary odd-order stepup and >> filtering chain. The ECL logic counter frontend use this as coarse >> counter frequency. The analog interpolators is a bit interesting in a >> few peculiarities but nothing really exciting. >> >> > Except if you believe that they actually use a Z5U capacitor (specified > in the parts list) for the interpolator TDC ramp capacitor. > If so, this would make for some interesting linearity and dielectric > absorption compensation software. The caps listed as Z5U in the part list is not the timing caps. C701 and C711 both being 100 pF NP0 is the timing caps. If you look careful you will see it referenced. A 7 us sample pulse will charge a polypropylen cap with the buffered value for a sligthly later performed 12 bit ADC conversion. Autocalibration will adjust the discharge current, measure the voltage bias and adjust the linearization data (65 bytes per channel). >> The crystal filters of that chain is setup in PI-filter style with the >> crystals in serial mode. >> >> >>> However it may be necessary to control the temperature of these crystals. >>> >> Indeed. I wonder if he really needs that level of sine purity. An LC >> tank should be sufficient to get started. >> >> > The filter phase instability is reduced significantly if one uses LC > filter traps tuned to the unwanted harmonics together with a low pass > filter rather than using a high Q bandpass filter. Agree. Any temperature effects will occur with very flat slopes as the tuning is far away from the frequency of interest. A number of shunting LCRs can be used, infact a suitable crystal could be used to shunt into ground. Cheers, Magnus From magnus at rubidium.dyndns.org Thu Apr 9 00:22:26 2009 From: magnus at rubidium.dyndns.org (Magnus Danielson) Date: Thu, 09 Apr 2009 02:22:26 +0200 Subject: [time-nuts] femtosecond jitter anyone? In-Reply-To: <49DD3B28.4040704@xtra.co.nz> References: <4CCD1C7E-6952-4FB4-8E1A-3B1A02618BC5@twentylogten.com> <49DD1288.4060103@rubidium.dyndns.org> <18D08480-6725-4251-BE78-145797B6DC31@twentylogten.com> <49DD21D5.6040109@rubidium.dyndns.org> <49DD3B28.4040704@xtra.co.nz> Message-ID: <49DD3FC2.5050408@rubidium.dyndns.org> Bruce Griffiths skrev: > Chris > > Chris Mack / N1SKY wrote: >>>> This is a good idea for testing.. >>>> >>> Applying jitter frequencies for jitter tolerance testing is standard >>> stuff and needs to be done. Jitter tolerance curves match up with MTIE >>> tolerance curves very neatly. >>> >>> >> Of course, here is the weird part... It's not SONET; but it is a chip >> that can be used for SONET... This is for a very specific form of >> audio clocking (not audiophile, nor consumer) for a mastering >> engineering application. Common input clock frequencies: 44.1kHz to >> 96kHz or also a 10MHz rubidium. >> >> The DSP PLL is this chip (I am still learning the intricacies of this >> chip): >> >> https://www.silabs.com/Support%20Documents/TechnicalDocs/Si5326.pdf >> >> The system clock (to drive the DSP and the DSP's DCO) is essentially >> a jitter reference, pins XA and XB (differential, single ended >> capable); Jitter is transferred nearly 1:1 from XA,XB to CLK_OUT. >> This is the 38.88 MHz reference from Vectron with some skirting >> issues to be filtered before connected to the XA and XB pins. >> >> The input (on CLK_IN pins) is the source clock to be cleaned (e.g., >> 44.1kHz to 96kHz or 10MHz Rb). >> >> The output (on CLK_OUT pins) is 11 MHz to 25MHz for 256x >> oversampling master clock for ADCs and DACs >> >> 24-bit accuracy for 40kHz (88.2kHz to 96kHz sample rate encompassing >> a 45/55 anti-alias filter) shows the need for sub picosecond timing >> aperture uncertainty. >> >> > These ADCs probably have internal jitter way above a few femtosec. > >> Of course 24-bit in the real world is hard to achieve (even the new >> "32-bit" converters have a problem with it) with issues internal to >> the sampling mechanisms in a DAC / ADC, but with some out-of-band >> dither and thermal management, coupled with low jitter sampling >> clock, there may be an additional bit or so to be obtained. This is >> all part of the experiment.... >> >> >>>> I have Howard Johnson's book for >>>> >> >>>> I think a normal LC tank would be more suitable for that task. >>>> >>> It's a good introductional level book for digital signals, but isn't >>> very applicable to waveshaping or clock characterisation and testing >>> >> Yes, HJ's books leaves me wanting a little more... seems like an >> analogue / RF book for digital folks. >> >> I am looking for sharp Q to get rid of any skirt around the 38,88MHz >> of the Vectron OCXO. >> >> > Unless you are prepared to place the crystals in an oven with the > temperature regulated tightly and carefully tune the filter periodically > then using a crystal filter (or any passive filter with a sufficiently > narrow bandwidth to cleanup the skirts) will not be particularly useful. > It would be much easier to use a low bandwidth analog PLL with a low > noise VCXO to cleanup the 38.88MHz signal. Consider using a low noise oscillator at a higher frequency and divide down. A high quality reference such as a 19,44 MHz OCXO should be the real reference, again readilly available. The typical frequency relationship is a handy 8 or 16 which allows for low noise divisions if needed. For those frequencies, SAW devices may be more suitable. >> Temperature can be obtained from cooling componentry already in situ, >> such that a known temperature is established. >> >> > > probably not much use unless one arranges to use this to tune the > crystal filter, even then thermal gradients, thermal transients and > aging will make this problematic. Sound nasty. Cheers, Magnus From sometimesyoufeellikeanut at twentylogten.com Thu Apr 9 00:28:35 2009 From: sometimesyoufeellikeanut at twentylogten.com (Chris Mack / N1SKY) Date: Wed, 8 Apr 2009 20:28:35 -0400 Subject: [time-nuts] femtosecond jitter anyone? In-Reply-To: <49DD3B28.4040704@xtra.co.nz> References: <4CCD1C7E-6952-4FB4-8E1A-3B1A02618BC5@twentylogten.com> <49DD1288.4060103@rubidium.dyndns.org> <18D08480-6725-4251-BE78-145797B6DC31@twentylogten.com> <49DD21D5.6040109@rubidium.dyndns.org> <49DD3B28.4040704@xtra.co.nz> Message-ID: <91291C16-6AC8-4BA7-9ADE-B21AC566B024@twentylogten.com> On Apr 8, 2009, at 8:02 PM, Bruce Griffiths wrote: > Unless you are prepared to place the crystals in an oven with the > temperature regulated tightly and carefully tune the filter > periodically > then using a crystal filter (or any passive filter with a sufficiently > narrow bandwidth to cleanup the skirts) will not be particularly > useful. > It would be much easier to use a low bandwidth analog PLL with a low > noise VCXO to cleanup the 38.88MHz signal. > http://www.national.com/pf/LM/LMK04000B.html Their app note uses a very low noise VCXO... The simulator software gets pretty close... Cheers, -chris From bruce.griffiths at xtra.co.nz Thu Apr 9 00:32:10 2009 From: bruce.griffiths at xtra.co.nz (Bruce Griffiths) Date: Thu, 09 Apr 2009 12:32:10 +1200 Subject: [time-nuts] 74HC4046 receiver In-Reply-To: <58CFF8BB33914D0AAA5E3B998E0F1B8D@NancysPC> References: <58CFF8BB33914D0AAA5E3B998E0F1B8D@NancysPC> Message-ID: <49DD420A.9010308@xtra.co.nz> Pete wrote: > A long thread was running on various ways to process a 10MHz > (or other) sinewave to reduce measured jitter (presumably limited > by slew rate). This note is a quick look at what the 74HC4046 > signal input circuit yields; since it was mentioned in 1 post as > possibly useful. > > Jitter was measured on a DTS-2075 with a 0.18uf blocking cap > and a 10:1 resistive divider probe. This provided +/- 250mV into > the DTS & an AC coupled, 500 ohm load on the 4046 output. > > The sinewave source was the 10MHz ref-out from a PM6681, it's > the quietest +9dBm signal available to me. > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > Pete You have provided no jitter measurment data??? Bruce From bruce.griffiths at xtra.co.nz Thu Apr 9 00:42:46 2009 From: bruce.griffiths at xtra.co.nz (Bruce Griffiths) Date: Thu, 09 Apr 2009 12:42:46 +1200 Subject: [time-nuts] femtosecond jitter anyone? In-Reply-To: <49DD3E78.6050303@rubidium.dyndns.org> References: <4CCD1C7E-6952-4FB4-8E1A-3B1A02618BC5@twentylogten.com> <49DD1288.4060103@rubidium.dyndns.org> <18D08480-6725-4251-BE78-145797B6DC31@twentylogten.com> <49DD21D5.6040109@rubidium.dyndns.org> <49DD2884.5040000@xtra.co.nz> <49DD2E1B.30203@rubidium.dyndns.org> <49DD30D1.5040704@xtra.co.nz> <49DD3E78.6050303@rubidium.dyndns.org> Message-ID: <49DD4486.4000100@xtra.co.nz> Hej Magnus Magnus Danielson wrote: > Hej Bruce, > > Bruce Griffiths skrev: > >> Magnus >> >> Magnus Danielson wrote: >> >>> Bruce Griffiths skrev: >>> >>> >>>> Magnus >>>> >>>> For examples of the use of crystals in filters for cleaning up the >>>> output of a crystal oscillator look at the circuit schematics for some >>>> of the early crystal frequency standards. >>>> Crystal filters were used quite liberally in some of these to clean up >>>> the outputs. >>>> >>>> >>> It's used in the step-up chain of the SR620 for instance. The SR620 has >>> a 10 MHz oscillator (TCXO or as in my case a Wenzel OCXO) which is >>> stepped up to 90 MHz using a fairly ordinary odd-order stepup and >>> filtering chain. The ECL logic counter frontend use this as coarse >>> counter frequency. The analog interpolators is a bit interesting in a >>> few peculiarities but nothing really exciting. >>> >>> >>> >> Except if you believe that they actually use a Z5U capacitor (specified >> in the parts list) for the interpolator TDC ramp capacitor. >> If so, this would make for some interesting linearity and dielectric >> absorption compensation software. >> > > The caps listed as Z5U in the part list is not the timing caps. C701 and > C711 both being 100 pF NP0 is the timing caps. If you look careful you > will see it referenced. A 7 us sample pulse will charge a polypropylen > cap with the buffered value for a sligthly later performed 12 bit ADC > conversion. > > The online version of the manual specifies both of these caps as Z5U (see attachment). This may be an error in this version of the manual, or perhaps early versions used Z5U?? 100pF NP0 surface mount caps have been available for decades. > Autocalibration will adjust the discharge current, measure the voltage > bias and adjust the linearization data (65 bytes per channel). > > Dielectric absorption and voltage dependence correction for Z5U caps would be very challenging. >>> The crystal filters of that chain is setup in PI-filter style with the >>> crystals in serial mode. >>> >>> >>> >>>> However it may be necessary to control the temperature of these crystals. >>>> >>>> >>> Indeed. I wonder if he really needs that level of sine purity. An LC >>> tank should be sufficient to get started. >>> >>> >>> >> The filter phase instability is reduced significantly if one uses LC >> filter traps tuned to the unwanted harmonics together with a low pass >> filter rather than using a high Q bandpass filter. >> > > Agree. Any temperature effects will occur with very flat slopes as the > tuning is far away from the frequency of interest. > > A number of shunting LCRs can be used, infact a suitable crystal could > be used to shunt into ground. > > Series tuned LC shunts are generally better as at resonance their ESR can be much lower than that of a crystal, the signal level that they can handle without damage is also much higher. Although a single LC series tuned shunt wont provide large attenuation one can always use one tuned to each significant harmonic per filter section. > Cheers, > Magnus > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > Bruce -------------- next part -------------- A non-text attachment was scrubbed... Name: SR620Parts.png Type: image/png Size: 50415 bytes Desc: not available Url : http://www.febo.com/pipermail/time-nuts/attachments/20090409/1009c52b/attachment-0001.png From bruce.griffiths at xtra.co.nz Thu Apr 9 00:50:33 2009 From: bruce.griffiths at xtra.co.nz (Bruce Griffiths) Date: Thu, 09 Apr 2009 12:50:33 +1200 Subject: [time-nuts] femtosecond jitter anyone? In-Reply-To: <91291C16-6AC8-4BA7-9ADE-B21AC566B024@twentylogten.com> References: <4CCD1C7E-6952-4FB4-8E1A-3B1A02618BC5@twentylogten.com> <49DD1288.4060103@rubidium.dyndns.org> <18D08480-6725-4251-BE78-145797B6DC31@twentylogten.com> <49DD21D5.6040109@rubidium.dyndns.org> <49DD3B28.4040704@xtra.co.nz> <91291C16-6AC8-4BA7-9ADE-B21AC566B024@twentylogten.com> Message-ID: <49DD4659.1070500@xtra.co.nz> Chris Mack / N1SKY wrote: > On Apr 8, 2009, at 8:02 PM, Bruce Griffiths wrote: > > > >> Unless you are prepared to place the crystals in an oven with the >> temperature regulated tightly and carefully tune the filter >> periodically >> then using a crystal filter (or any passive filter with a sufficiently >> narrow bandwidth to cleanup the skirts) will not be particularly >> useful. >> It would be much easier to use a low bandwidth analog PLL with a low >> noise VCXO to cleanup the 38.88MHz signal. >> >> > > http://www.national.com/pf/LM/LMK04000B.html > > Their app note uses a very low noise VCXO... The simulator software > gets pretty close... > > Cheers, > -chris > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > Chris If you divide the output down to ~38MHz using a noiseless divider then the performance is 20dB or more worse than can be achieved with a good ~38MHz crystal oscillator. This seems to be a complex method of degrading the performance over that possible with a simpler design. Bruce From peterawson at earthlink.net Thu Apr 9 01:09:24 2009 From: peterawson at earthlink.net (Pete) Date: Wed, 8 Apr 2009 19:09:24 -0600 Subject: [time-nuts] 74HC4046 receiver References: <58CFF8BB33914D0AAA5E3B998E0F1B8D@NancysPC> <49DD420A.9010308@xtra.co.nz> Message-ID: <8499DA729BD648078F010A5CC66F1C10@BASE1> Bruce, Quite correct, fumble fingers win again. As they say "here's the rest of the story". I was able to measure just 1 part. It is a NSC MM74HC4046N, date code 9018, presumably still available from Fairchild. The VCO was disabled (INH=H), the COMP input was grounded & I looked at the PC1 output. Transition times were <3ns & abberations were <5%. The resulting jitter measures: Input Vp-p Jitter ps rms 2.36 8.6 2 8.8 1.5 9.2 1 9.5 0.7 10.2 0.5 11.1 0.3 14.5 I tried comparing this with a 74AC04, but my setup must be too noisy as the best the 'AC04 could do was 12ps rms. The input to the 'AC04 was AC coupled & yielded 49/51% duty cycle, apparently switching cleanly with the 2.36Vp-p input. Ground bounch & ringing were <10%. Pete Rawson From bruce.griffiths at xtra.co.nz Thu Apr 9 01:47:57 2009 From: bruce.griffiths at xtra.co.nz (Bruce Griffiths) Date: Thu, 09 Apr 2009 13:47:57 +1200 Subject: [time-nuts] 74HC4046 receiver In-Reply-To: <8499DA729BD648078F010A5CC66F1C10@BASE1> References: <58CFF8BB33914D0AAA5E3B998E0F1B8D@NancysPC> <49DD420A.9010308@xtra.co.nz> <8499DA729BD648078F010A5CC66F1C10@BASE1> Message-ID: <49DD53CD.5020604@xtra.co.nz> Pete wrote: > Bruce, > > Quite correct, fumble fingers win again. As they say "here's > the rest of the story". > > I was able to measure just 1 part. It is a NSC MM74HC4046N, > date code 9018, presumably still available from Fairchild. The VCO > was disabled (INH=H), the COMP input was grounded & I looked > at the PC1 output. Transition times were <3ns & abberations were > <5%. The resulting jitter measures: > > Input Vp-p Jitter ps rms > 2.36 8.6 > 2 8.8 > 1.5 9.2 > 1 9.5 > 0.7 10.2 > 0.5 11.1 > 0.3 14.5 > > I tried comparing this with a 74AC04, but my setup must be too > noisy as the best the 'AC04 could do was 12ps rms. The input to > the 'AC04 was AC coupled & yielded 49/51% duty cycle, apparently > switching cleanly with the 2.36Vp-p input. Ground bounch & ringing > were <10%. > > Pete Rawson > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > Pete What were you using as the timing reference? Were you driving the start input with a reference and the STOP input with the 4046 (or AC04) output? Or were you using another setup? The Fairchild version of the 74HC4046 has lower sensitivity inputs than the corresponding Philips/NXP or TI parts. You would need to look at the corresponding National datasheet to see if their 74HC4046 its similar to either the Fairchild part or the others. With 2.36V pp sinewave input at 10MHz the input slew rate is ~ 75V/us at the threshold crossing of the AC04. It would only take about 1mV rms of noise at the AC04 input to produce an output jitter of 12ps. If the AC04 noisebandwidth is 100MHz this corresponds to ~ 100nV/rtHz which is possible. The way to test this is measure the AC04 output jitter as a function of the input signal slew rate and try to deduce the equivalent input noise from the results. Driving 2 AC04's from the same input signal may also be useful as to first order the source jitter will cancel if the time difference between the output transitions of the 2 AC04's is measured. The 1ps jitter that I quoted for an AC04 is the limiting value achieved when the AC04 input is driven by a high slew rate input signal not a ~2V pp 10MHz sinewave. Bruce From sometimesyoufeellikeanut at twentylogten.com Thu Apr 9 02:03:29 2009 From: sometimesyoufeellikeanut at twentylogten.com (Chris Mack / N1SKY) Date: Wed, 8 Apr 2009 22:03:29 -0400 Subject: [time-nuts] femtosecond jitter anyone? In-Reply-To: <49DD4659.1070500@xtra.co.nz> References: <4CCD1C7E-6952-4FB4-8E1A-3B1A02618BC5@twentylogten.com> <49DD1288.4060103@rubidium.dyndns.org> <18D08480-6725-4251-BE78-145797B6DC31@twentylogten.com> <49DD21D5.6040109@rubidium.dyndns.org> <49DD3B28.4040704@xtra.co.nz> <91291C16-6AC8-4BA7-9ADE-B21AC566B024@twentylogten.com> <49DD4659.1070500@xtra.co.nz> Message-ID: <8DC9EC52-5D5A-43E9-A69E-A244076F0673@twentylogten.com> On Apr 8, 2009, at 8:50 PM, Bruce Griffiths wrote: >> > Chris > > If you divide the output down to ~38MHz using a noiseless divider then > the performance is 20dB or more worse than can be achieved with a good > ~38MHz crystal oscillator. > Ah, this would work, but there is a synchronization aspect since framing on AES/EBU is in the mix (pun intended?) and there are more pieces of external equipment that all need to be synched (within AES11 framing sync margins)... The box / design of interest has ADCs, DACs, and a 38.88MHz OCXO of marginal performance coupled with the proposed DSP based PLLs generating a local clock for the ADCs and DACs all on the same circuit board in synch with external gear. This 38.88MHz is a DSP clock, essentially a microprocessor clock (albeit a very nice microprocessor clock) where the DSP simulates a PLL operating on an incoming clock source, and makes an output clock of a different frequency, but synchronized to be within AES standards for framing when considering the additional equipment scattered around the room, made by different manufacturers, different inner workings etc. The incoming clock source (master house clock) to this box / design of interest is in another rack mount box external to this design on the other side of the room and is anywhere from 44.1kHz up to a 10MHz Rubidium (see also http://www.antelopeaudio.com). This clock source on the other side of the room also drives other equipment to be in synch for any framing on AES/EBU digital. The output of the DSP PLL in this box / design of interest is 11MHz to 24MHz to feed the oversample clocks on the ADCs and DACs, synchronized to the external 44.1kHz to 10MHz master house clock a la the PLL and the rest of the equipment on the other side of the room... The only caveat is that the 38.88MHz DSP microprocessor clock must be low jitter in order to have the DSP PLL be low jitter.. The DSP PLL does not really care about absolute frequency in the long term (38.88MHz or 37MHz, doesn't matter), but it will rebroadcast short term effects of jitter to clocks of the ADCs and DACs in the box of interest. Sounds like maybe some LCs to filter out the additional harmonics and maybe attempt to get close into the carrier eh? Thanks Magnus and Bruce for being a sounding wall.... Cheers, -chris From bruce.griffiths at xtra.co.nz Thu Apr 9 02:22:21 2009 From: bruce.griffiths at xtra.co.nz (Bruce Griffiths) Date: Thu, 09 Apr 2009 14:22:21 +1200 Subject: [time-nuts] femtosecond jitter anyone? In-Reply-To: <8DC9EC52-5D5A-43E9-A69E-A244076F0673@twentylogten.com> References: <4CCD1C7E-6952-4FB4-8E1A-3B1A02618BC5@twentylogten.com> <49DD1288.4060103@rubidium.dyndns.org> <18D08480-6725-4251-BE78-145797B6DC31@twentylogten.com> <49DD21D5.6040109@rubidium.dyndns.org> <49DD3B28.4040704@xtra.co.nz> <91291C16-6AC8-4BA7-9ADE-B21AC566B024@twentylogten.com> <49DD4659.1070500@xtra.co.nz> <8DC9EC52-5D5A-43E9-A69E-A244076F0673@twentylogten.com> Message-ID: <49DD5BDD.8080300@xtra.co.nz> Chris Now we have a more complete picture of what you are trying to do our suggestions will perhaps be a little more useful. Cleaning up a marginal OCXO is quite complex and probably more expensive than obtaining an OCXO or other reference that has lower noise. Is it in fact possible to just substitute a low noise non oven crystal oscillator for the 38.88MHz OCXO? With an appropriate oscillator design it should be possible to significantly reduce the phase noise of the 38.88MHz source at the expense of long term drift and aging. Achieving low jitter with such a source isn't difficult. The other question that arises is why is the OCXO phase noise so poor at frequency offsets less than 12kHz? Bruce Chris Mack / N1SKY wrote: > On Apr 8, 2009, at 8:50 PM, Bruce Griffiths wrote: > >> Chris >> >> If you divide the output down to ~38MHz using a noiseless divider then >> the performance is 20dB or more worse than can be achieved with a good >> ~38MHz crystal oscillator. >> >> > > Ah, this would work, but there is a synchronization aspect since > framing on AES/EBU is in the mix (pun intended?) and there are more > pieces of external equipment that all need to be synched (within > AES11 framing sync margins)... > > The box / design of interest has ADCs, DACs, and a 38.88MHz OCXO of > marginal performance coupled with the proposed DSP based PLLs > generating a local clock for the ADCs and DACs all on the same > circuit board in synch with external gear. > > This 38.88MHz is a DSP clock, essentially a microprocessor clock > (albeit a very nice microprocessor clock) where the DSP simulates a > PLL operating on an incoming clock source, and makes an output clock > of a different frequency, but synchronized to be within AES standards > for framing when considering the additional equipment scattered > around the room, made by different manufacturers, different inner > workings etc. > > The incoming clock source (master house clock) to this box / design > of interest is in another rack mount box external to this design on > the other side of the room and is anywhere from 44.1kHz up to a 10MHz > Rubidium (see also http://www.antelopeaudio.com). This clock source > on the other side of the room also drives other equipment to be in > synch for any framing on AES/EBU digital. > > The output of the DSP PLL in this box / design of interest is 11MHz > to 24MHz to feed the oversample clocks on the ADCs and DACs, > synchronized to the external 44.1kHz to 10MHz master house clock a la > the PLL and the rest of the equipment on the other side of the room... > > The only caveat is that the 38.88MHz DSP microprocessor clock must be > low jitter in order to have the DSP PLL be low jitter.. The DSP PLL > does not really care about absolute frequency in the long term > (38.88MHz or 37MHz, doesn't matter), but it will rebroadcast short > term effects of jitter to clocks of the ADCs and DACs in the box of > interest. > > Sounds like maybe some LCs to filter out the additional harmonics and > maybe attempt to get close into the carrier eh? > > Thanks Magnus and Bruce for being a sounding wall.... > > Cheers, > -chris > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > From sometimesyoufeellikeanut at twentylogten.com Thu Apr 9 03:23:43 2009 From: sometimesyoufeellikeanut at twentylogten.com (Chris Mack / N1SKY) Date: Wed, 8 Apr 2009 23:23:43 -0400 Subject: [time-nuts] femtosecond jitter anyone? In-Reply-To: <49DD5BDD.8080300@xtra.co.nz> References: <4CCD1C7E-6952-4FB4-8E1A-3B1A02618BC5@twentylogten.com> <49DD1288.4060103@rubidium.dyndns.org> <18D08480-6725-4251-BE78-145797B6DC31@twentylogten.com> <49DD21D5.6040109@rubidium.dyndns.org> <49DD3B28.4040704@xtra.co.nz> <91291C16-6AC8-4BA7-9ADE-B21AC566B024@twentylogten.com> <49DD4659.1070500@xtra.co.nz> <8DC9EC52-5D5A-43E9-A69E-A244076F0673@twentylogten.com> <49DD5BDD.8080300@xtra.co.nz> Message-ID: <99D7BEE7-C033-42DE-A93D-03BE68E30FB4@twentylogten.com> Thanks Bruce, The 12kHz is a figure for the DSP PLL and how they measure it (starting at 12kHz usually for jitter over BW measurements).... I haven't touched SONET since 1997 and this may be a SONET spec? I am using the simulator software for the LMK04000 series to see what jitter is for the OXCO... -70dBc at 1 Hz, -100dBc 10Hz per the spec sheet with all the other datapoints comes out to 1.3ps (1Hz to 20MHz) of jitter RMS. So the OCXO is decent without having to purchase a better one (and the minimum quantity of 25 at $250 each +/-) for this initial prototype; this seems to be semi-custom since 38.88MHz OCXOs are not in stock at Digikey.... I plan on building a bunch of boxes over time with this OCXO in it and finding disparate OCXOs on ebay was not an option, especially if a new circuit board would need to be spun every time. I just didn't know if I could get better with some filtering, and get it into the femtosecond range... Currently this should be able to maintain 22 bits of accuracy at 40kHz, which is pretty doggone good, but was interested in pushing the envelope a little since I can go (with an input alias filter) to 96kHz... Yes, there is some internal jitter to the ADCs, some perhaps due to thermal, and the box is going to be hot with a power budget already at 250W hence the thermal / cooling and dither experiments and I was hoping to not be limited by the clock performance. I still want to filter such as to distribute a sine... Cheers, -chris On Apr 8, 2009, at 10:22 PM, Bruce Griffiths wrote: > Chris > > Now we have a more complete picture of what you are trying to do our > suggestions will perhaps be a little more useful. > > Cleaning up a marginal OCXO is quite complex and probably more > expensive than obtaining an OCXO or other reference that has lower > noise. > Is it in fact possible to just substitute a low noise non oven > crystal > oscillator for the 38.88MHz OCXO? > With an appropriate oscillator design it should be possible to > significantly reduce the phase noise of the 38.88MHz source at the > expense of long term drift and aging. > Achieving low jitter with such a source isn't difficult. > > The other question that arises is why is the OCXO phase noise so > poor at > frequency offsets less than 12kHz? > > Bruce > > Chris Mack / N1SKY wrote: >> On Apr 8, 2009, at 8:50 PM, Bruce Griffiths wrote: >> >>> Chris >>> >>> If you divide the output down to ~38MHz using a noiseless divider >>> then >>> the performance is 20dB or more worse than can be achieved with a >>> good >>> ~38MHz crystal oscillator. >>> >>> >> >> Ah, this would work, but there is a synchronization aspect since >> framing on AES/EBU is in the mix (pun intended?) and there are more >> pieces of external equipment that all need to be synched (within >> AES11 framing sync margins)... >> >> The box / design of interest has ADCs, DACs, and a 38.88MHz OCXO of >> marginal performance coupled with the proposed DSP based PLLs >> generating a local clock for the ADCs and DACs all on the same >> circuit board in synch with external gear. >> >> This 38.88MHz is a DSP clock, essentially a microprocessor clock >> (albeit a very nice microprocessor clock) where the DSP simulates a >> PLL operating on an incoming clock source, and makes an output clock >> of a different frequency, but synchronized to be within AES standards >> for framing when considering the additional equipment scattered >> around the room, made by different manufacturers, different inner >> workings etc. >> >> The incoming clock source (master house clock) to this box / design >> of interest is in another rack mount box external to this design on >> the other side of the room and is anywhere from 44.1kHz up to a 10MHz >> Rubidium (see also http://www.antelopeaudio.com). This clock source >> on the other side of the room also drives other equipment to be in >> synch for any framing on AES/EBU digital. >> >> The output of the DSP PLL in this box / design of interest is 11MHz >> to 24MHz to feed the oversample clocks on the ADCs and DACs, >> synchronized to the external 44.1kHz to 10MHz master house clock a la >> the PLL and the rest of the equipment on the other side of the >> room... >> >> The only caveat is that the 38.88MHz DSP microprocessor clock must be >> low jitter in order to have the DSP PLL be low jitter.. The DSP PLL >> does not really care about absolute frequency in the long term >> (38.88MHz or 37MHz, doesn't matter), but it will rebroadcast short >> term effects of jitter to clocks of the ADCs and DACs in the box of >> interest. >> >> Sounds like maybe some LCs to filter out the additional harmonics and >> maybe attempt to get close into the carrier eh? >> >> Thanks Magnus and Bruce for being a sounding wall.... >> >> Cheers, >> -chris >> >> >> _______________________________________________ >> time-nuts mailing list -- time-nuts at febo.com >> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/ >> listinfo/time-nuts >> and follow the instructions there. >> >> > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/ > time-nuts > and follow the instructions there. From peterawson at earthlink.net Thu Apr 9 03:52:48 2009 From: peterawson at earthlink.net (Pete) Date: Wed, 8 Apr 2009 21:52:48 -0600 Subject: [time-nuts] 74HC4046 receiver References: <58CFF8BB33914D0AAA5E3B998E0F1B8D@NancysPC> <49DD420A.9010308@xtra.co.nz><8499DA729BD648078F010A5CC66F1C10@BASE1> <49DD53CD.5020604@xtra.co.nz> Message-ID: <23E6E1D098F347438EE72F93EDF7B95E@BASE1> Bruce, The jitter measurements were made via the DTS PER function. This looks only at CH1 & the reference is the DTS internal 100MHz. OXCO. DTS-2075 jitter floor is < 3ps rms. The Fairchild & National parts have identical datasheets & spec SIGin sensitivity as 133mV @ Vcc=6V. The Philips version specs SIGin sensitivity as 35mV @ Vcc=6V. Fine idea to look at delta with 2ea 'AC04s driven from a common source; I'll try it in the next day. Unfortunately, I have no low jitter (<5ps) fast transition source to properly drive the parts. It's still worth a look. Pete From bruce.griffiths at xtra.co.nz Thu Apr 9 03:53:49 2009 From: bruce.griffiths at xtra.co.nz (Bruce Griffiths) Date: Thu, 09 Apr 2009 15:53:49 +1200 Subject: [time-nuts] femtosecond jitter anyone? In-Reply-To: <99D7BEE7-C033-42DE-A93D-03BE68E30FB4@twentylogten.com> References: <4CCD1C7E-6952-4FB4-8E1A-3B1A02618BC5@twentylogten.com> <49DD1288.4060103@rubidium.dyndns.org> <18D08480-6725-4251-BE78-145797B6DC31@twentylogten.com> <49DD21D5.6040109@rubidium.dyndns.org> <49DD3B28.4040704@xtra.co.nz> <91291C16-6AC8-4BA7-9ADE-B21AC566B024@twentylogten.com> <49DD4659.1070500@xtra.co.nz> <8DC9EC52-5D5A-43E9-A69E-A244076F0673@twentylogten.com> <49DD5BDD.8080300@xtra.co.nz> <99D7BEE7-C033-42DE-A93D-03BE68E30FB4@twentylogten.com> Message-ID: <49DD714D.2060608@xtra.co.nz> Chris The biggest problem with the OCXO is probably that it has a square wave output. With careful design it is possible to achieve a jitter of a few tens of femtosec for a logic level output from a limiter, but the OCXO designers are unlikely to have used such a limiter. To produce a sinewave output, I'd probably start with a low Q (5? to minimise phase shift tempco) tuned tank in the collector of a BJT driven by a logic leve output to get an approximate sine wave and follow it with an LC low pass filter with series tuned traps for the harmonics across the shunt elements of the LC filter and adjust the filter component values to achieve the desired response with the series tuned LC circuits shunt elements in place. Bruce Chris Mack / N1SKY wrote: > Thanks Bruce, > > The 12kHz is a figure for the DSP PLL and how they measure it > (starting at 12kHz usually for jitter over BW measurements).... I > haven't touched SONET since 1997 and this may be a SONET spec? > > I am using the simulator software for the LMK04000 series to see what > jitter is for the OXCO... -70dBc at 1 Hz, -100dBc 10Hz per the spec > sheet with all the other datapoints comes out to 1.3ps (1Hz to > 20MHz) of jitter RMS. > > I presume the -70dBc @ 1Hz is a phase noise spec for the OCXO? If so this is much higher than the state of the art for a sinewave output OCXO. > So the OCXO is decent without having to purchase a better one (and > the minimum quantity of 25 at $250 each +/-) for this initial > prototype; this seems to be semi-custom since 38.88MHz OCXOs are not > in stock at Digikey.... I plan on building a bunch of boxes over > time with this OCXO in it and finding disparate OCXOs on ebay was not > an option, especially if a new circuit board would need to be spun > every time. > > I just didn't know if I could get better with some filtering, and get > it into the femtosecond range... Currently this should be able to > maintain 22 bits of accuracy at 40kHz, which is pretty doggone good, > but was interested in pushing the envelope a little since I can go > (with an input alias filter) to 96kHz... Yes, there is some internal > jitter to the ADCs, some perhaps due to thermal, and the box is going > to be hot with a power budget already at 250W hence the thermal / > cooling and dither experiments and I was hoping to not be limited by > the clock performance. > > I still want to filter such as to distribute a sine... > > Cheers, > -chris > > > On Apr 8, 2009, at 10:22 PM, Bruce Griffiths wrote: > > >> Chris >> >> Now we have a more complete picture of what you are trying to do our >> suggestions will perhaps be a little more useful. >> >> Cleaning up a marginal OCXO is quite complex and probably more >> expensive than obtaining an OCXO or other reference that has lower >> noise. >> Is it in fact possible to just substitute a low noise non oven >> crystal >> oscillator for the 38.88MHz OCXO? >> With an appropriate oscillator design it should be possible to >> significantly reduce the phase noise of the 38.88MHz source at the >> expense of long term drift and aging. >> Achieving low jitter with such a source isn't difficult. >> >> The other question that arises is why is the OCXO phase noise so >> poor at >> frequency offsets less than 12kHz? >> >> Bruce >> >> Chris Mack / N1SKY wrote: >> >>> On Apr 8, 2009, at 8:50 PM, Bruce Griffiths wrote: >>> >>> >>>> Chris >>>> >>>> If you divide the output down to ~38MHz using a noiseless divider >>>> then >>>> the performance is 20dB or more worse than can be achieved with a >>>> good >>>> ~38MHz crystal oscillator. >>>> >>>> >>>> >>> Ah, this would work, but there is a synchronization aspect since >>> framing on AES/EBU is in the mix (pun intended?) and there are more >>> pieces of external equipment that all need to be synched (within >>> AES11 framing sync margins)... >>> >>> The box / design of interest has ADCs, DACs, and a 38.88MHz OCXO of >>> marginal performance coupled with the proposed DSP based PLLs >>> generating a local clock for the ADCs and DACs all on the same >>> circuit board in synch with external gear. >>> >>> This 38.88MHz is a DSP clock, essentially a microprocessor clock >>> (albeit a very nice microprocessor clock) where the DSP simulates a >>> PLL operating on an incoming clock source, and makes an output clock >>> of a different frequency, but synchronized to be within AES standards >>> for framing when considering the additional equipment scattered >>> around the room, made by different manufacturers, different inner >>> workings etc. >>> >>> The incoming clock source (master house clock) to this box / design >>> of interest is in another rack mount box external to this design on >>> the other side of the room and is anywhere from 44.1kHz up to a 10MHz >>> Rubidium (see also http://www.antelopeaudio.com). This clock source >>> on the other side of the room also drives other equipment to be in >>> synch for any framing on AES/EBU digital. >>> >>> The output of the DSP PLL in this box / design of interest is 11MHz >>> to 24MHz to feed the oversample clocks on the ADCs and DACs, >>> synchronized to the external 44.1kHz to 10MHz master house clock a la >>> the PLL and the rest of the equipment on the other side of the >>> room... >>> >>> The only caveat is that the 38.88MHz DSP microprocessor clock must be >>> low jitter in order to have the DSP PLL be low jitter.. The DSP PLL >>> does not really care about absolute frequency in the long term >>> (38.88MHz or 37MHz, doesn't matter), but it will rebroadcast short >>> term effects of jitter to clocks of the ADCs and DACs in the box of >>> interest. >>> >>> Sounds like maybe some LCs to filter out the additional harmonics and >>> maybe attempt to get close into the carrier eh? >>> >>> Thanks Magnus and Bruce for being a sounding wall.... >>> >>> Cheers, >>> -chris >>> >>> >>> _______________________________________________ >>> time-nuts mailing list -- time-nuts at febo.com >>> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/ >>> listinfo/time-nuts >>> and follow the instructions there. >>> >>> >>> >> _______________________________________________ >> time-nuts mailing list -- time-nuts at febo.com >> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/ >> time-nuts >> and follow the instructions there. >> > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > From tvb at LeapSecond.com Thu Apr 9 03:59:32 2009 From: tvb at LeapSecond.com (Tom Van Baak) Date: Wed, 8 Apr 2009 20:59:32 -0700 Subject: [time-nuts] femtosecond jitter anyone? References: <4CCD1C7E-6952-4FB4-8E1A-3B1A02618BC5@twentylogten.com> <49DD1288.4060103@rubidium.dyndns.org> <18D08480-6725-4251-BE78-145797B6DC31@twentylogten.com> <49DD21D5.6040109@rubidium.dyndns.org> <49DD3B28.4040704@xtra.co.nz><91291C16-6AC8-4BA7-9ADE-B21AC566B024@twentylogten.com><49DD4659.1070500@xtra.co.nz> <8DC9EC52-5D5A-43E9-A69E-A244076F0673@twentylogten.com> Message-ID: <2E4EACE099F748BBB079AFF8E5343614@pc52> > The incoming clock source (master house clock) to this box / design > of interest is in another rack mount box external to this design on > the other side of the room and is anywhere from 44.1kHz up to a 10MHz > Rubidium (see also http://www.antelopeaudio.com). This clock source > on the other side of the room also drives other equipment to be in > synch for any framing on AES/EBU digital. Can you comment more on the antelopeaudio box? I admit I know little about high-end audio, but it seems clear to me that the several companies that over the years have incorporated "atomic clocks" into their digital audio work might be misguided; confusing what is long-term accuracy with short-term stability. Sure, the word "atomic clock" sounds really cool. But high-quality OCXO typically have much better jitter and short-term stability than the telecom-style Rb oscillators that are used by audio companies. Or do I misunderstand? It would seem to me that very low jitter (or phase noise out to, say, 100 kHz, or ADEV from, say 10 us) is much more important for audio work than specifications about absolute frequency accuracy or long-term drift (such as what telecom Rb oscillators offer). Now if an audio company used surplus Sulzer, or FTS 1200, or Oscilloquartz BVA oscillators in their design, or even H-masers, well, that would make sense. But Rb? Something doesn't feel right about this. /tvb From bruce.griffiths at xtra.co.nz Thu Apr 9 04:02:13 2009 From: bruce.griffiths at xtra.co.nz (Bruce Griffiths) Date: Thu, 09 Apr 2009 16:02:13 +1200 Subject: [time-nuts] 74HC4046 receiver In-Reply-To: <23E6E1D098F347438EE72F93EDF7B95E@BASE1> References: <58CFF8BB33914D0AAA5E3B998E0F1B8D@NancysPC> <49DD420A.9010308@xtra.co.nz><8499DA729BD648078F010A5CC66F1C10@BASE1> <49DD53CD.5020604@xtra.co.nz> <23E6E1D098F347438EE72F93EDF7B95E@BASE1> Message-ID: <49DD7345.9020507@xtra.co.nz> Pete wrote: > Bruce, > > The jitter measurements were made via the DTS PER function. > This looks only at CH1 & the reference is the DTS internal > 100MHz. OXCO. DTS-2075 jitter floor is < 3ps rms. > > The Fairchild & National parts have identical datasheets & > spec SIGin sensitivity as 133mV @ Vcc=6V. The Philips > version specs SIGin sensitivity as 35mV @ Vcc=6V. > > Fine idea to look at delta with 2ea 'AC04s driven from a > common source; I'll try it in the next day. Unfortunately, I > have no low jitter (<5ps) fast transition source to properly > drive the parts. It's still worth a look. > > Pete > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > Pete When driving 2 AC04's from the same source and measuring the resultant differential jitter, the input source jitter is relatively unimportant particularly if the input signal risetime is transition times are sufficiently low ( < 5ns??). If all else fails and you can afford to wait long enough you could even use the PPS output from a GPS receiver. Driving both AC04's from a sinewave input and measuring the output differential jitter with different amplitude inputs allows one to estimate the noise from the measured output jitter and the known input signal slew rates. Adjusting the dc level at the AC04 input for a 50% output duty cycle is desirable to reduce the uncertainty in the estimates of the input signal slew rate at the switching threshold. Bruce From df6jb at ulrich-bangert.de Thu Apr 9 07:37:43 2009 From: df6jb at ulrich-bangert.de (Ulrich Bangert) Date: Thu, 9 Apr 2009 09:37:43 +0200 Subject: [time-nuts] Hadamard variance In-Reply-To: <1231b6a80904080559o7a4cf618r49276df9d7599820@mail.gmail.com> Message-ID: <40E2718386A642A5B19F87CACB573A13@athlon> Steve, > ocxo. I don't think I've seen this being used by anyone on > the list and wonder why? Easy explained: Because you will hardly find it in any free available software except mine which is written in the P language which in turn rules it out as a tool for you. 73s de Ulrich, DF6JB > -----Ursprungliche Nachricht----- > Von: time-nuts-bounces at febo.com > [mailto:time-nuts-bounces at febo.com] Im Auftrag von Steve Rooke > Gesendet: Mittwoch, 8. April 2009 15:00 > An: Discussion of precise time and frequency measurement > Betreff: [time-nuts] Hadamard variance > > > According to Wikipedia, this is insensitive to drift and so > seems like a better tool for measuring oscillators, like > ocxo. I don't think I've seen this being used by anyone on > the list and wonder why? > > 73, > Steve > -- > Steve Rooke - ZL3TUV & G8KVD & JAKDTTNW > Omnium finis imminet > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. From df6jb at ulrich-bangert.de Thu Apr 9 07:44:19 2009 From: df6jb at ulrich-bangert.de (Ulrich Bangert) Date: Thu, 9 Apr 2009 09:44:19 +0200 Subject: [time-nuts] Hadamard variance In-Reply-To: <40E2718386A642A5B19F87CACB573A13@athlon> Message-ID: <7CBA4D8B5D64494E8944F50D9771F669@athlon> Steve, ok, I correct myself. TVB of course has it too! Nice Eastern to everyone Ulrich > -----Ursprungliche Nachricht----- > Von: time-nuts-bounces at febo.com > [mailto:time-nuts-bounces at febo.com] Im Auftrag von Ulrich Bangert > Gesendet: Donnerstag, 9. April 2009 09:38 > An: 'Discussion of precise time and frequency measurement' > Betreff: Re: [time-nuts] Hadamard variance > > > Steve, > > > ocxo. I don't think I've seen this being used by anyone on > > the list and wonder why? > > Easy explained: Because you will hardly find it in any free > available software except mine which is written in the P > language which in turn rules it out as a tool for you. > > 73s de Ulrich, DF6JB > > > -----Ursprungliche Nachricht----- > > Von: time-nuts-bounces at febo.com > > [mailto:time-nuts-bounces at febo.com] Im Auftrag von Steve Rooke > > Gesendet: Mittwoch, 8. April 2009 15:00 > > An: Discussion of precise time and frequency measurement > > Betreff: [time-nuts] Hadamard variance > > > > > > According to Wikipedia, this is insensitive to drift and so > > seems like a better tool for measuring oscillators, like > > ocxo. I don't think I've seen this being used by anyone on > > the list and wonder why? > > > > 73, > > Steve > > -- > > Steve Rooke - ZL3TUV & G8KVD & JAKDTTNW > > Omnium finis imminet > > > > _______________________________________________ > > time-nuts mailing list -- time-nuts at febo.com > > To unsubscribe, go to > > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > > and follow the instructions there. > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. From magnus at rubidium.dyndns.org Thu Apr 9 07:59:59 2009 From: magnus at rubidium.dyndns.org (Magnus Danielson) Date: Thu, 09 Apr 2009 09:59:59 +0200 Subject: [time-nuts] femtosecond jitter anyone? In-Reply-To: <49DD4486.4000100@xtra.co.nz> References: <4CCD1C7E-6952-4FB4-8E1A-3B1A02618BC5@twentylogten.com> <49DD1288.4060103@rubidium.dyndns.org> <18D08480-6725-4251-BE78-145797B6DC31@twentylogten.com> <49DD21D5.6040109@rubidium.dyndns.org> <49DD2884.5040000@xtra.co.nz> <49DD2E1B.30203@rubidium.dyndns.org> <49DD30D1.5040704@xtra.co.nz> <49DD3E78.6050303@rubidium.dyndns.org> <49DD4486.4000100@xtra.co.nz> Message-ID: <49DDAAFF.5010608@rubidium.dyndns.org> Bruce Griffiths skrev: > Hej Magnus > > Magnus Danielson wrote: >> Hej Bruce, >> >> Bruce Griffiths skrev: >> >>> Magnus >>> >>> Magnus Danielson wrote: >>> >>>> Bruce Griffiths skrev: >>>> >>>> >>>>> Magnus >>>>> >>>>> For examples of the use of crystals in filters for cleaning up the >>>>> output of a crystal oscillator look at the circuit schematics for some >>>>> of the early crystal frequency standards. >>>>> Crystal filters were used quite liberally in some of these to clean up >>>>> the outputs. >>>>> >>>>> >>>> It's used in the step-up chain of the SR620 for instance. The SR620 has >>>> a 10 MHz oscillator (TCXO or as in my case a Wenzel OCXO) which is >>>> stepped up to 90 MHz using a fairly ordinary odd-order stepup and >>>> filtering chain. The ECL logic counter frontend use this as coarse >>>> counter frequency. The analog interpolators is a bit interesting in a >>>> few peculiarities but nothing really exciting. >>>> >>>> >>>> >>> Except if you believe that they actually use a Z5U capacitor (specified >>> in the parts list) for the interpolator TDC ramp capacitor. >>> If so, this would make for some interesting linearity and dielectric >>> absorption compensation software. >>> >> The caps listed as Z5U in the part list is not the timing caps. C701 and >> C711 both being 100 pF NP0 is the timing caps. If you look careful you >> will see it referenced. A 7 us sample pulse will charge a polypropylen >> cap with the buffered value for a sligthly later performed 12 bit ADC >> conversion. >> >> > > The online version of the manual specifies both of these caps as Z5U > (see attachment). > This may be an error in this version of the manual, or perhaps early > versions used Z5U?? > 100pF NP0 surface mount caps have been available for decades. My manual specifies NP0 for these. Maybe a hardware revision that occured between the manuals. >> Autocalibration will adjust the discharge current, measure the voltage >> bias and adjust the linearization data (65 bytes per channel). >> >> > Dielectric absorption and voltage dependence correction for Z5U caps > would be very challenging. I do not disagree with you on that, but we do not know how it actually works. I could lift the lid and try to identify what is really sitting in there. It could be that the online manual reflects the original mistake. >> Agree. Any temperature effects will occur with very flat slopes as the >> tuning is far away from the frequency of interest. >> >> A number of shunting LCRs can be used, infact a suitable crystal could >> be used to shunt into ground. >> >> > > Series tuned LC shunts are generally better as at resonance their ESR > can be much lower than that of a crystal, the signal level that they can > handle without damage is also much higher. > Although a single LC series tuned shunt wont provide large attenuation > one can always use one tuned to each significant harmonic per filter > section. It needs to be combined with a general low-pass filter of a few poles. Cheers, Magnus From bruce.griffiths at xtra.co.nz Thu Apr 9 09:42:21 2009 From: bruce.griffiths at xtra.co.nz (Bruce Griffiths) Date: Thu, 09 Apr 2009 21:42:21 +1200 Subject: [time-nuts] femtosecond jitter anyone? In-Reply-To: <49DDAAFF.5010608@rubidium.dyndns.org> References: <4CCD1C7E-6952-4FB4-8E1A-3B1A02618BC5@twentylogten.com> <49DD1288.4060103@rubidium.dyndns.org> <18D08480-6725-4251-BE78-145797B6DC31@twentylogten.com> <49DD21D5.6040109@rubidium.dyndns.org> <49DD2884.5040000@xtra.co.nz> <49DD2E1B.30203@rubidium.dyndns.org> <49DD30D1.5040704@xtra.co.nz> <49DD3E78.6050303@rubidium.dyndns.org> <49DD4486.4000100@xtra.co.nz> <49DDAAFF.5010608@rubidium.dyndns.org> Message-ID: <49DDC2FD.4080602@xtra.co.nz> Hej Magnus Magnus Danielson wrote: > Bruce Griffiths skrev: > >> Hej Magnus >> >> Magnus Danielson wrote: >> >>> Hej Bruce, >>> >>> Bruce Griffiths skrev: >>> >>> >>>> Magnus >>>> >>>> Magnus Danielson wrote: >>>> >>>> >>>>> Bruce Griffiths skrev: >>>>> >>>>> >>>>> >>>>>> Magnus >>>>>> >>>>>> For examples of the use of crystals in filters for cleaning up the >>>>>> output of a crystal oscillator look at the circuit schematics for some >>>>>> of the early crystal frequency standards. >>>>>> Crystal filters were used quite liberally in some of these to clean up >>>>>> the outputs. >>>>>> >>>>>> >>>>>> >>>>> It's used in the step-up chain of the SR620 for instance. The SR620 has >>>>> a 10 MHz oscillator (TCXO or as in my case a Wenzel OCXO) which is >>>>> stepped up to 90 MHz using a fairly ordinary odd-order stepup and >>>>> filtering chain. The ECL logic counter frontend use this as coarse >>>>> counter frequency. The analog interpolators is a bit interesting in a >>>>> few peculiarities but nothing really exciting. >>>>> >>>>> >>>>> >>>>> >>>> Except if you believe that they actually use a Z5U capacitor (specified >>>> in the parts list) for the interpolator TDC ramp capacitor. >>>> If so, this would make for some interesting linearity and dielectric >>>> absorption compensation software. >>>> >>>> >>> The caps listed as Z5U in the part list is not the timing caps. C701 and >>> C711 both being 100 pF NP0 is the timing caps. If you look careful you >>> will see it referenced. A 7 us sample pulse will charge a polypropylen >>> cap with the buffered value for a sligthly later performed 12 bit ADC >>> conversion. >>> >>> >>> >> The online version of the manual specifies both of these caps as Z5U >> (see attachment). >> This may be an error in this version of the manual, or perhaps early >> versions used Z5U?? >> 100pF NP0 surface mount caps have been available for decades. >> > > My manual specifies NP0 for these. Maybe a hardware revision that > occured between the manuals. > > >>> Autocalibration will adjust the discharge current, measure the voltage >>> bias and adjust the linearization data (65 bytes per channel). >>> >>> >>> >> Dielectric absorption and voltage dependence correction for Z5U caps >> would be very challenging. >> > > I do not disagree with you on that, but we do not know how it actually > works. I could lift the lid and try to identify what is really sitting > in there. > > Whether that is easy to do is another question. Some manufacturers (eg Philip's) had purple NP0 surface mount caps whereas X7R surface mount caps etc were light brown. > It could be that the online manual reflects the original mistake. > > >>> Agree. Any temperature effects will occur with very flat slopes as the >>> tuning is far away from the frequency of interest. >>> >>> A number of shunting LCRs can be used, infact a suitable crystal could >>> be used to shunt into ground. >>> >>> >>> >> Series tuned LC shunts are generally better as at resonance their ESR >> can be much lower than that of a crystal, the signal level that they can >> handle without damage is also much higher. >> Although a single LC series tuned shunt wont provide large attenuation >> one can always use one tuned to each significant harmonic per filter >> section. >> > > It needs to be combined with a general low-pass filter of a few poles. > > Placing the series tuned LC circuits in shunt with the LC low pass filter shunt capacitors would be convenient although some adjustment of the low pass element values would then be required. Filter design software would be useful for this, however real measurements and plus more realistic models for the inductors would be useful particularly is the series resonances of the inductors are located in the filter stop band. > Cheers, > Magnus > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > Bruce From jdb at lartmaker.nl Thu Apr 9 11:17:49 2009 From: jdb at lartmaker.nl (J.D. Bakker) Date: Thu, 9 Apr 2009 12:17:49 +0100 Subject: [time-nuts] femtosecond jitter anyone? In-Reply-To: <2E4EACE099F748BBB079AFF8E5343614@pc52> References: <4CCD1C7E-6952-4FB4-8E1A-3B1A02618BC5@twentylogten.com> <49DD1288.4060103@rubidium.dyndns.org> <18D08480-6725-4251-BE78-145797B6DC31@twentylogten.com> <49DD21D5.6040109@rubidium.dyndns.org> <49DD3B28.4040704@xtra.co.nz><91291C16-6AC8-4BA7-9ADE-B21AC566B024@twentyl ogten.com><49DD4659.1070500@xtra.co.nz> <8DC9EC52-5D5A-43E9-A69E-A244076F0673@twentylogten.com> <2E4EACE099F748BBB079AFF8E5343614@pc52> Message-ID: At 20:59 -0700 08-04-2009, Tom Van Baak wrote: > > The incoming clock source (master house clock) to this box / design >> of interest is in another rack mount box external to this design on >> the other side of the room and is anywhere from 44.1kHz up to a 10MHz >> Rubidium (see also http://www.antelopeaudio.com). This clock source >> on the other side of the room also drives other equipment to be in >> synch for any framing on AES/EBU digital. > >Can you comment more on the antelopeaudio box? [...] >Now if an audio company used surplus Sulzer, or FTS 1200, or >Oscilloquartz BVA oscillators in their design, or even H-masers, >well, that would make sense. But Rb? Something doesn't feel right >about this. The words 'snake oil' have been used in the audio community, for pretty much all the reasons you've mentioned. For everything but esoteric stuff like distributed phased microphone/speaker arrays the drift specs of a simple TCXO are sufficient. JDB. -- LART. 250 MIPS under one Watt. Free hardware design files. http://www.lartmaker.nl/ From jdb at lartmaker.nl Thu Apr 9 11:46:53 2009 From: jdb at lartmaker.nl (J.D. Bakker) Date: Thu, 9 Apr 2009 12:46:53 +0100 Subject: [time-nuts] femtosecond jitter anyone? In-Reply-To: <8DC9EC52-5D5A-43E9-A69E-A244076F0673@twentylogten.com> References: <4CCD1C7E-6952-4FB4-8E1A-3B1A02618BC5@twentylogten.com> <49DD1288.4060103@rubidium.dyndns.org> <18D08480-6725-4251-BE78-145797B6DC31@twentylogten.com> <49DD21D5.6040109@rubidium.dyndns.org> <49DD3B28.4040704@xtra.co.nz> <91291C16-6AC8-4BA7-9ADE-B21AC566B024@twentylogten.com> <49DD4659.1070500@xtra.co.nz> <8DC9EC52-5D5A-43E9-A69E-A244076F0673@twentylogten.com> Message-ID: At 22:03 -0400 08-04-2009, Chris Mack / N1SKY wrote: >On Apr 8, 2009, at 8:50 PM, Bruce Griffiths wrote: >>> >> Chris >> >> If you divide the output down to ~38MHz using a noiseless divider then >> the performance is 20dB or more worse than can be achieved with a good >> ~38MHz crystal oscillator. >> > >Ah, this would work, but there is a synchronization aspect since >framing on AES/EBU is in the mix (pun intended?) and there are more >pieces of external equipment that all need to be synched (within >AES11 framing sync margins)... From a jitter POV the AES11 profiles are insanely wide, and they make little sense if you're not using digital tape or other media which take their time to slew to their final speed. Look at the recent TI Asynchronous Sample Rate Converters (ASRCs); their rate estimators have a bandwidth much tighter than needed to track a worst-case AES11 signal. >This 38.88MHz is a DSP clock, essentially a microprocessor clock >(albeit a very nice microprocessor clock) where the DSP simulates a >PLL operating on an incoming clock source, and makes an output clock >of a different frequency, [...] > >The output of the DSP PLL in this box / design of interest is 11MHz >to 24MHz to feed the oversample clocks on the ADCs and DACs, >synchronized to the external 44.1kHz to 10MHz master house clock a la >the PLL and the rest of the equipment on the other side of the room... By 'DSP PLL', do you imply that the DSP controls a DDS? If so, is the DDS a separate chip or do you use a DAC hooked to your DSP? For best jitter performance in an audio system you may want to consider getting a free-running low noise XO with a frequency that is NOT a multiple of your sampling rate(s), have it drive your ADC/DAC converter directly and use an ASRC (either integrated or, preferably, FPGA/DSP) to go to your target output rate. As for fs jitter: I've yet to see a converter chip with differential clock inputs, and for a single ended clock input I expect that the total input-referred noise due to ground bounce &co is in the order of a ps, if not worse. (The story changes a bit for discrete converter designs, as those can have diff clock inputs with specified noise performance). JDB. [all things being equal, voltage pullability == lower Q == more phase noise. And that's even before you consider control port noise injection...] -- LART. 250 MIPS under one Watt. Free hardware design files. http://www.lartmaker.nl/ From sar10538 at gmail.com Thu Apr 9 11:29:43 2009 From: sar10538 at gmail.com (Steve Rooke) Date: Thu, 9 Apr 2009 23:29:43 +1200 Subject: [time-nuts] Hadamard variance In-Reply-To: <951FB64B18654ECE97BFC40BBDC1D2B3@pc52> References: <1231b6a80904080559o7a4cf618r49276df9d7599820@mail.gmail.com> <951FB64B18654ECE97BFC40BBDC1D2B3@pc52> Message-ID: <1231b6a80904090429i165b6627sb83ee88a25069e1b@mail.gmail.com> Hi Tom, 2009/4/9 Tom Van Baak : > I use it sometimes when I need to. But note that in most cases > you do NOT want to ignore drift. If you measure an OCXO for > the purpose of using it in a clock or appliance or radio or test > equipment you really do want to know if it has drift or not. ADEV > will show this, while HDEV will not. So you have to be careful > about using statistics that deliberately and quietly ignore effects > that may be important to your application. Indeed, I was thinking that HDEV would be a good tool to characterise free running OCXOs with it's insensitivity to drift but, of course, I would use ADEV to measure the performance of a GPS locked system or one running in holdover mode. > But before you run off and use HDEV for everything note that > the other practice that is far more common -- simply remove > frequency drift from the raw data before computing an ADEV > on the residuals. If you look at plots in professional journals you > will often find comments to the effect that phase, frequency, or > drift offsets have been added or removed prior to making said > phase, frequency, or stability plots. I had no intent to use HDEV exclusively, it seems like a useful tool to analyse free-running oscillators to measure the affects of noise while screening out drift (which we have some means of handling in holdover circuits). As a selection tool it seemed quite useful and I was asking if others felt the same way. Agreed, it is possible to factor out drift by pre-processing the data and then using just ADEV to compare all aspects of any open or closed system. > Here, to see the difference that HDEV makes (or not) see: > http://www.leapsecond.com/pages/hdev It seems to have an effect removing some of what must be drift with the OCXO plot but adds nothing to the PPS one. Do I take it that the OCXO was free-running and the PPS was locked to GPS, as this would account for the differences? > The command line program that I use (ADEV3) these days: > Tool for ADEV, MDEV, HDEV: > http://www.leapsecond.com/tools/adev3.exe > > Source code (compiles in windows, bsd, or linux) > http://www.leapsecond.com/tools/adev3.c Thanks for the pointers, I'll have a look at this instead. 73, Steve -- Steve Rooke - ZL3TUV & G8KVD & JAKDTTNW Omnium finis imminet From sar10538 at gmail.com Thu Apr 9 11:36:25 2009 From: sar10538 at gmail.com (Steve Rooke) Date: Thu, 9 Apr 2009 23:36:25 +1200 Subject: [time-nuts] Hadamard variance In-Reply-To: <40E2718386A642A5B19F87CACB573A13@athlon> References: <1231b6a80904080559o7a4cf618r49276df9d7599820@mail.gmail.com> <40E2718386A642A5B19F87CACB573A13@athlon> Message-ID: <1231b6a80904090436k7051bf40t810a6cb8f91650cc@mail.gmail.com> Ulrich, 2009/4/9 Ulrich Bangert : > Steve, > >> ocxo. I don't think I've seen this being used by anyone on >> the list and wonder why? > > Easy explained: Because you will hardly find it in any free available > software except mine which is written in the P language which in turn rules > it out as a tool for you. Woops, I'd better dust off my P skills then and swallow some humble pie to boot. You did take what I said about P before with a whole handful of salt I hope. If it was down to me I'd probably write everything in Forth or PL1. 73, Steve - ZL3TUV & G8KVD > 73s de Ulrich, DF6JB > >> -----Ursprungliche Nachricht----- >> Von: time-nuts-bounces at febo.com >> [mailto:time-nuts-bounces at febo.com] Im Auftrag von Steve Rooke >> Gesendet: Mittwoch, 8. April 2009 15:00 >> An: Discussion of precise time and frequency measurement >> Betreff: [time-nuts] Hadamard variance >> >> >> According to Wikipedia, this is insensitive to drift and so >> seems like a better tool for measuring oscillators, like >> ocxo. I don't think I've seen this being used by anyone on >> the list and wonder why? >> >> 73, >> Steve >> -- >> Steve Rooke - ZL3TUV & G8KVD & JAKDTTNW >> Omnium finis imminet >> >> _______________________________________________ >> time-nuts mailing list -- time-nuts at febo.com >> To unsubscribe, go to >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > -- Steve Rooke - ZL3TUV & G8KVD & JAKDTTNW Omnium finis imminet From sar10538 at gmail.com Thu Apr 9 11:37:32 2009 From: sar10538 at gmail.com (Steve Rooke) Date: Thu, 9 Apr 2009 23:37:32 +1200 Subject: [time-nuts] Hadamard variance In-Reply-To: <7CBA4D8B5D64494E8944F50D9771F669@athlon> References: <40E2718386A642A5B19F87CACB573A13@athlon> <7CBA4D8B5D64494E8944F50D9771F669@athlon> Message-ID: <1231b6a80904090437k37abf3cld10a87a57815b8bd@mail.gmail.com> 2009/4/9 Ulrich Bangert : > Steve, > > ok, I correct myself. TVB of course has it too! Sounds like it is catching :-) 73, Steve - ZL3TUV & G8KVD > Nice Eastern to everyone > Ulrich > >> -----Ursprungliche Nachricht----- >> Von: time-nuts-bounces at febo.com >> [mailto:time-nuts-bounces at febo.com] Im Auftrag von Ulrich Bangert >> Gesendet: Donnerstag, 9. April 2009 09:38 >> An: 'Discussion of precise time and frequency measurement' >> Betreff: Re: [time-nuts] Hadamard variance >> >> >> Steve, >> >> > ocxo. I don't think I've seen this being used by anyone on >> > the list and wonder why? >> >> Easy explained: Because you will hardly find it in any free >> available software except mine which is written in the P >> language which in turn rules it out as a tool for you. >> >> 73s de Ulrich, DF6JB >> >> > -----Ursprungliche Nachricht----- >> > Von: time-nuts-bounces at febo.com >> > [mailto:time-nuts-bounces at febo.com] Im Auftrag von Steve Rooke >> > Gesendet: Mittwoch, 8. April 2009 15:00 >> > An: Discussion of precise time and frequency measurement >> > Betreff: [time-nuts] Hadamard variance >> > >> > >> > According to Wikipedia, this is insensitive to drift and so >> > seems like a better tool for measuring oscillators, like >> > ocxo. I don't think I've seen this being used by anyone on >> > the list and wonder why? >> > >> > 73, >> > Steve >> > -- >> > Steve Rooke - ZL3TUV & G8KVD & JAKDTTNW >> > Omnium finis imminet >> > >> > _______________________________________________ >> > time-nuts mailing list -- time-nuts at febo.com >> > To unsubscribe, go to >> > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> > and follow the instructions there. >> >> >> _______________________________________________ >> time-nuts mailing list -- time-nuts at febo.com >> To unsubscribe, go to >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > -- Steve Rooke - ZL3TUV & G8KVD & JAKDTTNW Omnium finis imminet From sar10538 at gmail.com Thu Apr 9 11:51:47 2009 From: sar10538 at gmail.com (Steve Rooke) Date: Thu, 9 Apr 2009 23:51:47 +1200 Subject: [time-nuts] Characterising frequency standards In-Reply-To: <49DCA68A.4040105@xtra.co.nz> References: <1231b6a80904070509m5b8bb638gbc088500444254c3@mail.gmail.com> <49DC91B9.6090004@xtra.co.nz> <1231b6a80904080504n4a3a22dcr247fae5df39ed840@mail.gmail.com> <49DC984A.2010509@xtra.co.nz> <1231b6a80904080537r2944092bsbc9e31ba0de7f6c8@mail.gmail.com> <49DC9EB6.1040806@xtra.co.nz> <1231b6a80904080602w58ea54c4tdb56bc160e56b4ae@mail.gmail.com> <49DCA243.4020906@xtra.co.nz> <1231b6a80904080619y60199d73h244598262c1de1b9@mail.gmail.com> <49DCA68A.4040105@xtra.co.nz> Message-ID: <1231b6a80904090451qb9a9d85r91fa1d7e3b9364c2@mail.gmail.com> Bruce, 2009/4/9 Bruce Griffiths : >> Doesn't that imply that the data point should correspond to the whole >> sampling period and not just half of it? >> >> > The total measurement time is only deceased by 1 sec at the most if you > delete every second line. > The resampled data now has a sampling interval of 2 sec for the entire > measurment time. > > The original data samples are phase differences measured on the second > every second. > The resampled data are phase differences measured every 2 seconds on the > corresponding second transition. OK, I'm ready to be shot down on this but from what I can see right now the measurement period of 2 sec should be maintained to satisfy the measurement of drift which would otherwise be incorrectly interpreted if I processed 400000 sec of data as only 200000 sec. I can see that noise on the data can be broken down into two major groups, drift and what I would really see as noise, IE PN, flicker, random, etc. I guess I have been ignoring the whole drift component with my missing data used for the ADEV plots. The point to me though is that, even with the reduced data, an ADEV plot should be able to characterise 'noise' for the actual sampling duration of the data, IE. 1 sec. What would obviously be incorrect is the affects of drift which should logically show up as being twice as great. Maybe my idea of using the 1 sec sampling period would work out better with HDEV. 73, Steve -- Steve Rooke - ZL3TUV & G8KVD & JAKDTTNW Omnium finis imminet From sar10538 at gmail.com Thu Apr 9 12:00:13 2009 From: sar10538 at gmail.com (Steve Rooke) Date: Fri, 10 Apr 2009 00:00:13 +1200 Subject: [time-nuts] Characterising frequency standards In-Reply-To: <7911976D35924C91A61F679126F77F9E@pc52> References: <1231b6a80904070509m5b8bb638gbc088500444254c3@mail.gmail.com> <1231b6a80904080441p7a747a3h1f73bf8a2df30350@mail.gmail.com> <49DC91B9.6090004@xtra.co.nz> <1231b6a80904080504n4a3a22dcr247fae5df39ed840@mail.gmail.com> <7911976D35924C91A61F679126F77F9E@pc52> Message-ID: <1231b6a80904090500i1cd90f80w7983e03b4978cfa8@mail.gmail.com> Tom, 2009/4/9 Tom Van Baak : > The first argument to the adev1 program is the sampling interval t0. > The program doesn't know how far apart the input file samples are > taken so it is your job to specify this. The default is 1 second. > > If you have data taken one second apart then t0 = 1. > If you have data taken two seconds apart then t0 = 2. > If you have data taken 60 seconds apart then t0 = 60, etc. > > If, as in your case, you take raw one second data and remove > every other sample (a perfectly valid thing to do), then t0 = 2. > > Make sense now? It's still "continuous data" in the sense that all > measurements are a fixed interval apart. But in any ADEV > calculation you have to specify the raw data interval. I think the penny has dropped now, thanks. It's interesting that the ADEV calculation still works even without continuous data as all the reading I have done has led me to belive this was sacrosanct. What I now believe is that it's possible to measure oscillator performance with less than optimal test gear. This will enable me to see the effects of any experiments I make in the future. If you can't measure it, how can you know that what your doing is good or bad. 73, Steve -- Steve Rooke - ZL3TUV & G8KVD & JAKDTTNW Omnium finis imminet From jra at febo.com Thu Apr 9 12:08:05 2009 From: jra at febo.com (John Ackermann N8UR) Date: Thu, 09 Apr 2009 08:08:05 -0400 Subject: [time-nuts] 74HC4046 receiver In-Reply-To: <23E6E1D098F347438EE72F93EDF7B95E@BASE1> References: <58CFF8BB33914D0AAA5E3B998E0F1B8D@NancysPC> <49DD420A.9010308@xtra.co.nz><8499DA729BD648078F010A5CC66F1C10@BASE1> <49DD53CD.5020604@xtra.co.nz> <23E6E1D098F347438EE72F93EDF7B95E@BASE1> Message-ID: <49DDE525.6060703@febo.com> After my experiments last weekend (which will continue...) I am contemplating making up a simple circuit board with a Wenzel input circuit driving a 74AC04 output, to provide a fast transition time source that could be fed by a sine wave oscillator. I suspect the '04 output rise time is about as fast as anything that we'd reasonably homebrew, though I'd be happy to be proven wrong (Bruce???). I'm not considering turning this into a TAPR project, but I'll probably end up with more PC boards than I need, so if anyone is interested in getting a board (and sharing in the board cost), let me know. John ---- Pete wrote: > Bruce, > > The jitter measurements were made via the DTS PER function. > This looks only at CH1 & the reference is the DTS internal > 100MHz. OXCO. DTS-2075 jitter floor is < 3ps rms. > > The Fairchild & National parts have identical datasheets & > spec SIGin sensitivity as 133mV @ Vcc=6V. The Philips > version specs SIGin sensitivity as 35mV @ Vcc=6V. > > Fine idea to look at delta with 2ea 'AC04s driven from a > common source; I'll try it in the next day. Unfortunately, I > have no low jitter (<5ps) fast transition source to properly > drive the parts. It's still worth a look. > > Pete From bruce.griffiths at xtra.co.nz Thu Apr 9 13:47:59 2009 From: bruce.griffiths at xtra.co.nz (Bruce Griffiths) Date: Fri, 10 Apr 2009 01:47:59 +1200 Subject: [time-nuts] 74HC4046 receiver In-Reply-To: <49DDE525.6060703@febo.com> References: <58CFF8BB33914D0AAA5E3B998E0F1B8D@NancysPC> <49DD420A.9010308@xtra.co.nz><8499DA729BD648078F010A5CC66F1C10@BASE1> <49DD53CD.5020604@xtra.co.nz> <23E6E1D098F347438EE72F93EDF7B95E@BASE1> <49DDE525.6060703@febo.com> Message-ID: <49DDFC8F.6090807@xtra.co.nz> John How short a transition time do you want? 100ps or less is relatively easy with off the shelf parts as long as ECL or CML are OK. If you want a higher voltage swing can probably do 200ps or so with only a few parts. Tunnel diodes (they are still available) will easily achieve transition times of a few tens of picosec albeit with a relatively low swing. SRDs can be used to sharpen up slow (1ns or more) transitions. One can always use a high current longtailed pair switching 100mA or more into a 50 ohm load to keep the power supply transients within reasonable bounds whilst achieving fast transition times. This is the sort of output stage albeit with some series feedback in the emitters (or III-V FET sources) used in most hp pulse generators with fast transition times. If you want to achieve very low jitter then cascading a couple of limiter stages (longtailed pairs) with low pass filtered outputs which in turn drive the output stage (AC04 or whatever) will be better than an arbitrary Wenzel circuit feeding an AC04 at least for lower frequency sinewaves (< 40MHz or so). Just select the filter capacitor values for minimum jitter for the input frequency of interest. Characterisation of the jitter of an AC04 when driven with different amplitude sinewaves at the same frequency will be useful in optimising such designs. Bruce John Ackermann N8UR wrote: > After my experiments last weekend (which will continue...) I am > contemplating making up a simple circuit board with a Wenzel input > circuit driving a 74AC04 output, to provide a fast transition time > source that could be fed by a sine wave oscillator. I suspect the '04 > output rise time is about as fast as anything that we'd reasonably > homebrew, though I'd be happy to be proven wrong (Bruce???). > > I'm not considering turning this into a TAPR project, but I'll probably > end up with more PC boards than I need, so if anyone is interested in > getting a board (and sharing in the board cost), let me know. > > John > ---- > > Pete wrote: > >> Bruce, >> >> The jitter measurements were made via the DTS PER function. >> This looks only at CH1 & the reference is the DTS internal >> 100MHz. OXCO. DTS-2075 jitter floor is < 3ps rms. >> >> The Fairchild & National parts have identical datasheets & >> spec SIGin sensitivity as 133mV @ Vcc=6V. The Philips >> version specs SIGin sensitivity as 35mV @ Vcc=6V. >> >> Fine idea to look at delta with 2ea 'AC04s driven from a >> common source; I'll try it in the next day. Unfortunately, I >> have no low jitter (<5ps) fast transition source to properly >> drive the parts. It's still worth a look. >> >> Pete >> > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > From bruce.griffiths at xtra.co.nz Thu Apr 9 13:51:41 2009 From: bruce.griffiths at xtra.co.nz (Bruce Griffiths) Date: Fri, 10 Apr 2009 01:51:41 +1200 Subject: [time-nuts] Hadamard variance In-Reply-To: <1231b6a80904090429i165b6627sb83ee88a25069e1b@mail.gmail.com> References: <1231b6a80904080559o7a4cf618r49276df9d7599820@mail.gmail.com> <951FB64B18654ECE97BFC40BBDC1D2B3@pc52> <1231b6a80904090429i165b6627sb83ee88a25069e1b@mail.gmail.com> Message-ID: <49DDFD6D.3040207@xtra.co.nz> Steve Just dont get too carried away. Remember that the Hadamard deviation is only insensitive to linear frequency drift. If the drift is quadratic for example then it will affect the Hadamard deviation. Bruce Steve Rooke wrote: > Hi Tom, > > 2009/4/9 Tom Van Baak : > >> I use it sometimes when I need to. But note that in most cases >> you do NOT want to ignore drift. If you measure an OCXO for >> the purpose of using it in a clock or appliance or radio or test >> equipment you really do want to know if it has drift or not. ADEV >> will show this, while HDEV will not. So you have to be careful >> about using statistics that deliberately and quietly ignore effects >> that may be important to your application. >> > > Indeed, I was thinking that HDEV would be a good tool to characterise > free running OCXOs with it's insensitivity to drift but, of course, I > would use ADEV to measure the performance of a GPS locked system or > one running in holdover mode. > > >> But before you run off and use HDEV for everything note that >> the other practice that is far more common -- simply remove >> frequency drift from the raw data before computing an ADEV >> on the residuals. If you look at plots in professional journals you >> will often find comments to the effect that phase, frequency, or >> drift offsets have been added or removed prior to making said >> phase, frequency, or stability plots. >> > > I had no intent to use HDEV exclusively, it seems like a useful tool > to analyse free-running oscillators to measure the affects of noise > while screening out drift (which we have some means of handling in > holdover circuits). As a selection tool it seemed quite useful and I > was asking if others felt the same way. > > Agreed, it is possible to factor out drift by pre-processing the data > and then using just ADEV to compare all aspects of any open or closed > system. > > >> Here, to see the difference that HDEV makes (or not) see: >> http://www.leapsecond.com/pages/hdev >> > > It seems to have an effect removing some of what must be drift with > the OCXO plot but adds nothing to the PPS one. Do I take it that the > OCXO was free-running and the PPS was locked to GPS, as this would > account for the differences? > > >> The command line program that I use (ADEV3) these days: >> Tool for ADEV, MDEV, HDEV: >> http://www.leapsecond.com/tools/adev3.exe >> >> Source code (compiles in windows, bsd, or linux) >> http://www.leapsecond.com/tools/adev3.c >> > > Thanks for the pointers, I'll have a look at this instead. > > 73, > Steve > From sometimesyoufeellikeanut at twentylogten.com Thu Apr 9 13:59:59 2009 From: sometimesyoufeellikeanut at twentylogten.com (Chris Mack / N1SKY) Date: Thu, 9 Apr 2009 09:59:59 -0400 Subject: [time-nuts] femtosecond jitter anyone? In-Reply-To: <2E4EACE099F748BBB079AFF8E5343614@pc52> References: <4CCD1C7E-6952-4FB4-8E1A-3B1A02618BC5@twentylogten.com> <49DD1288.4060103@rubidium.dyndns.org> <18D08480-6725-4251-BE78-145797B6DC31@twentylogten.com> <49DD21D5.6040109@rubidium.dyndns.org> <49DD3B28.4040704@xtra.co.nz><91291C16-6AC8-4BA7-9ADE-B21AC566B024@twentylogten.com><49DD4659.1070500@xtra.co.nz> <8DC9EC52-5D5A-43E9-A69E-A244076F0673@twentylogten.com> <2E4EACE099F748BBB079AFF8E5343614@pc52> Message-ID: <0C063B33-62D5-4110-8295-E9EA9E822D3F@twentylogten.com> On Apr 8, 2009, at 11:59 PM, Tom Van Baak wrote: >> The incoming clock source (master house clock) to this box / design >> of interest is in another rack mount box external to this design on >> the other side of the room and is anywhere from 44.1kHz up to a 10MHz >> Rubidium (see also http://www.antelopeaudio.com). This clock source >> on the other side of the room also drives other equipment to be in >> synch for any framing on AES/EBU digital. > > Can you comment more on the antelopeaudio box? I admit I know > little about high-end audio, but it seems clear to me that the several > companies that over the years have incorporated "atomic clocks" > into their digital audio work might be misguided; confusing what is > long-term accuracy with short-term stability. > > Sure, the word "atomic clock" sounds really cool. But high-quality > OCXO typically have much better jitter and short-term stability than > the telecom-style Rb oscillators that are used by audio companies. > Or do I misunderstand? > > It would seem to me that very low jitter (or phase noise out to, say, > 100 kHz, or ADEV from, say 10 us) is much more important for > audio work than specifications about absolute frequency accuracy > or long-term drift (such as what telecom Rb oscillators offer). > > Now if an audio company used surplus Sulzer, or FTS 1200, or > Oscilloquartz BVA oscillators in their design, or even H-masers, > well, that would make sense. But Rb? Something doesn't feel right > about this. Hey Tom, For audiophile or consumer in the home, a Rb clock may be overkill especially if the price tag is huge... But the market will bear what the market will bear and there is already a user base. To note, the jitter does not matter as much in the transport chain up until the converter. Once at the converter jitter is paramount, but the jitter in the thermally hot chip will probably trump everything else. This is especially true for 16-bit 44.1kHz at the consumer level. However, this is for mastering, not audiophile or consumer applications. Mastering is the final creative and scientific step before an album is manufactured, after the recording studio phase is complete; every commercially released album is mastered (mastering does not use that huge mixing desk / console like you see on TV; the less equipment in front of the mastering engineer, the better, because of acoustic comb filtering bouncing off the gear). Mastering also comprises the possibility of archival. Imagine this: if you were the mastering engineer for Elvis 50 years ago, and if today's digital technology was available back then, would you want to archive the King's record inside Iron Mountain on MP3? Not really, you would want the most resolution possible for the re- release onto 32-bit 384kHz whiz-bang chip media in the future. And cumulative error for successive re-releases over the decade for frequency drift and re-archival is maybe another concern. For example, I am currently using a Rosendahl Nanoclocks (http:// www.rosendahl-studiotechnik.com/nanoclocks.html) for my house master word clock and a $6k Eventide Orville for processing of audio. The Eventide used to measure the Nanoclocks at 88200 Hz... now it measures 88201 Hz 4 years later... something drifted.... The Rosendahl uses normal ambient crystals (although they have trimmer caps) and use 74ACT00 logic to drive the distribution outputs. The Eventide, I assume uses normal ambient crystals too for the myriad of DSPs in it.... The Antelope Rb unit is $6k which is a little overboard in price considering one can get a Rb on ebay in the $200 range (age of the Rb unknown perhaps). However, Antelope also has OCXOs that discipline to the Rb for the long term (although they fail to disclose the useful life of a Rb clock and have brain-dead specs for phase noise; only one data point at 10kHz -140dBc)... caveat emptor in 20 years (hmmm let's see, $6k amortized over 20 years = $300/year)? The Antelope Rb and OCXO are all 75 ohm BNC. The normal mode of operation in a recording studio or mastering suite is to synchronize gear together with one master house "word" clock usually 44.1kHz, 48kHz, 88.2kHz or 96kHz (I usually use 88.2kHz; twice the CD sampling rate, then Sample Rate Convert (-140dB to -170dB dynamic range) before PQ coding a red book standard audio CD at a dithered 16-bit, 44.1kHz). This is all on 75 ohm BNC usually or AES11 "digital black" on higher frequencies characteristic of AES framing on 110 ohm differential. These house "word" clocks may have jitter in the nanosecond range to maybe 10ps or so... The math for full 24-bit accuracy for 88.2kHz sampling rate (44.1kHz BW) shows 0.43 ps of timing uncertainty. Even if it were 20 bits of accuracy, 6ps would be the limit... The converters I am using are 124 dB and 132 dB of dynamic range for ADC and DAC respectively. There could be some dynamic range gains with the proposed modifications to the standard application circuit for these converters, thusly a better clock desired or local clock cleaning of the house word clock wether it be word clock from crystals or Rb. I believe Mr. Lavry for his 127dB ADC uses an OCXO which helps achieve the specs. http://www.lavryengineering.com/ productspage_pro_ad122_96mk.html Hope this paints the landscape in the studio world (different from the consumer / audiophile at home).. We use more bits and higher sampling rates in the studio to give better results in aliasing filters during processing and the like. then SRC and dither to the final lower resolution product, keeping an eye for the higher resolution formats of the future. Cheers, -chris From swithrow at idcomm.com Thu Apr 9 14:04:26 2009 From: swithrow at idcomm.com (Skip Withrow) Date: Thu, 09 Apr 2009 08:04:26 -0600 Subject: [time-nuts] NIST Time & Frequency Seminar Message-ID: <20090409140426.8A241CC005E6@mailhost.idcomm.com> Hello Time Nuts, I recently became aware of the NIST Time & Frequency Seminar coming up shortly and looked it up as it sounded interesting (to a time-nut) and is almost in my back yard (well, at least commuting distance). You can check out the web page at http://tf.nist.gov/timefreq/seminars/T&Foverview.html. It all sounds very cool, UNTIL YOU CHECK OUT THE PRICE! Sure, I could see $300-$400 (which would still be pretty rich for my budget), but $1900? Obviously our tax dollars are not subsidizing this function. If anyone knows how to procure a discounted registration I would be most interested in hearing from you. Regards, Skip Withrow From jim77742 at gmail.com Thu Apr 9 14:15:26 2009 From: jim77742 at gmail.com (Jim Palfreyman) Date: Fri, 10 Apr 2009 00:15:26 +1000 Subject: [time-nuts] NIST Time & Frequency Seminar In-Reply-To: <20090409140426.8A241CC005E6@mailhost.idcomm.com> References: <20090409140426.8A241CC005E6@mailhost.idcomm.com> Message-ID: Damn I would love to go to that. But the US$1900 would be cheap bikkies compared to my airfare and accommodation! 2009/4/10 Skip Withrow > > Hello Time Nuts, > > I recently became aware of the NIST Time & Frequency Seminar coming up > shortly and looked it up as it sounded interesting (to a time-nut) and is > almost in my back yard (well, at least commuting distance). You can check > out the web page at http://tf.nist.gov/timefreq/seminars/T&Foverview.html. > > It all sounds very cool, UNTIL YOU CHECK OUT THE PRICE! Sure, I could see > $300-$400 (which would still be pretty rich for my budget), but $1900? > Obviously our tax dollars are not subsidizing this function. > > If anyone knows how to procure a discounted registration I would be most > interested in hearing from you. > > Regards, > Skip Withrow > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > From tvb at LeapSecond.com Thu Apr 9 14:28:50 2009 From: tvb at LeapSecond.com (Tom Van Baak) Date: Thu, 9 Apr 2009 07:28:50 -0700 Subject: [time-nuts] Hadamard variance References: <1231b6a80904080559o7a4cf618r49276df9d7599820@mail.gmail.com> <951FB64B18654ECE97BFC40BBDC1D2B3@pc52><1231b6a80904090429i165b6627sb83ee88a25069e1b@mail.gmail.com> <49DDFD6D.3040207@xtra.co.nz> Message-ID: > Steve > > Just dont get too carried away. > Remember that the Hadamard deviation is only insensitive to linear > frequency drift. > If the drift is quadratic for example then it will affect the Hadamard > deviation. > > Bruce Correct. This is another reason why the practice of removing systematic drift from raw data first and then computing ADEV on the residuals is quite useful. It allows you to separate the task of modeling systematic effects from the calculation of stability (ADEV) of the residuals. For example, you may suspect ahead of time, or you may find through analysis, that your DUT is following a slow logarithmic drift trend rather than just linear drift. Either way, you can remove the systematic effect to get to a closer measure of the intrinsic stability limits of the DUT. This is common with OCXO which have aged, say more than a few days, but less than a few months. It's pretty cool to see very linear drift rates each day, but to also notice that the rate itself slowly decreases week by week. As another example, you may find a strong correlation between temperature and frequency. You could plot ADEV of the raw data, and then plot ADEV of the temperature compensated residuals and observe the difference in the plots. /tvb From RLutwak at Comcast.net Thu Apr 9 14:35:18 2009 From: RLutwak at Comcast.net (Robert Lutwak) Date: Thu, 09 Apr 2009 10:35:18 -0400 Subject: [time-nuts] NIST Time & Frequency Seminar In-Reply-To: <20090409140426.8A241CC005E6@mailhost.idcomm.com> References: <20090409140426.8A241CC005E6@mailhost.idcomm.com> Message-ID: FYI (and FWIW), I think very highly of the NIST T&F seminar. You can't get this education in school and it's an invaluable resource for anyone wanting to get into the precision T&F business. Nowhere else can you have all of these topics organized and presented by the experts in the field. We routinely send all of our new engineers. To your point, though, I'm not aware of any discounts for participants. -RL ---------------- Robert Lutwak, Senior Scientist Symmetricom - Technology Realization Center 34 Tozer Rd. Beverly, MA 01915 (978) 232-1461 (desk) RLutwak at Symmetricom.com (Business) (339) 927-7896 (mobile) Lutwak at Alum.MIT.edu (Personal) At 10:04 AM 4/9/2009, you wrote: >Hello Time Nuts, > >I recently became aware of the NIST Time & Frequency Seminar coming up >shortly and looked it up as it sounded interesting (to a time-nut) and is >almost in my back yard (well, at least commuting distance). You can check >out the web page at http://tf.nist.gov/timefreq/seminars/T&Foverview.html. > >It all sounds very cool, UNTIL YOU CHECK OUT THE PRICE! Sure, I could see >$300-$400 (which would still be pretty rich for my budget), but $1900? >Obviously our tax dollars are not subsidizing this function. > >If anyone knows how to procure a discounted registration I would be most >interested in hearing from you. > >Regards, >Skip Withrow > >_______________________________________________ >time-nuts mailing list -- time-nuts at febo.com >To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >and follow the instructions there. -RL ---------------- Robert Lutwak, Senior Scientist Symmetricom - Technology Realization Center 34 Tozer Rd. Beverly, MA 01915 (978) 232-1461 (desk) RLutwak at Symmetricom.com (Business) (339) 927-7896 (mobile) Lutwak at Alum.MIT.edu (Personal) From tvb at LeapSecond.com Thu Apr 9 14:39:58 2009 From: tvb at LeapSecond.com (Tom Van Baak) Date: Thu, 9 Apr 2009 07:39:58 -0700 Subject: [time-nuts] Characterising frequency standards References: <1231b6a80904070509m5b8bb638gbc088500444254c3@mail.gmail.com> <1231b6a80904080441p7a747a3h1f73bf8a2df30350@mail.gmail.com> <49DC91B9.6090004@xtra.co.nz> <1231b6a80904080504n4a3a22dcr247fae5df39ed840@mail.gmail.com> <7911976D35924C91A61F679126F77F9E@pc52> <1231b6a80904090500i1cd90f80w7983e03b4978cfa8@mail.gmail.com> Message-ID: > I think the penny has dropped now, thanks. It's interesting that the > ADEV calculation still works even without continuous data as all the > reading I have done has led me to belive this was sacrosanct. We need to be careful about what you mean by "continuous". Let me probe a bit further to make sure you or others understand. The data that you first mentioned, some GPS and OCXO data at: http://www.leapsecond.com/pages/gpsdo-sim was recorded once per second, for 400,000 samples without any interruption; that's over 4 days of continuous data. As you see it is very possible to extract every other, or every 10th, every 60th, or every Nth point from this large data set to create a smaller data set. Is it as if you had several counters all connected to the same DUT. Perhaps one makes a new phase measurement each second, another makes a measurement every 10 seconds; maybe a third counter just measures once a minute. The key here is not how often they make measurements, but that they all keep running at their particular rate. The data sets you get from these counters all represent 4 days of measurement; what changes is the measurement interval, the tau0, or whatever your ADEV tool calls it. Now the ADEV plots you get from these counters will all match perfectly with the only exception being that the every-60 second counter cannot give you any ADEV points for tau less than 60; the every-10 second counter cannot give you points for tau less than 10 seconds; and for that matter; the every 1-second counter cannot give you points for tau less than 1 second. So what makes all these "continuous" is that the runs were not interrupted and that the data points were taken at regular intervals. The x-axis of an ADEV plot spans a logarithmic range of tau. The farthest point on the *right* is limited by how long your run was. If you collect data for 4 or 5 days you can compute and plot points out to around 1 day or 10^5 seconds. On the other hand, the farthest point on the *left* is limited by how fast you collect data. If you collect one point every 10 seconds, then tau=10 is your left-most point. Yes, it's common to collect data every second; in this case you can plot down to tau=1s. Some of my instruments can collect phase data at 1000 points per second (huge files!) and this means my leftmost ADEV point is 1 millisecond. Here's an example of collecting data at 10 Hz: http://www.leapsecond.com/pages/gpsdo/ You can see this allows me to plot from ADEV tau = 0.1 s. Does all this make sense now? > What I now believe is that it's possible to measure oscillator > performance with less than optimal test gear. This will enable me to > see the effects of any experiments I make in the future. If you can't > measure it, how can you know that what your doing is good or bad. Very true. So what one or several performance measurements are you after? /tvb From imp at bsdimp.com Thu Apr 9 14:52:48 2009 From: imp at bsdimp.com (M. Warner Losh) Date: Thu, 09 Apr 2009 08:52:48 -0600 (MDT) Subject: [time-nuts] NIST Time & Frequency Seminar In-Reply-To: References: <20090409140426.8A241CC005E6@mailhost.idcomm.com> Message-ID: <20090409.085248.232926226.imp@bsdimp.com> In message: Jim Palfreyman writes: : Damn I would love to go to that. But the US$1900 would be cheap bikkies : compared to my airfare and accommodation! Commuting down US-36 every day to go to the conference is no picknick either :) It is a good conference... Warner : 2009/4/10 Skip Withrow : : > : > Hello Time Nuts, : > : > I recently became aware of the NIST Time & Frequency Seminar coming up : > shortly and looked it up as it sounded interesting (to a time-nut) and is : > almost in my back yard (well, at least commuting distance). You can check : > out the web page at http://tf.nist.gov/timefreq/seminars/T&Foverview.html. : > : > It all sounds very cool, UNTIL YOU CHECK OUT THE PRICE! Sure, I could see : > $300-$400 (which would still be pretty rich for my budget), but $1900? : > Obviously our tax dollars are not subsidizing this function. : > : > If anyone knows how to procure a discounted registration I would be most : > interested in hearing from you. : > : > Regards, : > Skip Withrow : > : > _______________________________________________ : > time-nuts mailing list -- time-nuts at febo.com : > To unsubscribe, go to : > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts : > and follow the instructions there. : > : _______________________________________________ : time-nuts mailing list -- time-nuts at febo.com : To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts : and follow the instructions there. : : From gsteinba52 at aol.com Thu Apr 9 15:51:44 2009 From: gsteinba52 at aol.com (gsteinba52 at aol.com) Date: Thu, 09 Apr 2009 11:51:44 -0400 Subject: [time-nuts] SR620 Timing Capacitors Message-ID: <8CB874237428B05-3E0-7B4B@webmail-dh37.sysops.aol.com> Going to the horses' mouth (hope I got the right end here...), timing capacitors (C701 and C711) in the SRS SR620 counter are 'Ceramic? 100pf? 100v? 5%? C0G'? radial lead capacitors. SRS apologized for any errors - although the part number is correct, the description in the parts database is not. They provided me the manufacturers' part number to cross-reference. Very nice folks to deal with. Jerry From stanw1le at verizon.net Thu Apr 9 16:47:09 2009 From: stanw1le at verizon.net (Stan W1LE) Date: Thu, 09 Apr 2009 12:47:09 -0400 Subject: [time-nuts] SR620 Timing Capacitors In-Reply-To: <8CB874237428B05-3E0-7B4B@webmail-dh37.sysops.aol.com> References: <8CB874237428B05-3E0-7B4B@webmail-dh37.sysops.aol.com> Message-ID: <49DE268D.7000308@verizon.net> Hello Jerry, Thanks for the addenda. I just updated my manual. Some day I will have a SR620... Stan, W1LE Cape Cod FN41sr gsteinba52 at aol.com wrote: > Going to the horses' mouth (hope I got the right end here...), timing capacitors (C701 and C711) in the SRS SR620 counter are 'Ceramic? 100pf? 100v? 5%? C0G'? radial lead capacitors. > > SRS apologized for any errors - although the part number is correct, the description in the parts database is not. They provided me the manufacturers' part number to cross-reference. > > Very nice folks to deal with. > > Jerry > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > From david.partridge at dsl.pipex.com Thu Apr 9 16:56:22 2009 From: david.partridge at dsl.pipex.com (David C. Partridge) Date: Thu, 9 Apr 2009 17:56:22 +0100 Subject: [time-nuts] Hadamard variance In-Reply-To: <1231b6a80904090436k7051bf40t810a6cb8f91650cc@mail.gmail.com> References: <1231b6a80904080559o7a4cf618r49276df9d7599820@mail.gmail.com><40E2718386A642A5B19F87CACB573A13@athlon> <1231b6a80904090436k7051bf40t810a6cb8f91650cc@mail.gmail.com> Message-ID: PL/1 - now that brings back memories - nice language! Dave Partridge -----Original Message----- From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On Behalf Of Steve Rooke Sent: 09 April 2009 12:36 To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Hadamard variance >If it was down to me I'd probably write everything in Forth or PL1. 73, Steve - ZL3TUV & G8KVD From djl at montana.com Thu Apr 9 19:05:27 2009 From: djl at montana.com (Don Latham) Date: Thu, 9 Apr 2009 13:05:27 -0600 (MDT) Subject: [time-nuts] Hadamard variance In-Reply-To: <1231b6a80904090436k7051bf40t810a6cb8f91650cc@mail.gmail.com> References: <1231b6a80904080559o7a4cf618r49276df9d7599820@mail.gmail.com> <40E2718386A642A5B19F87CACB573A13@athlon> <1231b6a80904090436k7051bf40t810a6cb8f91650cc@mail.gmail.com> Message-ID: <1398.216.14.242.97.1239303927.squirrel@webmail.montana.com> Me too, Steve. Let us go Forth and Multiply :-) Don Steve Rooke > Ulrich, > > 2009/4/9 Ulrich Bangert : >> Steve, >> >>> ocxo. I don't think I've seen this being used by anyone on >>> the list and wonder why? >> >> Easy explained: Because you will hardly find it in any free available >> software except mine which is written in the P language which in turn >> rules >> it out as a tool for you. > > Woops, I'd better dust off my P skills then and swallow some humble > pie to boot. > > You did take what I said about P before with a whole handful of salt I > hope. If it was down to me I'd probably write everything in Forth or > PL1. > > 73, > Steve - ZL3TUV & G8KVD > >> 73s de Ulrich, DF6JB >> >>> -----Ursprungliche Nachricht----- >>> Von: time-nuts-bounces at febo.com >>> [mailto:time-nuts-bounces at febo.com] Im Auftrag von Steve Rooke >>> Gesendet: Mittwoch, 8. April 2009 15:00 >>> An: Discussion of precise time and frequency measurement >>> Betreff: [time-nuts] Hadamard variance >>> >>> >>> According to Wikipedia, this is insensitive to drift and so >>> seems like a better tool for measuring oscillators, like >>> ocxo. I don't think I've seen this being used by anyone on >>> the list and wonder why? >>> >>> 73, >>> Steve >>> -- >>> Steve Rooke - ZL3TUV & G8KVD & JAKDTTNW >>> Omnium finis imminet >>> >>> _______________________________________________ >>> time-nuts mailing list -- time-nuts at febo.com >>> To unsubscribe, go to >>> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >>> and follow the instructions there. >> >> >> _______________________________________________ >> time-nuts mailing list -- time-nuts at febo.com >> To unsubscribe, go to >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. >> > > > > -- > Steve Rooke - ZL3TUV & G8KVD & JAKDTTNW > Omnium finis imminet > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > -- Dr. Don Latham AJ7LL Six Mile Systems LLP 17850 Six Mile Road POB 134 Huson, MT, 59846 VOX 406-626-4304 www.lightningforensics.com www.sixmilesystems.com From w1ksz at earthlink.net Fri Apr 10 01:59:40 2009 From: w1ksz at earthlink.net (Richard W. Solomon) Date: Thu, 9 Apr 2009 21:59:40 -0400 (EDT) Subject: [time-nuts] Manually controlling the EFC on a Z3801/5 Message-ID: <30555685.1239328780471.JavaMail.root@mswamui-cedar.atl.sa.earthlink.net> Did you ever get an answer to this question ? I may have missed it, but I also am curious about this. 73, Dick, W1KSZ -----Original Message----- >From: Peter Vince >Sent: Mar 30, 2009 1:43 PM >To: time-nuts at febo.com >Subject: [time-nuts] Manually controlling the EFC on a Z3801/5 > >Is it possible to lock down, or control, the EFC on a Z3801 or Z3805? >Putting it into Holdover allows the system to steer it according to >its learnt characteristics, but I would quite like to bolt it down to >see how stable, or otherwise, the oscillator is. Unlike on the >Thunderbolt, I can't find any command to do that - does anyone know >if it is possible? > > Thanks, > > Peter > >_______________________________________________ >time-nuts mailing list -- time-nuts at febo.com >To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >and follow the instructions there. From optomatic at rogers.com Fri Apr 10 02:14:23 2009 From: optomatic at rogers.com (Patrick) Date: Thu, 09 Apr 2009 22:14:23 -0400 Subject: [time-nuts] OT favorite chip programmer/favorite ROM emulator Message-ID: <49DEAB7F.7090805@rogers.com> Hi Everyone Sorry for the off topic post. I have received such great advice in the past with regard to instrumentation purchases, I just can't resist. The caliber of knowledge on this list is second to none. I am looking for a low cost chip programmer(under $300, preferably under $200). Has anyone had a positive(or negative) experience with a manufacturer? I am also looking for a ROM emulator, does anyone have any advice? Thanks in advance-Patrick From jmiles at pop.net Fri Apr 10 02:35:33 2009 From: jmiles at pop.net (John Miles) Date: Thu, 9 Apr 2009 19:35:33 -0700 Subject: [time-nuts] OT favorite chip programmer/favorite ROM emulator In-Reply-To: <49DEAB7F.7090805@rogers.com> Message-ID: > > Hi Everyone > > Sorry for the off topic post. I have received such great advice in the > past with regard to instrumentation purchases, I just can't resist. The > caliber of knowledge on this list is second to none. > > I am looking for a low cost chip programmer(under $300, preferably under > $200). Has anyone had a positive(or negative) experience with a > manufacturer? What kind of chip programmer? Microcontrollers, or PROMs? If you're looking for an economical PROM burner, I'll put in a plug for this one: http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=290304315635 The seller's been around a long time, and is good to deal with. The board itself looks sort of disreputable, but it's actually quite functional, easy to use, and a real bargain. The device catalog is decent, if you don't mind occasionally having to look up equivalent part numbers. Avoid earlier versions that used hybrid LPT/USB connections, as they had some problems. -- john, KE5FX From holrum at hotmail.com Fri Apr 10 03:16:39 2009 From: holrum at hotmail.com (Mark Sims) Date: Fri, 10 Apr 2009 03:16:39 +0000 Subject: [time-nuts] OT favorite chip programmer/favorite ROM emulator In-Reply-To: References: Message-ID: By far the best programmer on the planet is still the Data I/O Unisite (followed by the 3980, 3900, and 2900 prorgrammers). If a Unisite can't program it, you are in bad shape... it probably can't be programmed. Bad news is a refurbed Unisite will set you back $25,000 plus the cost of socket adapters and software. Good news is with a little shopping around on Ebay, you can possibly snag one for around $100. The trick is to find one with the socket adapters you need. Also the more pin driver cards it has installed, the better (a full load is 17 cards/68 pin drivers). Also, one with the internal hard drive (aka MSM, aka Mass Storage Module) is very desirable. Booting from a (720Kb only) floppy can take several minutes. I have purchased several machines just because they had an adapter that I did not have. Also you need to make sure it comes with a full set of programming software (generally, the later the version better) because a current software set from DIO will set you back over $2000... For more info, check out Bruce Lane's guide to DIO machines on Ebay: http://reviews.ebay.com/Data-I-O-Device-Programmers-A-Condensed-Reference_W0QQugidZ10000000001698682?ssPageName=BUYGD:CAT:-1:SEARCH:3 ---------------------------------------- _________________________________________________________________ Rediscover Hotmail?: Get quick friend updates right in your inbox. http://windowslive.com/RediscoverHotmail?ocid=TXT_TAGLM_WL_HM_Rediscover_Updates1_042009 From sar10538 at gmail.com Fri Apr 10 07:09:13 2009 From: sar10538 at gmail.com (Steve Rooke) Date: Fri, 10 Apr 2009 19:09:13 +1200 Subject: [time-nuts] Manual for Z3805A Message-ID: <1231b6a80904100009uc477d5dh260348a577e198a4@mail.gmail.com> Does anyone have a manual for one of these as all I can find on the net is one for the Z3801A? 73, Steve -- Steve Rooke - ZL3TUV & G8KVD & JAKDTTNW Omnium finis imminet From david.partridge at dsl.pipex.com Fri Apr 10 07:14:57 2009 From: david.partridge at dsl.pipex.com (David C. Partridge) Date: Fri, 10 Apr 2009 08:14:57 +0100 Subject: [time-nuts] OT favorite chip programmer/favorite ROM emulator In-Reply-To: References: Message-ID: Another one to look at apparently is the Galep model 4(LPT) or 5(USB). I don't have one but when this question was asked recently elsewhere, they were very highly recommended - and very good support. Dave -----Original Message----- From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On Behalf Of Mark Sims Sent: 10 April 2009 04:17 To: time-nuts at febo.com Subject: [time-nuts] OT favorite chip programmer/favorite ROM emulator By far the best programmer on the planet is still the Data I/O Unisite (followed by the 3980, 3900, and 2900 prorgrammers). If a Unisite can't program it, you are in bad shape... it probably can't be programmed. Bad news is a refurbed Unisite will set you back $25,000 plus the cost of socket adapters and software. Good news is with a little shopping around on Ebay, you can possibly snag one for around $100. The trick is to find one with the socket adapters you need. Also the more pin driver cards it has installed, the better (a full load is 17 cards/68 pin drivers). Also, one with the internal hard drive (aka MSM, aka Mass Storage Module) is very desirable. Booting from a (720Kb only) floppy can take several minutes. I have purchased several machines just because they had an adapter that I did not have. Also you need to make sure it comes with a full set of programming software (generally, the later the version better) because a current software set from DIO will set you back over $2000... For more info, check out Bruce Lane's guide to DIO machines on Ebay: http://reviews.ebay.com/Data-I-O-Device-Programmers-A-Condensed-Reference_W0 QQugidZ10000000001698682?ssPageName=BUYGD:CAT:-1:SEARCH:3 ---------------------------------------- _________________________________________________________________ Rediscover HotmailR: Get quick friend updates right in your inbox. http://windowslive.com/RediscoverHotmail?ocid=TXT_TAGLM_WL_HM_Rediscover_Upd ates1_042009 _______________________________________________ time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. From df6jb at ulrich-bangert.de Fri Apr 10 09:21:11 2009 From: df6jb at ulrich-bangert.de (Ulrich Bangert) Date: Fri, 10 Apr 2009 11:21:11 +0200 Subject: [time-nuts] Characterising frequency standards In-Reply-To: <1231b6a80904090500i1cd90f80w7983e03b4978cfa8@mail.gmail.com> Message-ID: <4176CE16020C49449B55FCA770F8B7E5@athlon> Steve, > I think the penny has dropped now, thanks. It's interesting > that the ADEV calculation still works even without continuous > data as all the reading I have done has led me to belive this > was sacrosanct. The penny may be falling but it is not completely dropped: Of course you can feed your ADEV calculation with every second sample removed and setting Tau0 = 2. And of course you receive a result that now is in "harmony" with your all samples / Tau0 = 1 s computation. Had you done frequency measurements the reason for this appearant "harmony" is that your counter does not show significant different behaviour whether set to 1 s gate time or alternate 2 second gate time. Nevertheless leaving every second sample out is NOT exactly the same as continous data with Tau0 = 2 s. Instead it is data with Tau0 = 1 s and a DEAD TIME of 1s. There are dead time correction schemes available in the literature. Best regards Ulrich Bangert > -----Ursprungliche Nachricht----- > Von: time-nuts-bounces at febo.com > [mailto:time-nuts-bounces at febo.com] Im Auftrag von Steve Rooke > Gesendet: Donnerstag, 9. April 2009 14:00 > An: Tom Van Baak; Discussion of precise time and frequency measurement > Betreff: Re: [time-nuts] Characterising frequency standards > > > Tom, > > 2009/4/9 Tom Van Baak : > > The first argument to the adev1 program is the sampling > interval t0. > > The program doesn't know how far apart the input file samples are > > taken so it is your job to specify this. The default is 1 second. > > > > If you have data taken one second apart then t0 = 1. > > If you have data taken two seconds apart then t0 = 2. > > If you have data taken 60 seconds apart then t0 = 60, etc. > > > > If, as in your case, you take raw one second data and remove every > > other sample (a perfectly valid thing to do), then t0 = 2. > > > > Make sense now? It's still "continuous data" in the sense that all > > measurements are a fixed interval apart. But in any ADEV > calculation > > you have to specify the raw data interval. > > I think the penny has dropped now, thanks. It's interesting > that the ADEV calculation still works even without continuous > data as all the reading I have done has led me to belive this > was sacrosanct. > > What I now believe is that it's possible to measure > oscillator performance with less than optimal test gear. This > will enable me to see the effects of any experiments I make > in the future. If you can't measure it, how can you know that > what your doing is good or bad. > > 73, > Steve > -- > Steve Rooke - ZL3TUV & G8KVD & JAKDTTNW > Omnium finis imminet > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. From sar10538 at gmail.com Fri Apr 10 10:54:39 2009 From: sar10538 at gmail.com (Steve Rooke) Date: Fri, 10 Apr 2009 22:54:39 +1200 Subject: [time-nuts] Characterising frequency standards In-Reply-To: <4176CE16020C49449B55FCA770F8B7E5@athlon> References: <1231b6a80904090500i1cd90f80w7983e03b4978cfa8@mail.gmail.com> <4176CE16020C49449B55FCA770F8B7E5@athlon> Message-ID: <1231b6a80904100354m76be3cd7t20e09fd20aff346a@mail.gmail.com> Ulrich, 2009/4/10 Ulrich Bangert : > Steve, > >> I think the penny has dropped now, thanks. It's interesting >> that the ADEV calculation still works even without continuous >> data as all the reading I have done has led me to belive this >> was sacrosanct. > > The penny may be falling but it is not completely dropped: Of course you can > feed your ADEV calculation with every second sample removed and setting Tau0 > = 2. And of course you receive a result that now is in "harmony" with your > all samples / Tau0 = 1 s computation. Had you done frequency measurements > the reason for this appearant "harmony" is that your counter does not show > significant different behaviour whether set to 1 s gate time or alternate 2 > second gate time. So why would my counter show any significant differences between a 1 sec or 2 sec gate time? > Nevertheless leaving every second sample out is NOT exactly the same as > continous data with Tau0 = 2 s. Instead it is data with Tau0 = 1 s and a > DEAD TIME of 1s. There are dead time correction schemes available in the > literature. I've just done a Google search for "dead time correction scheme" and I just turn up results relating to particle physics where it seems measurements are unable to keep up with the flow of data, hence the need to factor in the dead time of system. This form of application does not appear to correlate with the measurement of plain oscillators. Yes there is dead time, per say, but I fail to see how this can detract significantly from continuous data given a sufficient data set size (as for a total measurement time). I guess what we need is a real data set which would show that this form of ADEV calculation produces incorrect results, IE. the proof of the pudding is in the eating. 73, Steve > Best regards > Ulrich Bangert > >> -----Ursprungliche Nachricht----- >> Von: time-nuts-bounces at febo.com >> [mailto:time-nuts-bounces at febo.com] Im Auftrag von Steve Rooke >> Gesendet: Donnerstag, 9. April 2009 14:00 >> An: Tom Van Baak; Discussion of precise time and frequency measurement >> Betreff: Re: [time-nuts] Characterising frequency standards >> >> >> Tom, >> >> 2009/4/9 Tom Van Baak : >> > The first argument to the adev1 program is the sampling >> interval t0. >> > The program doesn't know how far apart the input file samples are >> > taken so it is your job to specify this. The default is 1 second. >> > >> > If you have data taken one second apart then t0 = 1. >> > If you have data taken two seconds apart then t0 = 2. >> > If you have data taken 60 seconds apart then t0 = 60, etc. >> > >> > If, as in your case, you take raw one second data and remove every >> > other sample (a perfectly valid thing to do), then t0 = 2. >> > >> > Make sense now? It's still "continuous data" in the sense that all >> > measurements are a fixed interval apart. But in any ADEV >> calculation >> > you have to specify the raw data interval. >> >> I think the penny has dropped now, thanks. It's interesting >> that the ADEV calculation still works even without continuous >> data as all the reading I have done has led me to belive this >> was sacrosanct. >> >> What I now believe is that it's possible to measure >> oscillator performance with less than optimal test gear. This >> will enable me to see the effects of any experiments I make >> in the future. If you can't measure it, how can you know that >> what your doing is good or bad. >> >> 73, >> Steve >> -- >> Steve Rooke - ZL3TUV & G8KVD & JAKDTTNW >> Omnium finis imminet >> >> _______________________________________________ >> time-nuts mailing list -- time-nuts at febo.com >> To unsubscribe, go to >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > -- Steve Rooke - ZL3TUV & G8KVD & JAKDTTNW Omnium finis imminet From sar10538 at gmail.com Fri Apr 10 11:40:37 2009 From: sar10538 at gmail.com (Steve Rooke) Date: Fri, 10 Apr 2009 23:40:37 +1200 Subject: [time-nuts] Characterising frequency standards In-Reply-To: References: <1231b6a80904070509m5b8bb638gbc088500444254c3@mail.gmail.com> <1231b6a80904080441p7a747a3h1f73bf8a2df30350@mail.gmail.com> <49DC91B9.6090004@xtra.co.nz> <1231b6a80904080504n4a3a22dcr247fae5df39ed840@mail.gmail.com> <7911976D35924C91A61F679126F77F9E@pc52> <1231b6a80904090500i1cd90f80w7983e03b4978cfa8@mail.gmail.com> Message-ID: <1231b6a80904100440r6f01f398m995ad10aff589679@mail.gmail.com> Tom, 2009/4/10 Tom Van Baak : > We need to be careful about what you mean by "continuous". > Let me probe a bit further to make sure you or others understand. My reference to "continuous" data would be defined as measurements over a specific sampling period with each sample following directly after the previous. This seems to be what is generally required for the calculation of ADEV in the literature and postings on this group. Such that techniques like the picket fence are suggested as a way to deduce "continuous" data when using instruments that are unable to measure sequential cycles of the input. > The data that you first mentioned, some GPS and OCXO data at: > ? ?http://www.leapsecond.com/pages/gpsdo-sim > was recorded once per second, for 400,000 samples without any > interruption; that's over 4 days of continuous data. > > As you see it is very possible to extract every other, or every 10th, > every 60th, or every Nth point from this large data set to create a > smaller data set. > > Is it as if you had several counters all connected to the same DUT. > Perhaps one makes a new phase measurement each second, > another makes a measurement every 10 seconds; maybe a third > counter just measures once a minute. > > The key here is not how often they make measurements, but that > they all keep running at their particular rate. Agreed. > The data sets you get from these counters all represent 4 days > of measurement; what changes is the measurement interval, the > tau0, or whatever your ADEV tool calls it. > > Now the ADEV plots you get from these counters will all match > perfectly with the only exception being that the every-60 second > counter cannot give you any ADEV points for tau less than 60; > the every-10 second counter cannot give you points for tau less > than 10 seconds; and for that matter; the every 1-second counter > cannot give you points for tau less than 1 second. It is certainly true that 1 second sampled data collected at 60 second intervals cannot be fed into an ADEV calculation as having a tau of 1 sec as the resultant calculation will show incorrect results when noise like drift is a factor. If the data set is pre-processed and corrected for such effects as drift, I believe it should be possible to feed this discontinuous data as "continuous" data for the measurement of short tau with reasonable accuracy. > So what makes all these "continuous" is that the runs were not > interrupted and that the data points were taken at regular intervals. > > The x-axis of an ADEV plot spans a logarithmic range of tau. The > farthest point on the *right* is limited by how long your run was. If > you collect data for 4 or 5 days you can compute and plot points > out to around 1 day or 10^5 seconds. > > On the other hand, the farthest point on the *left* is limited by how > fast you collect data. If you collect one point every 10 seconds, > then tau=10 is your left-most point. Yes, it's common to collect data > every second; in this case you can plot down to tau=1s. Some of > my instruments can collect phase data at 1000 points per second > (huge files!) and this means my leftmost ADEV point is 1 millisecond. I guess it really depends on what level your measurement system is able to work. For, say, the output of a 10MHz OCXO it would be desirable to measure the source frequency although that would require a fast measurement system and significant storage. The benefits of this is that the input source is not degraded in the process of division down to a more manageable frequency. We are currently discussing the effects of the introduction of noise into frequency standards just with distribution amplifiers and dividers. The ability to measure such close in noise effects would indeed be a great bonus and I envy your abilty to perform that. > Here's an example of collecting data at 10 Hz: > http://www.leapsecond.com/pages/gpsdo/ > You can see this allows me to plot from ADEV tau = 0.1 s. > > Does all this make sense now? Yes, I understand. >> What I now believe is that it's possible to measure oscillator >> performance with less than optimal test gear. This will enable me to >> see the effects of any experiments I make in the future. If you can't >> measure it, how can you know that what your doing is good or bad. > > Very true. So what one or several performance measurements > are you after? Well there are a number of them. The selection of best free-running OCXOs. The effects of locking an OCXO to GPS and the "tuning" of this. Running a OCXO in active holdover mode. I'd like to separate the effects of temperature, rate of change of temperature, aging, humidity, atmospheric pressure and, possibly, gravity on a free-running OCXO. By changing just one variable at a time, I'd like to measure the effects of each one with respect to determining the correction required from a holdover circuit. Agreed, some of these are simply defined as frequency change in the oscillator but I will wish to measure the full system performance and need some form of yard-stick to work to. Now this may not give the most politically correct and acceptable results for such measurements as ADEV but it will give me something for comparison. If I can make it match the politically correct results of others, I also can make comparisons with their results too. Does all this make sense now? You see I need to understand things in my own mind and have problems when things do not make perfect sense to me. So if I as stupid questions or make ridiculous suggestions, it's just my way of learning by probing for the limits. There was a UK TV science program called Take Nobodies Word For It, a paradigm I have always lived by so I tend to prove things to my own satisfaction and probably re-invent the wheel a lot of times. I never went to uni so my classical education is limited but I have spent all my life learning off my own back. Kind regards, Steve > /tvb > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > -- Steve Rooke - ZL3TUV & G8KVD & JAKDTTNW Omnium finis imminet From sar10538 at gmail.com Fri Apr 10 11:45:10 2009 From: sar10538 at gmail.com (Steve Rooke) Date: Fri, 10 Apr 2009 23:45:10 +1200 Subject: [time-nuts] Hadamard variance In-Reply-To: <49DDFD6D.3040207@xtra.co.nz> References: <1231b6a80904080559o7a4cf618r49276df9d7599820@mail.gmail.com> <951FB64B18654ECE97BFC40BBDC1D2B3@pc52> <1231b6a80904090429i165b6627sb83ee88a25069e1b@mail.gmail.com> <49DDFD6D.3040207@xtra.co.nz> Message-ID: <1231b6a80904100445g381cc06eja1616eab3fe0f096@mail.gmail.com> Bruce, 2009/4/10 Bruce Griffiths : > Just dont get too carried away. > Remember that the Hadamard deviation is only insensitive to linear > frequency drift. > If the drift is quadratic for example then it will affect the Hadamard > deviation. Point well taken. In that case we need a new deviation measurement with 4 elements then :-) 73, Steve > Bruce > > Steve Rooke wrote: >> Hi Tom, >> >> 2009/4/9 Tom Van Baak : >> >>> I use it sometimes when I need to. But note that in most cases >>> you do NOT want to ignore drift. If you measure an OCXO for >>> the purpose of using it in a clock or appliance or radio or test >>> equipment you really do want to know if it has drift or not. ADEV >>> will show this, while HDEV will not. So you have to be careful >>> about using statistics that deliberately and quietly ignore effects >>> that may be important to your application. >>> >> >> Indeed, I was thinking that HDEV would be a good tool to characterise >> free running OCXOs with it's insensitivity to drift but, of course, I >> would use ADEV to measure the performance of a GPS locked system or >> one running in holdover mode. >> >> >>> But before you run off and use HDEV for everything note that >>> the other practice that is far more common -- simply remove >>> frequency drift from the raw data before computing an ADEV >>> on the residuals. If you look at plots in professional journals you >>> will often find comments to the effect that phase, frequency, or >>> drift offsets have been added or removed prior to making said >>> phase, frequency, or stability plots. >>> >> >> I had no intent to use HDEV exclusively, it seems like a useful tool >> to analyse free-running oscillators to measure the affects of noise >> while screening out drift (which we have some means of handling in >> holdover circuits). As a selection tool it seemed quite useful and I >> was asking if others felt the same way. >> >> Agreed, it is possible to factor out drift by pre-processing the data >> and then using just ADEV to compare all aspects of any open or closed >> system. >> >> >>> Here, to see the difference that HDEV makes (or not) see: >>> http://www.leapsecond.com/pages/hdev >>> >> >> It seems to have an effect removing some of what must be drift with >> the OCXO plot but adds nothing to the PPS one. Do I take it that the >> OCXO was free-running and the PPS was locked to GPS, as this would >> account for the differences? >> >> >>> The command line program that I use (ADEV3) these days: >>> Tool for ADEV, MDEV, HDEV: >>> http://www.leapsecond.com/tools/adev3.exe >>> >>> Source code (compiles in windows, bsd, or linux) >>> http://www.leapsecond.com/tools/adev3.c >>> >> >> Thanks for the pointers, I'll have a look at this instead. >> >> 73, >> Steve >> > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > -- Steve Rooke - ZL3TUV & G8KVD & JAKDTTNW Omnium finis imminet From sar10538 at gmail.com Fri Apr 10 11:50:46 2009 From: sar10538 at gmail.com (Steve Rooke) Date: Fri, 10 Apr 2009 23:50:46 +1200 Subject: [time-nuts] Hadamard variance In-Reply-To: References: <1231b6a80904080559o7a4cf618r49276df9d7599820@mail.gmail.com> <951FB64B18654ECE97BFC40BBDC1D2B3@pc52> <1231b6a80904090429i165b6627sb83ee88a25069e1b@mail.gmail.com> <49DDFD6D.3040207@xtra.co.nz> Message-ID: <1231b6a80904100450w3889ed85tba02c231897a433b@mail.gmail.com> It looks like there is a need for more tools to not only modify the data but to analyse the raw data to measure parameters like linear and logarithmic drift. I guess plain old statistics should give this sort of information. 73, Steve 2009/4/10 Tom Van Baak : >> Steve >> >> Just dont get too carried away. >> Remember that the Hadamard deviation is only insensitive to linear >> frequency drift. >> If the drift is quadratic for example then it will affect the Hadamard >> deviation. >> >> Bruce > > Correct. This is another reason why the practice of removing > systematic drift from raw data first and then computing ADEV > on the residuals is quite useful. > > It allows you to separate the task of modeling systematic effects > from the calculation of stability (ADEV) of the residuals. > > For example, you may suspect ahead of time, or you may find > through analysis, that your DUT is following a slow logarithmic > drift trend rather than just linear drift. Either way, you can remove > the systematic effect to get to a closer measure of the intrinsic > stability limits of the DUT. > > This is common with OCXO which have aged, say more than > a few days, but less than a few months. It's pretty cool to see > very linear drift rates each day, but to also notice that the rate > itself slowly decreases week by week. > > As another example, you may find a strong correlation between > temperature and frequency. You could plot ADEV of the raw > data, and then plot ADEV of the temperature compensated > residuals and observe the difference in the plots. > > /tvb > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > -- Steve Rooke - ZL3TUV & G8KVD & JAKDTTNW Omnium finis imminet From sar10538 at gmail.com Fri Apr 10 11:55:05 2009 From: sar10538 at gmail.com (Steve Rooke) Date: Fri, 10 Apr 2009 23:55:05 +1200 Subject: [time-nuts] Hadamard variance In-Reply-To: <1398.216.14.242.97.1239303927.squirrel@webmail.montana.com> References: <1231b6a80904080559o7a4cf618r49276df9d7599820@mail.gmail.com> <40E2718386A642A5B19F87CACB573A13@athlon> <1231b6a80904090436k7051bf40t810a6cb8f91650cc@mail.gmail.com> <1398.216.14.242.97.1239303927.squirrel@webmail.montana.com> Message-ID: <1231b6a80904100455t10f68069mdef966d3ea687ac8@mail.gmail.com> Hmmm... Think I've done enough going forth and multiplying in my life :-) Oh, if life was only as simple as going Forth! 73, Steve 2009/4/10 Don Latham : > Me too, Steve. Let us go Forth and Multiply :-) > Don > > Steve Rooke >> Ulrich, >> >> 2009/4/9 Ulrich Bangert : >>> Steve, >>> >>>> ocxo. I don't think I've seen this being used by anyone on >>>> the list and wonder why? >>> >>> Easy explained: Because you will hardly find it in any free available >>> software except mine which is written in the P language which in turn >>> rules >>> it out as a tool for you. >> >> Woops, I'd better dust off my P skills then and swallow some humble >> pie to boot. >> >> You did take what I said about P before with a whole handful of salt I >> hope. If it was down to me I'd probably write everything in Forth or >> PL1. >> >> 73, >> Steve - ZL3TUV & G8KVD >> >>> 73s de Ulrich, DF6JB >>> >>>> -----Ursprungliche Nachricht----- >>>> Von: time-nuts-bounces at febo.com >>>> [mailto:time-nuts-bounces at febo.com] Im Auftrag von Steve Rooke >>>> Gesendet: Mittwoch, 8. April 2009 15:00 >>>> An: Discussion of precise time and frequency measurement >>>> Betreff: [time-nuts] Hadamard variance >>>> >>>> >>>> According to Wikipedia, this is insensitive to drift and so >>>> seems like a better tool for measuring oscillators, like >>>> ocxo. I don't think I've seen this being used by anyone on >>>> the list and wonder why? >>>> >>>> 73, >>>> Steve >>>> -- >>>> Steve Rooke - ZL3TUV & G8KVD & JAKDTTNW >>>> Omnium finis imminet >>>> >>>> _______________________________________________ >>>> time-nuts mailing list -- time-nuts at febo.com >>>> To unsubscribe, go to >>>> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >>>> and follow the instructions there. >>> >>> >>> _______________________________________________ >>> time-nuts mailing list -- time-nuts at febo.com >>> To unsubscribe, go to >>> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >>> and follow the instructions there. >>> >> >> >> >> -- >> Steve Rooke - ZL3TUV & G8KVD & JAKDTTNW >> Omnium finis imminet >> >> _______________________________________________ >> time-nuts mailing list -- time-nuts at febo.com >> To unsubscribe, go to >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. >> > > > -- > Dr. Don Latham AJ7LL > Six Mile Systems LLP > 17850 Six Mile Road > POB 134 > Huson, MT, 59846 > VOX 406-626-4304 > www.lightningforensics.com > www.sixmilesystems.com > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > -- Steve Rooke - ZL3TUV & G8KVD & JAKDTTNW Omnium finis imminet From sar10538 at gmail.com Fri Apr 10 11:56:57 2009 From: sar10538 at gmail.com (Steve Rooke) Date: Fri, 10 Apr 2009 23:56:57 +1200 Subject: [time-nuts] Hadamard variance In-Reply-To: References: <1231b6a80904080559o7a4cf618r49276df9d7599820@mail.gmail.com> <40E2718386A642A5B19F87CACB573A13@athlon> <1231b6a80904090436k7051bf40t810a6cb8f91650cc@mail.gmail.com> Message-ID: <1231b6a80904100456j603a2748ib800c3bb65aa9c5e@mail.gmail.com> It was probably the first real high level language that I got to play with and I have fond memories of it. 73, Steve 2009/4/10 David C. Partridge : > PL/1 - now that brings back memories - nice language! > > Dave Partridge > -----Original Message----- > From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On > Behalf Of Steve Rooke > Sent: 09 April 2009 12:36 > To: Discussion of precise time and frequency measurement > Subject: Re: [time-nuts] Hadamard variance > >>If it was down to me I'd probably write everything in Forth or PL1. > > 73, > Steve - ZL3TUV & G8KVD > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > -- Steve Rooke - ZL3TUV & G8KVD & JAKDTTNW Omnium finis imminet From ik1odo at spin-it.com Fri Apr 10 12:04:49 2009 From: ik1odo at spin-it.com (Marco IK1ODO -2) Date: Fri, 10 Apr 2009 14:04:49 +0200 Subject: [time-nuts] R&S XSD-2 - help needed In-Reply-To: <1231b6a80904100450w3889ed85tba02c231897a433b@mail.gmail.co m> References: <1231b6a80904080559o7a4cf618r49276df9d7599820@mail.gmail.com> <951FB64B18654ECE97BFC40BBDC1D2B3@pc52> <1231b6a80904090429i165b6627sb83ee88a25069e1b@mail.gmail.com> <49DDFD6D.3040207@xtra.co.nz> <1231b6a80904100450w3889ed85tba02c231897a433b@mail.gmail.com> Message-ID: <20090410121612.59C3446A5E@mail.ebirds.it> Hello, I got a broken Rohde&Schwarz XSD-2 crystal oscillator module, type 283.6010.02 . By first, has anyone a schematic for it? Then, the dewar flask originally containing the oscillator mass is broken. Size was (approx) 65 mm internal diameter, 150 mm internal height. Who has similar dewars? The volume is close to 0.5 liters, and I have not found an useful replacement for common "thermos" flasks of that size. Any help appreciated! 73 - Marco IK1ODO / AI4YF From cfharris at erols.com Fri Apr 10 12:36:20 2009 From: cfharris at erols.com (Chuck Harris) Date: Fri, 10 Apr 2009 08:36:20 -0400 Subject: [time-nuts] OT favorite chip programmer/favorite ROM emulator In-Reply-To: References: Message-ID: <49DF3D44.7000902@erols.com> Mark Sims wrote: > By far the best programmer on the planet is still the Data I/O Unisite (followed by the 3980, 3900, and 2900 > prorgrammers). If a Unisite can't program it, you are in bad shape... it probably can't be programmed. That is really kind of a silly statement. Data I/O is known as the cadillac of programmers, but mostly because of its high price. Advin makes a programmer that will program everything the Data I/O will, using the same algorithms, for 1/10th the price. Further all of their software is available on their website for free download. Their intro model has 44 drivers, and will program devices up to 128 pins. Their top of the line model has 128 drivers and will program devices up to 304 pins... costs $3295. Used Advin programmers are a mixed bag. When the 3.3V devices came out, the voltage references on the pin driver DAC's got changed, so that obsoleted them for 3.3V devices. However, the software for every machine they ever made is available on their website. Also, their programmers use the host computer for much of the programmer's power, and there is an issue with some of the earlier machines and too fast PC's, so there might be a need to buy an older throttled down PC to host your Advin programmer. -Chuck Harris > > Bad news is a refurbed Unisite will set you back $25,000 plus the cost of socket adapters and software. Good news is > with a little shopping around on Ebay, you can possibly snag one for around $100. > > The trick is to find one with the socket adapters you need. Also the more pin driver cards it has installed, the > better (a full load is 17 cards/68 pin drivers). Also, one with the internal hard drive (aka MSM, aka Mass Storage > Module) is very desirable. Booting from a (720Kb only) floppy can take several minutes. > > I have purchased several machines just because they had an adapter that I did not have. Also you need to make sure > it comes with a full set of programming software (generally, the later the version better) because a current > software set from DIO will set you back over $2000... > > For more info, check out Bruce Lane's guide to DIO machines on Ebay: > http://reviews.ebay.com/Data-I-O-Device-Programmers-A-Condensed-Reference_W0QQugidZ10000000001698682?ssPageName=BUYGD:CAT:-1:SEARCH:3 > ---------------------------------------- > > > _________________________________________________________________ Rediscover Hotmail?: Get quick friend updates right > in your inbox. http://windowslive.com/RediscoverHotmail?ocid=TXT_TAGLM_WL_HM_Rediscover_Updates1_042009 > _______________________________________________ time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. > From magnus at rubidium.dyndns.org Fri Apr 10 15:51:26 2009 From: magnus at rubidium.dyndns.org (Magnus Danielson) Date: Fri, 10 Apr 2009 17:51:26 +0200 Subject: [time-nuts] Hadamard variance In-Reply-To: <1231b6a80904100445g381cc06eja1616eab3fe0f096@mail.gmail.com> References: <1231b6a80904080559o7a4cf618r49276df9d7599820@mail.gmail.com> <951FB64B18654ECE97BFC40BBDC1D2B3@pc52> <1231b6a80904090429i165b6627sb83ee88a25069e1b@mail.gmail.com> <49DDFD6D.3040207@xtra.co.nz> <1231b6a80904100445g381cc06eja1616eab3fe0f096@mail.gmail.com> Message-ID: <49DF6AFE.4040201@rubidium.dyndns.org> Steve Rooke skrev: > Bruce, > > 2009/4/10 Bruce Griffiths : >> Just dont get too carried away. >> Remember that the Hadamard deviation is only insensitive to linear >> frequency drift. >> If the drift is quadratic for example then it will affect the Hadamard >> deviation. > > Point well taken. In that case we need a new deviation measurement > with 4 elements then :-) Will not help to fully cancel the effect as crystal drift is a function of log. See Vig on crystal oscillators at IEEE UFFC pages. One needs to identify the drift shape, estimates its parameters and then remove the estimated value from phase or frequency data. Cheers, Magnus From df6jb at ulrich-bangert.de Fri Apr 10 16:59:46 2009 From: df6jb at ulrich-bangert.de (Ulrich Bangert) Date: Fri, 10 Apr 2009 18:59:46 +0200 Subject: [time-nuts] Hadamard variance In-Reply-To: <1231b6a80904100456j603a2748ib800c3bb65aa9c5e@mail.gmail.com> Message-ID: <103F10C3F49C42CA9ED1EA3D0626F6F9@athlon> Steve, > It was probably the first real high level language that I got > to play with and I have fond memories of it. I own a HP67 calculator and since when it came to the market I was too young to have the money to buy it, I have also lots of memories concerning these times. Neverthelesss it is truly NOT the tool that I use today. Best regards Ulrich Bangert > -----Ursprungliche Nachricht----- > Von: time-nuts-bounces at febo.com > [mailto:time-nuts-bounces at febo.com] Im Auftrag von Steve Rooke > Gesendet: Freitag, 10. April 2009 13:57 > An: Discussion of precise time and frequency measurement > Betreff: Re: [time-nuts] Hadamard variance > > > It was probably the first real high level language that I got > to play with and I have fond memories of it. > > 73, > Steve > > 2009/4/10 David C. Partridge : > > PL/1 - now that brings back memories - nice language! > > > > Dave Partridge > > -----Original Message----- > > From: time-nuts-bounces at febo.com > [mailto:time-nuts-bounces at febo.com] > > On Behalf Of Steve Rooke > > Sent: 09 April 2009 12:36 > > To: Discussion of precise time and frequency measurement > > Subject: Re: [time-nuts] Hadamard variance > > > >>If it was down to me I'd probably write everything in Forth or PL1. > > > > 73, > > Steve - ZL3TUV & G8KVD > > > > > > _______________________________________________ > > time-nuts mailing list -- time-nuts at febo.com > > To unsubscribe, go to > > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > > and follow the instructions there. > > > > > > -- > Steve Rooke - ZL3TUV & G8KVD & JAKDTTNW > Omnium finis imminet > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. From df6jb at ulrich-bangert.de Fri Apr 10 16:59:46 2009 From: df6jb at ulrich-bangert.de (Ulrich Bangert) Date: Fri, 10 Apr 2009 18:59:46 +0200 Subject: [time-nuts] Characterising frequency standards In-Reply-To: <1231b6a80904100354m76be3cd7t20e09fd20aff346a@mail.gmail.com> Message-ID: <7CC8385956C841D9B67F4A860C45215E@athlon> Steve, > So why would my counter show any significant differences > between a 1 sec or 2 sec gate time? suppose your source has a 0.5 Hz frequency modulation. Would you see it with 2 s gate time or a integer multiple of it? Would you notice it with 1 s gate time or an odd integer of it? > I've just done a Google search for "dead time correction > scheme" and I just turn up results relating to particle > physics where it seems measurements are unable to keep up > with the flow of data, hence the need to factor in the dead > time of system. Google for the STABLE32 manual. THIS literature will bring you a lot further, many well documented source examples in Forth and PL/1, hi. F.e. you may look here: http://www.wriley.com/ Best regards Ulrich Bangert > -----Ursprungliche Nachricht----- > Von: time-nuts-bounces at febo.com > [mailto:time-nuts-bounces at febo.com] Im Auftrag von Steve Rooke > Gesendet: Freitag, 10. April 2009 12:55 > An: Discussion of precise time and frequency measurement > Betreff: [!! SPAM] Re: [time-nuts] Characterising frequency standards > > > Ulrich, > > 2009/4/10 Ulrich Bangert : > > Steve, > > > >> I think the penny has dropped now, thanks. It's > interesting that the > >> ADEV calculation still works even without continuous data > as all the > >> reading I have done has led me to belive this was sacrosanct. > > > > The penny may be falling but it is not completely dropped: > Of course > > you can feed your ADEV calculation with every second sample removed > > and setting Tau0 = 2. And of course you receive a result > that now is > > in "harmony" with your all samples / Tau0 = 1 s > computation. Had you > > done frequency measurements the reason for this appearant > "harmony" is > > that your counter does not show significant different behaviour > > whether set to 1 s gate time or alternate 2 second gate time. > > So why would my counter show any significant differences > between a 1 sec or 2 sec gate time? > > > Nevertheless leaving every second sample out is NOT exactly > the same > > as continous data with Tau0 = 2 s. Instead it is data with > Tau0 = 1 s > > and a DEAD TIME of 1s. There are dead time correction schemes > > available in the literature. > > I've just done a Google search for "dead time correction > scheme" and I just turn up results relating to particle > physics where it seems measurements are unable to keep up > with the flow of data, hence the need to factor in the dead > time of system. This form of application does not appear to > correlate with the measurement of plain oscillators. Yes > there is dead time, per say, but I fail to see how this can > detract significantly from continuous data given a sufficient > data set size (as for a total measurement time). > > I guess what we need is a real data set which would show that > this form of ADEV calculation produces incorrect results, IE. > the proof of the pudding is in the eating. > > 73, > Steve > > > Best regards > > Ulrich Bangert > > > >> -----Ursprungliche Nachricht----- > >> Von: time-nuts-bounces at febo.com > [mailto:time-nuts-bounces at febo.com] > >> Im Auftrag von Steve Rooke > >> Gesendet: Donnerstag, 9. April 2009 14:00 > >> An: Tom Van Baak; Discussion of precise time and frequency > >> measurement > >> Betreff: Re: [time-nuts] Characterising frequency standards > >> > >> > >> Tom, > >> > >> 2009/4/9 Tom Van Baak : > >> > The first argument to the adev1 program is the sampling > >> interval t0. > >> > The program doesn't know how far apart the input file > samples are > >> > taken so it is your job to specify this. The default is 1 second. > >> > > >> > If you have data taken one second apart then t0 = 1. > >> > If you have data taken two seconds apart then t0 = 2. > >> > If you have data taken 60 seconds apart then t0 = 60, etc. > >> > > >> > If, as in your case, you take raw one second data and > remove every > >> > other sample (a perfectly valid thing to do), then t0 = 2. > >> > > >> > Make sense now? It's still "continuous data" in the > sense that all > >> > measurements are a fixed interval apart. But in any ADEV > >> calculation > >> > you have to specify the raw data interval. > >> > >> I think the penny has dropped now, thanks. It's > interesting that the > >> ADEV calculation still works even without continuous data > as all the > >> reading I have done has led me to belive this was sacrosanct. > >> > >> What I now believe is that it's possible to measure oscillator > >> performance with less than optimal test gear. This will > enable me to > >> see the effects of any experiments I make in the future. > If you can't > >> measure it, how can you know that what your doing is good or bad. > >> > >> 73, > >> Steve > >> -- > >> Steve Rooke - ZL3TUV & G8KVD & JAKDTTNW > >> Omnium finis imminet > >> > >> _______________________________________________ > >> time-nuts mailing list -- time-nuts at febo.com > >> To unsubscribe, go to > >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > >> and follow the instructions there. > > > > > > _______________________________________________ > > time-nuts mailing list -- time-nuts at febo.com > > To unsubscribe, go to > > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > > and follow the instructions there. > > > > > > -- > Steve Rooke - ZL3TUV & G8KVD & JAKDTTNW > Omnium finis imminet > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. From tvb at LeapSecond.com Fri Apr 10 17:42:25 2009 From: tvb at LeapSecond.com (Tom Van Baak) Date: Fri, 10 Apr 2009 10:42:25 -0700 Subject: [time-nuts] Characterising frequency standards References: <4176CE16020C49449B55FCA770F8B7E5@athlon> Message-ID: > Nevertheless leaving every second sample out is NOT exactly the same as > continous data with Tau0 = 2 s. Instead it is data with Tau0 = 1 s and a > DEAD TIME of 1s. There are dead time correction schemes available in the > literature. Ulrich, and Steve, Wait, are we talking phase measurements here or frequency measurements? My assumption with this thread is that Steve is simply taking phase (time error) measurements, as in my GPS raw data page, in which case there is no such thing as dead time. /tvb From cfharris at erols.com Fri Apr 10 18:00:38 2009 From: cfharris at erols.com (Chuck Harris) Date: Fri, 10 Apr 2009 14:00:38 -0400 Subject: [time-nuts] Hadamard variance In-Reply-To: <103F10C3F49C42CA9ED1EA3D0626F6F9@athlon> References: <103F10C3F49C42CA9ED1EA3D0626F6F9@athlon> Message-ID: <49DF8946.6060001@erols.com> Ulrich Bangert wrote: > Steve, > >> It was probably the first real high level language that I got >> to play with and I have fond memories of it. > > I own a HP67 calculator and since when it came to the market I was too young > to have the money to buy it, I have also lots of memories concerning these > times. > > Neverthelesss it is truly NOT the tool that I use today. Really? I ditched my newer calculators, and my HP67 is the only calculator I use now. If I need more power, I use a computer. -Chuck Harris From EWKehren at aol.com Fri Apr 10 18:23:49 2009 From: EWKehren at aol.com (EWKehren at aol.com) Date: Fri, 10 Apr 2009 14:23:49 EDT Subject: [time-nuts] R&S XSD-2 - help needed Message-ID: Do you have a picture of the unit and of the guts? Bert Kehren Miami In a message dated 4/10/2009 8:17:13 A.M. Eastern Daylight Time, ik1odo at spin-it.com writes: Hello, I got a broken Rohde&Schwarz XSD-2 crystal oscillator module, type 283.6010.02 . By first, has anyone a schematic for it? Then, the dewar flask originally containing the oscillator mass is broken. Size was (approx) 65 mm internal diameter, 150 mm internal height. Who has similar dewars? The volume is close to 0.5 liters, and I have not found an useful replacement for common "thermos" flasks of that size. Any help appreciated! 73 - Marco IK1ODO / AI4YF _______________________________________________ time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. **************Worried about job security? Check out the 5 safest jobs in a recession. (http://jobs.aol.com/gallery/growing-job-industries?ncid=emlcntuscare00000003) From ik1odo at spin-it.com Fri Apr 10 18:35:22 2009 From: ik1odo at spin-it.com (Marco IK1ODO) Date: Fri, 10 Apr 2009 20:35:22 +0200 Subject: [time-nuts] R&S XSD-2 - help needed In-Reply-To: References: Message-ID: At 20.23 10/04/2009, you wrote: >Do you have a picture of the unit and of the guts? Bert Kehren Miami I will take some pics and send to you tomorrow. Marco From EWKehren at aol.com Fri Apr 10 18:37:48 2009 From: EWKehren at aol.com (EWKehren at aol.com) Date: Fri, 10 Apr 2009 14:37:48 EDT Subject: [time-nuts] R&S XSD-2 - help needed Message-ID: My email is _Ewkehren at AOL.com_ (mailto:Ewkehren at AOL.com) Bert In a message dated 4/10/2009 2:36:44 P.M. Eastern Daylight Time, ik1odo at spin-it.com writes: At 20.23 10/04/2009, you wrote: >Do you have a picture of the unit and of the guts? Bert Kehren Miami I will take some pics and send to you tomorrow. Marco _______________________________________________ time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. **************Worried about job security? Check out the 5 safest jobs in a recession. (http://jobs.aol.com/gallery/growing-job-industries?ncid=emlcntuscare00000003) From magnus at rubidium.dyndns.org Fri Apr 10 20:09:33 2009 From: magnus at rubidium.dyndns.org (Magnus Danielson) Date: Fri, 10 Apr 2009 22:09:33 +0200 Subject: [time-nuts] Characterising frequency standards In-Reply-To: References: <4176CE16020C49449B55FCA770F8B7E5@athlon> Message-ID: <49DFA77D.1070405@rubidium.dyndns.org> Tom Van Baak skrev: >> Nevertheless leaving every second sample out is NOT exactly the same as >> continous data with Tau0 = 2 s. Instead it is data with Tau0 = 1 s and a >> DEAD TIME of 1s. There are dead time correction schemes available in the >> literature. > > Ulrich, and Steve, > > Wait, are we talking phase measurements here or frequency > measurements? My assumption with this thread is that Steve > is simply taking phase (time error) measurements, as in my > GPS raw data page, in which case there is no such thing as > dead time. I agree. I was also considering this earlier but put my mind to rest by assuming phase/time samples. Dead time is when the counter looses track of time in between two consecutive measurements. A zero dead-time counter uses the stop of one measure as the start of the next measure. If you have a series of time-error values taken each second and then drop every other sample and just recall that the time between the samples is now 2 seconds, then the tau0 has become 2s without causing dead-time. However, if the original data would have been kept, better statistical properties would be given, unless there is a strong repetitive disturbance at 2 s period, in which case it would be filtered out. An example when one does get dead-time, consider a frequency counter which measures frequency with a gate-time of say 2 s. However, before it re-arms and start the next measures is takes 300 ms. The two samples will have 2,3 s between its start and actually spans 4,3 seconds rather than 4 seconds. When doing Allan Deviation calculations on such a measurement series, it will be biased and the bias may be compensated, but these days counters with zero dead-time is readily available or the problem can be avoided by careful consideration. I believe Grenhall made some extensive analysis of the biasing of dead-time, so it should be available from NIST F&T online library. Before zero dead-time counters was available, a setup of two counters was used so that they where interleaved so the dead-time was the measure time of the other. I can collect some references to dead-time articles if anyone need them. I'd happy to. Cheers, Magnus From tvb at LeapSecond.com Fri Apr 10 20:38:55 2009 From: tvb at LeapSecond.com (Tom Van Baak) Date: Fri, 10 Apr 2009 13:38:55 -0700 Subject: [time-nuts] OT: 10 MHz data capture, help Message-ID: I have a old data device that is spitting out TTL data at 10 MHz. There's just a data line (no clock) but the edges clearly indicate an internal 10 MHz clock. I'd like to do a continuous capture of the bits, for up to tens of minutes, into a PC. That comes to about 1 GB of raw data. I can handle the decoding of the bits in software after the capture is done. This is a one-time experiment. What is the best/quickest/easiest way to capture data like this? I've looked at various USB or LAN logic analyzer and 'scopes but most seem to work on batches of data. I need a continuous capture. /tvb From wb6bnq at cox.net Fri Apr 10 20:57:59 2009 From: wb6bnq at cox.net (WB6BNQ) Date: Fri, 10 Apr 2009 13:57:59 -0700 Subject: [time-nuts] OT: 10 MHz data capture, help References: Message-ID: <49DFB2D7.C7CF34E3@cox.net> Hi TVB, How about directly capturing it by reading one of the logic bits of the parallel port ? Bill....WB6BNQ Tom Van Baak wrote: > I have a old data device that is spitting out TTL data at 10 MHz. > There's just a data line (no clock) but the edges clearly indicate > an internal 10 MHz clock. > > I'd like to do a continuous capture of the bits, for up to tens of > minutes, into a PC. That comes to about 1 GB of raw data. I can > handle the decoding of the bits in software after the capture is > done. This is a one-time experiment. > > What is the best/quickest/easiest way to capture data like this? > I've looked at various USB or LAN logic analyzer and 'scopes > but most seem to work on batches of data. I need a continuous > capture. > > /tvb > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. From dforbes at dakotacom.net Fri Apr 10 21:01:14 2009 From: dforbes at dakotacom.net (David Forbes) Date: Fri, 10 Apr 2009 14:01:14 -0700 Subject: [time-nuts] OT: 10 MHz data capture, help In-Reply-To: References: Message-ID: <49DFB39A.2030903@dakotacom.net> Tom Van Baak wrote: > I have a old data device that is spitting out TTL data at 10 MHz. > There's just a data line (no clock) but the edges clearly indicate > an internal 10 MHz clock. > > I'd like to do a continuous capture of the bits, for up to tens of > minutes, into a PC. That comes to about 1 GB of raw data. I can > handle the decoding of the bits in software after the capture is > done. This is a one-time experiment. > > What is the best/quickest/easiest way to capture data like this? > I've looked at various USB or LAN logic analyzer and 'scopes > but most seem to work on batches of data. I need a continuous > capture. > > /tvb > Tom, The common way to do this is with a fast PCI analog input card. There are models that run at several tens of MSPS. You should be able to write a very small C application using their drivers to continuously log the digitized data to a file as binary or ASCII values. Here's a 30MSPS card: http://www.advantech.com/products/PCI-1714U/mod_GF-HQHV.aspx --David Forbes, Tucson From magnus at rubidium.dyndns.org Fri Apr 10 21:15:15 2009 From: magnus at rubidium.dyndns.org (Magnus Danielson) Date: Fri, 10 Apr 2009 23:15:15 +0200 Subject: [time-nuts] OT: 10 MHz data capture, help In-Reply-To: References: Message-ID: <49DFB6E3.1010509@rubidium.dyndns.org> Tom Van Baak skrev: > I have a old data device that is spitting out TTL data at 10 MHz. > There's just a data line (no clock) but the edges clearly indicate > an internal 10 MHz clock. > > I'd like to do a continuous capture of the bits, for up to tens of > minutes, into a PC. That comes to about 1 GB of raw data. I can > handle the decoding of the bits in software after the capture is > done. This is a one-time experiment. > > What is the best/quickest/easiest way to capture data like this? > I've looked at various USB or LAN logic analyzer and 'scopes > but most seem to work on batches of data. I need a continuous > capture. Have a look at the GNSS sampler for instance. It can handle the data rate fairly easilly. A GNSS sampler would be easy to modify for this application. Using a standard 8 bit serdes clocking in at 10 MHz and outputing data in the rate of 1,25 MB would make it efficient. It's a standard USB chip in there and it handles continous streams fairly easilly. It's the same as in the software defined radio stuff, which would be another option. Regardless it would be able to handle your datastream without too much trouble. Cheers, Magnus From jdb at lartmaker.nl Fri Apr 10 22:23:04 2009 From: jdb at lartmaker.nl (J.D. Bakker) Date: Fri, 10 Apr 2009 23:23:04 +0100 Subject: [time-nuts] OT: 10 MHz data capture, help In-Reply-To: References: Message-ID: >I have a old data device that is spitting out TTL data at 10 MHz. >There's just a data line (no clock) but the edges clearly indicate >an internal 10 MHz clock. > >I'd like to do a continuous capture of the bits, for up to tens of >minutes, into a PC. That comes to about 1 GB of raw data. I can >handle the decoding of the bits in software after the capture is >done. This is a one-time experiment. Assuming this is a single data line, that's over 1MB per second, more than a traditional parallel port can easily handle. There are no cheap ubiquitous means to get that amount of data into a PC. The methods that I know of are expensive, either in money or engineering effort, including: - Get a digital I/O card. There are few of these around which can support your required data rate. One that I used in the distant past is the ADLink PCI-7200; I suspect NI may have a few offerings. You may have to DIY a shift register to get the data from serial to parallel. - Get a fast analog I/O card, record the data (now several GB worth) and apply some DSP to recover the digital data. This looks like a roundabout way, but analog I/O cards are more common and thus easier to borrow for an afternoon. Again NI has a few, but something like the HPSDR Mercury (http://www.hpsdr.org/) might work too; I'm not sure if the Mercury FPGA code can do 'wide' baseband sampling yet. A variant of this scheme would include a shift register and a simple D/A converter to get the rate down. - Build a board that converts the data stream to Ethernet or USB. I know of no COTS solutions for this, although I suspect the HPSDR Ozy FPGA can be re-coded to handle this. - Build a standalone data recorder, either with a microcontroller or CPLD/FPGA. JDB. [currently working on the standalone data recorder for a data capture application] -- LART. 250 MIPS under one Watt. Free hardware design files. http://www.lartmaker.nl/ From sar10538 at gmail.com Fri Apr 10 21:27:20 2009 From: sar10538 at gmail.com (Steve Rooke) Date: Sat, 11 Apr 2009 09:27:20 +1200 Subject: [time-nuts] Hadamard variance In-Reply-To: <103F10C3F49C42CA9ED1EA3D0626F6F9@athlon> References: <1231b6a80904100456j603a2748ib800c3bb65aa9c5e@mail.gmail.com> <103F10C3F49C42CA9ED1EA3D0626F6F9@athlon> Message-ID: <1231b6a80904101427g1115e4dei167fea7fccadee2a@mail.gmail.com> Ulrich, 2009/4/11 Ulrich Bangert : > Steve, > >> It was probably the first real high level language that I got >> to play with and I have fond memories of it. > > I own a HP67 calculator and since when it came to the market I was too young > to have the money to buy it, I have also lots of memories concerning these > times. My first was a Ti-57 and spent many a happy hour writing things to fit 50 program steps. It had no means of storage so I had to type them in each time I wanted to run a program. The next was a HP65 that I love dearly and still have that to this very day. You'd have to prise it from my cold dead hands but it sits in a draw and others have taken the day to day work. I've been playing with Plotter.exe and it's a very fine tool. I can see it being very useful in the future for me. Best wishes, Steve > Neverthelesss it is truly NOT the tool that I use today. > > Best regards > Ulrich Bangert > >> -----Ursprungliche Nachricht----- >> Von: time-nuts-bounces at febo.com >> [mailto:time-nuts-bounces at febo.com] Im Auftrag von Steve Rooke >> Gesendet: Freitag, 10. April 2009 13:57 >> An: Discussion of precise time and frequency measurement >> Betreff: Re: [time-nuts] Hadamard variance >> >> >> It was probably the first real high level language that I got >> to play with and I have fond memories of it. >> >> 73, >> Steve >> >> 2009/4/10 David C. Partridge : >> > PL/1 - now that brings back memories - nice language! >> > >> > Dave Partridge >> > -----Original Message----- >> > From: time-nuts-bounces at febo.com >> [mailto:time-nuts-bounces at febo.com] >> > On Behalf Of Steve Rooke >> > Sent: 09 April 2009 12:36 >> > To: Discussion of precise time and frequency measurement >> > Subject: Re: [time-nuts] Hadamard variance >> > >> >>If it was down to me I'd probably write everything in Forth or PL1. >> > >> > 73, >> > Steve - ZL3TUV & G8KVD >> > >> > >> > _______________________________________________ >> > time-nuts mailing list -- time-nuts at febo.com >> > To unsubscribe, go to >> > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> > and follow the instructions there. >> > >> >> >> >> -- >> Steve Rooke - ZL3TUV & G8KVD & JAKDTTNW >> Omnium finis imminet >> >> _______________________________________________ >> time-nuts mailing list -- time-nuts at febo.com >> To unsubscribe, go to >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > -- Steve Rooke - ZL3TUV & G8KVD & JAKDTTNW Omnium finis imminet From sar10538 at gmail.com Fri Apr 10 21:29:45 2009 From: sar10538 at gmail.com (Steve Rooke) Date: Sat, 11 Apr 2009 09:29:45 +1200 Subject: [time-nuts] Hadamard variance In-Reply-To: <49DF6AFE.4040201@rubidium.dyndns.org> References: <1231b6a80904080559o7a4cf618r49276df9d7599820@mail.gmail.com> <951FB64B18654ECE97BFC40BBDC1D2B3@pc52> <1231b6a80904090429i165b6627sb83ee88a25069e1b@mail.gmail.com> <49DDFD6D.3040207@xtra.co.nz> <1231b6a80904100445g381cc06eja1616eab3fe0f096@mail.gmail.com> <49DF6AFE.4040201@rubidium.dyndns.org> Message-ID: <1231b6a80904101429t34e677fh8adb39a333d04508@mail.gmail.com> 2009/4/11 Magnus Danielson : >> Point well taken. In that case we need a new deviation measurement >> with 4 elements then :-) > > Will not help to fully cancel the effect as crystal drift is a function > of log. See Vig on crystal oscillators at IEEE UFFC pages. > > One needs to identify the drift shape, estimates its parameters and then > remove the estimated value from phase or frequency data. I was not being serious Magnus, I did add the smiley. 73, Steve -- Steve Rooke - ZL3TUV & G8KVD & JAKDTTNW Omnium finis imminet From wb6bnq at cox.net Fri Apr 10 21:31:59 2009 From: wb6bnq at cox.net (WB6BNQ) Date: Fri, 10 Apr 2009 14:31:59 -0700 Subject: [time-nuts] OT: 10 MHz data capture, help References: Message-ID: <49DFBACF.564B23C0@cox.net> Tom Van Baak wrote: > I have a old data device that is spitting out TTL data at 10 MHz. > There's just a data line (no clock) but the edges clearly indicate > an internal 10 MHz clock. > > I'd like to do a continuous capture of the bits, for up to tens of > minutes, into a PC. That comes to about 1 GB of raw data. I can > handle the decoding of the bits in software after the capture is > done. This is a one-time experiment. > > What is the best/quickest/easiest way to capture data like this? > I've looked at various USB or LAN logic analyzer and 'scopes > but most seem to work on batches of data. I need a continuous > capture. > > /tvb Tom, As others have suggested, perhaps a Software Defined Receiver would do the trick. The best one on the market and the cheapest uses a very high speed A/D process for a range of 500Hz to 30MHz. Look at the following URL: http://www.rfspace.com/SDR-IQ.html Bill....WB6BNQ From sometimesyoufeellikeanut at twentylogten.com Fri Apr 10 21:34:12 2009 From: sometimesyoufeellikeanut at twentylogten.com (Chris Mack / N1SKY) Date: Fri, 10 Apr 2009 17:34:12 -0400 Subject: [time-nuts] OT: 10 MHz data capture, help In-Reply-To: <49DFB6E3.1010509@rubidium.dyndns.org> References: <49DFB6E3.1010509@rubidium.dyndns.org> Message-ID: I am on the road right now, so I am not in front of it, but I have the HandyScope HS3 100MHz USB which can run a strip chart recorder for days / years if you like; depending on hard drive space. The strip chart may be only available at lower speeds? I dunno... I can't remember.... but the Handyscope supports both block transfer and streaming transfer over USB last I knew for certain speeds... They also have exposed functions available in the DLLs that can probably be accessed via standard ActiveX / COM methodologies from any language include VB, C# / C++, PERL (win32 OLE) etc. http://www.tiepie.com/uk/products/External_Instruments/ USB_Oscilloscope/Handyscope_HS3.html Maybe you have seen this one already... I dunno if it could work for you? maybe? Cheers, -chris On Apr 10, 2009, at 5:15 PM, Magnus Danielson wrote: > Tom Van Baak skrev: >> I have a old data device that is spitting out TTL data at 10 MHz. >> There's just a data line (no clock) but the edges clearly indicate >> an internal 10 MHz clock. >> >> I'd like to do a continuous capture of the bits, for up to tens of >> minutes, into a PC. That comes to about 1 GB of raw data. I can >> handle the decoding of the bits in software after the capture is >> done. This is a one-time experiment. >> >> What is the best/quickest/easiest way to capture data like this? >> I've looked at various USB or LAN logic analyzer and 'scopes >> but most seem to work on batches of data. I need a continuous >> capture. > > Have a look at the GNSS sampler for instance. It can handle the data > rate fairly easilly. A GNSS sampler would be easy to modify for this > application. Using a standard 8 bit serdes clocking in at 10 MHz and > outputing data in the rate of 1,25 MB would make it efficient. It's a > standard USB chip in there and it handles continous streams fairly > easilly. It's the same as in the software defined radio stuff, which > would be another option. Regardless it would be able to handle your > datastream without too much trouble. > > Cheers, > Magnus > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/ > time-nuts > and follow the instructions there. From wb6bnq at cox.net Fri Apr 10 21:36:12 2009 From: wb6bnq at cox.net (WB6BNQ) Date: Fri, 10 Apr 2009 14:36:12 -0700 Subject: [time-nuts] OT: 10 MHz data capture, help References: <49DFBACF.564B23C0@cox.net> Message-ID: <49DFBBCC.9337DD35@cox.net> WB6BNQ wrote: > Tom Van Baak wrote: > > > I have a old data device that is spitting out TTL data at 10 MHz. > > There's just a data line (no clock) but the edges clearly indicate > > an internal 10 MHz clock. > > > > I'd like to do a continuous capture of the bits, for up to tens of > > minutes, into a PC. That comes to about 1 GB of raw data. I can > > handle the decoding of the bits in software after the capture is > > done. This is a one-time experiment. > > > > What is the best/quickest/easiest way to capture data like this? > > I've looked at various USB or LAN logic analyzer and 'scopes > > but most seem to work on batches of data. I need a continuous > > capture. > > > > /tvb > > Tom, > > As others have suggested, perhaps a Software Defined Receiver would do the > trick. The best one on the market and the cheapest uses a very high speed A/D > process for a range of 500Hz to 30MHz. > > Look at the following URL: http://www.rfspace.com/SDR-IQ.html > > Bill....WB6BNQ > I forgot to point out that the price is $499.00. QUITE reasonable ! Bill....WB6BNQ From jdb at lartmaker.nl Fri Apr 10 22:44:16 2009 From: jdb at lartmaker.nl (J.D. Bakker) Date: Fri, 10 Apr 2009 23:44:16 +0100 Subject: [time-nuts] OT: 10 MHz data capture, help In-Reply-To: <49DFBACF.564B23C0@cox.net> References: <49DFBACF.564B23C0@cox.net> Message-ID: At 14:31 -0700 10-04-2009, WB6BNQ wrote: >As others have suggested, perhaps a Software Defined Receiver would do the >trick. The best one on the market and the cheapest uses a very high speed A/D >process for a range of 500Hz to 30MHz. > >Look at the following URL: http://www.rfspace.com/SDR-IQ.html Doesn't the SDR-IQ use an AD6620 digital downconverter to reduce the bandwidth to a few hundred kHz? I've never used it, but its block diagram would appear to suggest so, plus it uses a FT245RL USB interface which is limited to full speed USB (ie 12Mbit). If so, that's not enough bandwidth for Tom's 10Mbit/sec signal. JDB. -- LART. 250 MIPS under one Watt. Free hardware design files. http://www.lartmaker.nl/ From phk at phk.freebsd.dk Fri Apr 10 22:20:48 2009 From: phk at phk.freebsd.dk (Poul-Henning Kamp) Date: Fri, 10 Apr 2009 22:20:48 +0000 Subject: [time-nuts] OT: 10 MHz data capture, help In-Reply-To: Your message of "Fri, 10 Apr 2009 13:38:55 MST." Message-ID: <20524.1239402048@critter.freebsd.dk> In message , "Tom Van Baak" writes: >What is the best/quickest/easiest way to capture data like this? >I've looked at various USB or LAN logic analyzer and 'scopes >but most seem to work on batches of data. I need a continuous >capture. GNUradios USRP ? -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 phk at FreeBSD.ORG | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. From holrum at hotmail.com Fri Apr 10 22:28:27 2009 From: holrum at hotmail.com (Mark Sims) Date: Fri, 10 Apr 2009 22:28:27 +0000 Subject: [time-nuts] OT favorite chip programmer/favorite ROM emulator In-Reply-To: References: Message-ID: Hello Chuck, I have used the Advin programmers and have run into every problem you mentioned, and then some... And forget those little USB programmers... they can work for simple EPROMS, but get into anything else and all bets are off. I much prefer the Data I/O machines... warts and all. They are totally independent of the host machine for programming control (they only need a VT100 terminal emulator). And their pin drivers have not had to change in 25 years. The base machine holds up to 68 pin drivers. The Pinsite modules for doing non-dip packages expands on that. Biggest wart is the Unisite design has not changed in over 25 years. It still uses 720Kb floppies... really now... 720Kb floppies in the year 2009... but that is a non-issue if you have one with the Mass Storage Module (which even though it may have a 512 meg drive on it, only uses 80 meg... silly). Also 8 meg of RAM is a bit silly... but with the programmer under host PC control is not a problem. And don't get me started on those silly compression pad sockets... I've worn out more than one Drunken Russian Sailor's Guide to Curses and Taunts there. DIO makes their living gouging their customers on upgrades and socket adapters (hey, why charge $2000 for a programmer when you can charge $40,000+). If you have a software set that works for you, don't spend the 2 grand to upgrade. But DIO algorithm CDs regularly show up on Ebay for cheap. I have a net cost of around zero dollars (or possibly a small net profit) in my unit and adapters which would have cost over $80,000 if bought new from DIO. I built it up out of around 10 Ebay machines (which I stripped of unique adapters, cleaned up, tested, and then resold the remains). It supports over 25,000 devices with algorithms that are the gold standard in the industry. I have never run into a device that I can't program (except for the MCM2801 and SDA2006 very early serial EEPROMS (which I built my own programmers for)). I don't think the machine will do 1702's either, but I have never needed to do one. Mark _________________________________________________________________ Rediscover Hotmail?: Get e-mail storage that grows with you. http://windowslive.com/RediscoverHotmail?ocid=TXT_TAGLM_WL_HM_Rediscover_Storage1_042009 From optomatic at rogers.com Fri Apr 10 22:56:47 2009 From: optomatic at rogers.com (Patrick) Date: Fri, 10 Apr 2009 18:56:47 -0400 Subject: [time-nuts] OT favorite chip programmer/favorite ROM emulator In-Reply-To: References: Message-ID: <49DFCEAF.8080104@rogers.com> Hi David Thanks for taking the time to post. Have a great Easter-Patrick David C. Partridge wrote: > Another one to look at apparently is the Galep model 4(LPT) or 5(USB). I > don't have one but when this question was asked recently elsewhere, they > were very highly recommended - and very good support. > > > > Dave > > -----Original Message----- > From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On > Behalf Of Mark Sims > Sent: 10 April 2009 04:17 > To: time-nuts at febo.com > Subject: [time-nuts] OT favorite chip programmer/favorite ROM emulator > > > By far the best programmer on the planet is still the Data I/O Unisite > (followed by the 3980, 3900, and 2900 prorgrammers). If a Unisite can't > program it, you are in bad shape... it probably can't be programmed. > > Bad news is a refurbed Unisite will set you back $25,000 plus the cost of > socket adapters and software. Good news is with a little shopping around on > Ebay, you can possibly snag one for around $100. > > The trick is to find one with the socket adapters you need. Also the more > pin driver cards it has installed, the better (a full load is 17 cards/68 > pin drivers). Also, one with the internal hard drive (aka MSM, aka Mass > Storage Module) is very desirable. Booting from a (720Kb only) floppy can > take several minutes. > > I have purchased several machines just because they had an adapter that I > did not have. Also you need to make sure it comes with a full set of > programming software (generally, the later the version better) because a > current software set from DIO will set you back over $2000... > > For more info, check out Bruce Lane's guide to DIO machines on Ebay: > http://reviews.ebay.com/Data-I-O-Device-Programmers-A-Condensed-Reference_W0 > QQugidZ10000000001698682?ssPageName=BUYGD:CAT:-1:SEARCH:3 > ---------------------------------------- > > > _________________________________________________________________ > Rediscover HotmailR: Get quick friend updates right in your inbox. > http://windowslive.com/RediscoverHotmail?ocid=TXT_TAGLM_WL_HM_Rediscover_Upd > ates1_042009 > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > From optomatic at rogers.com Fri Apr 10 22:58:22 2009 From: optomatic at rogers.com (Patrick) Date: Fri, 10 Apr 2009 18:58:22 -0400 Subject: [time-nuts] OT favorite chip programmer/favorite ROM emulator In-Reply-To: <49DFCEAF.8080104@rogers.com> References: <49DFCEAF.8080104@rogers.com> Message-ID: <49DFCF0E.2070607@rogers.com> Sorry everyone I was sending out my thanks and I accidentally posted to the list-Patrick Patrick wrote: > Hi David > > Thanks for taking the time to post. > > Have a great Easter-Patrick > > David C. Partridge wrote: > >> Another one to look at apparently is the Galep model 4(LPT) or 5(USB). I >> don't have one but when this question was asked recently elsewhere, they >> were very highly recommended - and very good support. >> >> >> >> Dave >> >> -----Original Message----- >> From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On >> Behalf Of Mark Sims >> Sent: 10 April 2009 04:17 >> To: time-nuts at febo.com >> Subject: [time-nuts] OT favorite chip programmer/favorite ROM emulator >> >> >> By far the best programmer on the planet is still the Data I/O Unisite >> (followed by the 3980, 3900, and 2900 prorgrammers). If a Unisite can't >> program it, you are in bad shape... it probably can't be programmed. >> >> Bad news is a refurbed Unisite will set you back $25,000 plus the cost of >> socket adapters and software. Good news is with a little shopping around on >> Ebay, you can possibly snag one for around $100. >> >> The trick is to find one with the socket adapters you need. Also the more >> pin driver cards it has installed, the better (a full load is 17 cards/68 >> pin drivers). Also, one with the internal hard drive (aka MSM, aka Mass >> Storage Module) is very desirable. Booting from a (720Kb only) floppy can >> take several minutes. >> >> I have purchased several machines just because they had an adapter that I >> did not have. Also you need to make sure it comes with a full set of >> programming software (generally, the later the version better) because a >> current software set from DIO will set you back over $2000... >> >> For more info, check out Bruce Lane's guide to DIO machines on Ebay: >> http://reviews.ebay.com/Data-I-O-Device-Programmers-A-Condensed-Reference_W0 >> QQugidZ10000000001698682?ssPageName=BUYGD:CAT:-1:SEARCH:3 >> ---------------------------------------- >> >> >> _________________________________________________________________ >> Rediscover HotmailR: Get quick friend updates right in your inbox. >> http://windowslive.com/RediscoverHotmail?ocid=TXT_TAGLM_WL_HM_Rediscover_Upd >> ates1_042009 >> _______________________________________________ >> time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. >> >> >> _______________________________________________ >> time-nuts mailing list -- time-nuts at febo.com >> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. >> >> >> > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > From eliocor at gmail.com Fri Apr 10 23:13:23 2009 From: eliocor at gmail.com (Elio Corbolante) Date: Sat, 11 Apr 2009 01:13:23 +0200 Subject: [time-nuts] OT: 10 MHz data capture, help Message-ID: <6077b10a0904101613q438f4040n20dfbcfcb280fc50@mail.gmail.com> > > ---------- Forwarded message ---------- > From: "Tom Van Baak" > To: "Discussion of precise time and frequency measurement" < > time-nuts at febo.com> > Date: Fri, 10 Apr 2009 13:38:55 -0700 > Subject: [time-nuts] OT: 10 MHz data capture, help > I'd like to do a continuous capture of the bits, for up to tens of > minutes, into a PC. That comes to about 1 GB of raw data. I can > handle the decoding of the bits in software after the capture is > done. This is a one-time experiment. > > What is the best/quickest/easiest way to capture data like this? > I've looked at various USB or LAN logic analyzer and 'scopes > but most seem to work on batches of data. I need a continuous > capture. > Maybe you can use one of those products: http://www.usbee.com/ just to not waste samples memory, you can deserialize the signal with a 8 bit Shift register and use the clock/8 as trigger for sampling received data. Unfortunately, the cheaper one (SX) lets you use only your PC memory as capture buffer. You have to resort to more expensive models to directly stream your data to HDD. Elio. From SAIDJACK at aol.com Fri Apr 10 23:18:19 2009 From: SAIDJACK at aol.com (SAIDJACK at aol.com) Date: Fri, 10 Apr 2009 19:18:19 EDT Subject: [time-nuts] OT: 10 MHz data capture, help Message-ID: Hello Tom, Not sure if someone said this already, the Wavecrest units can sample your data. Up to 40K samples per second continuous according to their literature, via GPIB. Their PC application software (VISI) has a scope mode where you can make this data visible just like on a two-channel sampling scope. If you are lucky, you can pick one up for ~$500 on Ebay, or rent one. bye, Said In a message dated 4/10/2009 16:13:59 Pacific Daylight Time, eliocor at gmail.com writes: > > ---------- Forwarded message ---------- > From: "Tom Van Baak" > To: "Discussion of precise time and frequency measurement" < > time-nuts at febo.com> > Date: Fri, 10 Apr 2009 13:38:55 -0700 > Subject: [time-nuts] OT: 10 MHz data capture, help > I'd like to do a continuous capture of the bits, for up to tens of > minutes, into a PC. That comes to about 1 GB of raw data. I can > handle the decoding of the bits in software after the capture is > done. This is a one-time experiment. > > What is the best/quickest/easiest way to capture data like this? > I've looked at various USB or LAN logic analyzer and 'scopes > but most seem to work on batches of data. I need a continuous > capture. > From SAIDJACK at aol.com Sat Apr 11 07:22:48 2009 From: SAIDJACK at aol.com (SAIDJACK at aol.com) Date: Sat, 11 Apr 2009 03:22:48 EDT Subject: [time-nuts] Fwd: OT: 10 MHz data capture, help Message-ID: Sorry, my previous post should have read: 40K individual Time Interval Measurements per second on the Wavecrest. I think it's the fastest time interval counter out there? Said From jra at febo.com Sat Apr 11 13:09:06 2009 From: jra at febo.com (John Ackermann N8UR) Date: Sat, 11 Apr 2009 09:09:06 -0400 Subject: [time-nuts] HP 5061A vs. FTS 4050 performance? Message-ID: <49E09672.9000409@febo.com> I think the (retrofitted FTS) tube in my nice, later production, 5061A Cs died. I have an FTS-4000 unit with a power supply problem, but with a working tube. I believe the FTS-4000 is the guts of the older FTS standards like the 4050. I'm wondering whether I'd end up with better performance putting the good tube into the 5061A, or keeping it in the FTS-4000 and fixing the power supply. Any thoughts? John From kilodelta4foxmike at gmail.com Sat Apr 11 14:16:01 2009 From: kilodelta4foxmike at gmail.com (Brian Kirby) Date: Sat, 11 Apr 2009 09:16:01 -0500 Subject: [time-nuts] HP 5061A vs. FTS 4050 performance? In-Reply-To: <49E09672.9000409@febo.com> References: <49E09672.9000409@febo.com> Message-ID: <49E0A621.9060101@gmail.com> You will be less miserable if you send me both units and buy yourself a new one...old time-nut proverb Brian John Ackermann N8UR wrote: > I think the (retrofitted FTS) tube in my nice, later production, 5061A > Cs died. I have an FTS-4000 unit with a power supply problem, but with > a working tube. I believe the FTS-4000 is the guts of the older FTS > standards like the 4050. > > I'm wondering whether I'd end up with better performance putting the > good tube into the 5061A, or keeping it in the FTS-4000 and fixing the > power supply. > > Any thoughts? > > John > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > From magnus at rubidium.dyndns.org Sat Apr 11 14:43:21 2009 From: magnus at rubidium.dyndns.org (Magnus Danielson) Date: Sat, 11 Apr 2009 16:43:21 +0200 Subject: [time-nuts] Fwd: OT: 10 MHz data capture, help In-Reply-To: References: Message-ID: <49E0AC89.7010606@rubidium.dyndns.org> SAIDJACK at aol.com skrev: > Sorry, my previous post should have read: 40K individual Time Interval > Measurements per second on the Wavecrest. I think it's the fastest time > interval counter out there? No. The HP5372A happily gives you a rate at 13,3 MHz sample rate. I think the SIA-3000 is higher than 40k too (I think I recall 200k) and I know that the Pendulum CNT-90 and followers also passes that rate. It is however far from that simple number, as maximum block length can vary alot and continous mode rate can be lower than burst-rate due to pure I/O concerns. In general will binary output perform better than ASCII output. The HP5372A binary output mode is actually pure core data values, which means that the CPU is only copying the databits and does I/O processing rather than elaborate calculations. The HP5372A also has a binary output option which would allow continous stream output at full rate as data is hooked in before the 8192 sample long block memory (where 1 or more samples is lost as reference samples, which explains the kind of odd varying sample lengths). A derivate of the HP5372A in VXI form can come up to 80 Msamples/s as I recall it. However, that is among the few major spec changes than from the HP5372A cases. So, there is two classes of performance: burst-rate and continous mode. Burst-rate mode is limited by maximum sample burst rate (essentially limited by the time between two sample) and burst length (number of samples). Continous mode is limited by sample rate alone, which really is an effect of I/O. Many counters actually lack a dedicated continous mode, but can be tricked into it by running them re-triggered and do synchronised binary readout. Very few counters have dedicated hardware features for accelerated continous mode. Cheers, Magnus From EWKehren at aol.com Sat Apr 11 17:35:03 2009 From: EWKehren at aol.com (EWKehren at aol.com) Date: Sat, 11 Apr 2009 13:35:03 EDT Subject: [time-nuts] HP 5061A vs. FTS 4050 performance? Message-ID: Do you know what the Power supply problem is. I have spares. Bert Miami In a message dated 4/11/2009 9:10:11 A.M. Eastern Daylight Time, jra at febo.com writes: I think the (retrofitted FTS) tube in my nice, later production, 5061A Cs died. I have an FTS-4000 unit with a power supply problem, but with a working tube. I believe the FTS-4000 is the guts of the older FTS standards like the 4050. I'm wondering whether I'd end up with better performance putting the good tube into the 5061A, or keeping it in the FTS-4000 and fixing the power supply. Any thoughts? John _______________________________________________ time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. **************Worried about job security? Check out the 5 safest jobs in a recession. (http://jobs.aol.com/gallery/growing-job-industries?ncid=emlcntuscare00000003) From SAIDJACK at aol.com Sat Apr 11 19:13:00 2009 From: SAIDJACK at aol.com (SAIDJACK at aol.com) Date: Sat, 11 Apr 2009 15:13:00 EDT Subject: [time-nuts] Fwd: OT: 10 MHz data capture, help Message-ID: Hi Magnus, thanks for the info, I got to look at that 5372A again. They were too costly when I last checked it out some time ago. There are several Wavecrest on Ebay, starting at ~$1200 for a working unit.. I would love to get my hand on a CNT-90, but again cost and availability is an issue. bye, Said In a message dated 4/11/2009 07:44:40 Pacific Daylight Time, magnus at rubidium.dyndns.org writes: No. The HP5372A happily gives you a rate at 13,3 MHz sample rate. I think the SIA-3000 is higher than 40k too (I think I recall 200k) and I know that the Pendulum CNT-90 and followers also passes that rate. From ed_palmer at sasktel.net Sat Apr 11 20:41:46 2009 From: ed_palmer at sasktel.net (Ed Palmer) Date: Sat, 11 Apr 2009 14:41:46 -0600 Subject: [time-nuts] Fwd: OT: 10 MHz data capture, help In-Reply-To: References: Message-ID: <49E1008A.7050302@sasktel.net> The Agilent web site has most of the manuals for the 5372a. The data sheet and the "Condensed Specification & Reference Guide" (over 100 pages!) gives you most of the functionality. The 5372a's biggest deficiencies for a time nut are its resolution of only 150ps and its maximum built-in timing period of 8 seconds. This means that even though it can calculate Allan Deviation, it's limited to about 1.5e-10 @ 1 sec. and it can't calculate anything beyond a tau of 8 seconds. You have to use external means to improve the noise floor (e.g. mixers). The 8 second limitation can be sidestepped if you use GPIB to pull the data and process it externally. The 13M readings per second that Magnus mentioned is limited to measuring the period of the incoming signal and then incrementing a count of how many measurements were in that range. There are 2000 'bins' that can be as small as 200ps wide. No time stamping, no calculations, just how many measurements were in that range. Useful but, at the same time, limited. I recently used it to collect 100M measurements of the 10 MHz output of a Navsync GPS receiver. I was able to infer the algorithm that they used to keep the output on frequency. If I remember correctly, it took less than 20 seconds to collect and plot the data! Ed SAIDJACK at aol.com wrote: > Hi Magnus, > > thanks for the info, I got to look at that 5372A again. They were too costly > when I last checked it out some time ago. > > There are several Wavecrest on Ebay, starting at ~$1200 for a working unit.. > > I would love to get my hand on a CNT-90, but again cost and availability is > an issue. > > bye, > Said > > > In a message dated 4/11/2009 07:44:40 Pacific Daylight Time, > magnus at rubidium.dyndns.org writes: > > No. The HP5372A happily gives you a rate at 13,3 MHz sample rate. I > think the SIA-3000 is higher than 40k too (I think I recall 200k) and I > know that the Pendulum CNT-90 and followers also passes that rate. > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > From magnus at rubidium.dyndns.org Sat Apr 11 20:52:59 2009 From: magnus at rubidium.dyndns.org (Magnus Danielson) Date: Sat, 11 Apr 2009 22:52:59 +0200 Subject: [time-nuts] Fwd: OT: 10 MHz data capture, help In-Reply-To: References: Message-ID: <49E1032B.8090904@rubidium.dyndns.org> Hi Said, SAIDJACK at aol.com skrev: > Hi Magnus, > > thanks for the info, I got to look at that 5372A again. They were too costly > when I last checked it out some time ago. Not too high if you look around. 950 USD and up it seems. > There are several Wavecrest on Ebay, starting at ~$1200 for a working unit.. Some at fantasy prices. Ah well. Any news on the reason for Wavecrest disaperance? I haven't seen any real news on being bought or folding... althought I would not be surprised about the later. > I would love to get my hand on a CNT-90, but again cost and availability is > an issue. They are still current, so it does not match the hobby folks, but quite nice. As always there is something to wish for, but that is what I always nag about. The live update graph mode is very useful. A Zoom feature and cursored read-out (as well as delta-cursors) would be nice, but that is left out for the TimeView software. You might have better success with finding them rebranded as Fluke. This is a result of the old Fluke-Philips cooperation. Look for Fluke PM 6690. Cheers, Magnus From magnus at rubidium.dyndns.org Sat Apr 11 21:31:30 2009 From: magnus at rubidium.dyndns.org (Magnus Danielson) Date: Sat, 11 Apr 2009 23:31:30 +0200 Subject: [time-nuts] Fwd: OT: 10 MHz data capture, help In-Reply-To: <49E1008A.7050302@sasktel.net> References: <49E1008A.7050302@sasktel.net> Message-ID: <49E10C32.1070700@rubidium.dyndns.org> Ed, Ed Palmer skrev: > The Agilent web site has most of the manuals for the 5372a. The data > sheet and the "Condensed Specification & Reference Guide" (over 100 > pages!) gives you most of the functionality. It is recommended reading regardless if you have one or not. > The 5372a's biggest deficiencies for a time nut are its resolution of > only 150ps and its maximum built-in timing period of 8 seconds. This > means that even though it can calculate Allan Deviation, it's limited to > about 1.5e-10 @ 1 sec. and it can't calculate anything beyond a tau of 8 > seconds. You have to use external means to improve the noise floor > (e.g. mixers). The 8 second limitation can be sidestepped if you use > GPIB to pull the data and process it externally. As has been done for instance by Bregni. An important detail to the 5372A architecture is the continously ticking time clock, so if you set up a single measure and read it out binary and then quickly setup another one you can run it in continous mode without problem. The 5372A programmers manual is about as detailed as it can get. I have not seen anything quite like it. > The 13M readings per second that Magnus mentioned is limited to > measuring the period of the incoming signal and then incrementing a > count of how many measurements were in that range. There is two modes, fast mode (13,3 MS/s) and normal mode (10 MS/s). Both has the same burst lengths, but for fast mode some data is not stored away, so counter-length is effectively reduced. It is reasnoble when running higher rates for shorter periods of time. The resolution is 200 ps for all types of measurements. > There are 2000 'bins' that can be as small as 200ps wide. > No time stamping, no > calculations, just how many measurements were in that range. Useful > but, at the same time, limited. That's the histogram hardware, which is unique to the 5372A compared to the 5371A. However, several normal measurements can also be run in fast mode. > I recently used it to collect 100M > measurements of the 10 MHz output of a Navsync GPS receiver. I was able > to infer the algorithm that they used to keep the output on frequency. > If I remember correctly, it took less than 20 seconds to collect and > plot the data! When you come to terms with it, it can be a very efficient measurement tool! The three most annoying things about it is memory size, time resolution and time-wrapping. There are a number of user interface issues and other limitations to annoy me, but those three annoys me mostly. Other than that, it is an instrument I trust and love. It still shines on some aspects. The Wavecrests shines on some things, the SRS 620 on others and the CNT-90 is to some degree much more handy. None of them fully replaces it however. Cheers, Magnus From sar10538 at gmail.com Sun Apr 12 07:49:29 2009 From: sar10538 at gmail.com (Steve Rooke) Date: Sun, 12 Apr 2009 19:49:29 +1200 Subject: [time-nuts] Characterising frequency standards In-Reply-To: <7CC8385956C841D9B67F4A860C45215E@athlon> References: <1231b6a80904100354m76be3cd7t20e09fd20aff346a@mail.gmail.com> <7CC8385956C841D9B67F4A860C45215E@athlon> Message-ID: <1231b6a80904120049t19925be4u5fcb6c0a606334fe@mail.gmail.com> Ulrich, 2009/4/11 Ulrich Bangert : >> So why would my counter show any significant differences >> between a 1 sec or 2 sec gate time? > > suppose your source has a 0.5 Hz frequency modulation. Would you see it with > 2 s gate time or a integer multiple of it? Would you notice it with 1 s gate > time or an odd integer of it? Agreed, if the source is modulated at exactly 1/2 the input frequency, the measurement would be blind to it. So the way to account for this would be to take half the readings, then skip one cycle and take the other half. Examination of the data would then show the modulation. >> I've just done a Google search for "dead time correction >> scheme" and I just turn up results relating to particle >> physics where it seems measurements are unable to keep up >> with the flow of data, hence the need to factor in the dead >> time of system. > > Google for the STABLE32 manual. THIS literature will bring you a lot > further, many well documented source examples in Forth and PL/1, hi. F.e. > you may look here: > > http://www.wriley.com/ Thanks for the pointers. Kind regards, Steve > > Best regards > Ulrich Bangert > >> -----Ursprungliche Nachricht----- >> Von: time-nuts-bounces at febo.com >> [mailto:time-nuts-bounces at febo.com] Im Auftrag von Steve Rooke >> Gesendet: Freitag, 10. April 2009 12:55 >> An: Discussion of precise time and frequency measurement >> Betreff: [!! SPAM] Re: [time-nuts] Characterising frequency standards >> >> >> Ulrich, >> >> 2009/4/10 Ulrich Bangert : >> > Steve, >> > >> >> I think the penny has dropped now, thanks. It's >> interesting that the >> >> ADEV calculation still works even without continuous data >> as all the >> >> reading I have done has led me to belive this was sacrosanct. >> > >> > The penny may be falling but it is not completely dropped: >> Of course >> > you can feed your ADEV calculation with every second sample removed >> > and setting Tau0 = 2. And of course you receive a result >> that now is >> > in "harmony" with your all samples / Tau0 = 1 s >> computation. Had you >> > done frequency measurements the reason for this appearant >> "harmony" is >> > that your counter does not show significant different behaviour >> > whether set to 1 s gate time or alternate 2 second gate time. >> >> So why would my counter show any significant differences >> between a 1 sec or 2 sec gate time? >> >> > Nevertheless leaving every second sample out is NOT exactly >> the same >> > as continous data with Tau0 = 2 s. Instead it is data with >> Tau0 = 1 s >> > and a DEAD TIME of 1s. There are dead time correction schemes >> > available in the literature. >> >> I've just done a Google search for "dead time correction >> scheme" and I just turn up results relating to particle >> physics where it seems measurements are unable to keep up >> with the flow of data, hence the need to factor in the dead >> time of system. This form of application does not appear to >> correlate with the measurement of plain oscillators. Yes >> there is dead time, per say, but I fail to see how this can >> detract significantly from continuous data given a sufficient >> data set size (as for a total measurement time). >> >> I guess what we need is a real data set which would show that >> this form of ADEV calculation produces incorrect results, IE. >> the proof of the pudding is in the eating. >> >> 73, >> Steve >> >> > Best regards >> > Ulrich Bangert >> > >> >> -----Ursprungliche Nachricht----- >> >> Von: time-nuts-bounces at febo.com >> [mailto:time-nuts-bounces at febo.com] >> >> Im Auftrag von Steve Rooke >> >> Gesendet: Donnerstag, 9. April 2009 14:00 >> >> An: Tom Van Baak; Discussion of precise time and frequency >> >> measurement >> >> Betreff: Re: [time-nuts] Characterising frequency standards >> >> >> >> >> >> Tom, >> >> >> >> 2009/4/9 Tom Van Baak : >> >> > The first argument to the adev1 program is the sampling >> >> interval t0. >> >> > The program doesn't know how far apart the input file >> samples are >> >> > taken so it is your job to specify this. The default is 1 second. >> >> > >> >> > If you have data taken one second apart then t0 = 1. >> >> > If you have data taken two seconds apart then t0 = 2. >> >> > If you have data taken 60 seconds apart then t0 = 60, etc. >> >> > >> >> > If, as in your case, you take raw one second data and >> remove every >> >> > other sample (a perfectly valid thing to do), then t0 = 2. >> >> > >> >> > Make sense now? It's still "continuous data" in the >> sense that all >> >> > measurements are a fixed interval apart. But in any ADEV >> >> calculation >> >> > you have to specify the raw data interval. >> >> >> >> I think the penny has dropped now, thanks. It's >> interesting that the >> >> ADEV calculation still works even without continuous data >> as all the >> >> reading I have done has led me to belive this was sacrosanct. >> >> >> >> What I now believe is that it's possible to measure oscillator >> >> performance with less than optimal test gear. This will >> enable me to >> >> see the effects of any experiments I make in the future. >> If you can't >> >> measure it, how can you know that what your doing is good or bad. >> >> >> >> 73, >> >> Steve >> >> -- >> >> Steve Rooke - ZL3TUV & G8KVD & JAKDTTNW >> >> Omnium finis imminet >> >> >> >> _______________________________________________ >> >> time-nuts mailing list -- time-nuts at febo.com >> >> To unsubscribe, go to >> >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> >> and follow the instructions there. >> > >> > >> > _______________________________________________ >> > time-nuts mailing list -- time-nuts at febo.com >> > To unsubscribe, go to >> > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> > and follow the instructions there. >> > >> >> >> >> -- >> Steve Rooke - ZL3TUV & G8KVD & JAKDTTNW >> Omnium finis imminet >> >> _______________________________________________ >> time-nuts mailing list -- time-nuts at febo.com >> To unsubscribe, go to >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > -- Steve Rooke - ZL3TUV & G8KVD & JAKDTTNW Omnium finis imminet From sar10538 at gmail.com Sun Apr 12 07:51:25 2009 From: sar10538 at gmail.com (Steve Rooke) Date: Sun, 12 Apr 2009 19:51:25 +1200 Subject: [time-nuts] Characterising frequency standards In-Reply-To: References: <4176CE16020C49449B55FCA770F8B7E5@athlon> Message-ID: <1231b6a80904120051h5ed4d5b8m236fd6aa09b12a22@mail.gmail.com> Tom, 2009/4/11 Tom Van Baak : >> Nevertheless leaving every second sample out is NOT exactly the same as >> continous data with Tau0 = 2 s. Instead it is data with Tau0 = 1 s and a >> DEAD TIME of 1s. There are dead time correction schemes available in the >> literature. > > Ulrich, and Steve, > > Wait, are we talking phase measurements here or frequency > measurements? My assumption with this thread is that Steve > is simply taking phase (time error) measurements, as in my > GPS raw data page, in which case there is no such thing as > dead time. Yes, phase measurements as in the original GPS.dat data set on your site. 73, Steve > > /tvb > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > -- Steve Rooke - ZL3TUV & G8KVD & JAKDTTNW Omnium finis imminet From sar10538 at gmail.com Sun Apr 12 08:15:14 2009 From: sar10538 at gmail.com (Steve Rooke) Date: Sun, 12 Apr 2009 20:15:14 +1200 Subject: [time-nuts] Characterising frequency standards In-Reply-To: <49DFA77D.1070405@rubidium.dyndns.org> References: <4176CE16020C49449B55FCA770F8B7E5@athlon> <49DFA77D.1070405@rubidium.dyndns.org> Message-ID: <1231b6a80904120115k676757d8lc339529102f4b24c@mail.gmail.com> 2009/4/11 Magnus Danielson : > Tom Van Baak skrev: >>> Nevertheless leaving every second sample out is NOT exactly the same as >>> continous data with Tau0 = 2 s. Instead it is data with Tau0 = 1 s and a >>> DEAD TIME of 1s. There are dead time correction schemes available in the >>> literature. >> >> Ulrich, and Steve, >> >> Wait, are we talking phase measurements here or frequency >> measurements? My assumption with this thread is that Steve >> is simply taking phase (time error) measurements, as in my >> GPS raw data page, in which case there is no such thing as >> dead time. > > I agree. I was also considering this earlier but put my mind to rest by > assuming phase/time samples. > > Dead time is when the counter looses track of time in between two > consecutive measurements. A zero dead-time counter uses the stop of one > measure as the start of the next measure. This becomes very important when the data to be measured has a degree of randomness and it is therefore important to capture all the data without any dead time. In the case of measurements of phase error in an oscillator, it should be possible to miss some data points provided that the frequency of capture is still known (assuming that accuracy of drift measurements is required). > If you have a series of time-error values taken each second and then > drop every other sample and just recall that the time between the > samples is now 2 seconds, then the tau0 has become 2s without causing > dead-time. However, if the original data would have been kept, better > statistical properties would be given, unless there is a strong > repetitive disturbance at 2 s period, in which case it would be filtered > out. Indeed, there would be a loss of statistical data but this could be made up by sampling over a period of twice the time. This system is blind to noise at 1/2 f but ways and means could be taken to account for that, IE. taking two data sets with a single cycle space between them or taking another small data set with 2 cycles skipped between each measurement. > An example when one does get dead-time, consider a frequency counter > which measures frequency with a gate-time of say 2 s. However, before it > re-arms and start the next measures is takes 300 ms. The two samples > will have 2,3 s between its start and actually spans 4,3 seconds rather > than 4 seconds. When doing Allan Deviation calculations on such a > measurement series, it will be biased and the bias may be compensated, > but these days counters with zero dead-time is readily available or the > problem can be avoided by careful consideration. I'm looking at what can be acheieved by a budget strapped amateur who would have trouble purchasing a later counter capable of measuring with zero dead time. > I believe Grenhall made some extensive analysis of the biasing of > dead-time, so it should be available from NIST F&T online library. I'll see what I can find. > Before zero dead-time counters was available, a setup of two counters > was used so that they where interleaved so the dead-time was the measure > time of the other. I could look at doing that perhaps. > I can collect some references to dead-time articles if anyone need them. > I'd happy to. 73, Steve > > Cheers, > Magnus > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > -- Steve Rooke - ZL3TUV & G8KVD & JAKDTTNW Omnium finis imminet From sar10538 at gmail.com Sun Apr 12 09:06:01 2009 From: sar10538 at gmail.com (Steve Rooke) Date: Sun, 12 Apr 2009 21:06:01 +1200 Subject: [time-nuts] Characterising frequency standards In-Reply-To: References: <1231b6a80904070509m5b8bb638gbc088500444254c3@mail.gmail.com> <1231b6a80904080441p7a747a3h1f73bf8a2df30350@mail.gmail.com> <49DC91B9.6090004@xtra.co.nz> <1231b6a80904080504n4a3a22dcr247fae5df39ed840@mail.gmail.com> <7911976D35924C91A61F679126F77F9E@pc52> <1231b6a80904090500i1cd90f80w7983e03b4978cfa8@mail.gmail.com> Message-ID: <1231b6a80904120206j310d0d66pbb78ea5c4a50c302@mail.gmail.com> If I take two sequential phase readings from an input source and place this into one data set and aniother two readings from the same source but spaced by one cycle and put this in a second data set. From the first data set I can calculate ADEV for tau = 1s and can calculate ADEV for tau = 2 sec from the second data set. If I now pre-process the data in the second set to remove all the effects of drift (given that I have already determined this), I now have two 1 sec samples which show a statistical difference and can be fed to ADEV with a tau0 = 1 sec producing a result for tau = 1 sec. The results from this second calculation should show equal accuracy as that using the first data set (given the limited size of the data set). I now collect a large data set but with a single cycle skipped between each sample. I feed this into ADEV using tau0 = 2 sec to produce tau results >= 2 sec. I then pre-process the data to remove any drift and feed this to ADEV with a tau0 = 1 sec to produce just the tau = 1 sec result. I now have a complete set of results for tau >= 1 sec. Agreed, there is the issue of modulation at 1/2 input f but ignoring this for the moment, this should give a valid result. Now indulge me while I have a flight of fantasy. As the effects of jitter and phase noise will produce a statistical distribution of measurements, any results from these ADEV calculations will be limited on accuracy by the size of the data set. Only if we sample for a very long time will we see the very limits of the effects of noise. The samples which deviate the most from the median will occur very infrequently and it is statistically likely that they will not occur adjacent to another highly deviated sample. We could pre-process the data to remove all drift and then sort it into an array of increasing size. This would give the greatest deviations at each end of the array. For 1 sec stability the deviation would be the greatest difference from the median of the first and last samples in the array. For a 2 sec stability, this same calculation could be made taking the first two and last two readings in the array and calculating their difference from 2 x the median. This calculation could be continued until all the data is used for the final calculation. In fact the whole sorted data set could be fed to ADEV to produce a result that would show better worse case measurement of the input source which still has some statistical probability. In theory, if we took an infinite number of samples, there would be a whole string of absolutely maximum deviation measurements in a row which would show the absolute worse case. Is any of this valid or just bad physics, I don't know, but I'm sure it will solicit interesting comment. 73, Steve 2009/4/10 Tom Van Baak : >> I think the penny has dropped now, thanks. It's interesting that the >> ADEV calculation still works even without continuous data as all the >> reading I have done has led me to belive this was sacrosanct. > > We need to be careful about what you mean by "continuous". > Let me probe a bit further to make sure you or others understand. > > The data that you first mentioned, some GPS and OCXO data at: > ? ?http://www.leapsecond.com/pages/gpsdo-sim > was recorded once per second, for 400,000 samples without any > interruption; that's over 4 days of continuous data. > > As you see it is very possible to extract every other, or every 10th, > every 60th, or every Nth point from this large data set to create a > smaller data set. > > Is it as if you had several counters all connected to the same DUT. > Perhaps one makes a new phase measurement each second, > another makes a measurement every 10 seconds; maybe a third > counter just measures once a minute. > > The key here is not how often they make measurements, but that > they all keep running at their particular rate. > > The data sets you get from these counters all represent 4 days > of measurement; what changes is the measurement interval, the > tau0, or whatever your ADEV tool calls it. > > Now the ADEV plots you get from these counters will all match > perfectly with the only exception being that the every-60 second > counter cannot give you any ADEV points for tau less than 60; > the every-10 second counter cannot give you points for tau less > than 10 seconds; and for that matter; the every 1-second counter > cannot give you points for tau less than 1 second. > > So what makes all these "continuous" is that the runs were not > interrupted and that the data points were taken at regular intervals. > > The x-axis of an ADEV plot spans a logarithmic range of tau. The > farthest point on the *right* is limited by how long your run was. If > you collect data for 4 or 5 days you can compute and plot points > out to around 1 day or 10^5 seconds. > > On the other hand, the farthest point on the *left* is limited by how > fast you collect data. If you collect one point every 10 seconds, > then tau=10 is your left-most point. Yes, it's common to collect data > every second; in this case you can plot down to tau=1s. Some of > my instruments can collect phase data at 1000 points per second > (huge files!) and this means my leftmost ADEV point is 1 millisecond. > > Here's an example of collecting data at 10 Hz: > http://www.leapsecond.com/pages/gpsdo/ > You can see this allows me to plot from ADEV tau = 0.1 s. > > Does all this make sense now? > >> What I now believe is that it's possible to measure oscillator >> performance with less than optimal test gear. This will enable me to >> see the effects of any experiments I make in the future. If you can't >> measure it, how can you know that what your doing is good or bad. > > Very true. So what one or several performance measurements > are you after? > > /tvb > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > -- Steve Rooke - ZL3TUV & G8KVD & JAKDTTNW Omnium finis imminet From bruce.griffiths at xtra.co.nz Sun Apr 12 09:06:55 2009 From: bruce.griffiths at xtra.co.nz (Bruce Griffiths) Date: Sun, 12 Apr 2009 21:06:55 +1200 Subject: [time-nuts] Characterising frequency standards In-Reply-To: <1231b6a80904120115k676757d8lc339529102f4b24c@mail.gmail.com> References: <4176CE16020C49449B55FCA770F8B7E5@athlon> <49DFA77D.1070405@rubidium.dyndns.org> <1231b6a80904120115k676757d8lc339529102f4b24c@mail.gmail.com> Message-ID: <49E1AF2F.50505@xtra.co.nz> Steve Steve Rooke wrote: > 2009/4/11 Magnus Danielson : > >> Tom Van Baak skrev: >> >>>> Nevertheless leaving every second sample out is NOT exactly the same as >>>> continous data with Tau0 = 2 s. Instead it is data with Tau0 = 1 s and a >>>> DEAD TIME of 1s. There are dead time correction schemes available in the >>>> literature. >>>> >>> Ulrich, and Steve, >>> >>> Wait, are we talking phase measurements here or frequency >>> measurements? My assumption with this thread is that Steve >>> is simply taking phase (time error) measurements, as in my >>> GPS raw data page, in which case there is no such thing as >>> dead time. >>> >> I agree. I was also considering this earlier but put my mind to rest by >> assuming phase/time samples. >> >> Dead time is when the counter looses track of time in between two >> consecutive measurements. A zero dead-time counter uses the stop of one >> measure as the start of the next measure. >> > > This becomes very important when the data to be measured has a degree > of randomness and it is therefore important to capture all the data > without any dead time. In the case of measurements of phase error in > an oscillator, it should be possible to miss some data points provided > that the frequency of capture is still known (assuming that accuracy > of drift measurements is required). > > >> If you have a series of time-error values taken each second and then >> drop every other sample and just recall that the time between the >> samples is now 2 seconds, then the tau0 has become 2s without causing >> dead-time. However, if the original data would have been kept, better >> statistical properties would be given, unless there is a strong >> repetitive disturbance at 2 s period, in which case it would be filtered >> out. >> > > Indeed, there would be a loss of statistical data but this could be > made up by sampling over a period of twice the time. This system is > blind to noise at 1/2 f but ways and means could be taken to account > for that, IE. taking two data sets with a single cycle space between > them or taking another small data set with 2 cycles skipped between > each measurement. > > >> An example when one does get dead-time, consider a frequency counter >> which measures frequency with a gate-time of say 2 s. However, before it >> re-arms and start the next measures is takes 300 ms. The two samples >> will have 2,3 s between its start and actually spans 4,3 seconds rather >> than 4 seconds. When doing Allan Deviation calculations on such a >> measurement series, it will be biased and the bias may be compensated, >> but these days counters with zero dead-time is readily available or the >> problem can be avoided by careful consideration. >> > > I'm looking at what can be acheieved by a budget strapped amateur who > would have trouble purchasing a later counter capable of measuring > with zero dead time. > > You don't need a full featured counter for this application. One can easily implement a zero deadtime counter or the equivalent thereof in an FPGA. >> I believe Grenhall made some extensive analysis of the biasing of >> dead-time, so it should be available from NIST F&T online library. >> > > I'll see what I can find. > > You still need to know the phase noise spectrum of the source being characterised. >> Before zero dead-time counters was available, a setup of two counters >> was used so that they where interleaved so the dead-time was the measure >> time of the other. >> > > I could look at doing that perhaps. > > Very easy to do at low cost in an FPGA. >> I can collect some references to dead-time articles if anyone need them. >> I'd happy to. >> > > 73, > Steve > > >> Cheers, >> Magnus >> >> _______________________________________________ >> time-nuts mailing list -- time-nuts at febo.com >> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. >> >> > > > > Brice From bruce.griffiths at xtra.co.nz Sun Apr 12 09:19:36 2009 From: bruce.griffiths at xtra.co.nz (Bruce Griffiths) Date: Sun, 12 Apr 2009 21:19:36 +1200 Subject: [time-nuts] Characterising frequency standards In-Reply-To: <1231b6a80904120206j310d0d66pbb78ea5c4a50c302@mail.gmail.com> References: <1231b6a80904070509m5b8bb638gbc088500444254c3@mail.gmail.com> <1231b6a80904080441p7a747a3h1f73bf8a2df30350@mail.gmail.com> <49DC91B9.6090004@xtra.co.nz> <1231b6a80904080504n4a3a22dcr247fae5df39ed840@mail.gmail.com> <7911976D35924C91A61F679126F77F9E@pc52> <1231b6a80904090500i1cd90f80w7983e03b4978cfa8@mail.gmail.com> <1231b6a80904120206j310d0d66pbb78ea5c4a50c302@mail.gmail.com> Message-ID: <49E1B228.9070106@xtra.co.nz> Steve Steve Rooke wrote: > If I take two sequential phase readings from an input source and place > this into one data set and aniother two readings from the same source > but spaced by one cycle and put this in a second data set. From the > first data set I can calculate ADEV for tau = 1s and can calculate > ADEV for tau = 2 sec from the second data set. If I now pre-process > the data in the second set to remove all the effects of drift (given > that I have already determined this), I now have two 1 sec samples > which show a statistical difference and can be fed to ADEV with a tau0 > = 1 sec producing a result for tau = 1 sec. The results from this > second calculation should show equal accuracy as that using the first > data set (given the limited size of the data set). > > You need to give far more detail as its unclear exactly what you are doing with what samples. Label all the phase samples and then show which samples belong to which data set. Also need to show clearly what you mean by skipping a cycle. > I now collect a large data set but with a single cycle skipped between > each sample. I feed this into ADEV using tau0 = 2 sec to produce tau > results >= 2 sec. I then pre-process the data to remove any drift and > feed this to ADEV with a tau0 = 1 sec to produce just the tau = 1 sec > result. I now have a complete set of results for tau >= 1 sec. Agreed, > there is the issue of modulation at 1/2 input f but ignoring this for > the moment, this should give a valid result. > > Again you need to give more detail. > Now indulge me while I have a flight of fantasy. > > As the effects of jitter and phase noise will produce a statistical > distribution of measurements, any results from these ADEV calculations > will be limited on accuracy by the size of the data set. Only if we > sample for a very long time will we see the very limits of the effects > of noise. What noise from what source? Noise in such measurements can originate in the measuring instrument or the source. For short measurement times quantisation noise and instrumental noise may mask the noise from the source but they are still present. > The samples which deviate the most from the median will > occur very infrequently and it is statistically likely that they will > not occur adjacent to another highly deviated sample. We could > pre-process the data to remove all drift and then sort it into an > array of increasing size. This would give the greatest deviations at > each end of the array. For 1 sec stability the deviation would be the > greatest difference from the median of the first and last samples in > the array. For a 2 sec stability, this same calculation could be made > taking the first two and last two readings in the array and > calculating their difference from 2 x the median. This calculation > could be continued until all the data is used for the final > calculation. In fact the whole sorted data set could be fed to ADEV to > produce a result that would show better worse case measurement of the > input source which still has some statistical probability. In theory, > if we took an infinite number of samples, there would be a whole > string of absolutely maximum deviation measurements in a row which > would show the absolute worse case. > > Is any of this valid or just bad physics, I don't know, but I'm sure > it will solicit interesting comment. > > No, not poor physics but poor statistics. > 73, > Steve > > 2009/4/10 Tom Van Baak : > >>> I think the penny has dropped now, thanks. It's interesting that the >>> ADEV calculation still works even without continuous data as all the >>> reading I have done has led me to belive this was sacrosanct. >>> >> We need to be careful about what you mean by "continuous". >> Let me probe a bit further to make sure you or others understand. >> >> The data that you first mentioned, some GPS and OCXO data at: >> http://www.leapsecond.com/pages/gpsdo-sim >> was recorded once per second, for 400,000 samples without any >> interruption; that's over 4 days of continuous data. >> >> As you see it is very possible to extract every other, or every 10th, >> every 60th, or every Nth point from this large data set to create a >> smaller data set. >> >> Is it as if you had several counters all connected to the same DUT. >> Perhaps one makes a new phase measurement each second, >> another makes a measurement every 10 seconds; maybe a third >> counter just measures once a minute. >> >> The key here is not how often they make measurements, but that >> they all keep running at their particular rate. >> >> The data sets you get from these counters all represent 4 days >> of measurement; what changes is the measurement interval, the >> tau0, or whatever your ADEV tool calls it. >> >> Now the ADEV plots you get from these counters will all match >> perfectly with the only exception being that the every-60 second >> counter cannot give you any ADEV points for tau less than 60; >> the every-10 second counter cannot give you points for tau less >> than 10 seconds; and for that matter; the every 1-second counter >> cannot give you points for tau less than 1 second. >> >> So what makes all these "continuous" is that the runs were not >> interrupted and that the data points were taken at regular intervals. >> >> The x-axis of an ADEV plot spans a logarithmic range of tau. The >> farthest point on the *right* is limited by how long your run was. If >> you collect data for 4 or 5 days you can compute and plot points >> out to around 1 day or 10^5 seconds. >> >> On the other hand, the farthest point on the *left* is limited by how >> fast you collect data. If you collect one point every 10 seconds, >> then tau=10 is your left-most point. Yes, it's common to collect data >> every second; in this case you can plot down to tau=1s. Some of >> my instruments can collect phase data at 1000 points per second >> (huge files!) and this means my leftmost ADEV point is 1 millisecond. >> >> Here's an example of collecting data at 10 Hz: >> http://www.leapsecond.com/pages/gpsdo/ >> You can see this allows me to plot from ADEV tau = 0.1 s. >> >> Does all this make sense now? >> >> >>> What I now believe is that it's possible to measure oscillator >>> performance with less than optimal test gear. This will enable me to >>> see the effects of any experiments I make in the future. If you can't >>> measure it, how can you know that what your doing is good or bad. >>> >> Very true. So what one or several performance measurements >> are you after? >> >> /tvb >> >> >> _______________________________________________ >> time-nuts mailing list -- time-nuts at febo.com >> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. >> >> > > > > Bruce From rexa at sonic.net Sun Apr 12 09:29:39 2009 From: rexa at sonic.net (Rex) Date: Sun, 12 Apr 2009 02:29:39 -0700 Subject: [time-nuts] Characterising frequency standards In-Reply-To: <49E1AF2F.50505@xtra.co.nz> References: <4176CE16020C49449B55FCA770F8B7E5@athlon> <49DFA77D.1070405@rubidium.dyndns.org> <1231b6a80904120115k676757d8lc339529102f4b24c@mail.gmail.com> <49E1AF2F.50505@xtra.co.nz> Message-ID: <49E1B483.7060206@sonic.net> Bruce Griffiths wrote: > ... > > Brice > > An impostor? An alias? :-) From bruce.griffiths at xtra.co.nz Sun Apr 12 10:32:33 2009 From: bruce.griffiths at xtra.co.nz (Bruce Griffiths) Date: Sun, 12 Apr 2009 22:32:33 +1200 Subject: [time-nuts] Characterising frequency standards In-Reply-To: <49E1B483.7060206@sonic.net> References: <4176CE16020C49449B55FCA770F8B7E5@athlon> <49DFA77D.1070405@rubidium.dyndns.org> <1231b6a80904120115k676757d8lc339529102f4b24c@mail.gmail.com> <49E1AF2F.50505@xtra.co.nz> <49E1B483.7060206@sonic.net> Message-ID: <49E1C341.1010606@xtra.co.nz> Rex wrote: > Bruce Griffiths wrote: > >> ... >> >> Brice >> >> >> > > An impostor? An alias? :-) > > > And I thought I was alluding to aliasing of the phase noise spectrum not the characters of the alphabet. Bruce > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > From magnus at rubidium.dyndns.org Sun Apr 12 13:10:04 2009 From: magnus at rubidium.dyndns.org (Magnus Danielson) Date: Sun, 12 Apr 2009 15:10:04 +0200 Subject: [time-nuts] Characterising frequency standards In-Reply-To: <1231b6a80904120115k676757d8lc339529102f4b24c@mail.gmail.com> References: <4176CE16020C49449B55FCA770F8B7E5@athlon> <49DFA77D.1070405@rubidium.dyndns.org> <1231b6a80904120115k676757d8lc339529102f4b24c@mail.gmail.com> Message-ID: <49E1E82C.5010700@rubidium.dyndns.org> Steve Rooke skrev: > 2009/4/11 Magnus Danielson : >> Tom Van Baak skrev: >>>> Nevertheless leaving every second sample out is NOT exactly the same as >>>> continous data with Tau0 = 2 s. Instead it is data with Tau0 = 1 s and a >>>> DEAD TIME of 1s. There are dead time correction schemes available in the >>>> literature. >>> Ulrich, and Steve, >>> >>> Wait, are we talking phase measurements here or frequency >>> measurements? My assumption with this thread is that Steve >>> is simply taking phase (time error) measurements, as in my >>> GPS raw data page, in which case there is no such thing as >>> dead time. >> I agree. I was also considering this earlier but put my mind to rest by >> assuming phase/time samples. >> >> Dead time is when the counter looses track of time in between two >> consecutive measurements. A zero dead-time counter uses the stop of one >> measure as the start of the next measure. > > This becomes very important when the data to be measured has a degree > of randomness and it is therefore important to capture all the data > without any dead time. In the case of measurements of phase error in > an oscillator, it should be possible to miss some data points provided > that the frequency of capture is still known (assuming that accuracy > of drift measurements is required). Depending on the dominant noise type, the ADEV measure will be biased. >> If you have a series of time-error values taken each second and then >> drop every other sample and just recall that the time between the >> samples is now 2 seconds, then the tau0 has become 2s without causing >> dead-time. However, if the original data would have been kept, better >> statistical properties would be given, unless there is a strong >> repetitive disturbance at 2 s period, in which case it would be filtered >> out. > > Indeed, there would be a loss of statistical data but this could be > made up by sampling over a period of twice the time. This system is > blind to noise at 1/2 f but ways and means could be taken to account > for that, IE. taking two data sets with a single cycle space between > them or taking another small data set with 2 cycles skipped between > each measurement. Actually, you can take any number of 2 cycle measures and be unable to detect the 1/2 f oscillation without detecting it. In order to be able to detect it you will need to take 2 measures and be able to make an odd number of cycles trigger difference between them to have a chance. The trouble is that the modulation is at the Nyquist frequency of the 1 cycle data, so it will fold down to DC on sampling it at half-rate. Canceling it from other DC offset errors could be challenging. Sampling it at 1/3 rate would discover it thought. >> An example when one does get dead-time, consider a frequency counter >> which measures frequency with a gate-time of say 2 s. However, before it >> re-arms and start the next measures is takes 300 ms. The two samples >> will have 2,3 s between its start and actually spans 4,3 seconds rather >> than 4 seconds. When doing Allan Deviation calculations on such a >> measurement series, it will be biased and the bias may be compensated, >> but these days counters with zero dead-time is readily available or the >> problem can be avoided by careful consideration. > > I'm looking at what can be acheieved by a budget strapped amateur who > would have trouble purchasing a later counter capable of measuring > with zero dead time. Beleive me, that's where I am too. Patience and saving money for things I really want and allowing accumulation over time has allowed me some pretty fancy tools in my private lab. Infact I have to lend some of my gear to commercial labs as I outperform them... >> I believe Grenhall made some extensive analysis of the biasing of >> dead-time, so it should be available from NIST F&T online library. > > I'll see what I can find. I recalled wrong. You should look for Barnes "Tables of Bias Functions, B1 and B2, for Variance Based on Finite Samples of Processes with Power Law Spectral Densities", NBS Technical Note 375, Janurary 1969 as well as Barnes and Allan "Variance Based on Data with Dead Time Between the Mesurements" NIST Technical Note 1318, 1990. A ahort into to the subject is found in NIST Special Publication 1065 by W.J. Riley as found on http://www.wriley.com along other excelent material. The good thing about that material is that he gives good references, as one should. >> Before zero dead-time counters was available, a setup of two counters >> was used so that they where interleaved so the dead-time was the measure >> time of the other. > > I could look at doing that perhaps. You should have two counters of equivalent performance, preferably same model. It's a rather expensive approach IMHO. Have a look at the possibility of picking up a HP 5371A or 5372A. You can usually snag one for about 600 USD or 1000 USD respectively on Ebay. Cheers, Magnus From magnus at rubidium.dyndns.org Sun Apr 12 13:13:58 2009 From: magnus at rubidium.dyndns.org (Magnus Danielson) Date: Sun, 12 Apr 2009 15:13:58 +0200 Subject: [time-nuts] Characterising frequency standards In-Reply-To: <49E1C341.1010606@xtra.co.nz> References: <4176CE16020C49449B55FCA770F8B7E5@athlon> <49DFA77D.1070405@rubidium.dyndns.org> <1231b6a80904120115k676757d8lc339529102f4b24c@mail.gmail.com> <49E1AF2F.50505@xtra.co.nz> <49E1B483.7060206@sonic.net> <49E1C341.1010606@xtra.co.nz> Message-ID: <49E1E916.20500@rubidium.dyndns.org> Bruce Griffiths skrev: > Rex wrote: >> Bruce Griffiths wrote: >> >>> ... >>> >>> Brice >>> >>> >>> >> An impostor? An alias? :-) >> >> >> > And I thought I was alluding to aliasing of the phase noise spectrum not > the characters of the alphabet. So it is not a case of shot noise of Bruce fingers? :) I know mine has some, and besides that there are several bugs in the language unit... Cheers, Magnus From bruce.griffiths at xtra.co.nz Sun Apr 12 13:25:56 2009 From: bruce.griffiths at xtra.co.nz (Bruce Griffiths) Date: Mon, 13 Apr 2009 01:25:56 +1200 Subject: [time-nuts] Characterising frequency standards In-Reply-To: <49E1E916.20500@rubidium.dyndns.org> References: <4176CE16020C49449B55FCA770F8B7E5@athlon> <49DFA77D.1070405@rubidium.dyndns.org> <1231b6a80904120115k676757d8lc339529102f4b24c@mail.gmail.com> <49E1AF2F.50505@xtra.co.nz> <49E1B483.7060206@sonic.net> <49E1C341.1010606@xtra.co.nz> <49E1E916.20500@rubidium.dyndns.org> Message-ID: <49E1EBE4.70905@xtra.co.nz> Hej Magnus Magnus Danielson wrote: > Bruce Griffiths skrev: > >> Rex wrote: >> >>> Bruce Griffiths wrote: >>> >>> >>>> ... >>>> >>>> Brice >>>> >>>> >>>> >>>> >>> An impostor? An alias? :-) >>> >>> >>> >>> >> And I thought I was alluding to aliasing of the phase noise spectrum not >> the characters of the alphabet. >> > > So it is not a case of shot noise of Bruce fingers? :) > I know mine has some, and besides that there are several bugs in the > language unit... > > Cheers, > Magnus > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > More a case of digital jitter. Perhaps the control system phase noise was too high. Bruce From holrum at hotmail.com Sun Apr 12 15:48:34 2009 From: holrum at hotmail.com (Mark Sims) Date: Sun, 12 Apr 2009 15:48:34 +0000 Subject: [time-nuts] Characterising frequency standards In-Reply-To: References: Message-ID: Hello Steve, Try this... take Tom's sample data set, run the numbers. Then, using a good random number generator, make another data set by randomly throwing out half (or more) of the samples (to simulate a non ZDT counter). Run the numbers again. See how they change. This should give you a good idea of how using a standard counter would affect your adev numbers. ---------------------------------------- _________________________________________________________________ Rediscover Hotmail?: Get e-mail storage that grows with you. http://windowslive.com/RediscoverHotmail?ocid=TXT_TAGLM_WL_HM_Rediscover_Storage1_042009 From wje at quackers.net Sun Apr 12 21:08:19 2009 From: wje at quackers.net (wje) Date: Sun, 12 Apr 2009 17:08:19 -0400 Subject: [time-nuts] HP 1938 revisited Message-ID: <49E25843.5090107@quackers.net> Fluke.l (China) was selling a number of 1938's on Ebay. I snagged one just to have a piece of HP history. It works just fine, but I've noticed something a little strange. Comparing the 1938 to both my cesium and GPS standards, there's a distinct periodic 1ns phase shift every second. Seems to smoothly advance 1ns for 500 ms, then retard back to the original phase point over the next 500ms. Question: is this to be expected? I'm assuming this is from the AFC loop, but I would have expected it to be better damped. I've searched both this group and the HP group; there really doesn't seem to be a great deal of info about these, other than schematics and some nice variance plots on leapsecond. Just what is the serial port and the PIC data lines useful for, if anything? -- Bill Ezell ---------- They said 'Windows or better' so I used Linux. From sar10538 at gmail.com Sun Apr 12 23:54:37 2009 From: sar10538 at gmail.com (Steve Rooke) Date: Mon, 13 Apr 2009 11:54:37 +1200 Subject: [time-nuts] Characterising frequency standards In-Reply-To: References: Message-ID: <1231b6a80904121654m4157003dp80b666c49fec218a@mail.gmail.com> Hi Mark, 2009/4/13 Mark Sims : > > Hello Steve, > > Try this... ?take Tom's sample data set, ?run the numbers. ?Then, ?using a good random number generator, ?make another data set by randomly throwing out half (or more) of the samples (to simulate a non ZDT counter). ?Run the numbers again. ?See how they change. ?This should give you a good idea of how using a standard counter would affect your adev numbers. But randomly throwing out data points would introduce ZDT. The whole point I was making was that the data set is well defined the "missing" data occurs every other sample therefore tau0 = 2 x (sample period of each sample). 73, Steve > > ---------------------------------------- > > > _________________________________________________________________ > Rediscover Hotmail?: Get e-mail storage that grows with you. > http://windowslive.com/RediscoverHotmail?ocid=TXT_TAGLM_WL_HM_Rediscover_Storage1_042009 > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > -- Steve Rooke - ZL3TUV & G8KVD & JAKDTTNW Omnium finis imminet From richard at karlquist.com Sun Apr 12 23:32:35 2009 From: richard at karlquist.com (Richard (Rick) Karlquist) Date: Sun, 12 Apr 2009 16:32:35 -0700 Subject: [time-nuts] HP 1938 revisited In-Reply-To: <49E25843.5090107@quackers.net> References: <49E25843.5090107@quackers.net> Message-ID: <49E27A13.6000508@karlquist.com> wje wrote: > Fluke.l (China) was selling a number of 1938's on Ebay. I snagged one > just to have a piece of HP history. > It works just fine, but I've noticed something a little strange. > > Comparing the 1938 to both my cesium and GPS standards, there's a > distinct periodic 1ns phase shift every second. Seems to smoothly > advance 1ns for 500 ms, then retard back to the original phase point > over the next 500ms. Question: is this to be expected? I'm assuming this > is from the AFC loop, but I would have expected it to be better damped. The AFC loop (as opposed to EFC) is a purely analog loop in which there is no mechanism for a 1 Hz oscillation. Now if you are talking about the EFC, that is another story. Depending on how you are driving the EFC, you can pickup noise from any number of sources. I vaguely remember there was an LED that flashed at 1 Hz if everything was working OK. You might see if that is the source of what you are seeing. > > I've searched both this group and the HP group; there really doesn't > seem to be a great deal of info about these, other than schematics and > some nice variance plots on leapsecond. Just what is the serial port and > the PIC data lines useful for, if anything? The serial port can be used to change the oven temperature set point and IIRC monitor various oven parameters. Probably nothing you want to play with if you want a working oscillator. If you want to experiment, I have released the software to talk to the serial port. It should be archived somewhere. In production, we ramped the temperature up and down and found the exact turnover temperature for each individual oscillator and set the oven to the turnover. This required that we make crystals that actually had a turnover. Many 10811 crystals did not have turnovers, only an inflection point. Rick Karlquist N6RK Designer of E1938A From sar10538 at gmail.com Mon Apr 13 00:34:36 2009 From: sar10538 at gmail.com (Steve Rooke) Date: Mon, 13 Apr 2009 12:34:36 +1200 Subject: [time-nuts] Characterising frequency standards In-Reply-To: <49E1B228.9070106@xtra.co.nz> References: <1231b6a80904070509m5b8bb638gbc088500444254c3@mail.gmail.com> <1231b6a80904080441p7a747a3h1f73bf8a2df30350@mail.gmail.com> <49DC91B9.6090004@xtra.co.nz> <1231b6a80904080504n4a3a22dcr247fae5df39ed840@mail.gmail.com> <7911976D35924C91A61F679126F77F9E@pc52> <1231b6a80904090500i1cd90f80w7983e03b4978cfa8@mail.gmail.com> <1231b6a80904120206j310d0d66pbb78ea5c4a50c302@mail.gmail.com> <49E1B228.9070106@xtra.co.nz> Message-ID: <1231b6a80904121734v141f37c9t14bb9662328776f2@mail.gmail.com> Bruce, 2009/4/12 Bruce Griffiths : > Steve > > Steve Rooke wrote: >> If I take two sequential phase readings from an input source and place >> this into one data set and aniother two readings from the same source >> but spaced by one cycle and put this in a second data set. From the >> first data set I can calculate ADEV for tau = 1s and can calculate >> ADEV for tau = 2 sec from the second data set. If I now pre-process >> the data in the second set to remove all the effects of drift (given >> that I have already determined this), I now have two 1 sec samples >> which show a statistical difference and can be fed to ADEV with a tau0 >> = 1 sec producing a result for tau = 1 sec. The results from this >> second calculation should show equal accuracy as that using the first >> data set (given the limited size of the data set). >> >> > You need to give far more detail as its unclear exactly what you are > doing with what samples. > Label all the phase samples and then show which samples belong to which > data set. > Also need to show clearly what you mean by skipping a cycle. Say I have a 1Hz input source and my counter measures the period of the first cycle and assigns this to A1. At the end of the first cycle the counter is able to be rest and re-triggered to capture the second cycle and assign this to A2. So far 2 sec have passed and I have two readings in data set A. I now repeat the experiment and assign the measurement of the first period to B1. The counter I am using this time is unable to stop at the end of the first measurement and retrigger immediately so I'm unable to measure the second cycle but is left in the armed position. When the third cycle starts, the counter triggers and completes the measurement of the third cycle which is now assigned to B2. For the purposes of my original text, the first data set refers to A1 & A2. Similarly the second data set refers to B1 & B2. Reference to pre-processing of the second data set refers to mathematically removing the effects of drift from B1 & B2 to produce a third data set which is used as the data input for an ADEV calculation where tau0 = 1 sec with output of tau = 1 sec. > >> I now collect a large data set but with a single cycle skipped between >> each sample. I feed this into ADEV using tau0 = 2 sec to produce tau >> results >= 2 sec. I then pre-process the data to remove any drift and >> feed this to ADEV with a tau0 = 1 sec to produce just the tau = 1 sec >> result. I now have a complete set of results for tau >= 1 sec. Agreed, >> there is the issue of modulation at 1/2 input f but ignoring this for >> the moment, this should give a valid result. >> >> > Again you need to give more detail. In this case the data set is constructed from the measurement of the cycle periods of a 1Hz input source where even cycles are skipped, hence each data point is a measurement of the period of each odd (1, 3, 5, 7...) cycle of the incoming waveform. In this case the time between each measurement is 2 sec so ADEV is calculated with tau = 2 sec for tau >= 2 sec. This data set is then mathematically processed to remove the effects of drift, bearing in mind the 2 sec spacing of each data point, and ADEV is then calculated with tau0 = 1 sec for tau = 1 sec. >> Now indulge me while I have a flight of fantasy. >> >> As the effects of jitter and phase noise will produce a statistical >> distribution of measurements, any results from these ADEV calculations >> will be limited on accuracy by the size of the data set. Only if we >> sample for a very long time will we see the very limits of the effects >> of noise. > What noise from what source? PN - White noise phase WPM, Flicker noise phase FPM, White noise frequency WFM, Flicker noise frequency FFM and Random walk frequency RWFM. > Noise in such measurements can originate in the measuring instrument or > the source. Indeed, and this is an important aspect to consider as we have been discussing the effects of induced jitter/PN to a frequency standard when it is buffered and divided down. Ideally measurements of ADEV would be made on the raw frequency standard source (eg. 10MHz) rather than, say, a divided 1Hz signal. > For short measurement times quantisation noise and instrumental noise > may mask the noise from the source but they are still present. Well, these form the noise floor of our measurement system. > > >> The samples which deviate the most from the median will >> occur very infrequently and it is statistically likely that they will >> not occur adjacent to another highly deviated sample. We could >> pre-process the data to remove all drift and then sort it into an >> array of increasing size. This would give the greatest deviations at >> each end of the array. For 1 sec stability the deviation would be the >> greatest difference from the median of the first and last samples in >> the array. For a 2 sec stability, this same calculation could be made >> taking the first two and last two readings in the array and >> calculating their difference from 2 x the median. This calculation >> could be continued until all the data is used for the final >> calculation. In fact the whole sorted data set could be fed to ADEV to >> produce a result that would show better worse case measurement of the >> input source which still has some statistical probability. In theory, >> if we took an infinite number of samples, there would be a whole >> string of absolutely maximum deviation measurements in a row which >> would show the absolute worse case. >> >> Is any of this valid or just bad physics, I don't know, but I'm sure >> it will solicit interesting comment. >> >> > No, not poor physics but poor statistics. Well, poor statistics possibly but that branch of mathematics is not only about interpreting data it is also about predicting events. What I proposed is predicting events that would otherwise occur very infrequently and hence be difficult to collect but would have a baring on the measurement of the total stability of an oscillator. I'm just thinking out loud. 73, Steve > >> 73, >> Steve >> >> 2009/4/10 Tom Van Baak : >> >>>> I think the penny has dropped now, thanks. It's interesting that the >>>> ADEV calculation still works even without continuous data as all the >>>> reading I have done has led me to belive this was sacrosanct. >>>> >>> We need to be careful about what you mean by "continuous". >>> Let me probe a bit further to make sure you or others understand. >>> >>> The data that you first mentioned, some GPS and OCXO data at: >>> ? ?http://www.leapsecond.com/pages/gpsdo-sim >>> was recorded once per second, for 400,000 samples without any >>> interruption; that's over 4 days of continuous data. >>> >>> As you see it is very possible to extract every other, or every 10th, >>> every 60th, or every Nth point from this large data set to create a >>> smaller data set. >>> >>> Is it as if you had several counters all connected to the same DUT. >>> Perhaps one makes a new phase measurement each second, >>> another makes a measurement every 10 seconds; maybe a third >>> counter just measures once a minute. >>> >>> The key here is not how often they make measurements, but that >>> they all keep running at their particular rate. >>> >>> The data sets you get from these counters all represent 4 days >>> of measurement; what changes is the measurement interval, the >>> tau0, or whatever your ADEV tool calls it. >>> >>> Now the ADEV plots you get from these counters will all match >>> perfectly with the only exception being that the every-60 second >>> counter cannot give you any ADEV points for tau less than 60; >>> the every-10 second counter cannot give you points for tau less >>> than 10 seconds; and for that matter; the every 1-second counter >>> cannot give you points for tau less than 1 second. >>> >>> So what makes all these "continuous" is that the runs were not >>> interrupted and that the data points were taken at regular intervals. >>> >>> The x-axis of an ADEV plot spans a logarithmic range of tau. The >>> farthest point on the *right* is limited by how long your run was. If >>> you collect data for 4 or 5 days you can compute and plot points >>> out to around 1 day or 10^5 seconds. >>> >>> On the other hand, the farthest point on the *left* is limited by how >>> fast you collect data. If you collect one point every 10 seconds, >>> then tau=10 is your left-most point. Yes, it's common to collect data >>> every second; in this case you can plot down to tau=1s. Some of >>> my instruments can collect phase data at 1000 points per second >>> (huge files!) and this means my leftmost ADEV point is 1 millisecond. >>> >>> Here's an example of collecting data at 10 Hz: >>> http://www.leapsecond.com/pages/gpsdo/ >>> You can see this allows me to plot from ADEV tau = 0.1 s. >>> >>> Does all this make sense now? >>> >>> >>>> What I now believe is that it's possible to measure oscillator >>>> performance with less than optimal test gear. This will enable me to >>>> see the effects of any experiments I make in the future. If you can't >>>> measure it, how can you know that what your doing is good or bad. >>>> >>> Very true. So what one or several performance measurements >>> are you after? >>> >>> /tvb >>> >>> >>> _______________________________________________ >>> time-nuts mailing list -- time-nuts at febo.com >>> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >>> and follow the instructions there. >>> >>> >> >> >> >> > > Bruce > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > -- Steve Rooke - ZL3TUV & G8KVD & JAKDTTNW Omnium finis imminet From sar10538 at gmail.com Mon Apr 13 00:50:00 2009 From: sar10538 at gmail.com (Steve Rooke) Date: Mon, 13 Apr 2009 12:50:00 +1200 Subject: [time-nuts] Characterising frequency standards In-Reply-To: <49E1E82C.5010700@rubidium.dyndns.org> References: <4176CE16020C49449B55FCA770F8B7E5@athlon> <49DFA77D.1070405@rubidium.dyndns.org> <1231b6a80904120115k676757d8lc339529102f4b24c@mail.gmail.com> <49E1E82C.5010700@rubidium.dyndns.org> Message-ID: <1231b6a80904121750w1d572dc1k9391bf5703ddc441@mail.gmail.com> 2009/4/13 Magnus Danielson : >>> Dead time is when the counter looses track of time in between two >>> consecutive measurements. A zero dead-time counter uses the stop of one >>> measure as the start of the next measure. >> >> This becomes very important when the data to be measured has a degree >> of randomness and it is therefore important to capture all the data >> without any dead time. In the case of measurements of phase error in >> an oscillator, it should be possible to miss some data points provided >> that the frequency of capture is still known (assuming that accuracy >> of drift measurements is required). > > Depending on the dominant noise type, the ADEV measure will be biased. If the noise has a component related to the measurement frequency, agreed, but I have already commented on that before. >> Indeed, there would be a loss of statistical data but this could be >> made up by sampling over a period of twice the time. This system is >> blind to noise at 1/2 f but ways and means could be taken to account >> for that, IE. taking two data sets with a single cycle space between >> them or taking another small data set with 2 cycles skipped between >> each measurement. > > Actually, you can take any number of 2 cycle measures and be unable to > detect the 1/2 f oscillation without detecting it. In order to be able > to detect it you will need to take 2 measures and be able to make an odd > number of cycles trigger difference between them to have a chance. Agreed. > The trouble is that the modulation is at the Nyquist frequency of the 1 > cycle data, so it will fold down to DC on sampling it at half-rate. > Canceling it from other DC offset errors could be challenging. Comparing the frequency calculated from the data would show a 2Hz offset with the fundamental frequency of the source. > Sampling it at 1/3 rate would discover it thought. Agreed. >> I'm looking at what can be acheieved by a budget strapped amateur who >> would have trouble purchasing a later counter capable of measuring >> with zero dead time. > > Beleive me, that's where I am too. Patience and saving money for things > I really want and allowing accumulation over time has allowed me some > pretty fancy tools in my private lab. Infact I have to lend some of my > gear to commercial labs as I outperform them... Well, that's a goal for me but I'm looking at what is achievable in the short term instead of sitting on my hands. > I recalled wrong. You should look for Barnes "Tables of Bias Functions, > B1 and B2, for Variance Based on Finite Samples of Processes with Power > Law Spectral Densities", NBS Technical Note 375, Janurary 1969 as well > as Barnes and Allan "Variance Based on Data with Dead Time Between the > Mesurements" NIST Technical Note 1318, 1990. > > A ahort into to the subject is found in NIST Special Publication 1065 by > W.J. Riley as found on http://www.wriley.com along other excelent > material. The good thing about that material is that he gives good > references, as one should. Thanks for the pointer. >> I could look at doing that perhaps. > > You should have two counters of equivalent performance, preferably same > model. It's a rather expensive approach IMHO. It may still be cheaper than the purchase of a counter capable of continuous collection, especially if you already have a counter that is capable at 1/2 f. > Have a look at the possibility of picking up a HP 5371A or 5372A. You > can usually snag one for about 600 USD or 1000 USD respectively on Ebay. I'd have to be a really good boy for Santa to bring me something of that ilk. Perhaps the lotto will come up one day :-) 73, Steve > Cheers, > Magnus > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > -- Steve Rooke - ZL3TUV & G8KVD & JAKDTTNW Omnium finis imminet From jltran at worldnet.att.net Mon Apr 13 00:54:30 2009 From: jltran at worldnet.att.net (J. L. Trantham) Date: Sun, 12 Apr 2009 19:54:30 -0500 Subject: [time-nuts] HP 1938 revisited In-Reply-To: <49E27A13.6000508@karlquist.com> Message-ID: <7C4D4B5459964B4B9A39359164BE6933@S0028384766> I, too, snagged one of these since it has the reputation of being the ultimate achievement of crystal oscillator technology with the goal of building a GPS controlled reference using a Brooks Shera controller card and a GPS receiver. Toward that end, since it takes a few minutes for the 1938 to 'lock', is there a signal that can be used to 'turn on' disciplining? It doesn't seem logical to try to discipline the oscillator until it has stabilized and, therefore, if the device is to be used from time to time, not staying on continuously, it will need a way to optimize turn on performance. Thanks in advance and I would appreciate any 'links' to any programs that would allow communication with the oscillator. Joe -----Original Message----- From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On Behalf Of Richard (Rick) Karlquist Sent: Sunday, April 12, 2009 6:33 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] HP 1938 revisited wje wrote: > Fluke.l (China) was selling a number of 1938's on Ebay. I snagged one > just to have a piece of HP history. > It works just fine, but I've noticed something a little strange. > > Comparing the 1938 to both my cesium and GPS standards, there's a > distinct periodic 1ns phase shift every second. Seems to smoothly > advance 1ns for 500 ms, then retard back to the original phase point > over the next 500ms. Question: is this to be expected? I'm assuming this > is from the AFC loop, but I would have expected it to be better damped. The AFC loop (as opposed to EFC) is a purely analog loop in which there is no mechanism for a 1 Hz oscillation. Now if you are talking about the EFC, that is another story. Depending on how you are driving the EFC, you can pickup noise from any number of sources. I vaguely remember there was an LED that flashed at 1 Hz if everything was working OK. You might see if that is the source of what you are seeing. > > I've searched both this group and the HP group; there really doesn't > seem to be a great deal of info about these, other than schematics and > some nice variance plots on leapsecond. Just what is the serial port and > the PIC data lines useful for, if anything? The serial port can be used to change the oven temperature set point and IIRC monitor various oven parameters. Probably nothing you want to play with if you want a working oscillator. If you want to experiment, I have released the software to talk to the serial port. It should be archived somewhere. In production, we ramped the temperature up and down and found the exact turnover temperature for each individual oscillator and set the oven to the turnover. This required that we make crystals that actually had a turnover. Many 10811 crystals did not have turnovers, only an inflection point. Rick Karlquist N6RK Designer of E1938A _______________________________________________ time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. From wje at quackers.net Mon Apr 13 01:15:23 2009 From: wje at quackers.net (wje) Date: Sun, 12 Apr 2009 21:15:23 -0400 Subject: [time-nuts] HP 1938 revisited (Richard (Rick) Karlquist) In-Reply-To: References: Message-ID: <49E2922B.7060705@quackers.net> Must be coupling in via the EFC, then. The phase shift does correlate precisely with the 1Hz LED. The EFC is just connected to the center tap of a 1meg pot, which is connected to +VREF and EFC shield. But, this is just for testing so I could trim the 1938 to my reference to check drift, of which there isn't a whole lot! For a real circuit, I'll have to be a bit more careful, now that I know this isn't an internal loop artifact. The EFC sensitivity is higher than my trusty 105B's. > > The AFC loop (as opposed to EFC) is a purely analog loop in which there > is no mechanism for a 1 Hz oscillation. > > Now if you are talking about the EFC, that is another story. Depending > on how you are driving the EFC, you can pickup noise from any number > of sources. > > I vaguely remember there was an LED that flashed at 1 Hz if everything > was working OK. You might see if that is the source of what you are > seeing. > > > Rick Karlquist N6RK > Designer of E1938A > From richard at karlquist.com Mon Apr 13 00:57:11 2009 From: richard at karlquist.com (Richard (Rick) Karlquist) Date: Sun, 12 Apr 2009 17:57:11 -0700 Subject: [time-nuts] HP 1938 revisited In-Reply-To: <7C4D4B5459964B4B9A39359164BE6933@S0028384766> References: <7C4D4B5459964B4B9A39359164BE6933@S0028384766> Message-ID: <49E28DE7.60605@karlquist.com> J. L. Trantham wrote: > I, too, snagged one of these since it has the reputation of being the > ultimate achievement of crystal oscillator technology with the goal of Thanks, we thought it was pretty good :-) > > Toward that end, since it takes a few minutes for the 1938 to 'lock', is > there a signal that can be used to 'turn on' disciplining? It doesn't seem > logical to try to discipline the oscillator until it has stabilized and, > therefore, if the device is to be used from time to time, not staying on > continuously, it will need a way to optimize turn on performance. There is nothing in the E1938A that "locks". The closest to lock is the oven current "cutting back". After that, the oven will settle within a few minutes to its set point. However, the crystal will exhibit high aging rates for hours. It will not get back to the aging it had when last turned off for something like a day. During this recovery time, you can discipline the oscillator if you like, but it won't give very good holdover performance if you lose GPS. No crystal oscillator will give the kind of performance you need for this application unless it is continuously ovenized. The SC cut is a big improvement over the AT cut in terms of a cold start, but is still not adequate for GPS work right after a cold start. Hope that helps. Rick Karlquist N6RK Designer of E1938A From xde-l2g3 at myamail.com Mon Apr 13 01:26:37 2009 From: xde-l2g3 at myamail.com (Mike Monett) Date: Sun, 12 Apr 2009 22:26:37 -0300 Subject: [time-nuts] time-nuts Rockwell Jupiter 12-channel GPS receiver OEM module References: Message-ID: If nobody has already mentioned it, Fluke.1 has the Rockwell Tu00-D205 high performance 12-channel GPS receiver OEM modules for $9.99 ea with free shipping worldwide, item number: 290306684157 These appear to have the 10KHz output described at http://www.jrmiller.demon.co.uk/projects/ministd/frqstd.htm tvb measured the performance at http://www.leapsecond.com/pages/gpsdo/ More documentation is at http://www.gpskit.nl/gps-readme.html Mike From jltran at worldnet.att.net Mon Apr 13 04:03:31 2009 From: jltran at worldnet.att.net (J. L. Trantham) Date: Sun, 12 Apr 2009 23:03:31 -0500 Subject: [time-nuts] HP 1938 revisited In-Reply-To: <49E28DE7.60605@karlquist.com> Message-ID: <50D082247E9747D7930F631CA1A37DD9@S0028384766> Thanks for the info. My plan is to develop a stable GPS disciplined reference suitable for use as a reference for Microwave work in the 10 GHz range that can be used in portable locations with relatively quick start up. Perhaps the 1938 would be better in the shop where it could be left on for weeks/months at a time and an LPRO 101 or a 10811 could be used for the portable application. Reasonably high drift rates could be accommodated if the GPS signal is reliable and the time constants (disciplining rate, drift rate, etc.) are appropriate. Thanks, Joe -----Original Message----- From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On Behalf Of Richard (Rick) Karlquist Sent: Sunday, April 12, 2009 7:57 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] HP 1938 revisited J. L. Trantham wrote: > I, too, snagged one of these since it has the reputation of being the > ultimate achievement of crystal oscillator technology with the goal of Thanks, we thought it was pretty good :-) > > Toward that end, since it takes a few minutes for the 1938 to 'lock', is > there a signal that can be used to 'turn on' disciplining? It doesn't seem > logical to try to discipline the oscillator until it has stabilized and, > therefore, if the device is to be used from time to time, not staying on > continuously, it will need a way to optimize turn on performance. There is nothing in the E1938A that "locks". The closest to lock is the oven current "cutting back". After that, the oven will settle within a few minutes to its set point. However, the crystal will exhibit high aging rates for hours. It will not get back to the aging it had when last turned off for something like a day. During this recovery time, you can discipline the oscillator if you like, but it won't give very good holdover performance if you lose GPS. No crystal oscillator will give the kind of performance you need for this application unless it is continuously ovenized. The SC cut is a big improvement over the AT cut in terms of a cold start, but is still not adequate for GPS work right after a cold start. Hope that helps. Rick Karlquist N6RK Designer of E1938A _______________________________________________ time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. From xde-l2g3 at myamail.com Mon Apr 13 04:31:48 2009 From: xde-l2g3 at myamail.com (Mike Monett) Date: Mon, 13 Apr 2009 01:31:48 -0300 Subject: [time-nuts] femtosecond jitter anyone? Message-ID: > Chris > The biggest problem with the OCXO is probably that it has a square > wave output. > With careful design it is possible to achieve a jitter of a few > tens of femtosec for a logic level output from a limiter, but the > OCXO designers are unlikely to have used such a limiter. [...] > Bruce Bruce This would be an excellent subject for a tutorial on precision system design. Do you have any links to support your claim of a tens of femtosec for a logic level from a limiter? I am not aware of any logic family that can support that jitter performance. When you post items that stretch the state of the art, it would be nice if you would show us all how to do the same. Mike From bruce.griffiths at xtra.co.nz Mon Apr 13 06:11:17 2009 From: bruce.griffiths at xtra.co.nz (Bruce Griffiths) Date: Mon, 13 Apr 2009 18:11:17 +1200 Subject: [time-nuts] femtosecond jitter anyone? In-Reply-To: References: Message-ID: <49E2D785.3070600@xtra.co.nz> Mike Monett wrote: > > Chris > > > The biggest problem with the OCXO is probably that it has a square > > wave output. > > > With careful design it is possible to achieve a jitter of a few > > tens of femtosec for a logic level output from a limiter, but the > > OCXO designers are unlikely to have used such a limiter. > > [...] > > > Bruce > > Bruce > > This would be an excellent subject for a tutorial on precision > system design. Do you have any links to support your claim of a tens > of femtosec for a logic level from a limiter? > > I am not aware of any logic family that can support that jitter > performance. > > When you post items that stretch the state of the art, it would be > nice if you would show us all how to do the same. > > Mike > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > Some ECL devices have jitter specs in the 100 to 200fsec range. see: http://www.onsemi.com A jitter of a few tens of femtosec is achieved by some clock drivers: http://www.analog.com/en/clock-and-timing/clock-generation-and-distribution/adclk905/products/product.html http://www.analog.com/en/clock-and-timing/clock-generation-and-distribution/adclk925/products/product.html Some ADC's have internal sampling jitter of a few tens of femtosec: http://www.analog.com/en/analog-to-digital-converters/ad-converters/ad9461/products/product.html However a very clean low noise source is required. Achieving a jitter of less than a 1picosec at 10MHz with a well designed limiter/filter cascade and a good source isn't too difficult, however the intrinsic random jitter of most common logic families is indeed a limiting factor. (HCOS inverters have typical random jitter of ~ 4ps, ACMOS inverters have an intrinsic random jitter of ~ 1ps faster CMOS families have lower random jitter). However such jitter can only be achieved if the logic gate input signal slew rate is fast enough or the gates input noise will increase the jitter. The achievable jitter increases as the input signal slew rate decreases (ie a s the frequency decreases for a fixed amplitude sinewave input). < 100ns jitter at 1Hz due to the limiter noise is routine (around 10ns should be possible). JPL achieved < 100ns decades ago. < 10ns jitter at 10Hz due to limiter noise is relatively easy whilst a potential jitter of around 1ns rms is achievable. However a clean low noise input signal is required. Bruce From SAIDJACK at aol.com Mon Apr 13 06:49:32 2009 From: SAIDJACK at aol.com (SAIDJACK at aol.com) Date: Mon, 13 Apr 2009 02:49:32 EDT Subject: [time-nuts] Fluke, and E1938 Message-ID: Thanks for the tip Magnus! One comment on the 1938 discussion: I recently fired-up my E1938 disciplined by our Fury GPSDO. It took 3+ days for the retrace (aging) to slow down significantly. Now it's working really well. Said In a message dated 4/11/2009 13:53:41 Pacific Daylight Time, magnus at rubidium.dyndns.org writes: You might have better success with finding them rebranded as Fluke. This is a result of the old Fluke-Philips cooperation. Look for Fluke PM 6690. Cheers, Magnus From nospam at oceanfree.net Mon Apr 13 09:43:25 2009 From: nospam at oceanfree.net (Eamon Skelton) Date: Mon, 13 Apr 2009 10:43:25 +0100 Subject: [time-nuts] time-nuts Rockwell Jupiter 12-channel GPS receiver OEM module In-Reply-To: References: Message-ID: <49E3093D.3030700@oceanfree.net> Mike Monett wrote: > If nobody has already mentioned it, Fluke.1 has the Rockwell > Tu00-D205 high performance 12-channel GPS receiver OEM modules for > $9.99 ea with free shipping worldwide, item number: 290306684157 > > These appear to have the 10KHz output described at > http://www.jrmiller.demon.co.uk/projects/ministd/frqstd.htm This website sells them too: http://www.weirdstuff.com/cgi-bin/item/20164 I wonder if it is suitable for use in a GPSDO? It looks quite different to the Jupiter T used in James Miller's design and the other Jupiters that Fluke.1 has sold in the past. -- Linux 2.6.26 From ernieperes at aol.com Mon Apr 13 10:29:12 2009 From: ernieperes at aol.com (ernieperes at aol.com) Date: Mon, 13 Apr 2009 06:29:12 -0400 Subject: [time-nuts] time-nuts Rockwell Jupiter 12-channel GPS receiver OEM module In-Reply-To: <49E3093D.3030700@oceanfree.net> References: <49E3093D.3030700@oceanfree.net> Message-ID: <8CB8A39D2AA99B1-F38-29CB@MBLK-M05.sysops.aol.com> Hi Gents, It is actually a Rockwell Microtracker gps module and not a JUPITER board!! 5channel +5V board... also the 20pin header is different then the JUPITER. I still have a few docs . Please contact offline if you need more. Rgds Ernie. -----Original Message----- From: Eamon Skelton To: Discussion of precise time and frequency measurement Sent: Mon, 13 Apr 2009 11:43 am Subject: Re: [time-nuts] time-nuts Rockwell Jupiter 12-channel GPS receiver OEM module Mike Monett wrote: > If nobody has already mentioned it, Fluke.1 has the Rockwell > Tu00-D205 high performance 12-channel GPS receiver OEM modules for > $9.99 ea with free shipping worldwide, item number: 290306684157 > > These appear to have the 10KHz output described at > http://www.jrmiller.demon.co.uk/projects/ministd/frqstd.htm This website sells them too: http://www.weirdstuff.com/cgi-bin/item/20164 I wonder if it is suitable for use in a GPSDO? It looks quite different to the Jupiter T used in James Miller's design and the other Jupiters that Fluke.1 has sold in the past. -- Linux 2.6.26 _______________________________________________ time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. From magnus at rubidium.dyndns.org Mon Apr 13 10:44:25 2009 From: magnus at rubidium.dyndns.org (Magnus Danielson) Date: Mon, 13 Apr 2009 12:44:25 +0200 Subject: [time-nuts] Characterising frequency standards In-Reply-To: <1231b6a80904121654m4157003dp80b666c49fec218a@mail.gmail.com> References: <1231b6a80904121654m4157003dp80b666c49fec218a@mail.gmail.com> Message-ID: <49E31789.7040000@rubidium.dyndns.org> Steve Rooke wrote: > Hi Mark, > > 2009/4/13 Mark Sims : > >> Hello Steve, >> >> Try this... take Tom's sample data set, run the numbers. Then, using a good random number generator, make another data set by randomly throwing out half (or more) of the samples (to simulate a non ZDT counter). Run the numbers again. See how they change. This should give you a good idea of how using a standard counter would affect your adev numbers. >> > > But randomly throwing out data points would introduce ZDT. It would introduce dead-time, it would not introduce zero dead-time (ZDT). Dropping every second sample of a phase/time-error series can maintain the zero dead-time property, but you loose the resolution for higher taus. > The whole > point I was making was that the data set is well defined the "missing" > data occurs every other sample therefore tau0 = 2 x (sample period of > each sample). > You can reduce the dataset size that way if you had phase/time-error samples and attain twice the tau, yes. The downside is that you also reduce the degrees of freedom in the dataset and thus the statistical precission. With a large enought dataset this may not be much of an issue. Cheers, Magnus From magnus at rubidium.dyndns.org Mon Apr 13 12:09:57 2009 From: magnus at rubidium.dyndns.org (Magnus Danielson) Date: Mon, 13 Apr 2009 14:09:57 +0200 Subject: [time-nuts] Characterising frequency standards In-Reply-To: <1231b6a80904121734v141f37c9t14bb9662328776f2@mail.gmail.com> References: <1231b6a80904070509m5b8bb638gbc088500444254c3@mail.gmail.com> <1231b6a80904080441p7a747a3h1f73bf8a2df30350@mail.gmail.com> <49DC91B9.6090004@xtra.co.nz> <1231b6a80904080504n4a3a22dcr247fae5df39ed840@mail.gmail.com> <7911976D35924C91A61F679126F77F9E@pc52> <1231b6a80904090500i1cd90f80w7983e03b4978cfa8@mail.gmail.com> <1231b6a80904120206j310d0d66pbb78ea5c4a50c302@mail.gmail.com> <49E1B228.9070106@xtra.co.nz> <1231b6a80904121734v141f37c9t14bb9662328776f2@mail.gmail.com> Message-ID: <49E32B95.70904@rubidium.dyndns.org> Steve, Steve Rooke wrote: > Bruce, > > 2009/4/12 Bruce Griffiths : >> Steve >> >> Steve Rooke wrote: >>> If I take two sequential phase readings from an input source and place >>> this into one data set and aniother two readings from the same source >>> but spaced by one cycle and put this in a second data set. From the >>> first data set I can calculate ADEV for tau = 1s and can calculate >>> ADEV for tau = 2 sec from the second data set. If I now pre-process >>> the data in the second set to remove all the effects of drift (given >>> that I have already determined this), I now have two 1 sec samples >>> which show a statistical difference and can be fed to ADEV with a tau0 >>> = 1 sec producing a result for tau = 1 sec. The results from this >>> second calculation should show equal accuracy as that using the first >>> data set (given the limited size of the data set). >>> >>> >> You need to give far more detail as its unclear exactly what you are >> doing with what samples. >> Label all the phase samples and then show which samples belong to which >> data set. >> Also need to show clearly what you mean by skipping a cycle. > > Say I have a 1Hz input source and my counter measures the period of > the first cycle and assigns this to A1. At the end of the first cycle > the counter is able to be rest and re-triggered to capture the second > cycle and assign this to A2. So far 2 sec have passed and I have two > readings in data set A. Strange counter. Traditionally counters rests after the stop event have occured, since they cannot know anything else.The Gate time gives a hint on the first point in time it can trigger, the gate just arms the stop event. There is no real end point. It can however rest and retrigger the start event ASAP when gate times are sufficiently large. It's just a smart rearrangement of what to do when to achieve zero dead-time for period/frequency measurements. You could also use a counter which is pseudo zero dead time in that it can time-stamp three values, two differences without deadtime but has deadtime after that. Essentially two counters where the stop event of the first is the start event of the next. > I now repeat the experiment and assign the measurement of the first > period to B1. The counter I am using this time is unable to stop at > the end of the first measurement and retrigger immediately so I'm > unable to measure the second cycle but is left in the armed position. > When the third cycle starts, the counter triggers and completes the > measurement of the third cycle which is now assigned to B2. This is what most normal counters do. > For the purposes of my original text, the first data set refers to A1 > & A2. Similarly the second data set refers to B1 & B2. Reference to > pre-processing of the second data set refers to mathematically > removing the effects of drift from B1 & B2 to produce a third data set > which is used as the data input for an ADEV calculation where tau0 = 1 > sec with output of tau = 1 sec. You would need to use bias adjustments, but the B1 & B2 period/frequency samples is badly tainted data and should not be used.having a deadtime at the size of tau0 is serious bussness. Removing the phase drift over the dead time does not aid you since if you remove the phase ramp of the evolving clock, that of f*t or v*t (depending on which normalisation you prefer), you have the background phase noise. What we want to do is to characterize this phase noise. Taking two samples of it back-to-back and taking two samples with a (equalent sized length) gap becomes two different filters. Maybe some ascii art may aid: __ __ | |__ |__| y1 y2 y3 A1 A2 A2-A1 = y2-y1 vs. __ __ __| |__ |__| y1 y2 y3 B1 B2 B2-B1 = y3-y1 Consider now the case when frequency samples has twice the tau of the above examples _____ __ | |__ |_____| y1 y2 y2-y1 These examples where all based on sequences of frequency measurements, just as you indicate in your caes. As you see on the differences, the nominal frequency cancels and the nominal phase error has also cancled out, so there is nothing to compensate there. Drift rate would however not be canceled, but for most of our sources, the noise is higher than the drift rate for shorter taus. Time-differences allows us to skip every other cycle thought. >>> I now collect a large data set but with a single cycle skipped between >>> each sample. I feed this into ADEV using tau0 = 2 sec to produce tau >>> results >= 2 sec. I then pre-process the data to remove any drift and >>> feed this to ADEV with a tau0 = 1 sec to produce just the tau = 1 sec >>> result. I now have a complete set of results for tau >= 1 sec. Agreed, >>> there is the issue of modulation at 1/2 input f but ignoring this for >>> the moment, this should give a valid result. >>> >>> >> Again you need to give more detail. > > In this case the data set is constructed from the measurement of the > cycle periods of a 1Hz input source where even cycles are skipped, > hence each data point is a measurement of the period of each odd (1, > 3, 5, 7...) cycle of the incoming waveform. In this case the time > between each measurement is 2 sec so ADEV is calculated with tau = 2 > sec for tau >= 2 sec. This data set is then mathematically processed > to remove the effects of drift, bearing in mind the 2 sec spacing of > each data point, and ADEV is then calculated with tau0 = 1 sec for tau > = 1 sec. How did you establish the effect of drift? >> What noise from what source? > > PN - White noise phase WPM, Flicker noise phase FPM, White noise > frequency WFM, Flicker noise frequency FFM and Random walk frequency > RWFM. These are just the names for the various 1/f power noises. They enter through a myriad of places, white phase noise and 1/f is common to amplifiers, 1/f^5 is thermal noise onto the same amplifiers. 1/f^2 is oscillator shaped white phase noise and 1/f^3 is oscillator shaped 1/f noise. Rubiola spends quite some time on that subject, both in his excelent book and in various papers. >> Noise in such measurements can originate in the measuring instrument or >> the source. > > Indeed, and this is an important aspect to consider as we have been > discussing the effects of induced jitter/PN to a frequency standard > when it is buffered and divided down. Ideally measurements of ADEV > would be made on the raw frequency standard source (eg. 10MHz) rather > than, say, a divided 1Hz signal. Yes and no. There are benefits in dividing it down, you can identify cycle slips easier and adjust for them, where as one 10 MHz cycle to another can be a bit anonymous. To get the best performance for ADEV at 1 s using a 1 Hz signal is not optimum thought. A slightly higher rate will allow for quicker gathering of high statistical freedom and thus improved statistical stability as allowed through the overlapping Allan Deviation estimator as compared to use the non-overlapping Allan Deviation estimator on the same time-stretch of samples. When running long runs, sufficient freedom may be achieved even using the non-overlapping estimator. A divide down does not have to make significant change to phase-noise, its effect can be minimized as we have discussed before. The 1 PPS signal is also quite historical artifact which is still quite handy. It allows direct comparision of non-equalent frequencies as the division ration is adjusted. It is also what comes out of a majority of GPS receivers. Few GPS receivers evaluate their time offset at a faster rate than 1 Hz anyway, but 2, 5, 10 and 20 Hz is available. The L1 C/A signal would allow for a rate of 1 kHz but it would require really good signal conditions. For high resolution work, the PPS is not that good, since beating two 10 MHz would give you some 5-7 decades of better resolution if you can handle the problems with slow slopes. >> For short measurement times quantisation noise and instrumental noise >> may mask the noise from the source but they are still present. > > Well, these form the noise floor of our measurement system. Some of them we can control, though better triggering devices, as learned the hard way and investigated by many. Other ways to handle it is to use cross-correlation techniques where two independent system noises sees the same signal, in which case only the input source noise correlate and the system noise effect can be partially canceled out. There are systematic noise problems also, such as lack of zero dead time, resolution, interpolator distorsion etc. Cheers, Magnus From richard at karlquist.com Mon Apr 13 13:16:27 2009 From: richard at karlquist.com (Richard (Rick) Karlquist) Date: Mon, 13 Apr 2009 06:16:27 -0700 Subject: [time-nuts] HP 1938 revisited In-Reply-To: <50D082247E9747D7930F631CA1A37DD9@S0028384766> References: <50D082247E9747D7930F631CA1A37DD9@S0028384766> Message-ID: <49E33B2B.7070204@karlquist.com> J. L. Trantham wrote: > Thanks for the info. > > My plan is to develop a stable GPS disciplined reference suitable for use as > a reference for Microwave work in the 10 GHz range that can be used in > portable locations with relatively quick start up. > > Perhaps the 1938 would be better in the shop where it could be left on for > weeks/months at a time and an LPRO 101 or a 10811 could be used for the > portable application. Reasonably high drift rates could be accommodated if > the GPS signal is reliable and the time constants (disciplining rate, drift > rate, etc.) are appropriate. > > Thanks, > > Joe The advantage of the E1938A over the 10811 is that it has very low tempco, which comes into play in the holdover mode (no GPS). If you always have GPS, you might as well just use a 10811. The 5071A cesium clock uses a 10811 that is disciplined all the time. There would be no advantage in replacing it with an E1938A. The loop in the 5071A is fairly slow, but would be considered fast by GPS standards. If the portable location involves severe temperature fluctuations, then possibly the E1938A could make sense. Rick Karlquist N6RK E1938A designer From magnus at rubidium.dyndns.org Mon Apr 13 15:04:12 2009 From: magnus at rubidium.dyndns.org (Magnus Danielson) Date: Mon, 13 Apr 2009 17:04:12 +0200 Subject: [time-nuts] Spring cleaning and antenna placement Message-ID: <49E3546C.7050704@rubidium.dyndns.org> Fellow timenuts, You know you are a time-nut when your spring cleanup dutines involves getting onto the rooftop and clean your GPS antennas. In my case my dual frequency antenna (really a survey antenna, a Novatel GPS 502 L1/L2) was due to lack of patience temporarily put up there in a not so fixed position, so that the wind shifter position and attitude as it slided down the tiles that it was effectively useless, especially as it was pointing mostly north into the big GPS hole and putting the antennas nuling power towards most of the low-attitude sats. Let's just say that I'm not too proud of that mounting... I know better, I know far better... but I am impatient to play with the news toys, so I hope people recognice the feeling. My biggest problem is that I have a large TV antenna pole sitting ontop of one of the chimneys. It is needed as the house is partly down a valey to get a nice and clean TV signal. Fairly new also, as the old antennas was broken. I have got part of the gear to mount the GPS antennas on the other chimney, but lack the proper antenna tubes. My big L1 choke rings (AT575) can be mounted without the central tube but I wish to use the combination of that and the three outer mounting screws. I need to build a mounting platform for it anyway. Besides, I think the way I pull cables and what cables I use could improve. My RG 58 is certainly not optimum, but it is cheap, easily available alongside connectors and suitable strip and crimp tools. So... hints for tubes and other mounting aspects would be nice. Cheers, Magnus From brooke at pacific.net Mon Apr 13 15:22:38 2009 From: brooke at pacific.net (brooke at pacific.net) Date: Mon, 13 Apr 2009 08:22:38 -0700 (PDT) Subject: [time-nuts] Spring cleaning and antenna placement In-Reply-To: <49E3546C.7050704@rubidium.dyndns.org> References: <49E3546C.7050704@rubidium.dyndns.org> Message-ID: <3583.SVVXXVxVQkI=.1239636158.squirrel@webmail.securepacific.net> Hi Magnus: Why not just put the GPS antenna at the top of the existing TV mast? http://www.prc68.com/I/Ant.shtml#SBant Have Fun, Brooke Clarke http://www.PRC68.com > Fellow timenuts, > > You know you are a time-nut when your spring cleanup dutines involves > getting onto the rooftop and clean your GPS antennas. In my case my dual > frequency antenna (really a survey antenna, a Novatel GPS 502 L1/L2) was > due to lack of patience temporarily put up there in a not so fixed > position, so that the wind shifter position and attitude as it slided > down the tiles that it was effectively useless, especially as it was > pointing mostly north into the big GPS hole and putting the antennas > nuling power towards most of the low-attitude sats. Let's just say that > I'm not too proud of that mounting... I know better, I know far > better... but I am impatient to play with the news toys, so I hope > people recognice the feeling. > > My biggest problem is that I have a large TV antenna pole sitting ontop > of one of the chimneys. It is needed as the house is partly down a valey > to get a nice and clean TV signal. Fairly new also, as the old antennas > was broken. > > I have got part of the gear to mount the GPS antennas on the other > chimney, but lack the proper antenna tubes. > > My big L1 choke rings (AT575) can be mounted without the central tube > but I wish to use the combination of that and the three outer mounting > screws. I need to build a mounting platform for it anyway. > > Besides, I think the way I pull cables and what cables I use could > improve. My RG 58 is certainly not optimum, but it is cheap, easily > available alongside connectors and suitable strip and crimp tools. > > So... hints for tubes and other mounting aspects would be nice. > > Cheers, > Magnus > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > From magnus at rubidium.dyndns.org Mon Apr 13 15:32:48 2009 From: magnus at rubidium.dyndns.org (Magnus Danielson) Date: Mon, 13 Apr 2009 17:32:48 +0200 Subject: [time-nuts] Spring cleaning and antenna placement In-Reply-To: <3583.SVVXXVxVQkI=.1239636158.squirrel@webmail.securepacific.net> References: <49E3546C.7050704@rubidium.dyndns.org> <3583.SVVXXVxVQkI=.1239636158.squirrel@webmail.securepacific.net> Message-ID: <49E35B20.3070904@rubidium.dyndns.org> brooke at pacific.net skrev: > Hi Magnus: > > Why not just put the GPS antenna at the top of the existing TV mast? > http://www.prc68.com/I/Ant.shtml#SBant It would be a little bit of a challenge... I think I have some 4-5 meter of additional heigth, the tiling is slippery and then antenna rig is kind of heavy, so it is not one of those things you do alone. At least I don't do it alone... I'm not a well trained radio amateur and the rooftop is not very well suited for elaborate exercises... I sure would like to have things like safety-line when working up there. I don't feel that safe up there. Cheers, Magnus From brooke at pacific.net Mon Apr 13 16:25:03 2009 From: brooke at pacific.net (brooke at pacific.net) Date: Mon, 13 Apr 2009 09:25:03 -0700 (PDT) Subject: [time-nuts] Spring cleaning and antenna placement In-Reply-To: <49E35B20.3070904@rubidium.dyndns.org> References: <49E3546C.7050704@rubidium.dyndns.org> <3583.SVVXXVxVQkI=.1239636158.squirrel@webmail.securepacific.net> <49E35B20.3070904@rubidium.dyndns.org> Message-ID: <3975.SVVXXVxVQkI=.1239639903.squirrel@webmail.securepacific.net> Hi Magnus: Safety is the # 1 concern. It may be that if you can minimize the multipath problems having the GPS antenna near the roof is not a problem? I'm starting to do some antenna related tests using the Polaris Guide (DAGR) GPS receiver, see: http://www.prc68.com/I/DAGR.shtml#GLS and scroll down for some zero base line tests of how well it does carrier phase distance and angle measurements (aka Gun Laying, Azimuth Determination, North Finding, Relative Survey Mode). Another test I'd like to do is measure multipath, but so far have not come up with a direct way to do it other that infer based on how poor/good some test result is. For example are the variations in the above tests due to multipath? Have Fun, Brooke http://www.PRC68.com > brooke at pacific.net skrev: >> Hi Magnus: >> >> Why not just put the GPS antenna at the top of the existing TV mast? >> http://www.prc68.com/I/Ant.shtml#SBant > > It would be a little bit of a challenge... I think I have some 4-5 meter > of additional heigth, the tiling is slippery and then antenna rig is > kind of heavy, so it is not one of those things you do alone. At least I > don't do it alone... I'm not a well trained radio amateur and the > rooftop is not very well suited for elaborate exercises... > > I sure would like to have things like safety-line when working up there. > I don't feel that safe up there. > > Cheers, > Magnus > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > From sar10538 at gmail.com Mon Apr 13 18:49:17 2009 From: sar10538 at gmail.com (Steve Rooke) Date: Tue, 14 Apr 2009 06:49:17 +1200 Subject: [time-nuts] Characterising frequency standards In-Reply-To: <49E31789.7040000@rubidium.dyndns.org> References: <1231b6a80904121654m4157003dp80b666c49fec218a@mail.gmail.com> <49E31789.7040000@rubidium.dyndns.org> Message-ID: <1231b6a80904131149v7549a5fj2e3427d7a69000e2@mail.gmail.com> 2009/4/13 Magnus Danielson : >> But randomly throwing out data points would introduce ZDT. > It would introduce dead-time, it would not introduce zero dead-time > (ZDT). Dropping every second sample of a phase/time-error series can > maintain the zero dead-time property, but you loose the resolution for > higher taus. First rule of posting, engage brain before typing :-) Yes, of course you are right Magnus and that was what I really meant. 73, Steve -- Steve Rooke - ZL3TUV & G8KVD & JAKDTTNW Omnium finis imminet From gwinn at raytheon.com Mon Apr 13 19:06:58 2009 From: gwinn at raytheon.com (Joseph M Gwinn) Date: Mon, 13 Apr 2009 15:06:58 -0400 Subject: [time-nuts] Spring cleaning and antenna placement In-Reply-To: <49E35B20.3070904@rubidium.dyndns.org> Message-ID: time-nuts-bounces at febo.com wrote on 04/13/2009 11:32:48 AM: > brooke at pacific.net skrev: > > Hi Magnus: > > > > Why not just put the GPS antenna at the top of the existing TV mast? > > http://www.prc68.com/I/Ant.shtml#SBant > > It would be a little bit of a challenge... I think I have some 4-5 meter > of additional height, the tiling is slippery and then antenna rig is > kind of heavy, so it is not one of those things you do alone. At least I > don't do it alone... I'm not a well trained radio amateur and the > rooftop is not very well suited for elaborate exercises... > > I sure would like to have things like safety-line when working up there. > I don't feel that safe up there. I don't know what it costs in Sweden, but in the US one can hire roofers or antenna installers to do such things, and they have the equipment. How did the TV mast get on the roof? Joe Gwinn From magnus at rubidium.dyndns.org Mon Apr 13 19:04:37 2009 From: magnus at rubidium.dyndns.org (Magnus Danielson) Date: Mon, 13 Apr 2009 21:04:37 +0200 Subject: [time-nuts] Characterising frequency standards In-Reply-To: <1231b6a80904131149v7549a5fj2e3427d7a69000e2@mail.gmail.com> References: <1231b6a80904121654m4157003dp80b666c49fec218a@mail.gmail.com> <49E31789.7040000@rubidium.dyndns.org> <1231b6a80904131149v7549a5fj2e3427d7a69000e2@mail.gmail.com> Message-ID: <49E38CC5.8070306@rubidium.dyndns.org> Steve Rooke skrev: > 2009/4/13 Magnus Danielson : >>> But randomly throwing out data points would introduce ZDT. >> It would introduce dead-time, it would not introduce zero dead-time >> (ZDT). Dropping every second sample of a phase/time-error series can >> maintain the zero dead-time property, but you loose the resolution for >> higher taus. > > First rule of posting, engage brain before typing :-) Yes, of course > you are right Magnus and that was what I really meant. I thought that you just made the mistake... :) Cheers, Magnus From mfeher at eozinc.com Mon Apr 13 19:32:18 2009 From: mfeher at eozinc.com (Mike Feher) Date: Mon, 13 Apr 2009 15:32:18 -0400 Subject: [time-nuts] Power Supplies for Rubidiums & OCXOs - etc... In-Reply-To: <49E38CC5.8070306@rubidium.dyndns.org> References: <1231b6a80904121654m4157003dp80b666c49fec218a@mail.gmail.com> <49E31789.7040000@rubidium.dyndns.org> <1231b6a80904131149v7549a5fj2e3427d7a69000e2@mail.gmail.com> <49E38CC5.8070306@rubidium.dyndns.org> Message-ID: <040a01c9bc6e$8fa21b80$aee65280$@com> I recently purchased a "lot" of 24 volt 5 amp switching power supplies. Well, they are marked 5 amps, but, I was able to get 7 out of them without any problem, with the exception that my resistive load was getting too hot. These are very nice supplies, look like an oversized laptop power supply. I have a bunch of Rubidium sources that require 24 volts and these obviously would be great. Packaged, with AC cord, they weigh a little less than 3 pounds. If you are interested in obtaining one or more, let me know. I would like $35 each, plus shipping. I do not think you will be disappointed. There are a lot of possible applications, besides Rubidiums and OCXOs. Regards - Mike Mike B. Feher, N4FS 89 Arnold Blvd. Howell, NJ, 07731 732-886-5960 From magnus at rubidium.dyndns.org Mon Apr 13 19:37:45 2009 From: magnus at rubidium.dyndns.org (Magnus Danielson) Date: Mon, 13 Apr 2009 21:37:45 +0200 Subject: [time-nuts] Spring cleaning and antenna placement In-Reply-To: References: Message-ID: <49E39489.8020503@rubidium.dyndns.org> Joseph M Gwinn skrev: > time-nuts-bounces at febo.com wrote on 04/13/2009 11:32:48 AM: > >> brooke at pacific.net skrev: >>> Hi Magnus: >>> >>> Why not just put the GPS antenna at the top of the existing TV mast? >>> http://www.prc68.com/I/Ant.shtml#SBant >> It would be a little bit of a challenge... I think I have some 4-5 meter > >> of additional height, the tiling is slippery and then antenna rig is >> kind of heavy, so it is not one of those things you do alone. At least I > >> don't do it alone... I'm not a well trained radio amateur and the >> rooftop is not very well suited for elaborate exercises... >> >> I sure would like to have things like safety-line when working up there. > >> I don't feel that safe up there. > > I don't know what it costs in Sweden, but in the US one can hire roofers > or antenna installers to do such things, and they have the equipment. > > How did the TV mast get on the roof? A professional TV mast rigger did the job. I had a look at it again... and I'd say it is more like 3 meters up from the chimney, but it is still 4 m up from the roof at the chimney so it is a bit hard to get to. Anyway, the repositioned antenna now makes the borrowed Ashtech Z-12 lock up at L1 and L2 for sufficient amount of sats, but the S/N is lowish, which I think I will blame on my RG-58, not too professionally done coax work... could TDR it thought. Hmm... why didn't I think of that? Cheers, Magnus From pico.2008 at sbcglobal.net Mon Apr 13 19:55:01 2009 From: pico.2008 at sbcglobal.net (Peter Putnam) Date: Mon, 13 Apr 2009 12:55:01 -0700 Subject: [time-nuts] Spring cleaning and antenna placement In-Reply-To: <49E39489.8020503@rubidium.dyndns.org> References: <49E39489.8020503@rubidium.dyndns.org> Message-ID: <49E39895.8040605@sbcglobal.net> Magnus, If you replace your RG-58 with RG-6 TV coax, your loss issues will disappear. The difference in impedance (75 ohms instead of 50) is not enough to cause problems. Adapters to the pre-fitted F connectors are readily available. And it's not expensive. Regards, Peter Magnus Danielson wrote: Joseph M Gwinn skrev: [1]time-nuts-bounces at febo.com wrote on 04/13/2009 11:32:48 AM: [2]brooke at pacific.net skrev: Hi Magnus: Why not just put the GPS antenna at the top of the existing TV mast? [3]http://www.prc68.com/I/Ant.shtml#SBant It would be a little bit of a challenge... I think I have some 4-5 meter of additional height, the tiling is slippery and then antenna rig is kind of heavy, so it is not one of those things you do alone. At least I don't do it alone... I'm not a well trained radio amateur and the rooftop is not very well suited for elaborate exercises... I sure would like to have things like safety-line when working up there. I don't feel that safe up there. I don't know what it costs in Sweden, but in the US one can hire roofers or antenna installers to do such things, and they have the equipment. How did the TV mast get on the roof? A professional TV mast rigger did the job. I had a look at it again... and I'd say it is more like 3 meters up from the chimney, but it is still 4 m up from the roof at the chimney so it is a bit hard to get to. Anyway, the repositioned antenna now makes the borrowed Ashtech Z-12 lock up at L1 and L2 for sufficient amount of sats, but the S/N is lowish, which I think I will blame on my RG-58, not too professionally done coax work... could TDR it thought. Hmm... why didn't I think of that? Cheers, Magnus _______________________________________________ time-nuts mailing list -- [4]time-nuts at febo.com To unsubscribe, go to [5]https://www.febo.com/cgi-bin/mailman/listinfo/time-nut s and follow the instructions there. References 1. mailto:time-nuts-bounces at febo.com 2. mailto:brooke at pacific.net 3. http://www.prc68.com/I/Ant.shtml#SBant 4. mailto:time-nuts at febo.com 5. https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts From holrum at hotmail.com Mon Apr 13 20:37:09 2009 From: holrum at hotmail.com (Mark Sims) Date: Mon, 13 Apr 2009 20:37:09 +0000 Subject: [time-nuts] Characterising frequency standards In-Reply-To: References: Message-ID: The whole purpose of taking a data set from a known ZDT counter and then throwing out random samples is to simulate the kind of data that a normal counter would produce. You could compare the results and get an idea of how using a normal counter for calculating adevs would compare to using a ZDT counter. I would start by generating random numbers from 0-3 and throwing out that many samples. With most normal counters you cannot guarantee that you would get a sample every other interval. It all depends upon how the counter works, what its timebase is, how it triggers and retriggers, how it is being read out, what the input signal is, etc. I would suspect that most counters would give a reading every two or three intervals. I have seen some counters give two consecutive back-to-back readings then a long dead time. ---------------------------------------- But randomly throwing out data points would introduce ZDT. The whole point I was making was that the data set is well defined the "missing" data occurs every other sample therefore tau0 = 2 x (sample period of each sample). _________________________________________________________________ Windows Live?: Keep your life in sync. http://windowslive.com/explore?ocid=TXT_TAGLM_WL_allup_1a_explore_042009 From magnus at rubidium.dyndns.org Mon Apr 13 23:05:00 2009 From: magnus at rubidium.dyndns.org (Magnus Danielson) Date: Tue, 14 Apr 2009 01:05:00 +0200 Subject: [time-nuts] Characterising frequency standards In-Reply-To: References: Message-ID: <49E3C51C.6030701@rubidium.dyndns.org> Mark, Mark Sims skrev: > The whole purpose of taking a data set from a known ZDT counter and then throwing out random samples is to simulate the kind of data that a normal counter would produce. You could compare the results and get an idea of how using a normal counter for calculating adevs would compare to using a ZDT counter. I would start by generating random numbers from 0-3 and throwing out that many samples. > > With most normal counters you cannot guarantee that you would get a sample every other interval. It all depends upon how the counter works, what its timebase is, how it triggers and retriggers, how it is being read out, what the input signal is, etc. I would suspect that most counters would give a reading every two or three intervals. I have seen some counters give two consecutive back-to-back readings then a long dead time. Most counters I know of would make one frequency measure, then miss the directly following just to trigger directly ontop the next, those for a PPS pulse it would measure the period between the first and second pulse, then dwell until the third pps pulse and measure until the fourth pulse, but then happily repeat this pattern. But measuring frequency/period like this is not very useful for post-processing in any Allan Deviation measure. The lack of back-to-back measures prohibits you from achieving the data you need. We rather use time-interval measures. Let's consider the same counter, we arm it with a PPS pulse from either of the sources, but then measure the time interval between two 1 kHz variants of the signal, or use the PPS as start of the TI and the stop channel sees the 1 kHz signal, I'll use the later as a reference, but the cases are equalent. The same counter can now dwell between the measurements, but most counters can withstand 1 measurement per second without too much trouble. The 1 kHz signal allow for a maximum of 1 ms delay from arming/start trigger to stop trigger. This still allows for plenty of time for the counter post-processing to occur and re-arming. As the clocks drift, dynamically would stop-channels choice of 1 kHz flanks shift, but it would be a fairly simple task to post-process that into a continous stream of PPS marks. Using these time-interval measures of tau0 being 1 s, we can now make any set of back-to-back frequency measures as we please, as long as they are integer multiples of tau0 by dropping n-1 samples inbetween and recall that the sample-series has converted to a tau0 of n seconds. We can also use the series directly for the Allan Deviation estimator of choice in either time or frequency form. Thus, the lack of zero dead time does not necesserilly prohibits the use, but care in setting up the signals and I/O can curcumvent the problem. Many counters is being used one way or another for continuous measures even if they are not exclusive ZDT counters, but it takes care. Having one or two of TVBs PIC dividers at hand should certainly be handy for doing tricks like this. Time-resolution of the counters as well as trigger noise may be issues to look at. When do one need true ZDT counters then? Well, if you want to make measurements for higher frequency modulations, you need that power, but most of the time they are just very handy tools. Cheers, Magnus From chris.cheney at tesco.net Tue Apr 14 07:57:23 2009 From: chris.cheney at tesco.net (Chris Cheney) Date: Tue, 14 Apr 2009 08:57:23 +0100 Subject: [time-nuts] Spring cleaning and antenna placement In-Reply-To: <49E39489.8020503@rubidium.dyndns.org> References: , <49E39489.8020503@rubidium.dyndns.org> Message-ID: <49E44FF3.17229.15E49D@chris.cheney.tesco.net> > I had a look at it again... and I'd say it is more like 3 meters up from > the chimney, but it is still 4 m up from the roof at the chimney so it is > a bit hard to get to. If you are in Scandinavia, the GPS birds will not spend much time (if any?) to the north of you. Slide 12 of http://web.ics.purdue.edu/~ecalais/teaching/geodesy/Satellite_orbits.pdf suggests that the most northerly orbital point is at the latitude of Denmark. Attach a boom, pointing southwards, to the mast at a _convenient point_ and mount your GPS antenna at the end of the boom. The boom is to take the GPS antenna out of the shadow of the TV antenna (but if the TV antenna is actually pointing south the boom may need to be quite long). (Hiring an antenna rigger still seems the best solution) Chris G3RSE From jmiles at pop.net Tue Apr 14 17:29:18 2009 From: jmiles at pop.net (John Miles) Date: Tue, 14 Apr 2009 10:29:18 -0700 Subject: [time-nuts] OT: Verilog/VHDL discussion list created... Message-ID: ... for those who would like to participate in HDL discussions that aren't on-topic for existing lists: http://groups.yahoo.com/group/HDLTalk Any VHDL or Verilog HDL-related topics are welcome. To keep spammers away, new member signups require moderator approval. For this reason, please indicate your interest(s) briefly when you join. This can be as brief as a call sign or company affiliation, just so I can tell you're not a freelance V14g^a salesman. -- john, KE5FX From newell at cei.net Tue Apr 14 17:36:14 2009 From: newell at cei.net (Scott Newell) Date: Tue, 14 Apr 2009 12:36:14 -0500 Subject: [time-nuts] OT: Verilog/VHDL discussion list created... In-Reply-To: Message-ID: <200904141736.n3EHaGPr019461@host22.the-web-host.com> At 12:29 PM 4/14/2009 , John Miles wrote: >... for those who would like to participate in HDL discussions that aren't >on-topic for existing lists: > >http://groups.yahoo.com/group/HDLTalk > >Any VHDL or Verilog HDL-related topics are welcome. How will this compare to comp.lang.verilog, comp.lang.vhdl, and comp.arch.fpga? -- newell N5TNL From cupido at mail.ua.pt Tue Apr 14 17:40:33 2009 From: cupido at mail.ua.pt (Luis Cupido) Date: Tue, 14 Apr 2009 18:40:33 +0100 Subject: [time-nuts] OT: Verilog/VHDL discussion list created... In-Reply-To: <200904141736.n3EHaGPr019461@host22.the-web-host.com> References: <200904141736.n3EHaGPr019461@host22.the-web-host.com> Message-ID: <49E4CA91.8010707@mail.ua.pt> I believe it is to be ham or hobby oriented Am I right ? (If so some rewording of the list purpose might be adequate... thinking out loud...) Luis Cupido ct1dmk. Scott Newell wrote: > At 12:29 PM 4/14/2009 , John Miles wrote: >> ... for those who would like to participate in HDL discussions that aren't >> on-topic for existing lists: >> >> http://groups.yahoo.com/group/HDLTalk >> >> Any VHDL or Verilog HDL-related topics are welcome. > > How will this compare to comp.lang.verilog, comp.lang.vhdl, and > comp.arch.fpga? > From jmiles at pop.net Tue Apr 14 19:00:46 2009 From: jmiles at pop.net (John Miles) Date: Tue, 14 Apr 2009 12:00:46 -0700 Subject: [time-nuts] OT: Verilog/VHDL discussion list created... In-Reply-To: <200904141736.n3EHaGPr019461@host22.the-web-host.com> Message-ID: > > At 12:29 PM 4/14/2009 , John Miles wrote: > >... for those who would like to participate in HDL discussions > that aren't > >on-topic for existing lists: > > > >http://groups.yahoo.com/group/HDLTalk > > > >Any VHDL or Verilog HDL-related topics are welcome. > > How will this compare to comp.lang.verilog, comp.lang.vhdl, and > comp.arch.fpga? Not everybody can stomach Google's perversion of Usenet (which admittedly was no small engineering feat in itself). -- john, KE5FX From msokolov at ivan.Harhan.ORG Tue Apr 14 19:12:01 2009 From: msokolov at ivan.Harhan.ORG (Michael Sokolov) Date: Tue, 14 Apr 2009 19:12:01 GMT Subject: [time-nuts] OT: Verilog/VHDL discussion list created... Message-ID: <0904141912.AA26396@ivan.Harhan.ORG> John Miles wrote: > Not everybody can stomach Google's perversion of Usenet (which admittedly > was no small engineering feat in itself). Aren't there still non-Google ways of accessing Usenet? MS From magnus at rubidium.dyndns.org Tue Apr 14 19:40:12 2009 From: magnus at rubidium.dyndns.org (Magnus Danielson) Date: Tue, 14 Apr 2009 21:40:12 +0200 Subject: [time-nuts] OT: Verilog/VHDL discussion list created... In-Reply-To: <0904141912.AA26396@ivan.Harhan.ORG> References: <0904141912.AA26396@ivan.Harhan.ORG> Message-ID: <49E4E69C.1060808@rubidium.dyndns.org> Michael Sokolov skrev: > John Miles wrote: > >> Not everybody can stomach Google's perversion of Usenet (which admittedly >> was no small engineering feat in itself). > > Aren't there still non-Google ways of accessing Usenet? There is. Find the Wikipedia page for Usenet to find several suggestions... I am really considering it. But prefering Yahoo over Google usenet is ehum... a bit strange. I have my own email-lists on my own server... if someone asked me to set the list up, I would just do it. Cheers, Magnus From cfharris at erols.com Tue Apr 14 19:58:16 2009 From: cfharris at erols.com (Chuck Harris) Date: Tue, 14 Apr 2009 15:58:16 -0400 Subject: [time-nuts] OT: Verilog/VHDL discussion list created... In-Reply-To: References: Message-ID: <49E4EAD8.9000602@erols.com> John Miles wrote: >> At 12:29 PM 4/14/2009 , John Miles wrote: >>> ... for those who would like to participate in HDL discussions >> that aren't >>> on-topic for existing lists: >>> >>> http://groups.yahoo.com/group/HDLTalk >>> >>> Any VHDL or Verilog HDL-related topics are welcome. >> How will this compare to comp.lang.verilog, comp.lang.vhdl, and >> comp.arch.fpga? > > Not everybody can stomach Google's perversion of Usenet (which admittedly > was no small engineering feat in itself). Google didn't do anything to usenet. They did provide a web based interface into usenet, and bought the dejanews archive of all non-binary groups. What did happen to usenet, is most ISP's stopped hosting newsgroups, and providing usenet service to their subscribers. They did this partly because of the success of yahoo groups, and google groups, and partly because of the risk of hosting any child pornography that might be passed along on usenet. -Chuck Harris From bg at lysator.liu.se Tue Apr 14 21:24:26 2009 From: bg at lysator.liu.se (bg at lysator.liu.se) Date: Tue, 14 Apr 2009 23:24:26 +0200 (CEST) Subject: [time-nuts] Spring cleaning and antenna placement In-Reply-To: <49E44FF3.17229.15E49D@chris.cheney.tesco.net> References: , <49E39489.8020503@rubidium.dyndns.org> <49E44FF3.17229.15E49D@chris.cheney.tesco.net> Message-ID: <55666.87.227.52.225.1239744266.squirrel@webmail.lysator.liu.se> > If you are in Scandinavia, the GPS birds will not spend much time (if > any?) to the north of you. Slide 12 of > http://web.ics.purdue.edu/~ecalais/teaching/geodesy/Satellite_orbits.pdf > suggests that the most northerly orbital point is at the latitude of > Denmark. With a decent antenna siting you see plenty of SVs to the north. Magnus problem is that there are lots of rather close by trees and stuff. These trees are also much taller than the antenna position. /Bj?rn From jmiles at pop.net Tue Apr 14 22:50:03 2009 From: jmiles at pop.net (John Miles) Date: Tue, 14 Apr 2009 15:50:03 -0700 Subject: [time-nuts] OT: Verilog/VHDL discussion list created... In-Reply-To: <49E4E69C.1060808@rubidium.dyndns.org> Message-ID: > Michael Sokolov skrev: > > John Miles wrote: > > > >> Not everybody can stomach Google's perversion of Usenet (which > admittedly > >> was no small engineering feat in itself). > > > > Aren't there still non-Google ways of accessing Usenet? > > There is. Find the Wikipedia page for Usenet to find several > suggestions... > > I am really considering it. > > But prefering Yahoo over Google usenet is ehum... a bit strange. > What objections are there to Yahoo Groups? I don't have a way to get NNTP traffic in my email inbox, nor would I want it if I could. -- john, KE5FX From jmiles at pop.net Tue Apr 14 22:56:06 2009 From: jmiles at pop.net (John Miles) Date: Tue, 14 Apr 2009 15:56:06 -0700 Subject: [time-nuts] OT: Verilog/VHDL discussion list created... In-Reply-To: <49E4EAD8.9000602@erols.com> Message-ID: > Google didn't do anything to usenet. They did provide a web based > interface into usenet, and bought the dejanews archive of all > non-binary groups. > If you were a hardcore DejaNews user, as I was, you were probably not very happy with the way Google handled the archive and its user interface. If you *were* happy with what they did, you're literally the first user I've encountered who was. It's neither here nor there, as I prefer email lists to Usenet, and I'm the one who started the group. :-P -- john, KE5FX From richard at karlquist.com Wed Apr 15 00:50:29 2009 From: richard at karlquist.com (Richard (Rick) Karlquist) Date: Tue, 14 Apr 2009 17:50:29 -0700 Subject: [time-nuts] femtosecond jitter anyone? In-Reply-To: <49E2D785.3070600@xtra.co.nz> References: <49E2D785.3070600@xtra.co.nz> Message-ID: <49E52F55.9010809@karlquist.com> Bruce Griffiths wrote: > Some ECL devices have jitter specs in the 100 to 200fsec range. > see: > http://www.onsemi.com > This is misleading. While it is true that they have this low jitter at multi-Gb/s rates, the jitter is much greater than this at lower clock rates. At 10 MHz, ECL devices can't do better than several ps random jitter. This is because of the broadband phase noise floor which is around -150 dBc/Hz. Rick Karlquist N6RK From bruce.griffiths at xtra.co.nz Wed Apr 15 01:26:59 2009 From: bruce.griffiths at xtra.co.nz (Bruce Griffiths) Date: Wed, 15 Apr 2009 13:26:59 +1200 Subject: [time-nuts] femtosecond jitter anyone? In-Reply-To: <49E52F55.9010809@karlquist.com> References: <49E2D785.3070600@xtra.co.nz> <49E52F55.9010809@karlquist.com> Message-ID: <49E537E3.9090807@xtra.co.nz> Rick The following NIST paper indicates that the conventional wisdom on ECL phase noise levels appear to be incorrect at least for some ECL divider configurations: http://www.am1.us/Papers/U11605%20Low%20Noise%20Synthesis-%20Walls.pdf Waveform symmetry and low power supply noise seem to be very important. The output jitter of a a gate is dependent on its phase noise properties, and the slew rate of its input signal at the threshold crossing. Surely if the SiGe ECL devices were driven with an input with a comparable slew rate surely its output jitter would be similar even for lower frequency inut signals? Bruce Richard (Rick) Karlquist wrote: > Bruce Griffiths wrote: > > >> Some ECL devices have jitter specs in the 100 to 200fsec range. >> see: >> http://www.onsemi.com >> >> > > This is misleading. While it is true that they have this > low jitter at multi-Gb/s rates, the jitter is much greater > than this at lower clock rates. At 10 MHz, ECL devices > can't do better than several ps random jitter. This is > because of the broadband phase noise floor which is around > -150 dBc/Hz. > > Rick Karlquist N6RK > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > From jra at febo.com Wed Apr 15 01:30:24 2009 From: jra at febo.com (John Ackermann N8UR) Date: Tue, 14 Apr 2009 21:30:24 -0400 Subject: [time-nuts] OT: Manual for Julie Research "Volt-A-Vider"? Message-ID: <49E538B0.6020907@febo.com> I just acquired a nice portable zener voltage reference with six-digit divider. It's a Julie Research Labs (JRL) "Volt-A-Vider" model GTX-355. There aren't many references to this device on the web, much less to its manual. Any chance someone here might have a manual, or a data sheet, or any info at all about it? It's supposed to be a pretty good unit; this one came out of NASA and after quite a while in storage was recently checked and found to be within a couple of PPM after 30 minutes warm-up. Thanks, John From ed_palmer at sasktel.net Wed Apr 15 02:15:16 2009 From: ed_palmer at sasktel.net (Ed Palmer) Date: Tue, 14 Apr 2009 20:15:16 -0600 Subject: [time-nuts] OT: Manual for Julie Research "Volt-A-Vider"? In-Reply-To: <49E538B0.6020907@febo.com> References: <49E538B0.6020907@febo.com> Message-ID: <49E54334.3060806@sasktel.net> This doesn't include your model #, but it may be of some help. http://web.archive.org/web/20020903124352/http://www.procinst.com/voltavider.PDF Ed John Ackermann N8UR wrote: > I just acquired a nice portable zener voltage reference with six-digit > divider. It's a Julie Research Labs (JRL) "Volt-A-Vider" model GTX-355. > There aren't many references to this device on the web, much less to > its manual. > > Any chance someone here might have a manual, or a data sheet, or any > info at all about it? > > It's supposed to be a pretty good unit; this one came out of NASA and > after quite a while in storage was recently checked and found to be > within a couple of PPM after 30 minutes warm-up. > > Thanks, > > John > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > From cfharris at erols.com Wed Apr 15 03:27:21 2009 From: cfharris at erols.com (Chuck Harris) Date: Tue, 14 Apr 2009 23:27:21 -0400 Subject: [time-nuts] OT: Verilog/VHDL discussion list created... In-Reply-To: References: Message-ID: <49E55419.6000402@erols.com> I was a hardcore dajanews user. I guess that I even know it by that name would indicate that I was around back then. Google wrecked dejanews in the spirit of political correctness, the nanny state, and trying to pretend that usenet is just a part of google groups. Erasing all of the email addresses, and other things. At one point they let you have the email addresses if you were logged in as a google user. I don't use google's deja interface anymore, so I don't know what they do now. -Chuck Harris John Miles wrote: >> Google didn't do anything to usenet. They did provide a web based >> interface into usenet, and bought the dejanews archive of all >> non-binary groups. >> > > If you were a hardcore DejaNews user, as I was, you were probably not very > happy with the way Google handled the archive and its user interface. If > you *were* happy with what they did, you're literally the first user I've > encountered who was. > > It's neither here nor there, as I prefer email lists to Usenet, and I'm the > one who started the group. :-P > > -- john, KE5FX > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > From msokolov at ivan.Harhan.ORG Wed Apr 15 03:44:27 2009 From: msokolov at ivan.Harhan.ORG (Michael Sokolov) Date: Wed, 15 Apr 2009 03:44:27 GMT Subject: [time-nuts] OT: Verilog/VHDL discussion list created... Message-ID: <0904150344.AA27234@ivan.Harhan.ORG> Chuck Harris wrote: > Google wrecked dejanews in the spirit of political correctness, > the nanny state, and trying to pretend that usenet is just a part > of google groups. Erasing all of the email addresses, and other things. Does anyone know exactly where (building, city, country, continent) do they store the raw data acquired from DejaNews? Any idea how many Marines it would take to storm that building and forcibly liberate the data? Would China, Russia, Iran, North Korea or any other country with balls be willing to send a platoon to do the job of liberating the Usenet archives for the People of Earth? MS From magnus at rubidium.dyndns.org Wed Apr 15 05:31:30 2009 From: magnus at rubidium.dyndns.org (Magnus Danielson) Date: Wed, 15 Apr 2009 07:31:30 +0200 Subject: [time-nuts] Spring cleaning and antenna placement In-Reply-To: <55666.87.227.52.225.1239744266.squirrel@webmail.lysator.liu.se> References: , <49E39489.8020503@rubidium.dyndns.org> <49E44FF3.17229.15E49D@chris.cheney.tesco.net> <55666.87.227.52.225.1239744266.squirrel@webmail.lysator.liu.se> Message-ID: <49E57132.3000601@rubidium.dyndns.org> bg at lysator.liu.se skrev: >> If you are in Scandinavia, the GPS birds will not spend much time (if >> any?) to the north of you. Slide 12 of >> http://web.ics.purdue.edu/~ecalais/teaching/geodesy/Satellite_orbits.pdf >> suggests that the most northerly orbital point is at the latitude of >> Denmark. > > With a decent antenna siting you see plenty of SVs to the north. Magnus > problem is that there are lots of rather close by trees and stuff. These > trees are also much taller than the antenna position. Indeed. The southbound sats goes almost over the head, but I also get long tracking periods for sats way up to the north. Since the house sits partly in a valey and the neighborhood is rich of trees there is plenty of foilage. To the north is a building, two stories high and ground level for it is just above the upper of mine, which pick up the extreme north direction. The location also requires an antenna mast forr the TV reception. With modern digital transmission it is best to have a good margin for reception, or there is no TV at all. If I had a flat roof I might just put a ladder up to the antenna, but unfortunately not so. Sky-view of GPS antennas was not of concern when picking this house. Maybe it should be for the next. Cheers, Magnus From phk at phk.freebsd.dk Wed Apr 15 06:01:39 2009 From: phk at phk.freebsd.dk (Poul-Henning Kamp) Date: Wed, 15 Apr 2009 06:01:39 +0000 Subject: [time-nuts] Spring cleaning and antenna placement In-Reply-To: Your message of "Wed, 15 Apr 2009 07:31:30 +0200." <49E57132.3000601@rubidium.dyndns.org> Message-ID: <76339.1239775299@critter.freebsd.dk> In message <49E57132.3000601 at rubidium.dyndns.org>, Magnus Danielson writes: >bg at lysator.liu.se skrev: >>> If you are in Scandinavia, the GPS birds will not spend much time (if >>> any?) to the north of you. Slide 12 of >>> http://web.ics.purdue.edu/~ecalais/teaching/geodesy/Satellite_orbits.pdf >>> suggests that the most northerly orbital point is at the latitude of >>> Denmark. > >> With a decent antenna siting you see plenty of SVs to the north. Just to clarify: At my latitude in Denmark, we just barely see the sats from the other siden skim over the horizon, nowhere nearly high enough to clear the mask angle. Once you get just a little bit further north, like Magnus is, the sats do clear the mask angle and contribute gainfully to the solution. I have heard rumours, but not seen it confirmed, that Northern Norway and Greenland has some of the most amazing DOP's seen anywhere on the planet because all their sats are around them, rather than overhead. Poul-Henning -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 phk at FreeBSD.ORG | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. From jra at febo.com Wed Apr 15 13:02:32 2009 From: jra at febo.com (John Ackermann N8UR) Date: Wed, 15 Apr 2009 09:02:32 -0400 Subject: [time-nuts] OT: Manual for Julie Research "Volt-A-Vider"? In-Reply-To: <49E54334.3060806@sasktel.net> References: <49E538B0.6020907@febo.com> <49E54334.3060806@sasktel.net> Message-ID: <49E5DAE8.40004@febo.com> Thanks, Ed! That certainly gives me some helpful info. John ---- Ed Palmer wrote: > This doesn't include your model #, but it may be of some help. > > http://web.archive.org/web/20020903124352/http://www.procinst.com/voltavider.PDF > > Ed > > John Ackermann N8UR wrote: >> I just acquired a nice portable zener voltage reference with six-digit >> divider. It's a Julie Research Labs (JRL) "Volt-A-Vider" model GTX-355. >> There aren't many references to this device on the web, much less to >> its manual. >> >> Any chance someone here might have a manual, or a data sheet, or any >> info at all about it? >> >> It's supposed to be a pretty good unit; this one came out of NASA and >> after quite a while in storage was recently checked and found to be >> within a couple of PPM after 30 minutes warm-up. >> >> Thanks, >> >> John >> >> _______________________________________________ >> time-nuts mailing list -- time-nuts at febo.com >> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. >> > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. From johnday at wordsnimages.com Wed Apr 15 13:43:17 2009 From: johnday at wordsnimages.com (John Day) Date: Wed, 15 Apr 2009 09:43:17 -0400 Subject: [time-nuts] OT: Verilog/VHDL discussion list created... In-Reply-To: <49E4CA91.8010707@mail.ua.pt> References: <200904141736.n3EHaGPr019461@host22.the-web-host.com> <49E4CA91.8010707@mail.ua.pt> Message-ID: At 01:40 PM 4/14/2009, Luis Cupido wrote: >I believe it is to be ham or hobby oriented >Am I right ? >(If so some rewording of the list purpose >might be adequate... thinking out loud...) The description does say: Focus includes but isn't limited to amateur radio and metrology applications. So I think your question is already covered Luis. John >Luis Cupido >ct1dmk. > >Scott Newell wrote: > > At 12:29 PM 4/14/2009 , John Miles wrote: > >> ... for those who would like to participate in HDL discussions that aren't > >> on-topic for existing lists: > >> > >> http://groups.yahoo.com/group/HDLTalk > >> > >> Any VHDL or Verilog HDL-related topics are welcome. > > > > How will this compare to comp.lang.verilog, comp.lang.vhdl, and > > comp.arch.fpga? > > > >_______________________________________________ >time-nuts mailing list -- time-nuts at febo.com >To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >and follow the instructions there. > > >-- >No virus found in this incoming message. >Checked by AVG. >Version: 7.5.557 / Virus Database: 270.11.55/2057 - Release Date: >4/13/2009 5:56 PM From majanoff at verizon.net Wed Apr 15 18:50:07 2009 From: majanoff at verizon.net (Mitchell Janoff) Date: Wed, 15 Apr 2009 14:50:07 -0400 Subject: [time-nuts] Datum 9390-6000 GPS Lock Problem. In-Reply-To: References: Message-ID: <004d01c9bdfa$ff7c2710$0601a8c0@delldesktop> Greetings. I have Datum 9390-6000, serial #2748 running firmware ET816KP. This is the model with the Rubidium frequency standard and it runs fine other than it looses the satellite lock and then can't re-lock. In some cases after power on/off sequences it will re-synch, but generally looses the satellite lock after a short while. The system checks out fine and the antenna single checks out also. I'm wondering if someone has a unit they are no longer using and would be willing to sell me or let me borrow their GPS card so I can see if my GPS card is the issue. If someone has this card, I'd be happy to send a pre-paid mailer and return the card promptly. Thanks for your help. Mitch. KC2MFB From hmurray at megapathdsl.net Thu Apr 16 06:54:33 2009 From: hmurray at megapathdsl.net (Hal Murray) Date: Wed, 15 Apr 2009 23:54:33 -0700 Subject: [time-nuts] OT: Verilog/VHDL discussion list created... Message-ID: <20090416065434.65C0CBCE2@ip-64-139-1-69.sjc.megapath.net> > What objections are there to Yahoo Groups? They won't let me see any message bodies unless I accept their cookies. I'm not sure what happens next if I jump through that hoop. I'm happy to sign-up/register/whatever if I want to sent/post something. I'm not willing to do much to read what others have said. There is a chicken/egg problem here. How can I tell if the group is interesting if they won't let me see anything? Their servers, their rules. My eyeballs, my rules. > Google didn't do anything to usenet. They did provide a web based > interface into usenet, and bought the dejanews archive of all > non-binary groups. "Google didn't do anything" is the key part. In particular, they didn't do anything when spammers discovered another free resource to be abused. -- These are my opinions, not necessarily my employer's. I hate spam. From eric.fort at gmail.com Thu Apr 16 10:04:27 2009 From: eric.fort at gmail.com (Eric Fort) Date: Thu, 16 Apr 2009 03:04:27 -0700 Subject: [time-nuts] OT: Verilog/VHDL discussion list created... In-Reply-To: References: <49E4EAD8.9000602@erols.com> Message-ID: <2ad2af430904160304j29ce4c60g818906bf5b8925d4@mail.gmail.com> On Tue, Apr 14, 2009 at 12:40 PM, Magnus Danielson < magnus at rubidium.dyndns.org> wrote: > > I have my own email-lists on my own server... if someone asked me to set > the list up, I would just do it. > > Cheers, > Magnus > > AND On Tue, Apr 14, 2009 at 3:50 PM, John Miles wrote: > > What objections are there to Yahoo Groups? I don't have a way to get NNTP > traffic in my email inbox, nor would I want it if I could. > > -- john, KE5FX > AND On Tue, Apr 14, 2009 at 3:56 PM, John Miles wrote: > > ...I prefer email lists to Usenet, and I'm the one who started the group. > :-P > > -- john, KE5FX > > My objection to yahoo groups is they require you to be a member of yahoo giving out all mannor of personal information just so you can access the group archives using some funky interface they provide. I tolerate participating in a few "yahoo groups" only because I can get limited functionality (no access to archives) by just using the list subscribe address in a standard mannor. I too run my own servers, and it is much prefered when a list is hosted with mailman or majordomo where full access to the archives is offered. With list hosting cheap to free, full webhosting with email list management in the $60-$75/yr range, and a virtual private server with full root access available for $120/yr available as options I'd be hard pressed to choose yahoo. Eric, AF6EP From cfharris at erols.com Thu Apr 16 12:16:15 2009 From: cfharris at erols.com (Chuck Harris) Date: Thu, 16 Apr 2009 08:16:15 -0400 Subject: [time-nuts] OT: Verilog/VHDL discussion list created... In-Reply-To: <20090416065434.65C0CBCE2@ip-64-139-1-69.sjc.megapath.net> References: <20090416065434.65C0CBCE2@ip-64-139-1-69.sjc.megapath.net> Message-ID: <49E7218F.1080107@erols.com> Hal Murray wrote: > >> Google didn't do anything to usenet. They did provide a web based >> interface into usenet, and bought the dejanews archive of all >> non-binary groups. > > "Google didn't do anything" is the key part. In particular, they didn't do > anything when spammers discovered another free resource to be abused. Google has no control over usenet. It is a beast that runs on its own absent any central control, or regulation. It is just another channel on the internet; just as IRC, www, email, limewire, kazaa, instant messenger, BitTorrent, and about 2000 other services. What google did to usenet is provide a portal that spammers find easy to use. AOL did the same thing... and so did a host of other ISP's. -Chuck Harris From cfharris at erols.com Thu Apr 16 12:21:53 2009 From: cfharris at erols.com (Chuck Harris) Date: Thu, 16 Apr 2009 08:21:53 -0400 Subject: [time-nuts] OT: Verilog/VHDL discussion list created... In-Reply-To: <2ad2af430904160304j29ce4c60g818906bf5b8925d4@mail.gmail.com> References: <49E4EAD8.9000602@erols.com> <2ad2af430904160304j29ce4c60g818906bf5b8925d4@mail.gmail.com> Message-ID: <49E722E1.3000809@erols.com> Eric Fort wrote: > My objection to yahoo groups is they require you to be a member of yahoo > giving out all mannor of personal information just so you can access the > group archives using some funky interface they provide. They do not! They ask for information, but they do nothing to verify that information. Be a man, learn to lie to the internet! By virtue of your giving us your ham call, we already know far more about your personal life than you really want us to know. From your call, we can know your real name, birth date, and address. Because the government asked you for your SSN as a requirement for issuing your license, there are elements that can get that too. Talk about giving out personal information! -Chuck Harris I tolerate > participating in a few "yahoo groups" only because I can get limited > functionality (no access to archives) by just using the list subscribe > address in a standard mannor. I too run my own servers, and it is much > prefered when a list is hosted with mailman or majordomo where full access > to the archives is offered. With list hosting cheap to free, full > webhosting with email list management in the $60-$75/yr range, and a virtual > private server with full root access available for $120/yr available as > options I'd be hard pressed to choose yahoo. > > Eric, AF6EP > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > From sometimesyoufeellikeanut at twentylogten.com Thu Apr 16 13:34:12 2009 From: sometimesyoufeellikeanut at twentylogten.com (Chris Mack) Date: Thu, 16 Apr 2009 09:34:12 -0400 Subject: [time-nuts] OT: Verilog/VHDL discussion list created... In-Reply-To: <49E722E1.3000809@erols.com> References: <49E4EAD8.9000602@erols.com> <2ad2af430904160304j29ce4c60g818906bf5b8925d4@mail.gmail.com> <49E722E1.3000809@erols.com> Message-ID: <949C8FC9-D02C-4E69-AA55-C5F059B01649@twentylogten.com> Firefox.... Tools->Clear Personal Data... You can even set it up to ask you to clear personal data when you close the browser and when you start.... Firefox also has add-ins like "ghost" and UserAgent to allow you to watch as you are being tracked by Google (through JavaScript)... Even AdBlock Plus to block ads and ads that have encoded UIDs to track you... (or another method of updating your LMHOSTS file to redirect common Ad URLs to 127.0.0.1; there's no place like 127.0.0.1) You can still use Anonymouse to browse too... but who knows if they aggregate demographic data or not... Ghost shows me that they use something like Google Analytics to track.... So I don't even bother.... But all this does not matter as your ISP is tracking you anyway (I also think it is a new federal requirement as of last year for ISPs to capture URLs and keep them on file for quite some time for folks in the US, perhaps for post mortem analysis for an event of the terror kind).... I was recently marked as a spammer (erroneously, by probably an automated system) and Comcast blocked ports 25 and 587 for me, intelligently and all by themselves on their own accord (these ports of course being the Comcast outgoing mail ports).... FYI for comcast folks, using port 26 apparently gets around this... When I called comcast to figure out why I could not send mail it took them forever to figure out that the ports were blocked and the reason why; and then transferring me to correct folks to chat with... They were able to inventory all the action on my service with multiple email addresses on my own .com domain... Everything is made out of Swiss Cheese.... Yummy delicious Swiss Cheese..... -chris On Apr 16, 2009, at 8:21 AM, Chuck Harris wrote: > > Eric Fort wrote: > >> My objection to yahoo groups is they require you to be a member of >> yahoo >> giving out all mannor of personal information just so you can >> access the >> group archives using some funky interface they provide. > > They do not! They ask for information, but they do nothing to verify > that information. Be a man, learn to lie to the internet! > > By virtue of your giving us your ham call, we already know far > more about your personal life than you really want us to know. From > your call, we can know your real name, birth date, and address. > Because > the government asked you for your SSN as a requirement for issuing > your > license, there are elements that can get that too. Talk about giving > out personal information! > > -Chuck Harris > > I tolerate >> participating in a few "yahoo groups" only because I can get limited >> functionality (no access to archives) by just using the list >> subscribe >> address in a standard mannor. I too run my own servers, and it is >> much >> prefered when a list is hosted with mailman or majordomo where full >> access >> to the archives is offered. With list hosting cheap to free, full >> webhosting with email list management in the $60-$75/yr range, and >> a virtual >> private server with full root access available for $120/yr >> available as >> options I'd be hard pressed to choose yahoo. >> Eric, AF6EP >> _______________________________________________ >> time-nuts mailing list -- time-nuts at febo.com >> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. From sometimesyoufeellikeanut at twentylogten.com Thu Apr 16 14:02:18 2009 From: sometimesyoufeellikeanut at twentylogten.com (Chris Mack) Date: Thu, 16 Apr 2009 10:02:18 -0400 Subject: [time-nuts] femtosecond jitter anyone? In-Reply-To: References: <4CCD1C7E-6952-4FB4-8E1A-3B1A02618BC5@twentylogten.com> <49DD1288.4060103@rubidium.dyndns.org> <18D08480-6725-4251-BE78-145797B6DC31@twentylogten.com> <49DD21D5.6040109@rubidium.dyndns.org> <49DD3B28.4040704@xtra.co.nz> <91291C16-6AC8-4BA7-9ADE-B21AC566B024@twentylogten.com> <49DD4659.1070500@xtra.co.nz> <8DC9EC52-5D5A-43E9-A69E-A244076F0673@twentylogten.com> Message-ID: Awesome... Thanks for being a sounding wall everyone.... Indeed I am using the SRCs from TI for both the 2 DACs and the single ADC... The 127dB discrete ADCs out there are approximately half bit more in dyn range than the 124dB core in the ADC... Indeed, there probably is some significant jitter in the clock section for the IC ADC (and it is single ended, which the Si5326 also supports form CMOS output)... However, I am hoping to try some thermal experiments and some dither in the analog domain to see what additional envelope pushing can be obtained... Unfortunately the data sheets for the ADC do not have the crucial information that normal high speed ADCs would have including temperature data and SFDR, SINAD, ENOB etc.. The specs are kinda brain-dead in this regard... But with distribution and PLLs, the jitter budget should be a little bit (pun intended?) better that what the clock portion of the converters can do (which is an unknown for this experiment), and who knows if the internal clock sections of said converters get better with temperature change.... Worse case, I get some Johnson noise out of the system perhaps... Or the temperature systems are removed and not included in the prototype, but the placeholder is there if it is needed... On the low jitter PLL side... In addition to the Si5326, I found that MultiGig has chips that will take 38.88MHz and create 2X or 4X with "0.34ps" jitter....caveat bandwidth of measurement... For the Si5326, the higher the reference (jitter reference / DSP clock) frequency the better the jitter from CLK_IN to CLK_OUT and jitter cleaning... Nice chips from Analog too... I am amazed at how low jitter can be.... Cheers, -chris On Apr 9, 2009, at 7:46 AM, J.D. Bakker wrote: > At 22:03 -0400 08-04-2009, Chris Mack / N1SKY wrote: >> On Apr 8, 2009, at 8:50 PM, Bruce Griffiths wrote: >>>> >>> Chris >>> >>> If you divide the output down to ~38MHz using a noiseless divider >>> then >>> the performance is 20dB or more worse than can be achieved with a >>> good >>> ~38MHz crystal oscillator. >>> >> >> Ah, this would work, but there is a synchronization aspect since >> framing on AES/EBU is in the mix (pun intended?) and there are more >> pieces of external equipment that all need to be synched (within >> AES11 framing sync margins)... > > From a jitter POV the AES11 profiles are insanely wide, and they make > little sense if you're not using digital tape or other media which > take their time to slew to their final speed. Look at the recent TI > Asynchronous Sample Rate Converters (ASRCs); their rate estimators > have a bandwidth much tighter than needed to track a worst-case AES11 > signal. > >> This 38.88MHz is a DSP clock, essentially a microprocessor clock >> (albeit a very nice microprocessor clock) where the DSP simulates a >> PLL operating on an incoming clock source, and makes an output clock >> of a different frequency, [...] >> >> The output of the DSP PLL in this box / design of interest is 11MHz >> to 24MHz to feed the oversample clocks on the ADCs and DACs, >> synchronized to the external 44.1kHz to 10MHz master house clock a la >> the PLL and the rest of the equipment on the other side of the >> room... > > By 'DSP PLL', do you imply that the DSP controls a DDS? If so, is the > DDS a separate chip or do you use a DAC hooked to your DSP? > > For best jitter performance in an audio system you may want to > consider getting a free-running low noise XO with a frequency that is > NOT a multiple of your sampling rate(s), have it drive your ADC/DAC > converter directly and use an ASRC (either integrated or, preferably, > FPGA/DSP) to go to your target output rate. > > As for fs jitter: I've yet to see a converter chip with differential > clock inputs, and for a single ended clock input I expect that the > total input-referred noise due to ground bounce &co is in the order > of a ps, if not worse. (The story changes a bit for discrete > converter designs, as those can have diff clock inputs with specified > noise performance). > > JDB. > [all things being equal, voltage pullability == lower Q == more phase > noise. And that's even before you consider control port noise > injection...] > -- > LART. 250 MIPS under one Watt. Free hardware design files. > http://www.lartmaker.nl/ > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. From david.partridge at dsl.pipex.com Thu Apr 16 15:12:14 2009 From: david.partridge at dsl.pipex.com (David C. Partridge) Date: Thu, 16 Apr 2009 16:12:14 +0100 Subject: [time-nuts] OT: Help requested with Solartron 7081 DVM Message-ID: <603068C2FAFD4DA991ADC2D9F6E3AC2D@APOLLO> Hi folks, apologies for yet another OT post. Is there anyone near (within say 30-40 miles) to Kenilworth, Warwickshire, England that can assist with resolving a fault on a Solartron 7081. Bill Ezell (BIG thank you) in the USA has been a providing a massive amount of off-line assistance by email but we don't seem to be getting to finding the "smoking gun", so I think we *may* now be at the stage of needing someone with stocks of RAM that will fit this(*), a ROM reader/burner(**), and probably a logic analyser. The obvious fault is that the display and LED annunciators are completely blank, though sometimes it will flash most/all of the LED annunciators simultaneously at about a 1 second interval. The display does work as it lights up if I disable the power down logic (which disables the processor board). As far as I can tell there is no DMA activity (display and I/O to floating logic board are driven using DMA). The really annoying thing is that it fired up ONCE while I was debugging the low +5V supply on the earthy I/O board but has never spoken to me since then. Loking at the CPU (68B09) pins, the IRQ line appears to be held low, and typically it is the GPIB chip (Intel P8291A) asserting the interrupt, the interrupt isn't getting cleared by the CPU reading the status from the GPIB chip. Removal of the GPIB chip moves the asserted interrupt to the next lower priority device which is the RS-232 interface, but otherwise things stay the same. Power supplies are good, I've reflowed most pins on the CPU board and checked connectivity especially where previous re-soldering work had been done, and the address select lines are being polled by the processor. There are no obvious shorts between or to ground on the data and address lines. (*) RAM is 6 off 5516/6117, 6 off 6116, or 2 off 6264 (currently fitted RAM is HM6117LP-4) (**) ROMs are TMS2564 or TMS2764 EPROMS (or equivalents) The Service Manual suggests this is one of ROM/RAM/CPU/DMA chips or the display related logic on the I/O board (I've checked most of this and it has outputs that match the pretty static inputs). Thnak you David Partridge From stake at btinternet.com Thu Apr 16 16:17:27 2009 From: stake at btinternet.com (Chris Stake) Date: Thu, 16 Apr 2009 17:17:27 +0100 Subject: [time-nuts] Homebrew GPSDO Message-ID: <006201c9beae$d60fb3b0$822f1b10$@com> Hi, I have purchased a Rockwell TU00-D200 series GPS receiver with the intention of making a cheap and cheerful GPSDO and learning about timing in general. I thought it would be similar to the Jupiter but it seems the connector pinout is not the same. I can't find any information about this model on the internet. Can anyone help with data? Regards Chris Stake From ernieperes at aol.com Thu Apr 16 20:22:03 2009 From: ernieperes at aol.com (ernieperes at aol.com) Date: Thu, 16 Apr 2009 16:22:03 -0400 Subject: [time-nuts] Homebrew GPSDO In-Reply-To: <006201c9beae$d60fb3b0$822f1b10$@com> References: <006201c9beae$d60fb3b0$822f1b10$@com> Message-ID: <8CB8CE823EC455D-1734-18E@FWM-D19.sysops.aol.com> Hi Chris, Did you get it from China? Can you make a picture from both side? Rgds Ernie. -----Original Message----- From: Chris Stake To: time-nuts at febo.com Sent: Thu, 16 Apr 2009 6:17 pm Subject: [time-nuts] Homebrew GPSDO Hi, I have purchased a Rockwell TU00-D200 series GPS receiver with the intention of making a cheap and cheerful GPSDO and learning about timing in general. I thought it would be similar to the Jupiter but it seems the connector pinout is not the same. I can't find any information about this model on the internet. Can anyone help with data? Regards Chris Stake _______________________________________________ time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. From stake at btinternet.com Thu Apr 16 21:12:50 2009 From: stake at btinternet.com (Chris Stake) Date: Thu, 16 Apr 2009 22:12:50 +0100 Subject: [time-nuts] Homebrew GPSDO In-Reply-To: <8CB8CE823EC455D-1734-18E@FWM-D19.sysops.aol.com> References: <006201c9beae$d60fb3b0$822f1b10$@com> <8CB8CE823EC455D-1734-18E@FWM-D19.sysops.aol.com> Message-ID: <000701c9bed8$19c3de50$4d4b9af0$@com> Hi Ernie, Yes it's from China, I tried to post pix but the files are too big and got rejected. http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&ssPageName=STRK:MEWNX:IT&ite m=300302965075 Chris -----Original Message----- From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On Behalf Of ernieperes at aol.com Sent: 16 April 2009 21:22 To: time-nuts at febo.com Subject: Re: [time-nuts] Homebrew GPSDO Hi Chris, Did you get it from China? Can you make a picture from both side? Rgds Ernie. -----Original Message----- From: Chris Stake To: time-nuts at febo.com Sent: Thu, 16 Apr 2009 6:17 pm Subject: [time-nuts] Homebrew GPSDO Hi, I have purchased a Rockwell TU00-D200 series GPS receiver with the intention of making a cheap and cheerful GPSDO and learning about timing in general. I thought it would be similar to the Jupiter but it seems the connector pinout is not the same. I can't find any information about this model on the internet. Can anyone help with data? Regards Chris Stake _______________________________________________ time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. _______________________________________________ time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. From rk at timing-consultants.com Thu Apr 16 21:29:00 2009 From: rk at timing-consultants.com (Rob Kimberley) Date: Thu, 16 Apr 2009 22:29:00 +0100 Subject: [time-nuts] Meinberg adding WWVB Products.. Message-ID: <9B5A9F4A528D4F119550883AE7015FE9@robinHP> http://www.meinberg.de/english/news/product-announcement-meinberg-adds-wwvb- products-to-their-product-range.htm Just spotted this for our US readers. Rob Kimberley From masondg44 at comcast.net Thu Apr 16 23:35:21 2009 From: masondg44 at comcast.net (Dave M) Date: Thu, 16 Apr 2009 19:35:21 -0400 Subject: [time-nuts] Update on next TBolt group buy References: Message-ID: Is there a target date in the foreseeable future (any info, for that matter) for the next TBolt group buy? Or did I miss it while away from home? Waiting patiently..... -- "In theory, there isn't any difference between theory and practice. In practice, there is." - Yogi Berra Dave M masondg44 at comcast dot net > Yes, there have been 3 or 4 large batches of TBolts sold through > TAPR over the past year or two. The price ranged from about 95 > to 125. Most were sold with power supply; some without (when the > source of cheap switching supplies ran out). For more info see: > http://www.leapsecond.com/tbolt-faq.htm > http://www.leapsecond.com/pages/tapr-tbolt/ > http://www.leapsecond.com/pages/tbolt/noise.htm > > Yes, there will be another group buy or two. However, this time > I'm testing all of them first and then announcing the sale (expect > mid-March) so that no one has that long wait between ordering > and paying/receiving. > > So hang on a bit longer and I'll send the details next month. > > Note a number of people have asked privately (you know who > you are) and those requests will be handled first. > From didier at cox.net Fri Apr 17 01:16:19 2009 From: didier at cox.net (Didier) Date: Thu, 16 Apr 2009 20:16:19 -0500 Subject: [time-nuts] Homebrew GPSDO In-Reply-To: <000701c9bed8$19c3de50$4d4b9af0$@com> References: <006201c9beae$d60fb3b0$822f1b10$@com><8CB8CE823EC455D-1734-18E@FWM-D19.sysops.aol.com> <000701c9bed8$19c3de50$4d4b9af0$@com> Message-ID: <46BB56AD4AEC446DA5DC7934FD974CA3@didierhp> Chris, You can upload the pics to my site, I'll put them with the other GPS receiver pictures at http://www.ko4bb.com/cgi-bin/manuals.pl?dir=05)_GPS_Timing/GPS_Receivers_Pic tures Make sure the file names are descriptive, or attach a text file with descriptions. Didier KO4BB > -----Original Message----- > From: time-nuts-bounces at febo.com > [mailto:time-nuts-bounces at febo.com] On Behalf Of Chris Stake > Sent: Thursday, April 16, 2009 4:13 PM > To: 'Discussion of precise time and frequency measurement' > Subject: Re: [time-nuts] Homebrew GPSDO > > Hi Ernie, > Yes it's from China, I tried to post pix but the files are > too big and got rejected. > > http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&ssPageName=STR > K:MEWNX:IT&ite > m=300302965075 > > > Chris > > -----Original Message----- > From: time-nuts-bounces at febo.com > [mailto:time-nuts-bounces at febo.com] On Behalf Of ernieperes at aol.com > Sent: 16 April 2009 21:22 > To: time-nuts at febo.com > Subject: Re: [time-nuts] Homebrew GPSDO > > Hi Chris, > > Did you get it from China? > Can you make a picture from both side? > > Rgds Ernie. > > > > -----Original Message----- > From: Chris Stake > To: time-nuts at febo.com > Sent: Thu, 16 Apr 2009 6:17 pm > Subject: [time-nuts] Homebrew GPSDO > > > > Hi, > I have purchased a Rockwell TU00-D200 series GPS receiver > with the intention of making a cheap and cheerful GPSDO and > learning about timing in general. I thought it would be > similar to the Jupiter but it seems the connector pinout is > not the same. I can't find any information about this model > on the internet. Can anyone help with data? > Regards > Chris Stake > > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com To unsubscribe, > go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > From rdarlington at gmail.com Fri Apr 17 01:52:36 2009 From: rdarlington at gmail.com (Robert Darlington) Date: Thu, 16 Apr 2009 19:52:36 -0600 Subject: [time-nuts] Update on next TBolt group buy In-Reply-To: References: Message-ID: Hah, I've been thinking about that all day and wondering the same thing. I'm sure TVB will post an announcement when he knows for sure. -bob On Thu, Apr 16, 2009 at 5:35 PM, Dave M wrote: > Is there a target date in the foreseeable future (any info, for that > matter) for the next TBolt group buy? Or did I miss it while away from > home? > Waiting patiently..... > > -- > "In theory, there isn't any difference between theory and practice. In > practice, there is." - Yogi Berra > > Dave M > masondg44 at comcast dot net > > > Yes, there have been 3 or 4 large batches of TBolts sold through >> TAPR over the past year or two. The price ranged from about 95 >> to 125. Most were sold with power supply; some without (when the >> source of cheap switching supplies ran out). For more info see: >> http://www.leapsecond.com/tbolt-faq.htm >> http://www.leapsecond.com/pages/tapr-tbolt/ >> http://www.leapsecond.com/pages/tbolt/noise.htm >> >> Yes, there will be another group buy or two. However, this time >> I'm testing all of them first and then announcing the sale (expect >> mid-March) so that no one has that long wait between ordering >> and paying/receiving. >> >> So hang on a bit longer and I'll send the details next month. >> >> Note a number of people have asked privately (you know who >> you are) and those requests will be handled first. >> >> > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > From ernieperes at aol.com Fri Apr 17 06:29:44 2009 From: ernieperes at aol.com (ernieperes at aol.com) Date: Fri, 17 Apr 2009 02:29:44 -0400 Subject: [time-nuts] Homebrew GPSDO In-Reply-To: <46BB56AD4AEC446DA5DC7934FD974CA3@didierhp> References: <006201c9beae$d60fb3b0$822f1b10$@com><8CB8CE823EC455D-1734-18E@FWM-D19.sysops.aol.com><000701c9bed8$19c3de50$4d4b9af0$@com> <46BB56AD4AEC446DA5DC7934FD974CA3@didierhp> Message-ID: <8CB8D3D0817B6FE-EC8-348C@WEBMAIL-DY25.sysops.aol.com> Hi Didier, need username and password, I tried but no luck. Rgds Ernie HG5ED. -----Original Message----- From: Didier To: 'Discussion of precise time and frequency measurement' Sent: Fri, 17 Apr 2009 3:16 am Subject: Re: [time-nuts] Homebrew GPSDO Chris, You can upload the pics to my site, I'll put them with the other GPS receiver pictures at http://www.ko4bb.com/cgi-bin/manuals.pl?dir=05)_GPS_Timing/GPS_Receivers_Pic tures Make sure the file names are descriptive, or attach a text file with descriptions. Didier KO4BB > -----Original Message----- > From: time-nuts-bounces at febo.com > [mailto:time-nuts-bounces at febo.com] On Behalf Of Chris Stake > Sent: Thursday, April 16, 2009 4:13 PM > To: 'Discussion of precise time and frequency measurement' > Subject: Re: [time-nuts] Homebrew GPSDO > > Hi Ernie, > Yes it's from China, I tried to post pix but the files are > too big and got rejected. > > http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&ssPageName=STR > K:MEWNX:IT&ite > m=300302965075 > > > Chris > > -----Original Message----- > From: time-nuts-bounces at febo.com > [mailto:time-nuts-bounces at febo.com] On Behalf Of ernieperes at aol.com > Sent: 16 April 2009 21:22 > To: time-nuts at febo.com > Subject: Re: [time-nuts] Homebrew GPSDO > > Hi Chris, > > Did you get it from China? > Can you make a picture from both side? > > Rgds Ernie. > > > > -----Original Message----- > From: Chris Stake > To: time-nuts at febo.com > Sent: Thu, 16 Apr 2009 6:17 pm > Subject: [time-nuts] Homebrew GPSDO > > > > Hi, > I have purchased a Rockwell TU00-D200 series GPS receiver > with the intention of making a cheap and cheerful GPSDO and > learning about timing in general. I thought it would be > similar to the Jupiter but it seems the connector pinout is > not the same. I can't find any information about this model > on the internet. Can anyone help with data? > Regards > Chris Stake > > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com To unsubscribe, > go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > _______________________________________________ time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. From bruce.griffiths at xtra.co.nz Fri Apr 17 06:43:19 2009 From: bruce.griffiths at xtra.co.nz (Bruce Griffiths) Date: Fri, 17 Apr 2009 18:43:19 +1200 Subject: [time-nuts] Homebrew GPSDO In-Reply-To: <8CB8D3D0817B6FE-EC8-348C@WEBMAIL-DY25.sysops.aol.com> References: <006201c9beae$d60fb3b0$822f1b10$@com><8CB8CE823EC455D-1734-18E@FWM-D19.sysops.aol.com><000701c9bed8$19c3de50$4d4b9af0$@com> <46BB56AD4AEC446DA5DC7934FD974CA3@didierhp> <8CB8D3D0817B6FE-EC8-348C@WEBMAIL-DY25.sysops.aol.com> Message-ID: <49E82507.8090904@xtra.co.nz> Ernie Upload them to manuals page on Didiers site start at: http://www.ko4bb.com/ The userid and password should still be the same as it has always been (both = "manuals" without the quotes) Didier will then move them. Bruce ernieperes at aol.com wrote: > Hi Didier, > > need username and password, I tried but no luck. > > Rgds Ernie HG5ED. > > > > > > > > -----Original Message----- > From: Didier > To: 'Discussion of precise time and frequency measurement' > > Sent: Fri, 17 Apr 2009 3:16 am > Subject: Re: [time-nuts] Homebrew GPSDO > > > > Chris, > > You can upload the pics to my site, I'll put them with the other GPS > receiver pictures at > > http://www.ko4bb.com/cgi-bin/manuals.pl?dir=05)_GPS_Timing/GPS_Receivers_Pic > > tures > > Make sure the file names are descriptive, or attach a text file with > descriptions. > > Didier KO4BB > >> -----Original Message----- >> From: time-nuts-bounces at febo.com >> [mailto:time-nuts-bounces at febo.com] On Behalf Of Chris Stake >> Sent: Thursday, April 16, 2009 4:13 PM >> To: 'Discussion of precise time and frequency measurement' >> Subject: Re: [time-nuts] Homebrew GPSDO >> >> Hi Ernie, >> Yes it's from China, I tried to post pix but the files are >> too big and got rejected. >> >> http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&ssPageName=STR >> K:MEWNX:IT&ite >> m=300302965075 >> >> >> Chris >> >> -----Original Message----- >> From: time-nuts-bounces at febo.com >> [mailto:time-nuts-bounces at febo.com] On Behalf Of ernieperes at aol.com >> Sent: 16 April 2009 21:22 >> To: time-nuts at febo.com >> Subject: Re: [time-nuts] Homebrew GPSDO >> >> Hi Chris, >> >> Did you get it from China? >> Can you make a picture from both side? >> >> Rgds Ernie. >> >> >> >> -----Original Message----- >> From: Chris Stake >> To: time-nuts at febo.com >> Sent: Thu, 16 Apr 2009 6:17 pm >> Subject: [time-nuts] Homebrew GPSDO >> >> >> >> Hi, >> I have purchased a Rockwell TU00-D200 series GPS receiver >> with the intention of making a cheap and cheerful GPSDO and >> learning about timing in general. I thought it would be >> similar to the Jupiter but it seems the connector pinout is >> not the same. I can't find any information about this model >> on the internet. Can anyone help with data? >> Regards >> Chris Stake >> >> >> >> _______________________________________________ >> time-nuts mailing list -- time-nuts at febo.com To unsubscribe, >> go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. >> >> >> _______________________________________________ >> time-nuts mailing list -- time-nuts at febo.com >> To unsubscribe, go to >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. >> >> >> _______________________________________________ >> time-nuts mailing list -- time-nuts at febo.com >> To unsubscribe, go to >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. >> > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > From ernieperes at aol.com Fri Apr 17 06:53:19 2009 From: ernieperes at aol.com (ernieperes at aol.com) Date: Fri, 17 Apr 2009 02:53:19 -0400 Subject: [time-nuts] Homebrew GPSDO In-Reply-To: <49E82507.8090904@xtra.co.nz> References: <006201c9beae$d60fb3b0$822f1b10$@com><8CB8CE823EC455D-1734-18E@FWM-D19.sysops.aol.com><000701c9bed8$19c3de50$4d4b9af0$@com> <46BB56AD4AEC446DA5DC7934FD974CA3@didierhp><8CB8D3D0817B6FE-EC8-348C@WEBMAIL-DY25.sysops.aol.com> <49E82507.8090904@xtra.co.nz> Message-ID: <8CB8D4053BD91A2-EC8-34C4@WEBMAIL-DY25.sysops.aol.com> Bruce, This is what I tried but did not work. I will try from my second PC later on. Rgds Ernie. -----Original Message----- From: Bruce Griffiths To: Discussion of precise time and frequency measurement Sent: Fri, 17 Apr 2009 8:43 am Subject: Re: [time-nuts] Homebrew GPSDO Ernie Upload them to manuals page on Didiers site start at: http://www.ko4bb.com/ The userid and password should still be the same as it has always been (both = "manuals" without the quotes) Didier will then move them. Bruce ernieperes at aol.com wrote: > Hi Didier, > > need username and password, I tried but no luck. > > Rgds Ernie HG5ED. > > > > > > > > -----Original Message----- > From: Didier > To: 'Discussion of precise time and frequency measurement' > > Sent: Fri, 17 Apr 2009 3:16 am > Subject: Re: [time-nuts] Homebrew GPSDO > > > > Chris, > > You can upload the pics to my site, I'll put them with the other GPS > receiver pictures at > > http://www.ko4bb.com/cgi-bin/manuals.pl?dir=05)_GPS_Timing/GPS_Receivers_Pic > > tures > > Make sure the file names are descriptive, or attach a text file with > descriptions. > > Didier KO4BB > >> -----Original Message----- >> From: time-nuts-bounces at febo.com >> [mailto:time-nuts-bounces at febo.com] On Behalf Of Chris Stake >> Sent: Thursday, April 16, 2009 4:13 PM >> To: 'Discussion of precise time and frequency measurement' >> Subject: Re: [time-nuts] Homebrew GPSDO >> >> Hi Ernie, >> Yes it's from China, I tried to post pix but the files are >> too big and got rejected. >> >> http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&ssPageName=STR >> K:MEWNX:IT&ite >> m=300302965075 >> >> >> Chris >> >> -----Original Message----- >> From: time-nuts-bounces at febo.com >> [mailto:time-nuts-bounces at febo.com] On Behalf Of ernieperes at aol.com >> Sent: 16 April 2009 21:22 >> To: time-nuts at febo.com >> Subject: Re: [time-nuts] Homebrew GPSDO >> >> Hi Chris, >> >> Did you get it from China? >> Can you make a picture from both side? >> >> Rgds Ernie. >> >> >> >> -----Original Message----- >> From: Chris Stake >> To: time-nuts at febo.com >> Sent: Thu, 16 Apr 2009 6:17 pm >> Subject: [time-nuts] Homebrew GPSDO >> >> >> >> Hi, >> I have purchased a Rockwell TU00-D200 series GPS receiver >> with the intention of making a cheap and cheerful GPSDO and >> learning about timing in general. I thought it would be >> similar to the Jupiter but it seems the connector pinout is >> not the same. I can't find any information about this model >> on the internet. Can anyone help with data? >> Regards >> Chris Stake >> >> >> >> _______________________________________________ >> time-nuts mailing list -- time-nuts at febo.com To unsubscribe, >> go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. >> >> >> _______________________________________________ >> time-nuts mailing list -- time-nuts at febo.com >> To unsubscribe, go to >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. >> >> >> _______________________________________________ >> time-nuts mailing list -- time-nuts at febo.com >> To unsubscribe, go to >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. >> > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > _______________________________________________ time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. From magnus at rubidium.dyndns.org Fri Apr 17 10:15:31 2009 From: magnus at rubidium.dyndns.org (Magnus Danielson) Date: Fri, 17 Apr 2009 12:15:31 +0200 Subject: [time-nuts] Rubidium is good for you... Message-ID: <49E856C3.40803@rubidium.dyndns.org> Fellow time-nuts, You find the strangest things when just surfing around ebay: Item number: 370158541330 Is it good for you??? Cheers, Magnus - not popping the lids... From bill at iaxs.net Fri Apr 17 10:44:11 2009 From: bill at iaxs.net (Bill Hawkins) Date: Fri, 17 Apr 2009 05:44:11 -0500 Subject: [time-nuts] Rubidium is good for you... In-Reply-To: <49E856C3.40803@rubidium.dyndns.org> References: <49E856C3.40803@rubidium.dyndns.org> Message-ID: Magnus, Here I am, one hour past the time of minimum human activity (US Central Daylight Time), trying to use alcohol to kill a food poisoning from sushi, and you introduce the idea that I ought to be drinking Rubidium! Thank you for the welcome distraction. I understand that you don't recommend it, just pointing out the aberrance of others and all that, but now I wonder. . . I have a pretty good time sense, able to wake up just before the alarm goes off. How much could that sense be improved by drinking Rubidium? And how could I synchronize to social time? Then, how could I connect to Ethernet with SNTP to synchronize others? I never dreamed that my purpose in life could extend so far. Imagine many smileys. Bill Hawkins -----Original Message----- From: Magnus Danielson Sent: Friday, April 17, 2009 5:16 AM Fellow time-nuts, You find the strangest things when just surfing around ebay: Item number: 370158541330 Is it good for you??? Cheers, Magnus - not popping the lids... From stake at btinternet.com Fri Apr 17 10:56:13 2009 From: stake at btinternet.com (Chris Stake) Date: Fri, 17 Apr 2009 11:56:13 +0100 Subject: [time-nuts] Rubidium is good for you... In-Reply-To: References: <49E856C3.40803@rubidium.dyndns.org> Message-ID: <00e901c9bf4b$20087f50$60197df0$@com> I suppose it could help to keep you regular? Chris Stake -----Original Message----- From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On Behalf Of Bill Hawkins Sent: 17 April 2009 11:44 To: 'Discussion of precise time and frequency measurement' Subject: Re: [time-nuts] Rubidium is good for you... Magnus, Here I am, one hour past the time of minimum human activity (US Central Daylight Time), trying to use alcohol to kill a food poisoning from sushi, and you introduce the idea that I ought to be drinking Rubidium! Thank you for the welcome distraction. I understand that you don't recommend it, just pointing out the aberrance of others and all that, but now I wonder. . . I have a pretty good time sense, able to wake up just before the alarm goes off. How much could that sense be improved by drinking Rubidium? And how could I synchronize to social time? Then, how could I connect to Ethernet with SNTP to synchronize others? I never dreamed that my purpose in life could extend so far. Imagine many smileys. Bill Hawkins -----Original Message----- From: Magnus Danielson Sent: Friday, April 17, 2009 5:16 AM Fellow time-nuts, You find the strangest things when just surfing around ebay: Item number: 370158541330 Is it good for you??? Cheers, Magnus - not popping the lids... _______________________________________________ time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. From alan.melia at btinternet.com Fri Apr 17 11:13:02 2009 From: alan.melia at btinternet.com (Alan Melia) Date: Fri, 17 Apr 2009 12:13:02 +0100 Subject: [time-nuts] Rubidium is good for you... References: <49E856C3.40803@rubidium.dyndns.org> Message-ID: <004501c9bf4d$7caa6aa0$0900a8c0@AM> I wonder what the FDA (Frequency Determining Association ??) has to say about that :-)) Alan G3NYK ----- Original Message ----- From: "Magnus Danielson" To: "Discussion of precise time and frequency measurement" Sent: Friday, April 17, 2009 11:15 AM Subject: [time-nuts] Rubidium is good for you... > Fellow time-nuts, > > You find the strangest things when just surfing around ebay: > Item number: 370158541330 > > Is it good for you??? > > Cheers, > Magnus - not popping the lids... > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. From had at to-way.com Fri Apr 17 14:40:18 2009 From: had at to-way.com (Had) Date: Fri, 17 Apr 2009 07:40:18 -0700 Subject: [time-nuts] High accuracy 20ns timing glonass/gps receiver| 2X 1PPS Item number: 300287488541 Message-ID: <20090417144021.6540BE04819@mail-in03.adhost.com> Hello 'Nuts" Has anyone tried one of the above receivers from fluke.l ? I have one coming and would be interested in talking with anyone who has fired up one of these. Thanks, Had From cdelect at juno.com Fri Apr 17 15:42:15 2009 From: cdelect at juno.com (Corby Dawson) Date: Fri, 17 Apr 2009 08:42:15 -0700 Subject: [time-nuts] Rubidium is good for you Message-ID: <20090417.084215.1852.0.cdelect@juno.com> As to the Recommended Daily Allowance. I think with the 40 or 50 junker units I have I am probably getting enough just by exposure. I suppose I could sleep with one under my pillow to increase the dose! Corby ____________________________________________________________ Save $10 on Flowers and Gifts! Shop now at www.ftd.com/16714 http://thirdpartyoffers.juno.com/TGL2141/fc/Dh4GRr5bIdweo2puMJ2NYD6SSTMW5p4KixJYXsjNTxs4RupOMS7Cus2S07W/ From dgcarlson at sbcglobal.net Fri Apr 17 15:43:44 2009 From: dgcarlson at sbcglobal.net (Dave Carlson) Date: Fri, 17 Apr 2009 08:43:44 -0700 Subject: [time-nuts] Rubidium is good for you... References: <49E856C3.40803@rubidium.dyndns.org> Message-ID: <94789E7B29E74D8EA30A80472272809E@symmetricom.com> Since it's in a liquid, it must be in the hydroxide or some other ionic-compound form. Who can say as to any nutritional benefits? Anyone know whether the mild radioactive decay carries over to these compounds? Dave ----- Original Message ----- From: "Magnus Danielson" To: "Discussion of precise time and frequency measurement" Sent: Friday, April 17, 2009 3:15 AM Subject: [time-nuts] Rubidium is good for you... Fellow time-nuts, You find the strangest things when just surfing around ebay: Item number: 370158541330 Is it good for you??? Cheers, Magnus - not popping the lids... _______________________________________________ time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. From holrum at hotmail.com Fri Apr 17 17:18:43 2009 From: holrum at hotmail.com (Mark Sims) Date: Fri, 17 Apr 2009 17:18:43 +0000 Subject: [time-nuts] Rubidium good? Cesium better! In-Reply-To: References: Message-ID: Ebay item 370176999888... now you can have your bowels timed to the picosecond.... _________________________________________________________________ Rediscover Hotmail?: Now available on your iPhone or BlackBerry http://windowslive.com/RediscoverHotmail?ocid=TXT_TAGLM_WL_HM_Rediscover_Mobile2_042009 From alan.melia at btinternet.com Fri Apr 17 17:16:42 2009 From: alan.melia at btinternet.com (Alan Melia) Date: Fri, 17 Apr 2009 18:16:42 +0100 Subject: [time-nuts] Rubidium is good for you... References: <49E856C3.40803@rubidium.dyndns.org> <94789E7B29E74D8EA30A80472272809E@symmetricom.com> Message-ID: <00cb01c9bf81$0ef20c00$0900a8c0@AM> What radioactive decay ?? There are isotopes of most of these naturally occuring "alkaline" elements but most are very stable.....you dont want the gas in your Rb lamp transmuting away !! There may even be "nutritional benefits in snake oil :-)) Alan G3NYK ----- Original Message ----- From: "Dave Carlson" To: "Discussion of precise time and frequency measurement" Sent: Friday, April 17, 2009 4:43 PM Subject: Re: [time-nuts] Rubidium is good for you... > Since it's in a liquid, it must be in the hydroxide or some other > ionic-compound form. > > Who can say as to any nutritional benefits? Anyone know whether the mild > radioactive decay carries over to these compounds? > > Dave > > ----- Original Message ----- > From: "Magnus Danielson" > To: "Discussion of precise time and frequency measurement" > > Sent: Friday, April 17, 2009 3:15 AM > Subject: [time-nuts] Rubidium is good for you... > > > Fellow time-nuts, > > You find the strangest things when just surfing around ebay: > Item number: 370158541330 > > Is it good for you??? > > Cheers, > Magnus - not popping the lids... > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. From steve-krull at cox.net Fri Apr 17 18:00:55 2009 From: steve-krull at cox.net (Steve Krull) Date: Fri, 17 Apr 2009 14:00:55 -0400 Subject: [time-nuts] Rubidium is good for you... In-Reply-To: <00cb01c9bf81$0ef20c00$0900a8c0@AM> Message-ID: <20090417140055.8AZXY.762428.imail@eastrmwml36> Especially if the snake oil is used to pan-fry a nice bit of chicken... Alan - see you at RAL! Steve WB0DBS ---- Alan Melia wrote: > What radioactive decay ?? There are isotopes of most of these naturally > occuring "alkaline" elements but most are very stable.....you dont want the > gas in your Rb lamp transmuting away !! > There may even be "nutritional benefits in snake oil :-)) > Alan G3NYK From bruce.griffiths at xtra.co.nz Fri Apr 17 21:47:03 2009 From: bruce.griffiths at xtra.co.nz (Bruce Griffiths) Date: Sat, 18 Apr 2009 09:47:03 +1200 Subject: [time-nuts] Rubidium is good for you... In-Reply-To: <20090417140055.8AZXY.762428.imail@eastrmwml36> References: <20090417140055.8AZXY.762428.imail@eastrmwml36> Message-ID: <49E8F8D7.9070407@xtra.co.nz> Steve Krull wrote: > Especially if the snake oil is used to pan-fry a nice bit of chicken... > Alan - see you at RAL! > Steve > WB0DBS > > ---- Alan Melia wrote: > >> What radioactive decay ?? There are isotopes of most of these naturally >> occuring "alkaline" elements but most are very stable.....you dont want the >> gas in your Rb lamp transmuting away !! >> There may even be "nutritional benefits in snake oil :-)) >> Alan G3NYK >> > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > Alan The Rubidium 87 in the absorption cell is a beta emitter with a half life of 4.88E10 years. It decays to Strontium 87 which is stable. However, the Rubidium 85 used as an optical bandpass filter in a conventional rubidium standard is stable. Bruce From service at frequencystandards.com Sat Apr 18 03:32:25 2009 From: service at frequencystandards.com (service at frequencystandards.com) Date: Fri, 17 Apr 2009 22:32:25 -0500 (CDT) Subject: [time-nuts] 5071 for sale Message-ID: <1402.75.163.229.68.1240025545.squirrel@www.frequencystandards.com> Some on the list have mentioned before their interest in obtaining an 5071 standard. I just received this e-mail today. I have never dealt with this company so cannot give any recommendation on them. I believe them to be an equipment reseller. Chuck Norton We have following item for sale. Agilent 5071b/214/015/UNQ(please offer) Best Regards, Catherine Solution Management & Affiliated Resource Technology Inc. Tel:886-2-87971799#11 fax:886-2-8751-1298 cell:886-911-278-899 e-mail:catherine.hsu at smart-inc.com.tw http://www.smart-inc.com.tw From jim77742 at gmail.com Sat Apr 18 12:46:56 2009 From: jim77742 at gmail.com (Jim Palfreyman) Date: Sat, 18 Apr 2009 22:46:56 +1000 Subject: [time-nuts] Rubidium is good for you... In-Reply-To: <49E8F8D7.9070407@xtra.co.nz> References: <20090417140055.8AZXY.762428.imail@eastrmwml36> <49E8F8D7.9070407@xtra.co.nz> Message-ID: But what about the one from ebay I'm drinking! 2009/4/18 Bruce Griffiths > Steve Krull wrote: > > Especially if the snake oil is used to pan-fry a nice bit of chicken... > > Alan - see you at RAL! > > Steve > > WB0DBS > > > > ---- Alan Melia wrote: > > > >> What radioactive decay ?? There are isotopes of most of these naturally > >> occuring "alkaline" elements but most are very stable.....you dont want > the > >> gas in your Rb lamp transmuting away !! > >> There may even be "nutritional benefits in snake oil :-)) > >> Alan G3NYK > >> > > _______________________________________________ > > time-nuts mailing list -- time-nuts at febo.com > > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > > and follow the instructions there. > > > > > Alan > > The Rubidium 87 in the absorption cell is a beta emitter with a half > life of 4.88E10 years. > It decays to Strontium 87 which is stable. > > However, the Rubidium 85 used as an optical bandpass filter in a > conventional rubidium standard is stable. > > Bruce > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > From jim77742 at gmail.com Sat Apr 18 13:01:13 2009 From: jim77742 at gmail.com (Jim Palfreyman) Date: Sat, 18 Apr 2009 23:01:13 +1000 Subject: [time-nuts] Rubidium good? Cesium better! In-Reply-To: References: Message-ID: Oh dear oh dear oh dear. I have some lead. Only $450/kg and will help improve the boundary layers between your epithelial cells and your red blood cells. The beauty of it is also that its effects are cumulative. So as time goes on the less you need to buy! As a special for the time-nuts list I'll reduce the lead to $250/kg. A bargain! Email me... 2009/4/18 Mark Sims > > Ebay item 370176999888... now you can have your bowels timed to the > picosecond.... > _________________________________________________________________ > Rediscover Hotmail?: Now available on your iPhone or BlackBerry > > http://windowslive.com/RediscoverHotmail?ocid=TXT_TAGLM_WL_HM_Rediscover_Mobile2_042009 > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > From cdelect at juno.com Sat Apr 18 16:11:09 2009 From: cdelect at juno.com (Corby Dawson) Date: Sat, 18 Apr 2009 09:11:09 -0700 Subject: [time-nuts] Rubidium is good for you Message-ID: <20090418.091109.3740.0.cdelect@juno.com> Yes the rubidium 87 isotope is technically radioactive as it does decay and have a half life. However it takes special techniques to measure as the activity level is so low. A piece of granite probably has more radioactivity than the tiny amount in a rubidium standard. This link gives some more details as well as a maximum daily requirement, mind the cautionary note! http://www.agilent.com/metrology/hazardous.shtml Also on Tom Van Baaks website are some PIX of Rb cells I took. I need to add the tiny one from an LPRO is recently acquired it's about 1/4" square! http://www.leapsecond.com/pages/rb-cells/ Cheers! Corby ____________________________________________________________ Save $10 on Flowers and Gifts! Shop now at www.ftd.com/16714 http://thirdpartyoffers.juno.com/TGL2141/fc/Dh4GRr5bIdw4RkUexf7ZwViCySzybvV1z4ExZZ5r9xmUJg9zxeH0Gyp8K1S/ From Arnold.Tibus at gmx.de Sat Apr 18 19:58:25 2009 From: Arnold.Tibus at gmx.de (Arnold Tibus) Date: Sat, 18 Apr 2009 21:58:25 +0200 Subject: [time-nuts] RF mixers for oscillator characterization, some questions In-Reply-To: <49DA92F9.8080100@xtra.co.nz> Message-ID: Bruce, Magnus, Pete, sorry for being late responding, but the Easter Holydays ... they are over now :( Thank you for the informations giving me some more ideas! I am still wondering about the specials of these mixers. What are their secrets, what the differences to "normal" or high level DBMs? Is high level a criteria? There are some companies selling the 10514A with SMB connectors. I have no idea what is a good or reasonable price fore and if I am running into possible risks to get deaf ones, for totally around $ 100,- ? In may 2007 there was aleady a short discours about the 10514A. Rick mentioned that today it could be possible to build a considerably better design with currently available technology. Does it mean it is really possible to build a DBM with currently available diodes, transformer cores etc. with similar or better characteristics as the old known commercial types? Or did he think to special chip designs? Are there no real merits anymore with the famous old hp 10514A? Would be interesting to learn more about. Arnold On Tue, 07 Apr 2009 11:40:41 +1200, Bruce Griffiths wrote: >Magnus >Magnus Danielson wrote: >> Bruce Griffiths skrev: >> >>> Pete wrote: >>> >>>> Arnold, >>>> >>>> I have had good experience with the SYPD series >>>> from Mini-circuits. I have not seen any used, but >>>> their new cost is reasonable. They do several things >>>> well e.g. the DC offset on the units I received is >>>> <1mV & they produce >2V p-p when driven @ >>>> +7dBm. >>>> >>>> Pete Rawson >>>> >>>> _______________________________________________ >>>> time-nuts mailing list -- time-nuts at febo.com >>>> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >>>> and follow the instructions there. >>>> >>>> >>>> >>> Pete >>> >>> These are OK except when one needs to isolate the IF ground from the RF >>> grounds to avoid low frequency ground loop problems. >>> The RPD and MPD through hole series are better in this regard as they >>> allow the IF ground to be isolated from the RF grounds. >>> >> >> It should be noted that several of their SMB mixers have separated >> grounds, but it is not documented in their datasheets. >> >> >>> The flicker phase noise characteristics of the mixer/phase detector >>> should be measured as some mixers/phase detectors have lower flicker >>> phase noise than others. >>> The termination of the IF port will affect the mixer phase noise. For >>> offset frequencies < 100kHz a capacitive termination of the IF port >>> which reflects the sum frequency back into the mixer reduces the mixer >>> phase noise. >>> >> >> It essentially sees a very low impedance at those frequencies. >> >> My experiments with capacitive loading of mixers basically indicates >> that the actual low-frequency slope of an unloaded mixer does not >> change, but the capacitor load filters the sum-frequency (with >> overtones) while a resistive 50 ohm load just loads the amplitude down >> and gives no significant change to performance. Optimum performance out >> of a mixer in my experience comes from fairly high-impedance load at low >> frequencies with a direct capacitive loading for filtering effects. >> >> A non-filtered response is quite interesting to see with a fairly slow >> beating frequency occuring. Kind of soothing waveforms floating slowly >> as waves over the scope. >> >> >The effect of reflecting the sum frequency back into the mixer is >documented in some Watkins Johnson and HP/Agilent appliction notes. >It can be very effective even at microwave frequencies. >>> The tradeoff is that the mixer output at higher offset >>> frequencies is attenuated by the IF port termination. >>> Terminating the IF port in a capacitor reduces the RF port impedance, so >>> that a low value series resistor (22 to 39 ohms - select for lowest >>> VSWR) is then required to improve the RF port VSWR. >>> >> >> Which in improves phase-stability as reflected waves has less impact. >> -3 dB pads have also been used by the good folks over at NIST at one time. >> >> >The best combination is a series resistor plus an attenuator pad. >>> Terminating the IF port with a capacitor also alters the mixer gain (as >>> a phase detector) so this needs to be measured in conjunction with the noise >>> >> >> Well... the normal 50 Ohm loading alters the mixer gain... not the cap. >> But since the normation is towards 50 Ohm... ah well... >> >> >>> 10514 and 10534 mixers using discrete diodes supposedly have lower >>> flicker noise than mixers using integrated quad diodes. >>> >> >> They however has common ground in their every day laboratory variants. >> There exist variants meant for production. However, they are not made >> out of that exquisite components, so their performance should be >> replicable, as have been pointed out before. >> >> >The B versions intended for through hole PCB mount have separate grounds >for all ports. >These don't seem to be as widely available as they once were although I >have an HP10534B one. >> Cheers, >> Magnus >> >> _______________________________________________ >> time-nuts mailing list -- time-nuts at febo.com >> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. >> >> >Bruce >_______________________________________________ >time-nuts mailing list -- time-nuts at febo.com >To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >and follow the instructions there. From bruce.griffiths at xtra.co.nz Sat Apr 18 20:51:50 2009 From: bruce.griffiths at xtra.co.nz (Bruce Griffiths) Date: Sun, 19 Apr 2009 08:51:50 +1200 Subject: [time-nuts] RF mixers for oscillator characterization, some questions In-Reply-To: References: Message-ID: <49EA3D66.7080007@xtra.co.nz> Arnold Arnold Tibus wrote: > Bruce, Magnus, Pete, > > sorry for being late responding, but the Easter Holydays ... > they are over now :( > > Thank you for the informations giving me some more ideas! > > I am still wondering about the specials of these mixers. > What are their secrets, what the differences to "normal" or high level DBMs? > Is high level a criteria? > > The dc offset at the mixer IF output (a measure of the diode matching and transformer balance) should be low as should its drift. The real criterion is low mixer phase noise particularly at low offset frequencies. The 10514 and 10534 are reputed to have low flicker phase noise. Using a high level mixer as suggested by NIST does have the advantage of allowing a preamp with higher input noise to be used to amplify the low pass filtered IF port output. > There are some companies selling the 10514A with SMB connectors. > I have no idea what is a good or reasonable price fore and if I am running > into possible risks to get deaf ones, for totally around $ 100,- ? > > That price appears significantly higher than the Minicircuits price: http://www.minicircuits.com/pdfs/ZP-10514.pdf However there is no guarantee that the modern 10514's use discrete diodes or what their flicker phase noise characteristics are. A mixer which has a common IF, LO and RF grounds is susceptible to low frequency ground loop noise. However you can use RF transformers at the RF and LOP ports to break the ground loops. > In may 2007 there was aleady a short discours about the 10514A. > Rick mentioned that today it could be possible to build a considerably better > design with currently available technology. > > Does it mean it is really possible to build a DBM with currently available > diodes, transformer cores etc. with similar or better characteristics > as the old known commercial types? Or did he think to special chip > designs? > Are there no real merits anymore with the famous old hp 10514A? > > They were widely used for such measurements and their phase noise was well characterised. You can achieve better diode matching with monolithic diode quads, however the flicker noise of such quads is reputed to be higher than equivalent discrete diode quads. > Would be interesting to learn more about. > > Arnold > > > On Tue, 07 Apr 2009 11:40:41 +1200, Bruce Griffiths wrote: > > >> Magnus >> > > >> Magnus Danielson wrote: >> >>> Bruce Griffiths skrev: >>> >>> >>>> Pete wrote: >>>> >>>> >>>>> Arnold, >>>>> >>>>> I have had good experience with the SYPD series >>>>> from Mini-circuits. I have not seen any used, but >>>>> their new cost is reasonable. They do several things >>>>> well e.g. the DC offset on the units I received is >>>>> <1mV & they produce >2V p-p when driven @ >>>>> +7dBm. >>>>> >>>>> Pete Rawson >>>>> >>>>> _______________________________________________ >>>>> time-nuts mailing list -- time-nuts at febo.com >>>>> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >>>>> and follow the instructions there. >>>>> >>>>> >>>>> >>>>> >>>> Pete >>>> >>>> These are OK except when one needs to isolate the IF ground from the RF >>>> grounds to avoid low frequency ground loop problems. >>>> The RPD and MPD through hole series are better in this regard as they >>>> allow the IF ground to be isolated from the RF grounds. >>>> >>>> >>> It should be noted that several of their SMB mixers have separated >>> grounds, but it is not documented in their datasheets. >>> >>> >>> >>>> The flicker phase noise characteristics of the mixer/phase detector >>>> should be measured as some mixers/phase detectors have lower flicker >>>> phase noise than others. >>>> The termination of the IF port will affect the mixer phase noise. For >>>> offset frequencies < 100kHz a capacitive termination of the IF port >>>> which reflects the sum frequency back into the mixer reduces the mixer >>>> phase noise. >>>> >>>> >>> It essentially sees a very low impedance at those frequencies. >>> >>> My experiments with capacitive loading of mixers basically indicates >>> that the actual low-frequency slope of an unloaded mixer does not >>> change, but the capacitor load filters the sum-frequency (with >>> overtones) while a resistive 50 ohm load just loads the amplitude down >>> and gives no significant change to performance. Optimum performance out >>> of a mixer in my experience comes from fairly high-impedance load at low >>> frequencies with a direct capacitive loading for filtering effects. >>> >>> A non-filtered response is quite interesting to see with a fairly slow >>> beating frequency occuring. Kind of soothing waveforms floating slowly >>> as waves over the scope. >>> >>> >>> >> The effect of reflecting the sum frequency back into the mixer is >> documented in some Watkins Johnson and HP/Agilent appliction notes. >> It can be very effective even at microwave frequencies. >> > > >>>> The tradeoff is that the mixer output at higher offset >>>> frequencies is attenuated by the IF port termination. >>>> Terminating the IF port in a capacitor reduces the RF port impedance, so >>>> that a low value series resistor (22 to 39 ohms - select for lowest >>>> VSWR) is then required to improve the RF port VSWR. >>>> >>>> >>> Which in improves phase-stability as reflected waves has less impact. >>> -3 dB pads have also been used by the good folks over at NIST at one time. >>> >>> >>> > > >> The best combination is a series resistor plus an attenuator pad. >> > > >>>> Terminating the IF port with a capacitor also alters the mixer gain (as >>>> a phase detector) so this needs to be measured in conjunction with the noise >>>> >>>> >>> Well... the normal 50 Ohm loading alters the mixer gain... not the cap. >>> But since the normation is towards 50 Ohm... ah well... >>> >>> >>> >>>> 10514 and 10534 mixers using discrete diodes supposedly have lower >>>> flicker noise than mixers using integrated quad diodes. >>>> >>>> >>> They however has common ground in their every day laboratory variants. >>> There exist variants meant for production. However, they are not made >>> out of that exquisite components, so their performance should be >>> replicable, as have been pointed out before. >>> >>> >>> > > >> The B versions intended for through hole PCB mount have separate grounds >> for all ports. >> These don't seem to be as widely available as they once were although I >> have an HP10534B one. >> > > >>> Cheers, >>> Magnus >>> >>> _______________________________________________ >>> time-nuts mailing list -- time-nuts at febo.com >>> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >>> and follow the instructions there. >>> >>> >>> > > >> Bruce >> > > >> _______________________________________________ >> time-nuts mailing list -- time-nuts at febo.com >> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. >> > > > > > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > Bruce From cdelect at juno.com Sun Apr 19 15:22:53 2009 From: cdelect at juno.com (Corby Dawson) Date: Sun, 19 Apr 2009 08:22:53 -0700 Subject: [time-nuts] RF Mixers for oscillator comparison Message-ID: <20090419.082254.1252.0.cdelect@juno.com> Arnold, Look at the top of page 3 on the link below. Not sure how they arrived at their conclusion but there is one opinion on the HP mixers! http://www.unusualresearch.com/AppNotes/TimeNuts/OptDualMixer.pdf Corby Dawson ____________________________________________________________ Debt collectors calling your house? Click here to consolidate into one payment. http://thirdpartyoffers.juno.com/TGL2141/fc/BLSrjpTIk3l9oQnolYGEY40TVwmsBD4opDDeVSRG36KHWHhZWexSiuRrXdm/ From bruce.griffiths at xtra.co.nz Sun Apr 19 21:03:36 2009 From: bruce.griffiths at xtra.co.nz (Bruce Griffiths) Date: Mon, 20 Apr 2009 09:03:36 +1200 Subject: [time-nuts] RF Mixers for oscillator comparison In-Reply-To: <20090419.082254.1252.0.cdelect@juno.com> References: <20090419.082254.1252.0.cdelect@juno.com> Message-ID: <49EB91A8.3000100@xtra.co.nz> Corby Dawson wrote: > Arnold, > > Look at the top of page 3 on the link below. Not sure how they arrived at > their conclusion but there is one opinion on the HP mixers! > > http://www.unusualresearch.com/AppNotes/TimeNuts/OptDualMixer.pdf > > Corby Dawson > ____________________________________________________________ > Debt collectors calling your house? Click here to consolidate into one payment. > http://thirdpartyoffers.juno.com/TGL2141/fc/BLSrjpTIk3l9oQnolYGEY40TVwmsBD4opDDeVSRG36KHWHhZWexSiuRrXdm/ > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > Statements about the low flicker noise of these mixers are sprinkled throughout the phase noise literature. Someone must have measured the phase noise of these and other mixers at some time. Its relatively easy to measure mixer phase noise: All one needs is a low noise preamp plus a sound card a 90 degree hybrid (or a suitable length of coax and a splitter) and a low noise source. However NIST papers often include a phase noise plot (attached) that illustrates that high level mixers can have a significantly lower phase noise than low level mixers (like the HP10514A). When choosing a mixer for this for phase noise measurement applications one may actually need to measure the phase noise characteristics of candidate mixers. Bruce -------------- next part -------------- A non-text attachment was scrubbed... Name: MixerNoise.png Type: image/png Size: 66148 bytes Desc: not available URL: From Arnold.Tibus at gmx.de Sun Apr 19 20:47:31 2009 From: Arnold.Tibus at gmx.de (Arnold Tibus) Date: Sun, 19 Apr 2009 22:47:31 +0200 Subject: [time-nuts] RF Mixers for oscillator comparison In-Reply-To: <20090419.082254.1252.0.cdelect@juno.com> Message-ID: On Sun, 19 Apr 2009 08:22:53 -0700, Corby Dawson wrote: >Arnold, >Look at the top of page 3 on the link below. Not sure how they arrived at >their conclusion but there is one opinion on the HP mixers! >http://www.unusualresearch.com/AppNotes/TimeNuts/OptDualMixer.pdf >Corby Dawson Corby, a real interesting paper, thank you. They seem to think very positive about this HP type of mixers. That HP/ Agilent is mentioning always their own model in all their ANs is understandable, but I do not see similar setups of other institutions or labs with other brands. Anyway, what they are doing is far more of what I want to. I do not have access to ultra stable and very low noise oscillators, nor I have small bw. Spectrum Analyzers and as well no FF-Test devices etc. I am still setting up my small private lab. Let me clarify the situation a bit. The oscillators I work with are mainly 10811 (models A and others), some reference oscillators of other brands, a PRS10, a LPRO, a FRK-HLN 5MHz, a Trimble Thunderbolt (with a defective temp. measuring device, try o find out the impact) and a 1938A, which I have to refurbish, (is about 4 Hz away from nom. frequency and showing some sudden functional stops, btw. I need a v e r y small 1:4 transformer RFTM-16/SM3, hp 9100-5563, can somebody help me? I could not find any!). A lot of work to find out, which oscillator ist the best to serve as reference and then to classify the others. Not so easy as private and somewhat limited "test lab". My TI-counters I use are a 5345A with TI-probes and a 53132A, also a 5334A and a B model, completed by some other equipment. (Cs Standards are not on in view :( ). So, I try to learn and improve the setup by adding a few mixers for the given task, intending to do things right. Most difficult is to get the needed material here. (Unfortunately shipment and VAT are a very important counting factor :( ) Always open I thank you all for the help and hints, (such dokuments are helpful for a lot of members not yet skilled and well equipped!) Arnold From Arnold.Tibus at gmx.de Sun Apr 19 21:43:12 2009 From: Arnold.Tibus at gmx.de (Arnold Tibus) Date: Sun, 19 Apr 2009 23:43:12 +0200 Subject: [time-nuts] RF mixers for oscillator characterization, some questions In-Reply-To: <49EA3D66.7080007@xtra.co.nz> Message-ID: Bruce, a very good summary! I do not know where I can get the proposed MinCircuits DBM here, I looked to all the big and international well known supplier of electronics parts with negativ result. If I have to import them from USA they could end up even above 100 $ ea. we have in Europe to take the high shipment costs and the 19% VAT into account. Is it likely to get used mixers with damaged diodes? Did somebody alredy look inside the metal case of the 10514A? Will it perhaps possible to reconnect the common ground connections such a way that the mentioned loops can be opened? Thank you Bruce, Arnold On Sun, 19 Apr 2009 08:51:50 +1200, Bruce Griffiths wrote: >Arnold >Arnold Tibus wrote: >> Bruce, Magnus, Pete, >> >> sorry for being late responding, but the Easter Holydays ... >> they are over now :( >> >> Thank you for the informations giving me some more ideas! >> >> I am still wondering about the specials of these mixers. >> What are their secrets, what the differences to "normal" or high level DBMs? >> Is high level a criteria? >> >> >The dc offset at the mixer IF output (a measure of the diode matching >and transformer balance) should be low as should its drift. >The real criterion is low mixer phase noise particularly at low offset >frequencies. >The 10514 and 10534 are reputed to have low flicker phase noise. >Using a high level mixer as suggested by NIST does have the advantage of >allowing a preamp with higher input noise to be used to amplify the low >pass filtered IF port output. >> There are some companies selling the 10514A with SMB connectors. >> I have no idea what is a good or reasonable price fore and if I am running >> into possible risks to get deaf ones, for totally around $ 100,- ? >> >> >That price appears significantly higher than the Minicircuits price: >http://www.minicircuits.com/pdfs/ZP-10514.pdf >However there is no guarantee that the modern 10514's use discrete >diodes or what their flicker phase noise characteristics are. >A mixer which has a common IF, LO and RF grounds is susceptible to low >frequency ground loop noise. >However you can use RF transformers at the RF and LOP ports to break the >ground loops. >> In may 2007 there was aleady a short discours about the 10514A. >> Rick mentioned that today it could be possible to build a considerably better >> design with currently available technology. >> >> Does it mean it is really possible to build a DBM with currently available >> diodes, transformer cores etc. with similar or better characteristics >> as the old known commercial types? Or did he think to special chip >> designs? >> Are there no real merits anymore with the famous old hp 10514A? >> >> >They were widely used for such measurements and their phase noise was >well characterised. >You can achieve better diode matching with monolithic diode quads, >however the flicker noise of such quads is reputed to be higher than >equivalent discrete diode quads. >> Would be interesting to learn more about. >> >> Arnold >> >> >> On Tue, 07 Apr 2009 11:40:41 +1200, Bruce Griffiths wrote: >> >> >>> Magnus >>> >> >> >>> Magnus Danielson wrote: >>> >>>> Bruce Griffiths skrev: >>>> >>>> >>>>> Pete wrote: >>>>> >>>>> >>>>>> Arnold, >>>>>> >>>>>> I have had good experience with the SYPD series >>>>>> from Mini-circuits. I have not seen any used, but >>>>>> their new cost is reasonable. They do several things >>>>>> well e.g. the DC offset on the units I received is >>>>>> <1mV & they produce >2V p-p when driven @ >>>>>> +7dBm. >>>>>> >>>>>> Pete Rawson >>>>>> >>>>>> _______________________________________________ >>>>>> time-nuts mailing list -- time-nuts at febo.com >>>>>> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >>>>>> and follow the instructions there. >>>>>> >>>>>> >>>>>> >>>>>> >>>>> Pete >>>>> >>>>> These are OK except when one needs to isolate the IF ground from the RF >>>>> grounds to avoid low frequency ground loop problems. >>>>> The RPD and MPD through hole series are better in this regard as they >>>>> allow the IF ground to be isolated from the RF grounds. >>>>> >>>>> >>>> It should be noted that several of their SMB mixers have separated >>>> grounds, but it is not documented in their datasheets. >>>> >>>> >>>> >>>>> The flicker phase noise characteristics of the mixer/phase detector >>>>> should be measured as some mixers/phase detectors have lower flicker >>>>> phase noise than others. >>>>> The termination of the IF port will affect the mixer phase noise. For >>>>> offset frequencies < 100kHz a capacitive termination of the IF port >>>>> which reflects the sum frequency back into the mixer reduces the mixer >>>>> phase noise. >>>>> >>>>> >>>> It essentially sees a very low impedance at those frequencies. >>>> >>>> My experiments with capacitive loading of mixers basically indicates >>>> that the actual low-frequency slope of an unloaded mixer does not >>>> change, but the capacitor load filters the sum-frequency (with >>>> overtones) while a resistive 50 ohm load just loads the amplitude down >>>> and gives no significant change to performance. Optimum performance out >>>> of a mixer in my experience comes from fairly high-impedance load at low >>>> frequencies with a direct capacitive loading for filtering effects. >>>> >>>> A non-filtered response is quite interesting to see with a fairly slow >>>> beating frequency occuring. Kind of soothing waveforms floating slowly >>>> as waves over the scope. >>>> >>>> >>>> >>> The effect of reflecting the sum frequency back into the mixer is >>> documented in some Watkins Johnson and HP/Agilent appliction notes. >>> It can be very effective even at microwave frequencies. >>> >> >> >>>>> The tradeoff is that the mixer output at higher offset >>>>> frequencies is attenuated by the IF port termination. >>>>> Terminating the IF port in a capacitor reduces the RF port impedance, so >>>>> that a low value series resistor (22 to 39 ohms - select for lowest >>>>> VSWR) is then required to improve the RF port VSWR. >>>>> >>>>> >>>> Which in improves phase-stability as reflected waves has less impact. >>>> -3 dB pads have also been used by the good folks over at NIST at one time. >>>> >>>> >>>> >> >> >>> The best combination is a series resistor plus an attenuator pad. >>> >> >> >>>>> Terminating the IF port with a capacitor also alters the mixer gain (as >>>>> a phase detector) so this needs to be measured in conjunction with the noise >>>>> >>>>> >>>> Well... the normal 50 Ohm loading alters the mixer gain... not the cap. >>>> But since the normation is towards 50 Ohm... ah well... >>>> >>>> >>>> >>>>> 10514 and 10534 mixers using discrete diodes supposedly have lower >>>>> flicker noise than mixers using integrated quad diodes. >>>>> >>>>> >>>> They however has common ground in their every day laboratory variants. >>>> There exist variants meant for production. However, they are not made >>>> out of that exquisite components, so their performance should be >>>> replicable, as have been pointed out before. >>>> >>>> >>>> >> >> >>> The B versions intended for through hole PCB mount have separate grounds >>> for all ports. >>> These don't seem to be as widely available as they once were although I >>> have an HP10534B one. >>> >> >> >>>> Cheers, >>>> Magnus >>>> >>>> _______________________________________________ >>>> time-nuts mailing list -- time-nuts at febo.com >>>> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >>>> and follow the instructions there. >>>> >>>> >>>> >> >> >>> Bruce >>> From bruce.griffiths at xtra.co.nz Sun Apr 19 22:00:29 2009 From: bruce.griffiths at xtra.co.nz (Bruce Griffiths) Date: Mon, 20 Apr 2009 10:00:29 +1200 Subject: [time-nuts] RF mixers for oscillator characterization, some questions In-Reply-To: References: Message-ID: <49EB9EFD.8050208@xtra.co.nz> Arnold Arnold Tibus wrote: > Bruce, > > a very good summary! > I do not know where I can get the proposed MinCircuits DBM > here, I looked to all the big and international well known > supplier of electronics parts with negativ result. > > If I have to import them from USA they could end up even above > 100 $ ea. we have in Europe to take the high shipment costs > and the 19% VAT into account. > > Is it likely to get used mixers with damaged diodes? > > Did somebody alredy look inside the metal case of the 10514A? > Will it perhaps possible to reconnect the common ground connections > such a way that the mentioned loops can be opened? > > Not without changing the IF port connector or at least insulating its shell from ground. It may be easier just to construct you own mixer if you cant easily obtain the PCB mount Mincircuits mixers that have separate IF and RF grounds. Another alternative is to use a couple of RF transformers to isolate the mixer common ground from the RF source grounds and just have the mixer IF port grounded via its coax cable. If necessary you can easily wind you own RF transformers if you can obtain suitable ferrite cores. I thought that there was a Minicircuits distributor in Germany(http://www.municom.de/products/products960.php). Ulrich may know more about this. > Thank you Bruce, > > Arnold > > > > On Sun, 19 Apr 2009 08:51:50 +1200, Bruce Griffiths wrote: > > >> Arnold >> > > >> Arnold Tibus wrote: >> >>> Bruce, Magnus, Pete, >>> >>> sorry for being late responding, but the Easter Holydays ... >>> they are over now :( >>> >>> Thank you for the informations giving me some more ideas! >>> >>> I am still wondering about the specials of these mixers. >>> What are their secrets, what the differences to "normal" or high level DBMs? >>> Is high level a criteria? >>> >>> >>> > > >> The dc offset at the mixer IF output (a measure of the diode matching >> and transformer balance) should be low as should its drift. >> The real criterion is low mixer phase noise particularly at low offset >> frequencies. >> The 10514 and 10534 are reputed to have low flicker phase noise. >> > > >> Using a high level mixer as suggested by NIST does have the advantage of >> allowing a preamp with higher input noise to be used to amplify the low >> pass filtered IF port output. >> >>> There are some companies selling the 10514A with SMB connectors. >>> I have no idea what is a good or reasonable price fore and if I am running >>> into possible risks to get deaf ones, for totally around $ 100,- ? >>> >>> >>> >> That price appears significantly higher than the Minicircuits price: >> http://www.minicircuits.com/pdfs/ZP-10514.pdf >> However there is no guarantee that the modern 10514's use discrete >> diodes or what their flicker phase noise characteristics are. >> > > > >> A mixer which has a common IF, LO and RF grounds is susceptible to low >> frequency ground loop noise. >> However you can use RF transformers at the RF and LOP ports to break the >> ground loops. >> >>> In may 2007 there was aleady a short discours about the 10514A. >>> Rick mentioned that today it could be possible to build a considerably better >>> design with currently available technology. >>> >>> Does it mean it is really possible to build a DBM with currently available >>> diodes, transformer cores etc. with similar or better characteristics >>> as the old known commercial types? Or did he think to special chip >>> designs? >>> Are there no real merits anymore with the famous old hp 10514A? >>> >>> >>> >> They were widely used for such measurements and their phase noise was >> well characterised. >> You can achieve better diode matching with monolithic diode quads, >> however the flicker noise of such quads is reputed to be higher than >> equivalent discrete diode quads. >> >>> Would be interesting to learn more about. >>> >>> Arnold >>> >>> >>> On Tue, 07 Apr 2009 11:40:41 +1200, Bruce Griffiths wrote: >>> >>> >>> >>>> Magnus >>>> >>>> >>> >>> >>>> Magnus Danielson wrote: >>>> >>>> >>>>> Bruce Griffiths skrev: >>>>> >>>>> >>>>> >>>>>> Pete wrote: >>>>>> >>>>>> >>>>>> >>>>>>> Arnold, >>>>>>> >>>>>>> I have had good experience with the SYPD series >>>>>>> from Mini-circuits. I have not seen any used, but >>>>>>> their new cost is reasonable. They do several things >>>>>>> well e.g. the DC offset on the units I received is >>>>>>> <1mV & they produce >2V p-p when driven @ >>>>>>> +7dBm. >>>>>>> >>>>>>> Pete Rawson >>>>>>> >>>>>>> _______________________________________________ >>>>>>> time-nuts mailing list -- time-nuts at febo.com >>>>>>> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >>>>>>> and follow the instructions there. >>>>>>> >>>>>>> >>>>>>> >>>>>>> >>>>>>> >>>>>> Pete >>>>>> >>>>>> These are OK except when one needs to isolate the IF ground from the RF >>>>>> grounds to avoid low frequency ground loop problems. >>>>>> The RPD and MPD through hole series are better in this regard as they >>>>>> allow the IF ground to be isolated from the RF grounds. >>>>>> >>>>>> >>>>>> >>>>> It should be noted that several of their SMB mixers have separated >>>>> grounds, but it is not documented in their datasheets. >>>>> >>>>> >>>>> >>>>> >>>>>> The flicker phase noise characteristics of the mixer/phase detector >>>>>> should be measured as some mixers/phase detectors have lower flicker >>>>>> phase noise than others. >>>>>> The termination of the IF port will affect the mixer phase noise. For >>>>>> offset frequencies < 100kHz a capacitive termination of the IF port >>>>>> which reflects the sum frequency back into the mixer reduces the mixer >>>>>> phase noise. >>>>>> >>>>>> >>>>>> >>>>> It essentially sees a very low impedance at those frequencies. >>>>> >>>>> My experiments with capacitive loading of mixers basically indicates >>>>> that the actual low-frequency slope of an unloaded mixer does not >>>>> change, but the capacitor load filters the sum-frequency (with >>>>> overtones) while a resistive 50 ohm load just loads the amplitude down >>>>> and gives no significant change to performance. Optimum performance out >>>>> of a mixer in my experience comes from fairly high-impedance load at low >>>>> frequencies with a direct capacitive loading for filtering effects. >>>>> >>>>> A non-filtered response is quite interesting to see with a fairly slow >>>>> beating frequency occuring. Kind of soothing waveforms floating slowly >>>>> as waves over the scope. >>>>> >>>>> >>>>> >>>>> >>>> The effect of reflecting the sum frequency back into the mixer is >>>> documented in some Watkins Johnson and HP/Agilent appliction notes. >>>> It can be very effective even at microwave frequencies. >>>> >>>> >>> >>> >>>>>> The tradeoff is that the mixer output at higher offset >>>>>> frequencies is attenuated by the IF port termination. >>>>>> Terminating the IF port in a capacitor reduces the RF port impedance, so >>>>>> that a low value series resistor (22 to 39 ohms - select for lowest >>>>>> VSWR) is then required to improve the RF port VSWR. >>>>>> >>>>>> >>>>>> >>>>> Which in improves phase-stability as reflected waves has less impact. >>>>> -3 dB pads have also been used by the good folks over at NIST at one time. >>>>> >>>>> >>>>> >>>>> >>> >>> >>>> The best combination is a series resistor plus an attenuator pad. >>>> >>>> >>> >>> >>>>>> Terminating the IF port with a capacitor also alters the mixer gain (as >>>>>> a phase detector) so this needs to be measured in conjunction with the noise >>>>>> >>>>>> >>>>>> >>>>> Well... the normal 50 Ohm loading alters the mixer gain... not the cap. >>>>> But since the normation is towards 50 Ohm... ah well... >>>>> >>>>> >>>>> >>>>> >>>>>> 10514 and 10534 mixers using discrete diodes supposedly have lower >>>>>> flicker noise than mixers using integrated quad diodes. >>>>>> >>>>>> >>>>>> >>>>> They however has common ground in their every day laboratory variants. >>>>> There exist variants meant for production. However, they are not made >>>>> out of that exquisite components, so their performance should be >>>>> replicable, as have been pointed out before. >>>>> >>>>> >>>>> >>>>> >>> >>> >>>> The B versions intended for through hole PCB mount have separate grounds >>>> for all ports. >>>> These don't seem to be as widely available as they once were although I >>>> have an HP10534B one. >>>> >>>> >>> >>> >>>>> Cheers, >>>>> Magnus >>>>> >>>>> _______________________________________________ >>>>> time-nuts mailing list -- time-nuts at febo.com >>>>> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >>>>> and follow the instructions there. >>>>> >>>>> >>>>> >>>>> >>> >>> >>>> Bruce >>>> >>>> > > > > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > Bruce From bruce.griffiths at xtra.co.nz Sun Apr 19 22:04:04 2009 From: bruce.griffiths at xtra.co.nz (Bruce Griffiths) Date: Mon, 20 Apr 2009 10:04:04 +1200 Subject: [time-nuts] RF mixers for oscillator characterization, some questions In-Reply-To: <49EB9EFD.8050208@xtra.co.nz> References: <49EB9EFD.8050208@xtra.co.nz> Message-ID: <49EB9FD4.7030505@xtra.co.nz> Arnold Additional German source for Minicircuits: http://www.industrialelectronics.de/ Bruce Bruce Griffiths wrote: > Arnold > > Arnold Tibus wrote: > >> Bruce, >> >> a very good summary! >> I do not know where I can get the proposed MinCircuits DBM >> here, I looked to all the big and international well known >> supplier of electronics parts with negativ result. >> >> If I have to import them from USA they could end up even above >> 100 $ ea. we have in Europe to take the high shipment costs >> and the 19% VAT into account. >> >> Is it likely to get used mixers with damaged diodes? >> >> Did somebody alredy look inside the metal case of the 10514A? >> Will it perhaps possible to reconnect the common ground connections >> such a way that the mentioned loops can be opened? >> >> >> > Not without changing the IF port connector or at least insulating its > shell from ground. > It may be easier just to construct you own mixer if you cant easily > obtain the PCB mount Mincircuits mixers that have separate IF and RF > grounds. > Another alternative is to use a couple of RF transformers to isolate the > mixer common ground from the RF source grounds and just have the mixer > IF port grounded via its coax cable. > If necessary you can easily wind you own RF transformers if you can > obtain suitable ferrite cores. > I thought that there was a Minicircuits distributor in > Germany(http://www.municom.de/products/products960.php). > Ulrich may know more about this. > >> Thank you Bruce, >> >> Arnold >> >> >> >> On Sun, 19 Apr 2009 08:51:50 +1200, Bruce Griffiths wrote: >> >> >> >>> Arnold >>> >>> >> >> >>> Arnold Tibus wrote: >>> >>> >>>> Bruce, Magnus, Pete, >>>> >>>> sorry for being late responding, but the Easter Holydays ... >>>> they are over now :( >>>> >>>> Thank you for the informations giving me some more ideas! >>>> >>>> I am still wondering about the specials of these mixers. >>>> What are their secrets, what the differences to "normal" or high level DBMs? >>>> Is high level a criteria? >>>> >>>> >>>> >>>> >> >> >>> The dc offset at the mixer IF output (a measure of the diode matching >>> and transformer balance) should be low as should its drift. >>> The real criterion is low mixer phase noise particularly at low offset >>> frequencies. >>> The 10514 and 10534 are reputed to have low flicker phase noise. >>> >>> >> >> >>> Using a high level mixer as suggested by NIST does have the advantage of >>> allowing a preamp with higher input noise to be used to amplify the low >>> pass filtered IF port output. >>> >>> >>>> There are some companies selling the 10514A with SMB connectors. >>>> I have no idea what is a good or reasonable price fore and if I am running >>>> into possible risks to get deaf ones, for totally around $ 100,- ? >>>> >>>> >>>> >>>> >>> That price appears significantly higher than the Minicircuits price: >>> http://www.minicircuits.com/pdfs/ZP-10514.pdf >>> However there is no guarantee that the modern 10514's use discrete >>> diodes or what their flicker phase noise characteristics are. >>> >>> >> >> >>> A mixer which has a common IF, LO and RF grounds is susceptible to low >>> frequency ground loop noise. >>> However you can use RF transformers at the RF and LOP ports to break the >>> ground loops. >>> >>> >>>> In may 2007 there was aleady a short discours about the 10514A. >>>> Rick mentioned that today it could be possible to build a considerably better >>>> design with currently available technology. >>>> >>>> Does it mean it is really possible to build a DBM with currently available >>>> diodes, transformer cores etc. with similar or better characteristics >>>> as the old known commercial types? Or did he think to special chip >>>> designs? >>>> Are there no real merits anymore with the famous old hp 10514A? >>>> >>>> >>>> >>>> >>> They were widely used for such measurements and their phase noise was >>> well characterised. >>> You can achieve better diode matching with monolithic diode quads, >>> however the flicker noise of such quads is reputed to be higher than >>> equivalent discrete diode quads. >>> >>> >>>> Would be interesting to learn more about. >>>> >>>> Arnold >>>> >>>> >>>> On Tue, 07 Apr 2009 11:40:41 +1200, Bruce Griffiths wrote: >>>> >>>> >>>> >>>> >>>>> Magnus >>>>> >>>>> >>>>> >>>> >>>> >>>> >>>>> Magnus Danielson wrote: >>>>> >>>>> >>>>> >>>>>> Bruce Griffiths skrev: >>>>>> >>>>>> >>>>>> >>>>>> >>>>>>> Pete wrote: >>>>>>> >>>>>>> >>>>>>> >>>>>>> >>>>>>>> Arnold, >>>>>>>> >>>>>>>> I have had good experience with the SYPD series >>>>>>>> from Mini-circuits. I have not seen any used, but >>>>>>>> their new cost is reasonable. They do several things >>>>>>>> well e.g. the DC offset on the units I received is >>>>>>>> <1mV & they produce >2V p-p when driven @ >>>>>>>> +7dBm. >>>>>>>> >>>>>>>> Pete Rawson >>>>>>>> >>>>>>>> _______________________________________________ >>>>>>>> time-nuts mailing list -- time-nuts at febo.com >>>>>>>> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >>>>>>>> and follow the instructions there. >>>>>>>> >>>>>>>> >>>>>>>> >>>>>>>> >>>>>>>> >>>>>>>> >>>>>>> Pete >>>>>>> >>>>>>> These are OK except when one needs to isolate the IF ground from the RF >>>>>>> grounds to avoid low frequency ground loop problems. >>>>>>> The RPD and MPD through hole series are better in this regard as they >>>>>>> allow the IF ground to be isolated from the RF grounds. >>>>>>> >>>>>>> >>>>>>> >>>>>>> >>>>>> It should be noted that several of their SMB mixers have separated >>>>>> grounds, but it is not documented in their datasheets. >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> >>>>>>> The flicker phase noise characteristics of the mixer/phase detector >>>>>>> should be measured as some mixers/phase detectors have lower flicker >>>>>>> phase noise than others. >>>>>>> The termination of the IF port will affect the mixer phase noise. For >>>>>>> offset frequencies < 100kHz a capacitive termination of the IF port >>>>>>> which reflects the sum frequency back into the mixer reduces the mixer >>>>>>> phase noise. >>>>>>> >>>>>>> >>>>>>> >>>>>>> >>>>>> It essentially sees a very low impedance at those frequencies. >>>>>> >>>>>> My experiments with capacitive loading of mixers basically indicates >>>>>> that the actual low-frequency slope of an unloaded mixer does not >>>>>> change, but the capacitor load filters the sum-frequency (with >>>>>> overtones) while a resistive 50 ohm load just loads the amplitude down >>>>>> and gives no significant change to performance. Optimum performance out >>>>>> of a mixer in my experience comes from fairly high-impedance load at low >>>>>> frequencies with a direct capacitive loading for filtering effects. >>>>>> >>>>>> A non-filtered response is quite interesting to see with a fairly slow >>>>>> beating frequency occuring. Kind of soothing waveforms floating slowly >>>>>> as waves over the scope. >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> >>>>> The effect of reflecting the sum frequency back into the mixer is >>>>> documented in some Watkins Johnson and HP/Agilent appliction notes. >>>>> It can be very effective even at microwave frequencies. >>>>> >>>>> >>>>> >>>> >>>> >>>> >>>>>>> The tradeoff is that the mixer output at higher offset >>>>>>> frequencies is attenuated by the IF port termination. >>>>>>> Terminating the IF port in a capacitor reduces the RF port impedance, so >>>>>>> that a low value series resistor (22 to 39 ohms - select for lowest >>>>>>> VSWR) is then required to improve the RF port VSWR. >>>>>>> >>>>>>> >>>>>>> >>>>>>> >>>>>> Which in improves phase-stability as reflected waves has less impact. >>>>>> -3 dB pads have also been used by the good folks over at NIST at one time. >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> >>>> >>>> >>>> >>>>> The best combination is a series resistor plus an attenuator pad. >>>>> >>>>> >>>>> >>>> >>>> >>>> >>>>>>> Terminating the IF port with a capacitor also alters the mixer gain (as >>>>>>> a phase detector) so this needs to be measured in conjunction with the noise >>>>>>> >>>>>>> >>>>>>> >>>>>>> >>>>>> Well... the normal 50 Ohm loading alters the mixer gain... not the cap. >>>>>> But since the normation is towards 50 Ohm... ah well... >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> >>>>>>> 10514 and 10534 mixers using discrete diodes supposedly have lower >>>>>>> flicker noise than mixers using integrated quad diodes. >>>>>>> >>>>>>> >>>>>>> >>>>>>> >>>>>> They however has common ground in their every day laboratory variants. >>>>>> There exist variants meant for production. However, they are not made >>>>>> out of that exquisite components, so their performance should be >>>>>> replicable, as have been pointed out before. >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> >>>> >>>> >>>> >>>>> The B versions intended for through hole PCB mount have separate grounds >>>>> for all ports. >>>>> These don't seem to be as widely available as they once were although I >>>>> have an HP10534B one. >>>>> >>>>> >>>>> >>>> >>>> >>>> >>>>>> Cheers, >>>>>> Magnus >>>>>> >>>>>> _______________________________________________ >>>>>> time-nuts mailing list -- time-nuts at febo.com >>>>>> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >>>>>> and follow the instructions there. >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> >>>> >>>> >>>> >>>>> Bruce >>>>> >>>>> >>>>> >> >> >> >> _______________________________________________ >> time-nuts mailing list -- time-nuts at febo.com >> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. >> >> >> > Bruce > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > From Arnold.Tibus at gmx.de Sun Apr 19 22:04:57 2009 From: Arnold.Tibus at gmx.de (Arnold Tibus) Date: Mon, 20 Apr 2009 00:04:57 +0200 Subject: [time-nuts] RF Mixers for oscillator comparison In-Reply-To: <49EB91A8.3000100@xtra.co.nz> Message-ID: On Mon, 20 Apr 2009 09:03:36 +1200, Bruce Griffiths wrote: >Corby Dawson wrote: >> Arnold, >> >> Look at the top of page 3 on the link below. Not sure how they arrived at >> their conclusion but there is one opinion on the HP mixers! >> >> http://www.unusualresearch.com/AppNotes/TimeNuts/OptDualMixer.pdf >> >> Corby Dawson >> ____________________________________________________________ >> Debt collectors calling your house? Click here to consolidate into one payment. >> http://thirdpartyoffers.juno.com/TGL2141/fc/BLSrjpTIk3l9oQnolYGEY40TVwmsBD4opDDeVSRG36KHWHhZWexSiuRrXdm/ >> >> _______________________________________________ >> time-nuts mailing list -- time-nuts at febo.com >> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. >> >> >Statements about the low flicker noise of these mixers are sprinkled >throughout the phase noise literature. >Someone must have measured the phase noise of these and other mixers at >some time. >Its relatively easy to measure mixer phase noise: >All one needs is a low noise preamp plus a sound card a 90 degree hybrid >(or a suitable length of coax and a splitter) and a low noise source. >However NIST papers often include a phase noise plot (attached) that >illustrates that high level mixers can have a significantly lower phase >noise than low level mixers (like the HP10514A). >When choosing a mixer for this for phase noise measurement applications >one may actually need to measure the phase noise characteristics of >candidate mixers. >Bruce Wow, a good overview, Bruce! But remain the questions: which are these high level mixers, are they readily available? Are they affordable? Perhaps not, why are they then not applied more often? Arnold From bruce.griffiths at xtra.co.nz Sun Apr 19 22:25:28 2009 From: bruce.griffiths at xtra.co.nz (Bruce Griffiths) Date: Mon, 20 Apr 2009 10:25:28 +1200 Subject: [time-nuts] RF Mixers for oscillator comparison In-Reply-To: References: Message-ID: <49EBA4D8.4080605@xtra.co.nz> Arnold Some of the early equipment produced by NIST used mixers from a company that eventually became into Minicirucits. Suitable candidates from the Minicircuits range are: TUF-1H+: http://www.minicircuits.com/pdfs/TUF-1H+.pdf This mixer doesnt have isolated RF, LO and IF grounds so external transformers would be rrequired. It does have somewhat higher port to port isolation than most mixers. The minicircuits phase detectors such as: http://www.minicircuits.com/pdfs/RPD-1+.pdf http://www.minicircuits.com/pdfs/MPD-1+.pdf are worth considering, at least they have separate RF and IF grounds, a high maximum output as well as low dc offset and offset drift. All of these are below $US25 (at the source). The phase detectors are perhaps the safest option however measurement of their phase noise would be advisable. Bruce Arnold Tibus wrote: > On Mon, 20 Apr 2009 09:03:36 +1200, Bruce Griffiths wrote: > > >> Corby Dawson wrote: >> >>> Arnold, >>> >>> Look at the top of page 3 on the link below. Not sure how they arrived at >>> their conclusion but there is one opinion on the HP mixers! >>> >>> http://www.unusualresearch.com/AppNotes/TimeNuts/OptDualMixer.pdf >>> >>> Corby Dawson >>> ____________________________________________________________ >>> Debt collectors calling your house? Click here to consolidate into one payment. >>> http://thirdpartyoffers.juno.com/TGL2141/fc/BLSrjpTIk3l9oQnolYGEY40TVwmsBD4opDDeVSRG36KHWHhZWexSiuRrXdm/ >>> >>> _______________________________________________ >>> time-nuts mailing list -- time-nuts at febo.com >>> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >>> and follow the instructions there. >>> >>> >>> >> Statements about the low flicker noise of these mixers are sprinkled >> throughout the phase noise literature. >> Someone must have measured the phase noise of these and other mixers at >> some time. >> > > >> Its relatively easy to measure mixer phase noise: >> All one needs is a low noise preamp plus a sound card a 90 degree hybrid >> (or a suitable length of coax and a splitter) and a low noise source. >> > > >> However NIST papers often include a phase noise plot (attached) that >> illustrates that high level mixers can have a significantly lower phase >> noise than low level mixers (like the HP10514A). >> When choosing a mixer for this for phase noise measurement applications >> one may actually need to measure the phase noise characteristics of >> candidate mixers. >> > > >> Bruce >> > > > Wow, a good overview, Bruce! > > But remain the questions: > which are these high level mixers, are they readily available? > Are they affordable? > Perhaps not, why are they then not applied more often? > > Arnold > > > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > From Arnold.Tibus at gmx.de Sun Apr 19 22:32:48 2009 From: Arnold.Tibus at gmx.de (Arnold Tibus) Date: Mon, 20 Apr 2009 00:32:48 +0200 Subject: [time-nuts] RF mixers for oscillator characterization, some questions In-Reply-To: <49EB9EFD.8050208@xtra.co.nz> Message-ID: Bruce, I will try it, I looked aready to that homepage. The point is, a lot of distributors do sell only to registrated companies with a tax number, no chance for a private person to get anything. Ulrich does have therefore no problems with that issue I suppose. It was easier for me when I was still in our Aircraft and Satellite building company. But I will try it the next working days. I see the points you explain, reasonable. But there I have still no problems with my fingers to modify and manipulate even very small hardware, if the inner parts are held well together, I could fix everything in a new small housing with new connections. It would even be possible to fit in the mentioned additional isolating transformes. Hopefully it will not create new unsymmetries (but the use is for LF). Arnold On Mon, 20 Apr 2009 10:00:29 +1200, Bruce Griffiths wrote: >Arnold >Arnold Tibus wrote: >> Bruce, >> >> a very good summary! >> I do not know where I can get the proposed MinCircuits DBM >> here, I looked to all the big and international well known >> supplier of electronics parts with negativ result. >> >> If I have to import them from USA they could end up even above >> 100 $ ea. we have in Europe to take the high shipment costs >> and the 19% VAT into account. >> >> Is it likely to get used mixers with damaged diodes? >> >> Did somebody alredy look inside the metal case of the 10514A? >> Will it perhaps possible to reconnect the common ground connections >> such a way that the mentioned loops can be opened? >> >> >Not without changing the IF port connector or at least insulating its >shell from ground. >It may be easier just to construct you own mixer if you cant easily >obtain the PCB mount Mincircuits mixers that have separate IF and RF >grounds. >Another alternative is to use a couple of RF transformers to isolate the >mixer common ground from the RF source grounds and just have the mixer >IF port grounded via its coax cable. >If necessary you can easily wind you own RF transformers if you can >obtain suitable ferrite cores. >I thought that there was a Minicircuits distributor in >Germany(http://www.municom.de/products/products960.php). >Ulrich may know more about this. >> Thank you Bruce, >> >> Arnold >> >> >> >> On Sun, 19 Apr 2009 08:51:50 +1200, Bruce Griffiths wrote: >> >> >>> Arnold >>> >> >> >>> Arnold Tibus wrote: >>> >>>> Bruce, Magnus, Pete, >>>> >>>> sorry for being late responding, but the Easter Holydays ... >>>> they are over now :( >>>> >>>> Thank you for the informations giving me some more ideas! >>>> >>>> I am still wondering about the specials of these mixers. >>>> What are their secrets, what the differences to "normal" or high level DBMs? >>>> Is high level a criteria? >>>> >>>> >>>> >> >> >>> The dc offset at the mixer IF output (a measure of the diode matching >>> and transformer balance) should be low as should its drift. >>> The real criterion is low mixer phase noise particularly at low offset >>> frequencies. >>> The 10514 and 10534 are reputed to have low flicker phase noise. >>> >> >> >>> Using a high level mixer as suggested by NIST does have the advantage of >>> allowing a preamp with higher input noise to be used to amplify the low >>> pass filtered IF port output. >>> >>>> There are some companies selling the 10514A with SMB connectors. >>>> I have no idea what is a good or reasonable price fore and if I am running >>>> into possible risks to get deaf ones, for totally around $ 100,- ? >>>> >>>> >>>> >>> That price appears significantly higher than the Minicircuits price: >>> http://www.minicircuits.com/pdfs/ZP-10514.pdf >>> However there is no guarantee that the modern 10514's use discrete >>> diodes or what their flicker phase noise characteristics are. >>> >> >> >> >>> A mixer which has a common IF, LO and RF grounds is susceptible to low >>> frequency ground loop noise. >>> However you can use RF transformers at the RF and LOP ports to break the >>> ground loops. >>> >>>> In may 2007 there was aleady a short discours about the 10514A. >>>> Rick mentioned that today it could be possible to build a considerably better >>>> design with currently available technology. >>>> >>>> Does it mean it is really possible to build a DBM with currently available >>>> diodes, transformer cores etc. with similar or better characteristics >>>> as the old known commercial types? Or did he think to special chip >>>> designs? >>>> Are there no real merits anymore with the famous old hp 10514A? >>>> >>>> >>>> >>> They were widely used for such measurements and their phase noise was >>> well characterised. >>> You can achieve better diode matching with monolithic diode quads, >>> however the flicker noise of such quads is reputed to be higher than >>> equivalent discrete diode quads. >>> >>>> Would be interesting to learn more about. >>>> >>>> Arnold >>>> >>>> >>>> On Tue, 07 Apr 2009 11:40:41 +1200, Bruce Griffiths wrote: >>>> >>>> >>>> >>>>> Magnus >>>>> >>>>> >>>> >>>> >>>>> Magnus Danielson wrote: >>>>> >>>>> >>>>>> Bruce Griffiths skrev: >>>>>> >>>>>> >>>>>> >>>>>>> Pete wrote: >>>>>>> >>>>>>> >>>>>>> >>>>>>>> Arnold, >>>>>>>> >>>>>>>> I have had good experience with the SYPD series >>>>>>>> from Mini-circuits. I have not seen any used, but >>>>>>>> their new cost is reasonable. They do several things >>>>>>>> well e.g. the DC offset on the units I received is >>>>>>>> <1mV & they produce >2V p-p when driven @ >>>>>>>> +7dBm. >>>>>>>> >>>>>>>> Pete Rawson >>>>>>>> >>>>>>>> _______________________________________________ >>>>>>>> time-nuts mailing list -- time-nuts at febo.com >>>>>>>> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >>>>>>>> and follow the instructions there. >>>>>>>> >>>>>>>> >>>>>>>> >>>>>>>> >>>>>>>> >>>>>>> Pete >>>>>>> >>>>>>> These are OK except when one needs to isolate the IF ground from the RF >>>>>>> grounds to avoid low frequency ground loop problems. >>>>>>> The RPD and MPD through hole series are better in this regard as they >>>>>>> allow the IF ground to be isolated from the RF grounds. >>>>>>> >>>>>>> >>>>>>> >>>>>> It should be noted that several of their SMB mixers have separated >>>>>> grounds, but it is not documented in their datasheets. >>>>>> >>>>>> >>>>>> >>>>>> >>>>>>> The flicker phase noise characteristics of the mixer/phase detector >>>>>>> should be measured as some mixers/phase detectors have lower flicker >>>>>>> phase noise than others. >>>>>>> The termination of the IF port will affect the mixer phase noise. For >>>>>>> offset frequencies < 100kHz a capacitive termination of the IF port >>>>>>> which reflects the sum frequency back into the mixer reduces the mixer >>>>>>> phase noise. >>>>>>> >>>>>>> >>>>>>> >>>>>> It essentially sees a very low impedance at those frequencies. >>>>>> >>>>>> My experiments with capacitive loading of mixers basically indicates >>>>>> that the actual low-frequency slope of an unloaded mixer does not >>>>>> change, but the capacitor load filters the sum-frequency (with >>>>>> overtones) while a resistive 50 ohm load just loads the amplitude down >>>>>> and gives no significant change to performance. Optimum performance out >>>>>> of a mixer in my experience comes from fairly high-impedance load at low >>>>>> frequencies with a direct capacitive loading for filtering effects. >>>>>> >>>>>> A non-filtered response is quite interesting to see with a fairly slow >>>>>> beating frequency occuring. Kind of soothing waveforms floating slowly >>>>>> as waves over the scope. >>>>>> >>>>>> >>>>>> >>>>>> >>>>> The effect of reflecting the sum frequency back into the mixer is >>>>> documented in some Watkins Johnson and HP/Agilent appliction notes. >>>>> It can be very effective even at microwave frequencies. >>>>> >>>>> >>>> >>>> >>>>>>> The tradeoff is that the mixer output at higher offset >>>>>>> frequencies is attenuated by the IF port termination. >>>>>>> Terminating the IF port in a capacitor reduces the RF port impedance, so >>>>>>> that a low value series resistor (22 to 39 ohms - select for lowest >>>>>>> VSWR) is then required to improve the RF port VSWR. >>>>>>> >>>>>>> >>>>>>> >>>>>> Which in improves phase-stability as reflected waves has less impact. >>>>>> -3 dB pads have also been used by the good folks over at NIST at one time. >>>>>> >>>>>> >>>>>> >>>>>> >>>> >>>> >>>>> The best combination is a series resistor plus an attenuator pad. >>>>> >>>>> >>>> >>>> >>>>>>> Terminating the IF port with a capacitor also alters the mixer gain (as >>>>>>> a phase detector) so this needs to be measured in conjunction with the noise >>>>>>> >>>>>>> >>>>>>> >>>>>> Well... the normal 50 Ohm loading alters the mixer gain... not the cap. >>>>>> But since the normation is towards 50 Ohm... ah well... >>>>>> >>>>>> >>>>>> >>>>>> >>>>>>> 10514 and 10534 mixers using discrete diodes supposedly have lower >>>>>>> flicker noise than mixers using integrated quad diodes. >>>>>>> >>>>>>> >>>>>>> >>>>>> They however has common ground in their every day laboratory variants. >>>>>> There exist variants meant for production. However, they are not made >>>>>> out of that exquisite components, so their performance should be >>>>>> replicable, as have been pointed out before. >>>>>> >>>>>> >>>>>> >>>>>> >>>> >>>> >>>>> The B versions intended for through hole PCB mount have separate grounds >>>>> for all ports. >>>>> These don't seem to be as widely available as they once were although I >>>>> have an HP10534B one. >>>>> >>>>> >>>> >>>> >>>>>> Cheers, >>>>>> Magnus >>>>>> >>>> >>>> >>>>> Bruce >>>>> >>>>> >> >Bruce From Arnold.Tibus at gmx.de Sun Apr 19 22:46:47 2009 From: Arnold.Tibus at gmx.de (Arnold Tibus) Date: Mon, 20 Apr 2009 00:46:47 +0200 Subject: [time-nuts] RF Mixers for oscillator comparison In-Reply-To: <49EBA4D8.4080605@xtra.co.nz> Message-ID: Bruce, Are such as SRA-1H or SRA-3H no possible candidates? Such I have still somewhere in a drawer. Arnold On Mon, 20 Apr 2009 10:25:28 +1200, Bruce Griffiths wrote: >Arnold >Some of the early equipment produced by NIST used mixers from a company >that eventually became into Minicirucits. >Suitable candidates from the Minicircuits range are: >TUF-1H+: >http://www.minicircuits.com/pdfs/TUF-1H+.pdf >This mixer doesnt have isolated RF, LO and IF grounds so external >transformers would be rrequired. >It does have somewhat higher port to port isolation than most mixers. >The minicircuits phase detectors such as: >http://www.minicircuits.com/pdfs/RPD-1+.pdf >http://www.minicircuits.com/pdfs/MPD-1+.pdf >are worth considering, at least they have separate RF and IF grounds, a >high maximum output as well as low dc offset and offset drift. >All of these are below $US25 (at the source). >The phase detectors are perhaps the safest option however measurement of >their phase noise would be advisable. >Bruce >Arnold Tibus wrote: >> On Mon, 20 Apr 2009 09:03:36 +1200, Bruce Griffiths wrote: >> >> >>> Corby Dawson wrote: >>> >>>> Arnold, >>>> >>>> Look at the top of page 3 on the link below. Not sure how they arrived at >>>> their conclusion but there is one opinion on the HP mixers! >>>> >>>> http://www.unusualresearch.com/AppNotes/TimeNuts/OptDualMixer.pdf >>>> >>>> Corby Dawson >>>> ____________________________________________________________ >>>> Debt collectors calling your house? Click here to consolidate into one payment. >>>> http://thirdpartyoffers.juno.com/TGL2141/fc/BLSrjpTIk3l9oQnolYGEY40TVwmsBD4opDDeVSRG36KHWHhZWexSiuRrXdm/ >>>> >>>> _______________________________________________ >>>> time-nuts mailing list -- time-nuts at febo.com >>>> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >>>> and follow the instructions there. >>>> >>>> >>>> >>> Statements about the low flicker noise of these mixers are sprinkled >>> throughout the phase noise literature. >>> Someone must have measured the phase noise of these and other mixers at >>> some time. >>> >> >> >>> Its relatively easy to measure mixer phase noise: >>> All one needs is a low noise preamp plus a sound card a 90 degree hybrid >>> (or a suitable length of coax and a splitter) and a low noise source. >>> >> >> >>> However NIST papers often include a phase noise plot (attached) that >>> illustrates that high level mixers can have a significantly lower phase >>> noise than low level mixers (like the HP10514A). >>> When choosing a mixer for this for phase noise measurement applications >>> one may actually need to measure the phase noise characteristics of >>> candidate mixers. >>> >> >> >>> Bruce >>> >> >> >> Wow, a good overview, Bruce! >> >> But remain the questions: >> which are these high level mixers, are they readily available? >> Are they affordable? >> Perhaps not, why are they then not applied more often? >> >> Arnold >> >> >> >> >> _______________________________________________ >> time-nuts mailing list -- time-nuts at febo.com >> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. >> >> >_______________________________________________ >time-nuts mailing list -- time-nuts at febo.com >To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >and follow the instructions there. From bruce.griffiths at xtra.co.nz Sun Apr 19 22:59:10 2009 From: bruce.griffiths at xtra.co.nz (Bruce Griffiths) Date: Mon, 20 Apr 2009 10:59:10 +1200 Subject: [time-nuts] RF Mixers for oscillator comparison In-Reply-To: References: Message-ID: <49EBACBE.5060008@xtra.co.nz> Arnold They do have lower isolation than the phase detectors and the TUF mixers. However it would be well worthwhile measuring their dc offset, its drift and their phase noise. Its possible to mitigate the effects of lower isolation by using low phase noise isolation amplifiers. If you do this please make it available so that it can be used by others in making similar decisions. It would be useful if anyone else who can measure the phase noise of any mixers they have do so. In this way we can build up information on the phase noise performance of various mixers without having to purchase mixers for such measurements. Bruce Arnold Tibus wrote: > Bruce, > > Are such as > SRA-1H or SRA-3H no possible candidates? > Such I have still somewhere in a drawer. > > Arnold > > On Mon, 20 Apr 2009 10:25:28 +1200, Bruce Griffiths wrote: > > >> Arnold >> > > >> Some of the early equipment produced by NIST used mixers from a company >> that eventually became into Minicirucits. >> > > >> Suitable candidates from the Minicircuits range are: >> > > >> TUF-1H+: >> http://www.minicircuits.com/pdfs/TUF-1H+.pdf >> > > >> This mixer doesnt have isolated RF, LO and IF grounds so external >> transformers would be rrequired. >> It does have somewhat higher port to port isolation than most mixers. >> > > >> The minicircuits phase detectors such as: >> > > >> http://www.minicircuits.com/pdfs/RPD-1+.pdf >> > > >> http://www.minicircuits.com/pdfs/MPD-1+.pdf >> > > >> are worth considering, at least they have separate RF and IF grounds, a >> high maximum output as well as low dc offset and offset drift. >> > > > >> All of these are below $US25 (at the source). >> > > >> The phase detectors are perhaps the safest option however measurement of >> their phase noise would be advisable. >> > > >> Bruce >> > > >> Arnold Tibus wrote: >> >>> On Mon, 20 Apr 2009 09:03:36 +1200, Bruce Griffiths wrote: >>> >>> >>> >>>> Corby Dawson wrote: >>>> >>>> >>>>> Arnold, >>>>> >>>>> Look at the top of page 3 on the link below. Not sure how they arrived at >>>>> their conclusion but there is one opinion on the HP mixers! >>>>> >>>>> http://www.unusualresearch.com/AppNotes/TimeNuts/OptDualMixer.pdf >>>>> >>>>> Corby Dawson >>>>> ____________________________________________________________ >>>>> Debt collectors calling your house? Click here to consolidate into one payment. >>>>> http://thirdpartyoffers.juno.com/TGL2141/fc/BLSrjpTIk3l9oQnolYGEY40TVwmsBD4opDDeVSRG36KHWHhZWexSiuRrXdm/ >>>>> >>>>> _______________________________________________ >>>>> time-nuts mailing list -- time-nuts at febo.com >>>>> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >>>>> and follow the instructions there. >>>>> >>>>> >>>>> >>>>> >>>> Statements about the low flicker noise of these mixers are sprinkled >>>> throughout the phase noise literature. >>>> Someone must have measured the phase noise of these and other mixers at >>>> some time. >>>> >>>> >>> >>> >>>> Its relatively easy to measure mixer phase noise: >>>> All one needs is a low noise preamp plus a sound card a 90 degree hybrid >>>> (or a suitable length of coax and a splitter) and a low noise source. >>>> >>>> >>> >>> >>>> However NIST papers often include a phase noise plot (attached) that >>>> illustrates that high level mixers can have a significantly lower phase >>>> noise than low level mixers (like the HP10514A). >>>> When choosing a mixer for this for phase noise measurement applications >>>> one may actually need to measure the phase noise characteristics of >>>> candidate mixers. >>>> >>>> >>> >>> >>>> Bruce >>>> >>>> >>> Wow, a good overview, Bruce! >>> >>> But remain the questions: >>> which are these high level mixers, are they readily available? >>> Are they affordable? >>> Perhaps not, why are they then not applied more often? >>> >>> Arnold >>> >>> >>> >>> >>> _______________________________________________ >>> time-nuts mailing list -- time-nuts at febo.com >>> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >>> and follow the instructions there. >>> >>> >>> > > > >> _______________________________________________ >> time-nuts mailing list -- time-nuts at febo.com >> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. >> > > > > > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > From magnus at rubidium.dyndns.org Sun Apr 19 23:06:57 2009 From: magnus at rubidium.dyndns.org (Magnus Danielson) Date: Mon, 20 Apr 2009 01:06:57 +0200 Subject: [time-nuts] RF mixers for oscillator characterization, some questions In-Reply-To: References: Message-ID: <49EBAE91.1090204@rubidium.dyndns.org> Hej Arnold, Arnold Tibus skrev: > Bruce, > > a very good summary! > I do not know where I can get the proposed MinCircuits DBM > here, I looked to all the big and international well known > supplier of electronics parts with negativ result. > > If I have to import them from USA they could end up even above > 100 $ ea. we have in Europe to take the high shipment costs > and the 19% VAT into account. It was not too hard to find their official list of representatives. That is what I usually do besides the top catalog firms. Prices does not seem too bad... http://www.minicircuits.com/cgi-bin/modelsearch?search_type=model&model=ZP-10514&tb_no= > Is it likely to get used mixers with damaged diodes? > > Did somebody alredy look inside the metal case of the 10514A? You made me remember I needed too.... > Will it perhaps possible to reconnect the common ground connections > such a way that the mentioned loops can be opened? Yes. The grounds is separated on the PCB, so it is only on the front plate that they actually interconnect when the BNCs screw tight. What's inside then? Well, there is 4 small torroid cores (as compared to the 10534A which has only two cores). It also has 4 diodes (marked as HP 82) and 2 50 Ohm resistors. The L and R ports have an isolational transformer each, with the 50 Ohm resistor loading on the secondary side. A inner transformer then follows, with two secondaries, hooked up like expected for a double balanced mixer. Essentially this is a double balanced mixer with additional isolational transformers and 50 Ohms terminations. This does not match the datasheet from MiniCircuit for ZP-10514: http://www.minicircuits.com/pdfs/ZP-10514.pdf Cheers, Magnus From Arnold.Tibus at gmx.de Sun Apr 19 23:15:32 2009 From: Arnold.Tibus at gmx.de (Arnold Tibus) Date: Mon, 20 Apr 2009 01:15:32 +0200 Subject: [time-nuts] RF Mixers for oscillator comparison In-Reply-To: <49EBACBE.5060008@xtra.co.nz> Message-ID: Bruce, fine, I will do what possible, but not this night anymore, it is very late already (early morning) ! Would be of high interest what others are experiencing. Thanks a lot, Arnold On Mon, 20 Apr 2009 10:59:10 +1200, Bruce Griffiths wrote: >Arnold >They do have lower isolation than the phase detectors and the TUF mixers. >However it would be well worthwhile measuring their dc offset, its drift >and their phase noise. >Its possible to mitigate the effects of lower isolation by using low >phase noise isolation amplifiers. >If you do this please make it available so that it can be used by others >in making similar decisions. >It would be useful if anyone else who can measure the phase noise of any >mixers they have do so. >In this way we can build up information on the phase noise performance >of various mixers without having to purchase mixers for such measurements. >Bruce >Arnold Tibus wrote: >> Bruce, >> >> Are such as >> SRA-1H or SRA-3H no possible candidates? >> Such I have still somewhere in a drawer. >> >> Arnold >> >> On Mon, 20 Apr 2009 10:25:28 +1200, Bruce Griffiths wrote: >> >> >>> Arnold >>> >> >> >>> Some of the early equipment produced by NIST used mixers from a company >>> that eventually became into Minicirucits. >>> >> >> >>> Suitable candidates from the Minicircuits range are: >>> >> >> >>> TUF-1H+: >>> http://www.minicircuits.com/pdfs/TUF-1H+.pdf >>> >> >> >>> This mixer doesnt have isolated RF, LO and IF grounds so external >>> transformers would be rrequired. >>> It does have somewhat higher port to port isolation than most mixers. >>> >> >> >>> The minicircuits phase detectors such as: >>> >> >> >>> http://www.minicircuits.com/pdfs/RPD-1+.pdf >>> >> >> >>> http://www.minicircuits.com/pdfs/MPD-1+.pdf >>> >> >> >>> are worth considering, at least they have separate RF and IF grounds, a >>> high maximum output as well as low dc offset and offset drift. >>> >> >> >> >>> All of these are below $US25 (at the source). >>> >> >> >>> The phase detectors are perhaps the safest option however measurement of >>> their phase noise would be advisable. >>> >> >> >>> Bruce >>> >> >> >>> Arnold Tibus wrote: >>> >>>> On Mon, 20 Apr 2009 09:03:36 +1200, Bruce Griffiths wrote: >>>> >>>> >>>> >>>>> Corby Dawson wrote: >>>>> >>>>> >>>>>> Arnold, >>>>>> >>>>>> Look at the top of page 3 on the link below. Not sure how they arrived at >>>>>> their conclusion but there is one opinion on the HP mixers! >>>>>> >>>>>> http://www.unusualresearch.com/AppNotes/TimeNuts/OptDualMixer.pdf >>>>>> >>>>>> Corby Dawson >>>>>> ____________________________________________________________ >>>>>> Debt collectors calling your house? Click here to consolidate into one payment. >>>>>> http://thirdpartyoffers.juno.com/TGL2141/fc/BLSrjpTIk3l9oQnolYGEY40TVwmsBD4opDDeVSRG36KHWHhZWexSiuRrXdm/ >>>>>> >>>>>> _______________________________________________ >>>>>> time-nuts mailing list -- time-nuts at febo.com >>>>>> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >>>>>> and follow the instructions there. >>>>>> >>>>>> >>>>>> >>>>>> >>>>> Statements about the low flicker noise of these mixers are sprinkled >>>>> throughout the phase noise literature. >>>>> Someone must have measured the phase noise of these and other mixers at >>>>> some time. >>>>> >>>>> >>>> >>>> >>>>> Its relatively easy to measure mixer phase noise: >>>>> All one needs is a low noise preamp plus a sound card a 90 degree hybrid >>>>> (or a suitable length of coax and a splitter) and a low noise source. >>>>> >>>>> >>>> >>>> >>>>> However NIST papers often include a phase noise plot (attached) that >>>>> illustrates that high level mixers can have a significantly lower phase >>>>> noise than low level mixers (like the HP10514A). >>>>> When choosing a mixer for this for phase noise measurement applications >>>>> one may actually need to measure the phase noise characteristics of >>>>> candidate mixers. >>>>> >>>>> >>>> >>>> >>>>> Bruce >>>>> >>>>> >>>> Wow, a good overview, Bruce! >>>> >>>> But remain the questions: >>>> which are these high level mixers, are they readily available? >>>> Are they affordable? >>>> Perhaps not, why are they then not applied more often? >>>> >>>> Arnold >>>> From magnus at rubidium.dyndns.org Sun Apr 19 23:20:30 2009 From: magnus at rubidium.dyndns.org (Magnus Danielson) Date: Mon, 20 Apr 2009 01:20:30 +0200 Subject: [time-nuts] RF mixers for oscillator characterization, some questions In-Reply-To: <49EB9EFD.8050208@xtra.co.nz> References: <49EB9EFD.8050208@xtra.co.nz> Message-ID: <49EBB1BE.3080906@rubidium.dyndns.org> Bruce Griffiths skrev: > Arnold > > Arnold Tibus wrote: >> Bruce, >> >> a very good summary! >> I do not know where I can get the proposed MinCircuits DBM >> here, I looked to all the big and international well known >> supplier of electronics parts with negativ result. >> >> If I have to import them from USA they could end up even above >> 100 $ ea. we have in Europe to take the high shipment costs >> and the 19% VAT into account. >> >> Is it likely to get used mixers with damaged diodes? >> >> Did somebody alredy look inside the metal case of the 10514A? >> Will it perhaps possible to reconnect the common ground connections >> such a way that the mentioned loops can be opened? >> >> > Not without changing the IF port connector or at least insulating its > shell from ground. > It may be easier just to construct you own mixer if you cant easily > obtain the PCB mount Mincircuits mixers that have separate IF and RF > grounds. Bruce, many SMD mixers also have separate LO, IF and RF grounds. It is just not documented in the datasheets. The recommended footprint pattern (on say RMS-5+) actually ties them together. The MiniCircuit SMD mixers I have been able to investigated (some of them have open bottom, so looking in just takes a sharp eye) is not hooked up with a internally forced common ground. A simple DC resistance measurement would indicate if a particular model has their grounds connected together, but really, they should fix their datasheets. I guess it just haven't been important for them before. > Another alternative is to use a couple of RF transformers to isolate the > mixer common ground from the RF source grounds and just have the mixer > IF port grounded via its coax cable. > If necessary you can easily wind you own RF transformers if you can > obtain suitable ferrite cores. > I thought that there was a Minicircuits distributor in > Germany(http://www.municom.de/products/products960.php). > Ulrich may know more about this. Actually, MiniCircuits web indicates two. Cheers, Magnus From bruce.griffiths at xtra.co.nz Sun Apr 19 23:21:15 2009 From: bruce.griffiths at xtra.co.nz (Bruce Griffiths) Date: Mon, 20 Apr 2009 11:21:15 +1200 Subject: [time-nuts] RF mixers for oscillator characterization, some questions In-Reply-To: <49EBAE91.1090204@rubidium.dyndns.org> References: <49EBAE91.1090204@rubidium.dyndns.org> Message-ID: <49EBB1EB.9080005@xtra.co.nz> Hej Magnus Magnus Danielson wrote: > Hej Arnold, > > Arnold Tibus skrev: >> Bruce, >> a very good summary! >> I do not know where I can get the proposed MinCircuits DBM here, I >> looked to all the big and international well known supplier of >> electronics parts with negativ result. >> If I have to import them from USA they could end up even above 100 $ >> ea. we have in Europe to take the high shipment costs and the 19% VAT >> into account. > > It was not too hard to find their official list of representatives. > That is what I usually do besides the top catalog firms. > > Prices does not seem too bad... > http://www.minicircuits.com/cgi-bin/modelsearch?search_type=model&model=ZP-10514&tb_no= > > >> Is it likely to get used mixers with damaged diodes? >> >> Did somebody alredy look inside the metal case of the 10514A? > > You made me remember I needed too.... > >> Will it perhaps possible to reconnect the common ground connections >> such a way that the mentioned loops can be opened? > > Yes. The grounds is separated on the PCB, so it is only on the front > plate that they actually interconnect when the BNCs screw tight. > > What's inside then? > > Well, there is 4 small torroid cores (as compared to the 10534A which > has only two cores). It also has 4 diodes (marked as HP 82) and 2 50 > Ohm resistors. > > The L and R ports have an isolational transformer each, with the 50 > Ohm resistor loading on the secondary side. A inner transformer then > follows, with two secondaries, hooked up like expected for a double > balanced mixer. Essentially this is a double balanced mixer with > additional isolational transformers and 50 Ohms terminations. > Its a little strange to terminate a mixer RF or LO port with 50 ohms to ground as usually the IF port termination largely determines (together with diode on impedance) the input impedance seen at the RF and LO ports. Are you sure that the first transformer isnt a splitter with the 50 ohm termination being the internal splitter termination? > This does not match the datasheet from MiniCircuit for ZP-10514: > http://www.minicircuits.com/pdfs/ZP-10514.pdf > > Cheers, > Magnus > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > Bruce From bruce.griffiths at xtra.co.nz Sun Apr 19 23:31:31 2009 From: bruce.griffiths at xtra.co.nz (Bruce Griffiths) Date: Mon, 20 Apr 2009 11:31:31 +1200 Subject: [time-nuts] RF mixers for oscillator characterization, some questions In-Reply-To: <49EBB1BE.3080906@rubidium.dyndns.org> References: <49EB9EFD.8050208@xtra.co.nz> <49EBB1BE.3080906@rubidium.dyndns.org> Message-ID: <49EBB453.7070209@xtra.co.nz> Hej Magnus Magnus Danielson wrote: > Bruce Griffiths skrev: >> Arnold >> >> Arnold Tibus wrote: >>> Bruce, >>> a very good summary! >>> I do not know where I can get the proposed MinCircuits DBM here, I >>> looked to all the big and international well known supplier of >>> electronics parts with negativ result. >>> If I have to import them from USA they could end up even above 100 $ >>> ea. we have in Europe to take the high shipment costs and the 19% >>> VAT into account. >>> Is it likely to get used mixers with damaged diodes? >>> >>> Did somebody alredy look inside the metal case of the 10514A? >>> Will it perhaps possible to reconnect the common ground connections >>> such a way that the mentioned loops can be opened? >>> >>> >> Not without changing the IF port connector or at least insulating its >> shell from ground. >> It may be easier just to construct you own mixer if you cant easily >> obtain the PCB mount Mincircuits mixers that have separate IF and RF >> grounds. > > Bruce, many SMD mixers also have separate LO, IF and RF grounds. It is > just not documented in the datasheets. The recommended footprint > pattern (on say RMS-5+) actually ties them together. The MiniCircuit > SMD mixers I have been able to investigated (some of them have open > bottom, so looking in just takes a sharp eye) is not hooked up with a > internally forced common ground. A simple DC resistance measurement > would indicate if a particular model has their grounds connected > together, but really, they should fix their datasheets. I guess it > just haven't been important for them before. > Yes its likely that at least some SMT mixers have isolated grounds, however not all will. In particular all Minicircuits SMT phase detectors appear to have a common ground: The bottom view of the SYPD series phase detectors (attached) seems to indicate that all grounds are connected together internally (or at least externally on the package). >> Another alternative is to use a couple of RF transformers to isolate the >> mixer common ground from the RF source grounds and just have the mixer >> IF port grounded via its coax cable. >> If necessary you can easily wind you own RF transformers if you can >> obtain suitable ferrite cores. >> I thought that there was a Minicircuits distributor in >> Germany(http://www.municom.de/products/products960.php). >> Ulrich may know more about this. > > Actually, MiniCircuits web indicates two. > > Cheers, > Magnus > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > Bruce -------------- next part -------------- A non-text attachment was scrubbed... Name: SYPD.png Type: image/png Size: 49950 bytes Desc: not available URL: From magnus at rubidium.dyndns.org Sun Apr 19 23:54:18 2009 From: magnus at rubidium.dyndns.org (Magnus Danielson) Date: Mon, 20 Apr 2009 01:54:18 +0200 Subject: [time-nuts] RF mixers for oscillator characterization, some questions In-Reply-To: <49EBB453.7070209@xtra.co.nz> References: <49EB9EFD.8050208@xtra.co.nz> <49EBB1BE.3080906@rubidium.dyndns.org> <49EBB453.7070209@xtra.co.nz> Message-ID: <49EBB9AA.4010402@rubidium.dyndns.org> Hej Bruce, Bruce Griffiths skrev: > Hej Magnus > > Magnus Danielson wrote: >> Bruce Griffiths skrev: >>> Arnold >>> >>> Arnold Tibus wrote: >>>> Bruce, >>>> a very good summary! >>>> I do not know where I can get the proposed MinCircuits DBM here, I >>>> looked to all the big and international well known supplier of >>>> electronics parts with negativ result. >>>> If I have to import them from USA they could end up even above 100 $ >>>> ea. we have in Europe to take the high shipment costs and the 19% >>>> VAT into account. >>>> Is it likely to get used mixers with damaged diodes? >>>> >>>> Did somebody alredy look inside the metal case of the 10514A? >>>> Will it perhaps possible to reconnect the common ground connections >>>> such a way that the mentioned loops can be opened? >>>> >>>> >>> Not without changing the IF port connector or at least insulating its >>> shell from ground. >>> It may be easier just to construct you own mixer if you cant easily >>> obtain the PCB mount Mincircuits mixers that have separate IF and RF >>> grounds. >> Bruce, many SMD mixers also have separate LO, IF and RF grounds. It is >> just not documented in the datasheets. The recommended footprint >> pattern (on say RMS-5+) actually ties them together. The MiniCircuit >> SMD mixers I have been able to investigated (some of them have open >> bottom, so looking in just takes a sharp eye) is not hooked up with a >> internally forced common ground. A simple DC resistance measurement >> would indicate if a particular model has their grounds connected >> together, but really, they should fix their datasheets. I guess it >> just haven't been important for them before. >> > Yes its likely that at least some SMT mixers have isolated grounds, > however not all will. > > In particular all Minicircuits SMT phase detectors appear to have a > common ground: > The bottom view of the SYPD series phase detectors (attached) seems to > indicate that all grounds are connected together internally (or at least > externally on the package). Appears is the key word. I have a Minicircuits SMT mixer which does have separate ground in real life but this is not visible in either the datasheets internal schematic, pin list or layout. The SYPD could infact also have them. The SYPD-1 does not seem too unreasnoble to actually have separate grounds. If it has separate grounds, the pairs should be 1-6, 2-5 and 3-4. The lack of these details in the datasheets rules out being able to make conclusive decisions on this. Sample them and measure rules. The way these are manufactured, having to bond the grounds together within the encapsulation would be a nuance. Now, to make it clear, I do _NOT_ say that all of them has isolated grounds, but I say that some of them do have them, even if not explicitly documented in the datasheets. This also makes it hard to select amongst them to find those which do have isolated and those that don't. The plain and ugly truth is that we do not know, except that we may not be having the correct information. We just have to be careful not to draw conclusions from information which was not designed to convey this detail. Cheers, Magnus From magnus at rubidium.dyndns.org Mon Apr 20 00:11:53 2009 From: magnus at rubidium.dyndns.org (Magnus Danielson) Date: Mon, 20 Apr 2009 02:11:53 +0200 Subject: [time-nuts] RF mixers for oscillator characterization, some questions In-Reply-To: <49EBB1EB.9080005@xtra.co.nz> References: <49EBAE91.1090204@rubidium.dyndns.org> <49EBB1EB.9080005@xtra.co.nz> Message-ID: <49EBBDC9.5010400@rubidium.dyndns.org> Bruce Griffiths skrev: > Hej Magnus > > Magnus Danielson wrote: >> Hej Arnold, >> >> Arnold Tibus skrev: >>> Bruce, >>> a very good summary! >>> I do not know where I can get the proposed MinCircuits DBM here, I >>> looked to all the big and international well known supplier of >>> electronics parts with negativ result. >>> If I have to import them from USA they could end up even above 100 $ >>> ea. we have in Europe to take the high shipment costs and the 19% VAT >>> into account. >> It was not too hard to find their official list of representatives. >> That is what I usually do besides the top catalog firms. >> >> Prices does not seem too bad... >> http://www.minicircuits.com/cgi-bin/modelsearch?search_type=model&model=ZP-10514&tb_no= >> >> >>> Is it likely to get used mixers with damaged diodes? >>> >>> Did somebody alredy look inside the metal case of the 10514A? >> You made me remember I needed too.... >> >>> Will it perhaps possible to reconnect the common ground connections >>> such a way that the mentioned loops can be opened? >> Yes. The grounds is separated on the PCB, so it is only on the front >> plate that they actually interconnect when the BNCs screw tight. >> >> What's inside then? >> >> Well, there is 4 small torroid cores (as compared to the 10534A which >> has only two cores). It also has 4 diodes (marked as HP 82) and 2 50 >> Ohm resistors. >> >> The L and R ports have an isolational transformer each, with the 50 >> Ohm resistor loading on the secondary side. A inner transformer then >> follows, with two secondaries, hooked up like expected for a double >> balanced mixer. Essentially this is a double balanced mixer with >> additional isolational transformers and 50 Ohms terminations. >> > Its a little strange to terminate a mixer RF or LO port with 50 ohms to > ground as usually the IF port termination largely determines (together > with diode on impedance) the input impedance seen at the RF and LO ports. I was also reacting to this... > Are you sure that the first transformer isnt a splitter with the 50 ohm > termination being the internal splitter termination? Yes. But looking more closely on them, they look like RF chokes, such that common mode is suppressed. Having an RF choke there, loading it with a resistor seems reasonable, as it needs to be loaded even for lower frequencies to be useful. Cheers, Magnus From bruce.griffiths at xtra.co.nz Mon Apr 20 00:19:18 2009 From: bruce.griffiths at xtra.co.nz (Bruce Griffiths) Date: Mon, 20 Apr 2009 12:19:18 +1200 Subject: [time-nuts] RF mixers for oscillator characterization, some questions In-Reply-To: <49EBBDC9.5010400@rubidium.dyndns.org> References: <49EBAE91.1090204@rubidium.dyndns.org> <49EBB1EB.9080005@xtra.co.nz> <49EBBDC9.5010400@rubidium.dyndns.org> Message-ID: <49EBBF86.5060100@xtra.co.nz> Hej magnus Magnus Danielson wrote: > Bruce Griffiths skrev: >> Hej Magnus >> >> Magnus Danielson wrote: >>> Hej Arnold, >>> >>> Arnold Tibus skrev: >>>> Bruce, >>>> a very good summary! >>>> I do not know where I can get the proposed MinCircuits DBM here, I >>>> looked to all the big and international well known supplier of >>>> electronics parts with negativ result. >>>> If I have to import them from USA they could end up even above 100 $ >>>> ea. we have in Europe to take the high shipment costs and the 19% VAT >>>> into account. >>> It was not too hard to find their official list of representatives. >>> That is what I usually do besides the top catalog firms. >>> >>> Prices does not seem too bad... >>> http://www.minicircuits.com/cgi-bin/modelsearch?search_type=model&model=ZP-10514&tb_no= >>> >>> >>> >>>> Is it likely to get used mixers with damaged diodes? >>>> >>>> Did somebody alredy look inside the metal case of the 10514A? >>> You made me remember I needed too.... >>> >>>> Will it perhaps possible to reconnect the common ground connections >>>> such a way that the mentioned loops can be opened? >>> Yes. The grounds is separated on the PCB, so it is only on the front >>> plate that they actually interconnect when the BNCs screw tight. >>> >>> What's inside then? >>> >>> Well, there is 4 small torroid cores (as compared to the 10534A which >>> has only two cores). It also has 4 diodes (marked as HP 82) and 2 50 >>> Ohm resistors. >>> >>> The L and R ports have an isolational transformer each, with the 50 >>> Ohm resistor loading on the secondary side. A inner transformer then >>> follows, with two secondaries, hooked up like expected for a double >>> balanced mixer. Essentially this is a double balanced mixer with >>> additional isolational transformers and 50 Ohms terminations. >>> >> Its a little strange to terminate a mixer RF or LO port with 50 ohms to >> ground as usually the IF port termination largely determines (together >> with diode on impedance) the input impedance seen at the RF and LO >> ports. > > I was also reacting to this... > >> Are you sure that the first transformer isnt a splitter with the 50 ohm >> termination being the internal splitter termination? > > Yes. But looking more closely on them, they look like RF chokes, such > that common mode is suppressed. Having an RF choke there, loading it > with a resistor seems reasonable, as it needs to be loaded even for > lower frequencies to be useful. > > Cheers, > Magnus > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > Do you mean a common mode choke with a common mode termination or perhaps a Guanella balun? Bruce From magnus at rubidium.dyndns.org Mon Apr 20 00:30:42 2009 From: magnus at rubidium.dyndns.org (Magnus Danielson) Date: Mon, 20 Apr 2009 02:30:42 +0200 Subject: [time-nuts] RF mixers for oscillator characterization, some questions In-Reply-To: <49EBBF86.5060100@xtra.co.nz> References: <49EBAE91.1090204@rubidium.dyndns.org> <49EBB1EB.9080005@xtra.co.nz> <49EBBDC9.5010400@rubidium.dyndns.org> <49EBBF86.5060100@xtra.co.nz> Message-ID: <49EBC232.3020402@rubidium.dyndns.org> Hej Bruce, Bruce Griffiths skrev: > Hej magnus > >> Yes. But looking more closely on them, they look like RF chokes, such >> that common mode is suppressed. Having an RF choke there, loading it >> with a resistor seems reasonable, as it needs to be loaded even for >> lower frequencies to be useful. >> >> Cheers, >> Magnus >> >> _______________________________________________ >> time-nuts mailing list -- time-nuts at febo.com >> To unsubscribe, go to >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. >> > Do you mean a common mode choke with a common mode termination or > perhaps a Guanella balun? It's a common mode choke. I had to look very careful at the windings. What I think is resistors could also be inductors, but I kind of doubt it. Cheers, Magnus From bruce.griffiths at xtra.co.nz Mon Apr 20 00:53:53 2009 From: bruce.griffiths at xtra.co.nz (Bruce Griffiths) Date: Mon, 20 Apr 2009 12:53:53 +1200 Subject: [time-nuts] RF mixers for oscillator characterization, some questions In-Reply-To: <49EBC232.3020402@rubidium.dyndns.org> References: <49EBAE91.1090204@rubidium.dyndns.org> <49EBB1EB.9080005@xtra.co.nz> <49EBBDC9.5010400@rubidium.dyndns.org> <49EBBF86.5060100@xtra.co.nz> <49EBC232.3020402@rubidium.dyndns.org> Message-ID: <49EBC7A1.7070909@xtra.co.nz> Hej Magnus Magnus Danielson wrote: > Hej Bruce, > > Bruce Griffiths skrev: >> Hej magnus >> >>> Yes. But looking more closely on them, they look like RF chokes, such >>> that common mode is suppressed. Having an RF choke there, loading it >>> with a resistor seems reasonable, as it needs to be loaded even for >>> lower frequencies to be useful. >>> >>> Cheers, >>> Magnus >>> >>> _______________________________________________ >>> time-nuts mailing list -- time-nuts at febo.com >>> To unsubscribe, go to >>> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >>> and follow the instructions there. >>> >> Do you mean a common mode choke with a common mode termination or >> perhaps a Guanella balun? > > It's a common mode choke. I had to look very careful at the windings. > > What I think is resistors could also be inductors, but I kind of doubt > it. > > Cheers, > Magnus > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > Can you post an image so we can all have a guess? Bruce From magnus at rubidium.dyndns.org Mon Apr 20 01:15:23 2009 From: magnus at rubidium.dyndns.org (Magnus Danielson) Date: Mon, 20 Apr 2009 03:15:23 +0200 Subject: [time-nuts] RF mixers for oscillator characterization, some questions In-Reply-To: <49EBC7A1.7070909@xtra.co.nz> References: <49EBAE91.1090204@rubidium.dyndns.org> <49EBB1EB.9080005@xtra.co.nz> <49EBBDC9.5010400@rubidium.dyndns.org> <49EBBF86.5060100@xtra.co.nz> <49EBC232.3020402@rubidium.dyndns.org> <49EBC7A1.7070909@xtra.co.nz> Message-ID: <49EBCCAB.8000807@rubidium.dyndns.org> Bruce Griffiths skrev: > Hej Magnus > > Magnus Danielson wrote: >> Hej Bruce, >> >> Bruce Griffiths skrev: >>> Hej magnus >>> >>>> Yes. But looking more closely on them, they look like RF chokes, such >>>> that common mode is suppressed. Having an RF choke there, loading it >>>> with a resistor seems reasonable, as it needs to be loaded even for >>>> lower frequencies to be useful. >>>> >>>> Cheers, >>>> Magnus >>>> >>>> _______________________________________________ >>>> time-nuts mailing list -- time-nuts at febo.com >>>> To unsubscribe, go to >>>> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >>>> and follow the instructions there. >>>> >>> Do you mean a common mode choke with a common mode termination or >>> perhaps a Guanella balun? >> It's a common mode choke. I had to look very careful at the windings. >> >> What I think is resistors could also be inductors, but I kind of doubt >> it. >> >> Cheers, >> Magnus >> >> _______________________________________________ >> time-nuts mailing list -- time-nuts at febo.com >> To unsubscribe, go to >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. >> > > Can you post an image so we can all have a guess? It's not that easy to get everything into one picture, sveral is needed, besides the fact that the PCB is double-sided. The cores is fairly smal and the rubber fittings that holds them makes it harder to take a good photo. It takes time to make quality photos that is useful for the purpose. I'll see what I can do, but I think I would prioritze other things. Cheers, Magnus From magnus at rubidium.dyndns.org Mon Apr 20 01:58:38 2009 From: magnus at rubidium.dyndns.org (Magnus Danielson) Date: Mon, 20 Apr 2009 03:58:38 +0200 Subject: [time-nuts] Spring cleaning and antenna placement In-Reply-To: <49E57132.3000601@rubidium.dyndns.org> References: , <49E39489.8020503@rubidium.dyndns.org> <49E44FF3.17229.15E49D@chris.cheney.tesco.net> <55666.87.227.52.225.1239744266.squirrel@webmail.lysator.liu.se> <49E57132.3000601@rubidium.dyndns.org> Message-ID: <49EBD6CE.2030600@rubidium.dyndns.org> Magnus Danielson skrev: > bg at lysator.liu.se skrev: >>> If you are in Scandinavia, the GPS birds will not spend much time (if >>> any?) to the north of you. Slide 12 of >>> http://web.ics.purdue.edu/~ecalais/teaching/geodesy/Satellite_orbits.pdf >>> suggests that the most northerly orbital point is at the latitude of >>> Denmark. >> With a decent antenna siting you see plenty of SVs to the north. Magnus >> problem is that there are lots of rather close by trees and stuff. These >> trees are also much taller than the antenna position. > > Indeed. The southbound sats goes almost over the head, but I also get > long tracking periods for sats way up to the north. > > Since the house sits partly in a valey and the neighborhood is rich of > trees there is plenty of foilage. To the north is a building, two > stories high and ground level for it is just above the upper of mine, > which pick up the extreme north direction. > > The location also requires an antenna mast forr the TV reception. With > modern digital transmission it is best to have a good margin for > reception, or there is no TV at all. > > If I had a flat roof I might just put a ladder up to the antenna, but > unfortunately not so. > > Sky-view of GPS antennas was not of concern when picking this house. > Maybe it should be for the next. To follow up on this... I have now received my LNAs and I have installed one. The LNA gives me a 16 dB boost, but lack of a bias tee force me to use a passive splitter to act as the bias tee, and that sets me back 6 dB, so I effectively only gets 10 dB of boost, but the effect is certainly there, the Z-12 tracks significantly better. Just goes to show that LNA may come to assistance. Thought this may be useful to some. A second LNA could boost me up even more, but using a proper bias tee should give me about 6 dB. Cheers, Magnus From brooke at pacific.net Mon Apr 20 02:10:57 2009 From: brooke at pacific.net (Brooke Clarke) Date: Sun, 19 Apr 2009 19:10:57 -0700 Subject: [time-nuts] Spring cleaning and antenna placement In-Reply-To: <49EBD6CE.2030600@rubidium.dyndns.org> References: , <49E39489.8020503@rubidium.dyndns.org> <49E44FF3.17229.15E49D@chris.cheney.tesco.net> <55666.87.227.52.225.1239744266.squirrel@webmail.lysator.liu.se> <49E57132.3000601@rubidium.dyndns.org> <49EBD6CE.2030600@rubidium.dyndns.org> Message-ID: <49EBD9B1.1060605@pacific.net> Hi Magnus: The improvement is probably due to a noise figure reduction from use of the LNA if it's near the antenna rather than at the receiver end of the cable run. Have Fun, Brooke Clarke http://www.prc68.com Magnus Danielson wrote: > Magnus Danielson skrev: >> bg at lysator.liu.se skrev: >>>> If you are in Scandinavia, the GPS birds will not spend much time (if >>>> any?) to the north of you. Slide 12 of >>>> http://web.ics.purdue.edu/~ecalais/teaching/geodesy/Satellite_orbits.pdf >>>> >>>> suggests that the most northerly orbital point is at the latitude of >>>> Denmark. >>> With a decent antenna siting you see plenty of SVs to the north. Magnus >>> problem is that there are lots of rather close by trees and stuff. These >>> trees are also much taller than the antenna position. >> >> Indeed. The southbound sats goes almost over the head, but I also get >> long tracking periods for sats way up to the north. >> >> Since the house sits partly in a valey and the neighborhood is rich of >> trees there is plenty of foilage. To the north is a building, two >> stories high and ground level for it is just above the upper of mine, >> which pick up the extreme north direction. >> >> The location also requires an antenna mast forr the TV reception. With >> modern digital transmission it is best to have a good margin for >> reception, or there is no TV at all. >> >> If I had a flat roof I might just put a ladder up to the antenna, but >> unfortunately not so. >> >> Sky-view of GPS antennas was not of concern when picking this house. >> Maybe it should be for the next. > > To follow up on this... I have now received my LNAs and I have installed > one. The LNA gives me a 16 dB boost, but lack of a bias tee force me to > use a passive splitter to act as the bias tee, and that sets me back 6 > dB, so I effectively only gets 10 dB of boost, but the effect is > certainly there, the Z-12 tracks significantly better. > > Just goes to show that LNA may come to assistance. Thought this may be > useful to some. A second LNA could boost me up even more, but using a > proper bias tee should give me about 6 dB. > > Cheers, > Magnus > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > From df6jb at ulrich-bangert.de Mon Apr 20 07:21:02 2009 From: df6jb at ulrich-bangert.de (Ulrich Bangert) Date: Mon, 20 Apr 2009 09:21:02 +0200 Subject: [time-nuts] RF Mixers for oscillator comparison In-Reply-To: Message-ID: <6518875C64B4405BBDDA20CD106CFAD1@athlon> Arnold, as Bruce did already mention Minicircuits names MUNICOM as one of their German distributors. The second source is Industrial Electronics Gmbh where I buy Minicircuit parts from, just because they are located in the northern part of Germany as me. They can supply a lot of parts right out of their own stock and need only few parts to order themselves from the US. They deliver also in small quantities like 1-5 but be prepared to pay a higher price per part in small quantities. Minicircuits have a BROAD range of mixers. Among other they built the RAY-3, a 23 dBm high level mixer, that I have seen used in oscillator characterization publications. My understanding about the benefits of high level mixers for that purpose is that it allows you to work with higher RF levels which in turn leads to a higher IF level which in turn may lead to a better overall s/n of the system. On the other hand Minicircuits now supplies a class of "high output level" mixers that may perhaps serve the same purpose. Best regards Ulrich Bangert > -----Ursprungliche Nachricht----- > Von: time-nuts-bounces at febo.com > [mailto:time-nuts-bounces at febo.com] Im Auftrag von Arnold Tibus > Gesendet: Montag, 20. April 2009 00:05 > An: Discussion of precise time and frequency measurement > Betreff: Re: [time-nuts] RF Mixers for oscillator comparison > > > On Mon, 20 Apr 2009 09:03:36 +1200, Bruce Griffiths wrote: > > >Corby Dawson wrote: > >> Arnold, > >> > >> Look at the top of page 3 on the link below. Not sure how they > >> arrived at their conclusion but there is one opinion on the HP > >> mixers! > >> > >> http://www.unusualresearch.com/AppNotes/TimeNuts/OptDualMixer.pdf > >> > >> Corby Dawson > >> ____________________________________________________________ > >> Debt collectors calling your house? Click here to > consolidate into > >> one payment. > >> > http://thirdpartyoffers.juno.com/TGL2141/fc/BLSrjpTIk3l9oQnolYGEY40TV > >> wmsBD4opDDeVSRG36KHWHhZWexSiuRrXdm/ > >> > >> _______________________________________________ > >> time-nuts mailing list -- time-nuts at febo.com > >> To unsubscribe, go to > >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > >> and follow the instructions there. > >> > >> > >Statements about the low flicker noise of these mixers are sprinkled > >throughout the phase noise literature. Someone must have > measured the > >phase noise of these and other mixers at some time. > > >Its relatively easy to measure mixer phase noise: > >All one needs is a low noise preamp plus a sound card a 90 degree > >hybrid (or a suitable length of coax and a splitter) and a low noise > >source. > > >However NIST papers often include a phase noise plot (attached) that > >illustrates that high level mixers can have a significantly > lower phase > >noise than low level mixers (like the HP10514A). When > choosing a mixer > >for this for phase noise measurement applications one may > actually need > >to measure the phase noise characteristics of candidate mixers. > > >Bruce > > > Wow, a good overview, Bruce! > > But remain the questions: > which are these high level mixers, are they readily available? > Are they affordable? > Perhaps not, why are they then not applied more often? > > Arnold > > > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. From GandalfG8 at aol.com Mon Apr 20 07:49:22 2009 From: GandalfG8 at aol.com (GandalfG8 at aol.com) Date: Mon, 20 Apr 2009 03:49:22 EDT Subject: [time-nuts] RF Mixers for oscillator comparison Message-ID: In a message dated 20/04/2009 08:22:05 GMT Daylight Time, df6jb at ulrich-bangert.de writes: Minicircuits have a BROAD range of mixers. Among other they built the RAY-3, a 23 dBm high level mixer, that I have seen used in oscillator characterization publications. My understanding about the benefits of high level mixers for that purpose is that it allows you to work with higher RF levels which in turn leads to a higher IF level which in turn may lead to a better overall s/n of the system. --------------- An Ebay seller is offering some Stellex high level mixers, Item # 260382178618. I don't know if these would be of any interest in this application but perhaps worth taking a look. I bought a couple a while ago to try out in a radio front end but haven't had time to play with them yet. There's also a couple of links there to WJ and Minicircuits app notes on mixer usage and measurements. regards Nigel GM8PZR From bruce.griffiths at xtra.co.nz Mon Apr 20 10:15:18 2009 From: bruce.griffiths at xtra.co.nz (Bruce Griffiths) Date: Mon, 20 Apr 2009 22:15:18 +1200 Subject: [time-nuts] RF Mixers for oscillator comparison In-Reply-To: References: Message-ID: <49EC4B36.30507@xtra.co.nz> GandalfG8 at aol.com wrote: > > In a message dated 20/04/2009 08:22:05 GMT Daylight Time, > df6jb at ulrich-bangert.de writes: > > Minicircuits have a BROAD range of mixers. Among other they built the > RAY-3, > a 23 dBm high level mixer, that I have seen used in oscillator > characterization publications. My understanding about the benefits of high > level mixers for that purpose is that it allows you to work with higher RF > levels which in turn leads to a higher IF level which in turn may lead to a > better overall s/n of the system. > > > > --------------- > An Ebay seller is offering some Stellex high level mixers, Item # > 260382178618. > I don't know if these would be of any interest in this application but > perhaps worth taking a look. > I bought a couple a while ago to try out in a radio front end but haven't > had time to play with them yet. > There's also a couple of links there to WJ and Minicircuits app notes on > mixer usage and measurements. > > regards > > Nigel > GM8PZR > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > Nigel Those Stellex mixers definitely do have common RF, IF and LO grounds. Either external RF transformers for the RF and LO ports would be required to break low frequency ground loops or a low noise differential input amplifier at the IF port (after the low pass filter) could be useful in minimising mains related spurs. The low phase noise isolation amplifier with +27dBm output required to drive the LO ports would be interesting to design. Bruce From Arnold.Tibus at gmx.de Mon Apr 20 15:14:19 2009 From: Arnold.Tibus at gmx.de (Arnold Tibus) Date: Mon, 20 Apr 2009 17:14:19 +0200 Subject: [time-nuts] RF mixers for oscillator characterization, some questions In-Reply-To: <49EBAE91.1090204@rubidium.dyndns.org> Message-ID: Hej Magnus, On Mon, 20 Apr 2009 01:06:57 +0200, Magnus Danielson wrote: >> >> Did somebody alredy look inside the metal case of the 10514A? >You made me remember I needed too.... >> Will it perhaps possible to reconnect the common ground connections >> such a way that the mentioned loops can be opened? >Yes. The grounds is separated on the PCB, so it is only on the front >plate that they actually interconnect when the BNCs screw tight. >What's inside then? >Well, there is 4 small torroid cores (as compared to the 10534A which >has only two cores). It also has 4 diodes (marked as HP 82) and 2 50 Ohm >resistors. >The L and R ports have an isolational transformer each, with the 50 Ohm >resistor loading on the secondary side. A inner transformer then >follows, with two secondaries, hooked up like expected for a double >balanced mixer. Essentially this is a double balanced mixer with >additional isolational transformers and 50 Ohms terminations. >This does not match the datasheet from MiniCircuit for ZP-10514: >http://www.minicircuits.com/pdfs/ZP-10514.pdf >Cheers, >Magnus thanks to your response the informations went deeper into very informative details, so I know what to do. I will take one of these relay metal cans and have a critical inside look... For the moment I am fully satisfied, thank you to everybody, Arnold From Arnold.Tibus at gmx.de Mon Apr 20 15:31:39 2009 From: Arnold.Tibus at gmx.de (Arnold Tibus) Date: Mon, 20 Apr 2009 17:31:39 +0200 Subject: [time-nuts] RF Mixers for oscillator comparison In-Reply-To: <6518875C64B4405BBDDA20CD106CFAD1@athlon> Message-ID: Ulrich, On Mon, 20 Apr 2009 09:21:02 +0200, Ulrich Bangert wrote: >Arnold, >as Bruce did already mention Minicircuits names MUNICOM as one of their >German distributors. The second source is Industrial Electronics Gmbh where >I buy Minicircuit parts from, just because they are located in the northern >part of Germany as me. They can supply a lot of parts right out of their own >stock and need only few parts to order themselves from the US. They deliver >also in small quantities like 1-5 but be prepared to pay a higher price per >part in small quantities. >Minicircuits have a BROAD range of mixers. Among other they built the RAY-3, >a 23 dBm high level mixer, that I have seen used in oscillator >characterization publications. My understanding about the benefits of high >level mixers for that purpose is that it allows you to work with higher RF >levels which in turn leads to a higher IF level which in turn may lead to a >better overall s/n of the system. >On the other hand Minicircuits now supplies a class of "high output level" >mixers that may perhaps serve the same purpose. >Best regards >Ulrich Bangert I see that Minicircuits is a good second source with a wide range of interesting parts. I have to dig now what useful parts I already have for this purpose. Sure, more questions will come up, so I will then be back and ask again... As always, thank you! Arnold From n0tvj at atmc.net Mon Apr 20 15:39:04 2009 From: n0tvj at atmc.net (Al N0tvj) Date: Mon, 20 Apr 2009 11:39:04 -0400 Subject: [time-nuts] Question on aEfratom 10 Mhz Osc Message-ID: <39DF77E88E21462AB7BC050A8C661B81@N0TVJ> Hi Does anyone have the specification or pin out on a Efratom PN 105243-003 10 MHz Crystal Oscillator. It was part of a Lucent RFG-XO. Any help would be appreciated greatly. Thank you Al White N0TVJ From KE9H at austin.rr.com Mon Apr 20 16:56:26 2009 From: KE9H at austin.rr.com (Graham / KE9H) Date: Mon, 20 Apr 2009 11:56:26 -0500 Subject: [time-nuts] Question on an Efratom 10 Mhz Osc In-Reply-To: <39DF77E88E21462AB7BC050A8C661B81@N0TVJ> References: <39DF77E88E21462AB7BC050A8C661B81@N0TVJ> Message-ID: <49ECA93A.7020406@austin.rr.com> Al: I have some information gleaned from eBay sales about this part, I can not vouch for the accuracy. The part is available on eBay, under either the Datum or Efratom brand, with suffixes -001, -002, or -003. From RDR Electronics on eBay: "The oven status pin goes low when the oven is warm (probably open collector). Don't know what the total range of the EFC is, but it seems to sit around 4.5 volts. We measured the EFC sensitivity at 5.75x10e-7/volt (5.75Hz/volt)." ".jpg" of pinout attached. Don't know if this reflector strips off attachments, so I will also copy you directly. --- Graham / KE9H == Al N0tvj wrote: > Hi > > Does anyone have the specification or pin out on a > > Efratom PN 105243-003 10 MHz Crystal Oscillator. > > It was part of a Lucent RFG-XO. > > Any help would be appreciated greatly. > > Thank you > > Al White N0TVJ > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > > -------------- next part -------------- A non-text attachment was scrubbed... Name: 10mhz1 (Small).jpg Type: image/jpeg Size: 53369 bytes Desc: not available URL: -------------- next part -------------- A non-text attachment was scrubbed... Name: 10mhz5 (Small).jpg Type: image/jpeg Size: 30955 bytes Desc: not available URL: From stanley_reynolds at yahoo.com Mon Apr 20 17:26:40 2009 From: stanley_reynolds at yahoo.com (Stanley Reynolds) Date: Mon, 20 Apr 2009 10:26:40 -0700 (PDT) Subject: [time-nuts] Question on aEfratom 10 Mhz Osc In-Reply-To: <39DF77E88E21462AB7BC050A8C661B81@N0TVJ> References: <39DF77E88E21462AB7BC050A8C661B81@N0TVJ> Message-ID: <390907.79871.qm@web30307.mail.mud.yahoo.com> Some info here: http://www.n4iqt.com/rfgmxo/ Stanley ----- Original Message ---- From: Al N0tvj To: time-nuts at febo.com Sent: Monday, April 20, 2009 10:39:04 AM Subject: [time-nuts] Question on aEfratom 10 Mhz Osc Hi Does anyone have the specification or pin out on a Efratom PN 105243-003? 10 MHz Crystal Oscillator. It was part of a Lucent RFG-XO. Any help would be appreciated greatly. Thank you Al White N0TVJ _______________________________________________ time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. From magnus at rubidium.dyndns.org Mon Apr 20 17:35:15 2009 From: magnus at rubidium.dyndns.org (Magnus Danielson) Date: Mon, 20 Apr 2009 19:35:15 +0200 Subject: [time-nuts] Spring cleaning and antenna placement In-Reply-To: <49EBD9B1.1060605@pacific.net> References: , <49E39489.8020503@rubidium.dyndns.org> <49E44FF3.17229.15E49D@chris.cheney.tesco.net> <55666.87.227.52.225.1239744266.squirrel@webmail.lysator.liu.se> <49E57132.3000601@rubidium.dyndns.org> <49EBD6CE.2030600@rubidium.dyndns.org> <49EBD9B1.1060605@pacific.net> Message-ID: <49ECB253.3010909@rubidium.dyndns.org> Brooke Clarke skrev: > Hi Magnus: > > The improvement is probably due to a noise figure reduction from use of > the LNA if it's near the antenna rather than at the receiver end of the > cable run. A number of assumptions is wrong there... I have an active antenna (Novatel GPS 502), followed by about 30 m of RG-58 which initially went straight into the Z12 using only a BNC to N adapter. The LNA is inserted along with a passive splitter (with DC through from one of the ports) at the receiver end of the 30 m RG-58. The non-optimum setup makes the passive splitter enter before the LNA, but the passive splitter is just a poor bias tee. So I am pretty sure that the improved S/N is mainly from gain and secondary from improved noise figure. I don't know the noise figure of the Z-12 antenna input. If I had a passive antenna this type of arrangement would be even worse, but luckily I didn't start out there... Cheers, Magnus From bg at lysator.liu.se Mon Apr 20 20:11:11 2009 From: bg at lysator.liu.se (bg at lysator.liu.se) Date: Mon, 20 Apr 2009 22:11:11 +0200 (CEST) Subject: [time-nuts] Spring cleaning and antenna placement In-Reply-To: <49ECB253.3010909@rubidium.dyndns.org> References: , <49E39489.8020503@rubidium.dyndns.org> <49E44FF3.17229.15E49D@chris.cheney.tesco.net> <55666.87.227.52.225.1239744266.squirrel@webmail.lysator.liu.se> <49E57132.3000601@rubidium.dyndns.org> <49EBD6CE.2030600@rubidium.dyndns.org> <49EBD9B1.1060605@pacific.net> <49ECB253.3010909@rubidium.dyndns.org> Message-ID: <56175.87.227.52.225.1240258271.squirrel@webmail.lysator.liu.se> > Brooke Clarke skrev: >> Hi Magnus: >> >> The improvement is probably due to a noise figure reduction from use of >> the LNA if it's near the antenna rather than at the receiver end of the >> cable run. > > > So I am pretty sure that the improved S/N is mainly from gain and > secondary from improved noise figure. I don't know the noise figure of > the Z-12 antenna input. I agree. You are most probably bitten by the finite range of the AGC on the recevier antenna port. On the roof subject... Have taken the week off from work to do some roof maintainance. Must get the time to make some extra cable holes in the roof. ;-) And make some improvements on the GPS antenna mountings. -- Bj?rn From magnus at rubidium.dyndns.org Mon Apr 20 22:17:56 2009 From: magnus at rubidium.dyndns.org (Magnus Danielson) Date: Tue, 21 Apr 2009 00:17:56 +0200 Subject: [time-nuts] Spring cleaning and antenna placement In-Reply-To: <56175.87.227.52.225.1240258271.squirrel@webmail.lysator.liu.se> References: , <49E39489.8020503@rubidium.dyndns.org> <49E44FF3.17229.15E49D@chris.cheney.tesco.net> <55666.87.227.52.225.1239744266.squirrel@webmail.lysator.liu.se> <49E57132.3000601@rubidium.dyndns.org> <49EBD6CE.2030600@rubidium.dyndns.org> <49EBD9B1.1060605@pacific.net> <49ECB253.3010909@rubidium.dyndns.org> <56175.87.227.52.225.1240258271.squirrel@webmail.lysator.liu.se> Message-ID: <49ECF494.8060802@rubidium.dyndns.org> bg at lysator.liu.se skrev: >> Brooke Clarke skrev: >>> Hi Magnus: >>> >>> The improvement is probably due to a noise figure reduction from use of >>> the LNA if it's near the antenna rather than at the receiver end of the >>> cable run. >> >> So I am pretty sure that the improved S/N is mainly from gain and >> secondary from improved noise figure. I don't know the noise figure of >> the Z-12 antenna input. > > I agree. You are most probably bitten by the finite range of the AGC on > the recevier antenna port. Probably. I should investigate just how the actual gain structure looks both externally and in the various receivers. Adding another LNA improved the state further. I think severe close-in multipath is my main problem right now, not the gain. > On the roof subject... Have taken the week off from work to do some roof > maintainance. Must get the time to make some extra cable holes in the > roof. ;-) And make some improvements on the GPS antenna mountings. Hmm... maybe I should just hire you... I'll think I can offer beer, food, bed and interesting conversations over various gear as part of the compensation package. :) Cheers, Magnus From peterl at standingwave.org Tue Apr 21 01:42:34 2009 From: peterl at standingwave.org (Peter Loron) Date: Mon, 20 Apr 2009 18:42:34 -0700 Subject: [time-nuts] FS: Agilent 53131A counter w 3GHz option Message-ID: I have a like-new Agilent 53131A 10-digit counter for sale with the following options: - 010: High stability oven - 030: Adds 3rd input for up to 3GHz It is in excellent shape and is still in calibration which was last performed in August 2008. If interested, I can send pictures, etc. Thanks! -Pete From jra at febo.com Tue Apr 21 13:19:30 2009 From: jra at febo.com (John Ackermann N8UR) Date: Tue, 21 Apr 2009 09:19:30 -0400 Subject: [time-nuts] Announcement: TAPR TADD-2 PPS Divider Board Now Available Message-ID: <49EDC7E2.3040008@febo.com> The TADD-2 divider is now available for purchase from TAPR. The TADD-2 accepts a 5 or 10 MHz input signal and generates 1 PPS outputs (as well as other pulse rates). It has six low-impedance output channels, each of which can be individually configured, and has a sync circuit that allows the output pulse train to be synchronized to an external source such as a GPS. Preliminary tests show a temperature sensitivity of about 50 ps/degree C, and an RMS jitter level of <20 picoseconds. The divider is based on a Microchip PIC device, and the code was written by Tom Van Baak and Richard McCorkle. The source code is being released as Open Source Software. The TADD-2 is sold as a kit. It uses through-hole components so doesn't require any special tools for assembly. The TADD-2 is the same form factor as the other TADD boards, and fits in the same enclosure (also available from TAPR). The price is $69, or $62 for TAPR members. Shipment should start in the next two weeks. More information about the TADD-2 is available at http://www.tapr.org/kits_tadd-2.html . The assembly/instruction manual (which is still very preliminary and incomplete) is at http://www.tapr.org/~n8ur/TADD-2_Manual.pdf . In an earlier posting, I mentioned that I was also working on a miniaturized, "dongle" version of the TADD-2. That work continues, and we hope to make the TADD-2 Mini available sometime this summer. I'll post an update when the details firm up. John From magnus at rubidium.dyndns.org Tue Apr 21 19:35:41 2009 From: magnus at rubidium.dyndns.org (Magnus Danielson) Date: Tue, 21 Apr 2009 21:35:41 +0200 Subject: [time-nuts] Announcement: TAPR TADD-2 PPS Divider Board Now Available In-Reply-To: <49EDC7E2.3040008@febo.com> References: <49EDC7E2.3040008@febo.com> Message-ID: <49EE200D.2040801@rubidium.dyndns.org> John, John Ackermann N8UR skrev: > The TADD-2 divider is now available for purchase from TAPR. > > The TADD-2 accepts a 5 or 10 MHz input signal and generates 1 PPS > outputs (as well as other pulse rates). It has six low-impedance output > channels, each of which can be individually configured, and has a sync > circuit that allows the output pulse train to be synchronized to an > external source such as a GPS. > > Preliminary tests show a temperature sensitivity of about 50 ps/degree > C, and an RMS jitter level of <20 picoseconds. > > The divider is based on a Microchip PIC device, and the code was written > by Tom Van Baak and Richard McCorkle. The source code is being released > as Open Source Software. > > The TADD-2 is sold as a kit. It uses through-hole components so doesn't > require any special tools for assembly. The TADD-2 is the same form > factor as the other TADD boards, and fits in the same enclosure (also > available from TAPR). > > The price is $69, or $62 for TAPR members. Shipment should start in the > next two weeks. > > More information about the TADD-2 is available at > http://www.tapr.org/kits_tadd-2.html . The assembly/instruction manual > (which is still very preliminary and incomplete) is at > http://www.tapr.org/~n8ur/TADD-2_Manual.pdf . > > In an earlier posting, I mentioned that I was also working on a > miniaturized, "dongle" version of the TADD-2. That work continues, and > we hope to make the TADD-2 Mini available sometime this summer. I'll > post an update when the details firm up. Looks very interesting. Good work. I especially like the fact that it supports both 5 and 10 MHz in the form of a jumper and also that it has multiple frequency outputs but re-jumpable to get multiple PPS outputs for instance. Should be usefull for many things and cases. Cheers, Magnus From brooke at pacific.net Tue Apr 21 21:06:48 2009 From: brooke at pacific.net (Brooke Clarke) Date: Tue, 21 Apr 2009 14:06:48 -0700 Subject: [time-nuts] DSP WWVB Receiver Idea Message-ID: <49EE3568.3000907@pacific.net> Hi: On the PICLIST there has been a discussion about the CMAX WWVB front ends and noise. Olin mentioned that you could use a dsPIC to look at the I and Q signals resulting from mixing the WWVB signal with a carrier at 60 kHz. His example case was to use a cheap crystal (+ or - 3 Hz) and so use a 10 Hz low pass filter on the I and Q signals prior to squaring and adding them. But wouldn't it be better to use a LO with say 1,000 times better stability (still very reasonable priced) and some other DSP method of recovering the phase and amplitude of the WWVB signal. (Olin was only looking at the AM signal). I don't know DSP methods so am asking is there a way to demodulate the signal with a very narrow effective bandwidth so that the s/n is good 24/7 even on the left and right coasts? -- Have Fun, Brooke Clarke http://www.prc68.com From phk at phk.freebsd.dk Tue Apr 21 21:21:19 2009 From: phk at phk.freebsd.dk (Poul-Henning Kamp) Date: Tue, 21 Apr 2009 21:21:19 +0000 Subject: [time-nuts] DSP WWVB Receiver Idea In-Reply-To: Your message of "Tue, 21 Apr 2009 14:06:48 MST." <49EE3568.3000907@pacific.net> Message-ID: <56813.1240348879@critter.freebsd.dk> In message <49EE3568.3000907 at pacific.net>, Brooke Clarke writes: >On the PICLIST there has been a discussion about the CMAX WWVB front ends and >noise. Olin mentioned that you could use a dsPIC to look at the I and Q >signals resulting from mixing the WWVB signal with a carrier at 60 kHz. His >example case was to use a cheap crystal (+ or - 3 Hz) and so use a 10 Hz low >pass filter on the I and Q signals prior to squaring and adding them. Don't bother with I & Q, put an ADC directly on your antenna and do it in software. See http://phk.freebsd.dk/AducLoran for inspiration. -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 phk at FreeBSD.ORG | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. From weijiazhen at sina.com Wed Apr 22 06:15:24 2009 From: weijiazhen at sina.com (weijiazhen at sina.com) Date: Wed, 22 Apr 2009 14:15:24 +0800 Subject: [time-nuts] ultra stability ocxo Message-ID: <20090422061524.55104AA66F6@mail3-127.sinamail.sina.com.cn> My company is in China, which has a huge market for Time & Frequency products, especially for ultra stability ocxo. We are looking forward to working toghther with you and selling your products in China as an agency .waiting your reply weijiazhen From time-nuts at kasperkp.dk Wed Apr 22 06:25:05 2009 From: time-nuts at kasperkp.dk (Kasper Pedersen) Date: Wed, 22 Apr 2009 08:25:05 +0200 Subject: [time-nuts] DSP WWVB Receiver Idea In-Reply-To: <49EE3568.3000907@pacific.net> References: <49EE3568.3000907@pacific.net> Message-ID: <49EEB841.3060406@kasperkp.dk> Brooke Clarke wrote: > On the PICLIST there has been a discussion about the CMAX WWVB front > ends and noise. Olin mentioned that you could use a dsPIC to look at > the I and Q signals resulting from mixing the WWVB signal with a > carrier at 60 kHz. His example case was to use a cheap crystal (+ or > - 3 Hz) and so use a 10 Hz low pass filter on the I and Q signals > prior to squaring and adding them. I've built such a thing ( http://n1.taur.dk/dcf/ ). The zero-if I/Q approach has a few things that make it less ideal than it sounds. There's the 1/f noise, discovering and compensating for DC offset on each of the channels requires that you remove the input, and it might not be a nice divider from 10MHz. If you choose a small arbitrary offset you can solve these problems in software, only the filters in hardware need to be wider. Having the first filters wide, I found, was a good thing: In the very early morning I get a lot of sferics, and my steep filter rang like a bell with every crackle. A low-Q front end allowed throwing those samples away. Since that was done I have added a narrow bandwidth phase integrator (2mHz) in software, and it will happily pull out ~10ns rms phase with a +60dB carrier 1Hz from center. It even stayed locked when the antenna amplifier broke and output 5Vp-p instead. The real advantage of the I/Q method is that the bandpass filter becomes two lowpass, and two lowpass is easier than a similar width bandpass with enough precision and phase stability to be centered around 60kHz (and if you use crystal resonators in the front end you can't track anything else, and you get a problem with suppressing sferics). You might not be able to get continuous reception no matter how hard you try; I've seen inversions where the carrier just slowly fades and comes back inverted with no apparent phase jumps (it looks like extremely slow bpsk). If I did it today I'd try phk's approach first. Preferably with a somewhat tuned antenna to keep harmonics from PAL horizontal retrace from clipping the converter. The one above was built with what was available in the junkbox at the time. /Kasper Pedersen From rvassar at rob-vassar.com Wed Apr 22 19:55:38 2009 From: rvassar at rob-vassar.com (Robert Vassar) Date: Wed, 22 Apr 2009 14:55:38 -0500 Subject: [time-nuts] [Fwd: Re: Code Review for NTP upgrade requested.] References: <49EF7396.5010001@sun.com> Message-ID: <03E7A38B-7CC0-47B7-9F42-601831D700E1@rob-vassar.com> In case anyone here is interested in the OpenSolaris project. Brian sent this to me a few minutes ago, and I am forwarding with his permission. Rob KC6OOM/5 Begin forwarded message: > > From: Brian Utterback > Date: April 22, 2009 2:29:22 PM CDT > To: Robert Vassar > Subject: Re: Code Review for NTP upgrade requested. > > > Sure. Great. > > Robert Vassar wrote: >> Brian Utterback wrote: >>> I am very pleased to announce that I have just posted the webrev for >>> the upgrade of NTP version in Solaris to cr.opensolaris.org. >>> >>> As members of this mailing list know, I'm upgrading >>> NTP from the currently included version 3 to version 4, specifically >>> version 4.2.5p161. There are two steps to this, since the packages >>> currently reside in the ON consolidation, and afterwards they will >>> reside in the SFW consolidation. >>> >>> I currently have the SFW webrevs available. I will have the ON >>> webrevs >>> soon. Please help to code review the modifications. >>> >>> The webrev is at: >>> >>> http://cr.opensolaris.org/~blu/ntpv4/sfwnv-webrev/ >>> >>> All comments will be gratefully appreciated. >> May I forward this to the time-nuts? >> Rob > > -- > blu > > "Mark my words, nanotechnology is going to be huge!" > ---------------------------------------------------------------------- > Brian Utterback - Solaris RPE, Sun Microsystems, Inc. > Ph:877-259-7345, Em:brian.utterback-at-ess-you-enn-dot-kom > > From chris at chriscaudle.org Thu Apr 23 04:19:39 2009 From: chris at chriscaudle.org (Chris Caudle) Date: Wed, 22 Apr 2009 23:19:39 -0500 (CDT) Subject: [time-nuts] time-nuts Digest, Vol 57, Issue 41 In-Reply-To: References: Message-ID: <48470.70.250.173.139.1240460379.squirrel@email.powweb.com> I'm a little late following up on this, but hopefully not too out of context. On Wed, April 8, 2009 10:23 pm, Chris Mack wrote: > The box / design of interest has ADCs, DACs, and a 38.88MHz OCXO of > marginal performance coupled with the proposed DSP based PLLs > generating a local clock for the ADCs and DACs all on the same > circuit board in synch with external gear. This sounds like a very complicated way to avoid having to make a PLL. Why don't you just use a good quality VCXO in a PLL to sync to the house clock, and a really low loop frequency, assuming your VCXO phase noise specs are better than the house clock phase noise at the PLL corner frequency? > This 38.88MHz is a DSP clock, essentially a microprocessor clock > (albeit a very nice microprocessor clock) where the DSP simulates a > PLL operating on an incoming clock source, and makes an output clock > of a different frequency, but synchronized to be within AES standards Yeah, but the out clock is an integer multiple of the in clock, so you don't really need to jump through synthesizer hoops when a simple divider in a PLL will do. I looked at something similar to see if you could save cost by avoiding the need to have different VCXO's for 44.1k based and 48k based material, and it is difficult to find off the shelf devices that have suitably low phase noise and no spurs in the phase noise. I think in the end it probably ends up being simpler to get the performance you are looking for by just buying a good VCXO, or two if you need to handle 44.1k and 48k based material. > The incoming clock source (master house clock) to this box / design > of interest is in another rack mount box external to this design on Have you considered making your box the clock master? It is easier to make a low jitter clock which is not pullable, so making everything else sync to the converter is one way to just avoid a big range of clock cleaning work. > Sounds like maybe some LCs to filter out the additional harmonics and > maybe attempt to get close into the carrier eh? If you are trying to clean up close in phase noise by using LC filters, that seems like the wrong way to get there. Why are you even using an ovenized oscillator to begin with if you have to synchronize to another clock? It's not like you care about aging if you are locking to house sync, your output frequency is just going to be a multiple of what comes in. A good quality VCXO should be a lot cheaper than the $250 you quoted for the ovenized units you were looking at. > The 12kHz is a figure for the DSP PLL and how they measure it Because that device is optimized for high bit rate data transfer applications, where you usually have a high corner frequency on the clock recovery PLL so that you track source drift and get rid of jitter caused by ISI. Basically the opposite of what you want for audio applications. This is a baseband sampling application, so phase noise on the sampling clock is converted to sidebands on the output of the D/A converter, or encoded as sidebands in the digital output of the A/D converter. Because of masking in the auditory system, the sensitivity to sidebands becomes lower the closer to the fundamental the sidebands are spaced, so you want very low phase noise from a few hundred Hz up to 30kHz or so, below a few hundred Hz you care less and less, and above 30kHz you care less until it causes aliasing in your ADC, but fortunately the phase noise typically decreases at farther offsets from carrier, so that problem sort of solves itself. > sheet with all the other datapoints comes out to 1.3ps (1Hz to > 20MHz) of jitter RMS. Look at 300Hz to 30kHz, that is what you care about. The 300Hz figure is arguable, some say as high as 500Hz, some as low as 100Hz. You can aim for low phase noise down to 50 Hz if you want to really knock yourself out. The current state of the art seems to be the Grimm Audio equipment, which has a phase noise spec of about -125dBc at 100Hz, and an integrated noise floor of 2ps above 10Hz. Not super low compared to some communications equipment, and that gear is getting raves for audio quality. When in slave mode the corner frequency on the PLL is really low, I think around 0.1Hz. The claim is that incoming jitter is attenuated 90dB at 10Hz offset, and 60dB/decade above that. The design still pullable +/-50ppm when in slave mode (meets class 2 requirements for AES11). Can you get much lower phase noise than that and still pull across a 100ppm range? Phase noise and pull range are inversely related, but I haven't worked out what the theoretical limits should be for that pull range (I think you should be able to calculate a limit based on the Q required to give that much pull range). > I still want to filter such as to distribute a sine... I didn't understand this. Usually you want a very fast edge rate so that the clock input is not affected by noise. There are times that you want to keep a sine moving around because you don't want to introduce a lot of power supply noise from logic output stages switching, but using a logic output and then filtering it doesn't help there. I assume when you say distribute you mean inside the box, right? So at some point you are going to have to square up the signal again when you get to the converter chips, which expect a logic clock, not a sine wave. What is the point of distributing as a sine instead of just a square wave? -- Chris Caudle From chris at chriscaudle.org Thu Apr 23 16:25:22 2009 From: chris at chriscaudle.org (Chris Caudle) Date: Thu, 23 Apr 2009 11:25:22 -0500 (CDT) Subject: [time-nuts] femtosecond jitter anyone? In-Reply-To: References: Message-ID: <46448.15.203.233.77.1240503922.squirrel@email.powweb.com> Just for the sake of indexing the archives, I'm sending this message to point out the correct subject line of my immediately previous message (Thu Apr 23 04:19:39 UTC 2009). I always hate it when mail has the digest header instead of the real subject, then I went and did it myself. -- Chris Caudle From sometimesyoufeellikeanut at twentylogten.com Thu Apr 23 17:14:18 2009 From: sometimesyoufeellikeanut at twentylogten.com (Chris Mack) Date: Thu, 23 Apr 2009 13:14:18 -0400 Subject: [time-nuts] femtosecond jitter anyone? In-Reply-To: <48470.70.250.173.139.1240460379.squirrel@email.powweb.com> References: <48470.70.250.173.139.1240460379.squirrel@email.powweb.com> Message-ID: Hey Chris, Thanks for the response... notes below On Apr 23, 2009, at 12:19 AM, Chris Caudle wrote: > I'm a little late following up on this, but hopefully not too out of > context. > > On Wed, April 8, 2009 10:23 pm, Chris Mack wrote: >> The box / design of interest has ADCs, DACs, and a 38.88MHz OCXO of >> marginal performance coupled with the proposed DSP based PLLs >> generating a local clock for the ADCs and DACs all on the same >> circuit board in synch with external gear. > > This sounds like a very complicated way to avoid having to make a PLL. > Why don't you just use a good quality VCXO in a PLL to sync to the > house > clock, and a really low loop frequency, assuming your VCXO phase noise > specs are better than the house clock phase noise at the PLL corner > frequency? > The Silicon Labs DSPLL(TM) chip is a 3 port device... Ovenized xtal on the reference clock port (also clocks the DSP internally), input clock (house word clock or rubidium) port, and output clocked port (cleaned version of input clock). The xtal reference port needs a low jitter clock as it will transfer its jitter to the output clock in a 1:1 ratio.... The frequency is not as critical (long term) e.g., aging. If the input clock is a 10MHz rubidium that has some short term issues with close-in phase noise, the DSPLL will clean it as best it can compared to jitter on the ovenized reference port.... Yes, the DSPLL is a little bit of a different animal from conventional VCXO PLLs perhaps? The DSPLL is a commercially available chip from Silicon Labs (drop it on the PCB, terminate differential or single ended I/O, decouple / filter power, and program over SPI), similar to National Semiconductor analogue PLL chips (LMK04000 family) except that this Silicon Labs chip uses a DSP (and a virtualized digitally controlled oscillator implemented in the DSP in a standard virtual PLL loop) internal to its inner workings. I can also get every frequency I desire out of this Silicon Labs part no matter what I put into it for frequency to synch to (house word clock in the kHz range or rubidium at 10MHz), and the National Semiconductor could not get some frequencies with discrete and standard frequency valued VCXOs (according to their simulator, perhaps their numerator / divisor registers do not have enough resolution and would be sometimes out of range)... And some frequency outputs of the National part had some phase noise issues as I recall. I had trouble finding a proper VCXO for the National part for the frequencies of interest and it was in the $50 range where the Silicon Labs chip is in the $30 range with no need for a VCXO (albeit an ovenized oscillator, but as shown below the ovenized will provide a rock solid internal reference when not synchronized to an external clock)... The Silicon Labs also provides great jitter specs for the SONET crowd in the femtosecond region (caveat BW of measurement)... With these DSP based PLLs and clock distribution I am probably going to be somewhere just below 1ps of jitter.... >> This 38.88MHz is a DSP clock, essentially a microprocessor clock >> (albeit a very nice microprocessor clock) where the DSP simulates a >> PLL operating on an incoming clock source, and makes an output clock >> of a different frequency, but synchronized to be within AES standards > > Yeah, but the out clock is an integer multiple of the in clock, so you > don't really need to jump through synthesizer hoops when a simple > divider > in a PLL will do. > Indeed, however, it is a full fractional type DSP PLL and is approximately 0.000 ppm for the desired output frequencies compared to input frequencies in the frequency plan (as I recall... I haven't run the Silicon Labs simulator for the DSP PLL in a couple of months)... The DSP PLL also has dividers on the clock outputs for integer related clocks (e.g., 11 / 22 MHz and 12 / 24MHz used for the oversampled 44.1kHz and 48kHz that add some jitter I think... not too bad though as I recall).... > I looked at something similar to see if you could save cost by > avoiding > the need to have different VCXO's for 44.1k based and 48k based > material, > and it is difficult to find off the shelf devices that have suitably > low > phase noise and no spurs in the phase noise. I think in the end it > probably ends up being simpler to get the performance you are > looking for > by just buying a good VCXO, or two if you need to handle 44.1k and 48k > based material. > I now have the design down to 2 PLLs from 3 PLLs and am now distributing the 256 and 128 x oversampled clock frequencies of 11.2896 MHz and 12,288 MHz after the disclosure of some low jitter ECL distribution chips by Bruce (thanks Bruce)... I still have one performance issue to *maybe* figure out and that is the rise time from the DSP PLL chips is slow; maybe 1.2 to 1.4 V/ns (74AC is faster I think?)... Even though they are ECL, LVPECL, LVDS etc. based clock outputs, they could use some sharpening themselves to take advantage of the input to output jitter rise time requirements for the LVPECL clock distribution chips... The jitter with the slow rise time input is still somewhat acceptable and the jitter budget probably is fine enough to not need the extra sharpening... maybe... I dunno if I want to get into it and possibly run the risk of having to respin the design if I can't get the sharpening circuit to work and run the risk of not being able to get bang for the buck to test as much as possible on the first spin... I did find a paper using step recovery diodes to sharpen edges (coupled with some filtering) which seems to be in alignment with the limiting and filtering approach mentioned by Bruce... I wonder if there are additional ICs or methods to get sharper edges these days... >> The incoming clock source (master house clock) to this box / design >> of interest is in another rack mount box external to this design on > > Have you considered making your box the clock master? It is easier to > make a low jitter clock which is not pullable, so making everything > else > sync to the converter is one way to just avoid a big range of clock > cleaning work. > This is a good idea... I have thought about copying and distributing the 38.88MHz external to the box as a master clock for other DSPLL based boxes, but unfortunately all the other equipment is made by other manufacturers that adhere to the house word clock being the sample rate (e.g., 44.1kHz, 48kHz, 96kHz, up to 192kHz) all on 75 ohm BNC and with jitter in the ps range (they all do their own cleaning and PLL reclocking up to 12 / 24MHz or 11 / 22MHz depending on the internal oversampling frequencies desired by their converters or DSPs).... Any equipment I make in the future can use the 38.88MHz, so that I don't need an OCXO in each box I make, but the other stuff is not available to this without external clock making and cleaning to get it to the 44.1kHz or equivalent... hence probably this in the rest of the world with standard mfg practices for house word clock only: >> Sounds like maybe some LCs to filter out the additional harmonics and >> maybe attempt to get close into the carrier eh? > > If you are trying to clean up close in phase noise by using LC > filters, > that seems like the wrong way to get there. > > Why are you even using an ovenized oscillator to begin with if you > have to > synchronize to another clock? It's not like you care about aging if > you > are locking to house sync, your output frequency is just going to be a > multiple of what comes in. A good quality VCXO should be a lot > cheaper > than the $250 you quoted for the ovenized units you were looking at. > The ovenized can also be the internal clock if there are no external clocks to synch to in a standalone application or if this box is the master. It would still provide sub ps jitter for the internal converters with the required bit accuracy in the jitter department as part of this experiment. The reference port on the DSPLL can also be used as the system clock for internal or master clocking mode... >> The 12kHz is a figure for the DSP PLL and how they measure it > > Because that device is optimized for high bit rate data transfer > applications, where you usually have a high corner frequency on the > clock > recovery PLL so that you track source drift and get rid of jitter > caused > by ISI. Basically the opposite of what you want for audio > applications. > This is a baseband sampling application, so phase noise on the > sampling > clock is converted to sidebands on the output of the D/A converter, or > encoded as sidebands in the digital output of the A/D converter. > Because > of masking in the auditory system, the sensitivity to sidebands > becomes > lower the closer to the fundamental the sidebands are spaced, so you > want > very low phase noise from a few hundred Hz up to 30kHz or so, below > a few > hundred Hz you care less and less, and above 30kHz you care less > until it > causes aliasing in your ADC, but fortunately the phase noise typically > decreases at farther offsets from carrier, so that problem sort of > solves > itself. > Ah.. I've been wondering about this... I have only had brief exposure to the data transfer application of SONET in the 1990s during college as an intern.... The good news is that the jitter transfer on the Silicon Labs DSPLL decreases from the 1:1 the closer into the carrier below 12 kHz.... This information is somewhere around page 140 if I recall in the family reference doc for the part, rather than the data sheet proper. >> sheet with all the other datapoints comes out to 1.3ps (1Hz to >> 20MHz) of jitter RMS. > > Look at 300Hz to 30kHz, that is what you care about. The 300Hz > figure is > arguable, some say as high as 500Hz, some as low as 100Hz. You can > aim > for low phase noise down to 50 Hz if you want to really knock yourself > out. The current state of the art seems to be the Grimm Audio > equipment, > which has a phase noise spec of about -125dBc at 100Hz, and an > integrated > noise floor of 2ps above 10Hz. Not super low compared to some > communications equipment, and that gear is getting raves for audio > quality. > When in slave mode the corner frequency on the PLL is really low, I > think > around 0.1Hz. The claim is that incoming jitter is attenuated 90dB at > 10Hz offset, and 60dB/decade above that. > The design still pullable +/-50ppm when in slave mode (meets class 2 > requirements for AES11). Can you get much lower phase noise than > that and > still pull across a 100ppm range? Phase noise and pull range are > inversely related, but I haven't worked out what the theoretical > limits > should be for that pull range (I think you should be able to > calculate a > limit based on the Q required to give that much pull range). > hmmm... this is a good question... the DSPLL has a frequency offset alarm that could trigger the host micro to perhaps try a re-lock; perhaps OK for varispeed, and individual session flexibility, but probably not good for drift during a session (although I don't think drift in a session would be too bad unless massive temperature changes on cheap gear / clocks)... I don't know if the alarm is useful for these purposes or if it is intended for SONET stuff and margins only... I haven't got this far yet in the design... I am ultimately looking to use a rubidium for the real long term system reference and generate house word clocks (or AES) output from the box to drive other gear, so hopefully this wont be an issue... Of course, the DSPLL filter BW can be changed by some SPI commands, but there is an ICAL that probably needs to be done which can take up to 1.2 seconds to complete (data sheet specified max).... >> I still want to filter such as to distribute a sine... > > I didn't understand this. Usually you want a very fast edge rate so > that > the clock input is not affected by noise. There are times that you > want > to keep a sine moving around because you don't want to introduce a > lot of > power supply noise from logic output stages switching, but using a > logic > output and then filtering it doesn't help there. I assume when you > say > distribute you mean inside the box, right? So at some point you are > going > to have to square up the signal again when you get to the converter > chips, > which expect a logic clock, not a sine wave. What is the point of > distributing as a sine instead of just a square wave? > Yah, I was originally going with a $33/each 2 layer PCB and didn't want the sharp edges running everywhere long distance for turning the box into a radio station. I have bit the bullet and am now looking at a 4 layer board... the question is to embed or not to embed the clock into the PCB, with sharp edges for EMI purposes; then we get into blind and buried vias perhaps... on the cost front: yikes.... And I wonder the signal integrity issues... luckily I just upgraded to Altium from Protel for my PCB design CAD system with the newer functionality for signal integrity analysis... It's been 10 years since I have used SpecctraQuest and I wonder what the new Altium signal integrity looks like... The DSPLL chips can take a sine on any of the input ports and square it up for you internally.... However, it would be ideal to pass some fast and sharp edges, say above 2 or 3 V/ns perhaps to keep distribution jitter low on LVPECL buffers / splitters.... Thanks for the sounding wall opportunity... Cheers, -chris From max at maxsmusicplace.com Thu Apr 23 21:01:08 2009 From: max at maxsmusicplace.com (Max Robinson) Date: Thu, 23 Apr 2009 16:01:08 -0500 Subject: [time-nuts] DSP WWVB Receiver Idea References: <49EE3568.3000907@pacific.net> <49EEB841.3060406@kasperkp.dk> Message-ID: This message sent me on a Google search to find what I had missed about WWVB. The terms I and Q signals sends me into phase modulation space. The only reference I found on this is a 45 degree phase shift at 10 minutes after the hour and a return 5 minutes later. Is there something else going on with the phase of the WWVB carrier that I haven't heard about? Regards. Max. K 4 O D S. Email: max at maxsmusicplace.com Transistor site http://www.funwithtransistors.net Vacuum tube site: http://www.funwithtubes.net Music site: http://www.maxsmusicplace.com To subscribe to the fun with tubes group send an email to, funwithtubes-subscribe at yahoogroups.com ----- Original Message ----- From: "Kasper Pedersen" To: "Discussion of precise time and frequency measurement" Sent: Wednesday, April 22, 2009 1:25 AM Subject: Re: [time-nuts] DSP WWVB Receiver Idea > Brooke Clarke wrote: >> On the PICLIST there has been a discussion about the CMAX WWVB front ends >> and noise. Olin mentioned that you could use a dsPIC to look at the I >> and Q signals resulting from mixing the WWVB signal with a carrier at 60 >> kHz. His example case was to use a cheap crystal (+ or - 3 Hz) and so >> use a 10 Hz low pass filter on the I and Q signals prior to squaring and >> adding them. > > I've built such a thing ( http://n1.taur.dk/dcf/ ). The zero-if I/Q > approach has a few things that make it less ideal than it sounds. There's > the 1/f noise, discovering and compensating for DC offset on each of the > channels requires that you remove the input, and it might not be a nice > divider from 10MHz. > If you choose a small arbitrary offset you can solve these problems in > software, only the filters in hardware need to be wider. Having the first > filters wide, I found, was a good thing: In the very early morning I get a > lot of sferics, and my steep filter rang like a bell with every crackle. A > low-Q front end allowed throwing those samples away. > > Since that was done I have added a narrow bandwidth phase integrator > (2mHz) in software, and it will happily pull out ~10ns rms phase with a > +60dB carrier 1Hz from center. It even stayed locked when the antenna > amplifier broke and output 5Vp-p instead. > > The real advantage of the I/Q method is that the bandpass filter becomes > two lowpass, and two lowpass is easier than a similar width bandpass with > enough precision and phase stability to be centered around 60kHz (and if > you use crystal resonators in the front end you can't track anything else, > and you get a problem with suppressing sferics). > > You might not be able to get continuous reception no matter how hard you > try; I've seen inversions where the carrier just slowly fades and comes > back inverted with no apparent phase jumps (it looks like extremely slow > bpsk). > > If I did it today I'd try phk's approach first. Preferably with a somewhat > tuned antenna to keep harmonics from PAL horizontal retrace from clipping > the converter. The one above was built with what was available in the > junkbox at the time. > > /Kasper Pedersen > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > From brooke at pacific.net Thu Apr 23 23:40:04 2009 From: brooke at pacific.net (Brooke Clarke) Date: Thu, 23 Apr 2009 16:40:04 -0700 Subject: [time-nuts] DSP WWVB Receiver Idea In-Reply-To: References: <49EE3568.3000907@pacific.net> <49EEB841.3060406@kasperkp.dk> Message-ID: <49F0FC54.2050204@pacific.net> Hi Max: That's what I was talking about. The HP 117 is really a frequency comparator and it displays that phase shift. The magnitude of the shift is a sanity check on the plot scale factor. http://www.prc68.com/I/117A.shtml Have Fun, Brooke Clarke http://www.prc68.com Max Robinson wrote: > This message sent me on a Google search to find what I had missed about > WWVB. The terms I and Q signals sends me into phase modulation space. > The only reference I found on this is a 45 degree phase shift at 10 > minutes after the hour and a return 5 minutes later. Is there something > else going on with the phase of the WWVB carrier that I haven't heard > about? > > Regards. > > Max. K 4 O D S. > > Email: max at maxsmusicplace.com > > Transistor site http://www.funwithtransistors.net > Vacuum tube site: http://www.funwithtubes.net > Music site: http://www.maxsmusicplace.com > > To subscribe to the fun with tubes group send an email to, > funwithtubes-subscribe at yahoogroups.com > > ----- Original Message ----- From: "Kasper Pedersen" > > To: "Discussion of precise time and frequency measurement" > > Sent: Wednesday, April 22, 2009 1:25 AM > Subject: Re: [time-nuts] DSP WWVB Receiver Idea > > >> Brooke Clarke wrote: >>> On the PICLIST there has been a discussion about the CMAX WWVB front >>> ends and noise. Olin mentioned that you could use a dsPIC to look at >>> the I and Q signals resulting from mixing the WWVB signal with a >>> carrier at 60 kHz. His example case was to use a cheap crystal (+ or >>> - 3 Hz) and so use a 10 Hz low pass filter on the I and Q signals >>> prior to squaring and adding them. >> >> I've built such a thing ( http://n1.taur.dk/dcf/ ). The zero-if I/Q >> approach has a few things that make it less ideal than it sounds. >> There's the 1/f noise, discovering and compensating for DC offset on >> each of the channels requires that you remove the input, and it might >> not be a nice divider from 10MHz. >> If you choose a small arbitrary offset you can solve these problems in >> software, only the filters in hardware need to be wider. Having the >> first filters wide, I found, was a good thing: In the very early >> morning I get a lot of sferics, and my steep filter rang like a bell >> with every crackle. A low-Q front end allowed throwing those samples >> away. >> >> Since that was done I have added a narrow bandwidth phase integrator >> (2mHz) in software, and it will happily pull out ~10ns rms phase with >> a +60dB carrier 1Hz from center. It even stayed locked when the >> antenna amplifier broke and output 5Vp-p instead. >> >> The real advantage of the I/Q method is that the bandpass filter >> becomes two lowpass, and two lowpass is easier than a similar width >> bandpass with enough precision and phase stability to be centered >> around 60kHz (and if you use crystal resonators in the front end you >> can't track anything else, and you get a problem with suppressing >> sferics). >> >> You might not be able to get continuous reception no matter how hard >> you try; I've seen inversions where the carrier just slowly fades and >> comes back inverted with no apparent phase jumps (it looks like >> extremely slow bpsk). >> >> If I did it today I'd try phk's approach first. Preferably with a >> somewhat tuned antenna to keep harmonics from PAL horizontal retrace >> from clipping the converter. The one above was built with what was >> available in the junkbox at the time. >> >> /Kasper Pedersen >> >> _______________________________________________ >> time-nuts mailing list -- time-nuts at febo.com >> To unsubscribe, go to >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. >> >> > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > From xde-l2g3 at myamail.com Fri Apr 24 00:09:23 2009 From: xde-l2g3 at myamail.com (Mike Monett) Date: Thu, 23 Apr 2009 21:09:23 -0300 Subject: [time-nuts] Geocities Shutting Down Message-ID: To all, As you know by now, Yahoo is shutting down Geocities. If anyone has some important web pages to move, may I suggest http://www.000webhost.com/ It is free, fast, and very reliable. You can sign on and start uploading to your new web site in a few minutes. The FTP logon and uploads are quick, with no blocked file extensions, and they give extremely generous web space. Unless you are Dieter, you will probably never approach the bandwidth limits. Unlike many sites that place a obnoxious blinking banner ad at the top of your web page, they place a tiny static ad at the bottom of the page that says "Site Powered by 000webhost.com". Few people will even notice it. You can upgrade to a paid subscription anytime you like. I have searched the web for places to put my stuff, and these people are by far the best I've found. Give them a try and let us know if you like them. Mike From mikes at flatsurface.com Fri Apr 24 01:47:44 2009 From: mikes at flatsurface.com (Mike S) Date: Thu, 23 Apr 2009 21:47:44 -0400 Subject: [time-nuts] Geocities Shutting Down In-Reply-To: References: Message-ID: <20090424014745.955391165C1@hamburg.alientech.net> At 08:09 PM 4/23/2009, Mike Monett wrote... >As you know by now, Yahoo is shutting down Geocities. If anyone has >some >important web pages to move, may I suggest... SPAM. From max at maxsmusicplace.com Fri Apr 24 02:37:33 2009 From: max at maxsmusicplace.com (Max Robinson) Date: Thu, 23 Apr 2009 21:37:33 -0500 Subject: [time-nuts] Geocities Shutting Down References: Message-ID: Does this include Angelfire? I think they are a subsidiary of Geocities. Regards. Max. K 4 O D S. Email: max at maxsmusicplace.com Transistor site http://www.funwithtransistors.net Vacuum tube site: http://www.funwithtubes.net Music site: http://www.maxsmusicplace.com To subscribe to the fun with tubes group send an email to, funwithtubes-subscribe at yahoogroups.com ----- Original Message ----- From: "Mike Monett" To: Sent: Thursday, April 23, 2009 7:09 PM Subject: [time-nuts] Geocities Shutting Down > To all, > > As you know by now, Yahoo is shutting down Geocities. If anyone has some > important web pages to move, may I suggest http://www.000webhost.com/ > > It is free, fast, and very reliable. You can sign on and start uploading > to > your new web site in a few minutes. > > The FTP logon and uploads are quick, with no blocked file extensions, and > they give extremely generous web space. Unless you are Dieter, you will > probably never approach the bandwidth limits. > > Unlike many sites that place a obnoxious blinking banner ad at the top of > your web page, they place a tiny static ad at the bottom of the page that > says "Site Powered by 000webhost.com". Few people will even notice it. You > can upgrade to a paid subscription anytime you like. > > I have searched the web for places to put my stuff, and these people are > by > far the best I've found. Give them a try and let us know if you like them. > > Mike > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > From chris at chriscaudle.org Fri Apr 24 03:29:31 2009 From: chris at chriscaudle.org (Chris Caudle) Date: Thu, 23 Apr 2009 22:29:31 -0500 (CDT) Subject: [time-nuts] femtosecond jitter anyone? In-Reply-To: References: Message-ID: <33002.70.250.173.139.1240543771.squirrel@email.powweb.com> By the way, I'm a little new to the list, someone give me and Chris M. a nudge if this gets a little too audio-specialized and you want us to take this off list. > The Silicon Labs DSPLL(TM) chip is a 3 port device... I'm pretty familiar with the SiLabs devices, those are the ones I investigated before giving up as not suitable for audio. Your mileage may vary. I may have to re-evaluate my opinion as well, I noticed a few things I had missed before after you mentioned them. > The frequency is not as critical (long term) e.g., aging. Which is why I wondered why all the drama with the expensive oven units. Why not just put a $10 TCXO on there and spend the savings elsewhere? > Yes, the DSPLL is a little bit of a different animal from conventional > VCXO PLLs perhaps? Yes and no. The principles are the same, but you get different artifacts because you are effectively moving to a sampled domain for clock control. Spurs in the phase noise, for example. > I can also get every frequency I desire out of this Silicon Labs part Yes, but the performance is not identical for every input/output frequency relationship. SiLabs have done some really clever things to minimize those kinds of problems, but look very closely at the phase noise plots, you'll see some significant spurs, and the 1/f corner frequency is too high for my liking. > Labs chip is in the $30 range with no need for a VCXO (albeit an > ovenized oscillator Why the big hang up on ovenized? AES11 recommends 1ppm for multi-studio synchronization systems, and just 10ppm for single studio systems. You could do a couple ppm with TCXO, especially if you don't plan on taking your equipment outdoors, i.e. it will stay in a narrow temperature range. > The Silicon Labs also provides great jitter specs for the SONET crowd > in the femtosecond region (caveat BW of measurement)... Are you talking about the Si5319, or something in that range? Look at the phase noise specs. At 100Hz offset just -65dBc/Hz. Not too expensive quartz oscillators can do -125dBc/Hz, good ones can do -135dBc or -145dBc at 100Hz offset from carrier. The Si5319 doesn't really hit its stride until 100kHz offset from carrier, which is way outside what you care about for audio sampling. [Came back to edit this: just noticed that those phase noise numbers were with a 622MHz output, so you can't compare apples to apples by looking at a dBc/Hz number for a 12MHz clock; I wish they would just use absolute numbers, s/Hz values; If that phase noise plot scales, it would be about -95dBc/Hz for 12MHz, which is not bad, but still not as good as you could get with a clean fundamental crystal). The Si5300 seems to have a phase noise floor that increases at around 60dB/decade from 1000Hz down. That makes me a little nervous for audio use because it is starting to increase rapidly while still in the frequency range that can cause audible sidebands. Also, the datasheet just shows telecom frequencies, I would want to measure and verify the performance with the intended input/output frequencies, and also verify that no spurs popped up if the input clock was a little off nominal, e.g. use a VCXO as an input, and sweep it through its adjustment range while monitoring the output of the synthesizer phase noise. Do you have an eval board and a way to measure phase noise? I could probably hook you up with an eval board if you need it, but I don't have anything that can measure phase noise down to those levels at the moment. > With these DSP based PLLs and clock distribution I am probably going > to be somewhere just below 1ps of jitter.... Single numbers like that are not as useful as phase noise plots. Look at the AES preprints from Chris Travis and Bruno Putzeys, they have a lot more to say on the subject than is appropriate for this email. Preprint 6122 by Putzeys is especially good, as is 6293 by Chris Travis. > This is a good idea... I have thought about copying and distributing > the 38.88MHz external to the box as a master clock for other DSPLL > based boxes, I meant either generate 44.1kHz word clock directly, or send the clock to an AES3 transmitter with data line muted AES11 style, or send the 11.2896MHz clock out like Digidesign does for their so-called "SuperClock" inputs. 38.88MHz is pretty unusual, only your custom equipment would be able to use it. If this is a two channel mastering studio, how many analog conversions are you going to have? If you do all the processing digital, only the A/D and D/A need the clean clocks, everything else just needs to be able to recover the data with no errors. If you are doing lots of conversions because you still have a lot of analog processing then I could see why you might need several devices with the supremo PLL's inside. > internal oversampling frequencies desired by their converters or > DSPs) Only conversion between domains matters (analog to digital, or digital to analog). Anything which is digital in to DSP to digital out can have a pretty nasty clock and still work fine. They are just synchronous digital designs, so clock jitter has no effect on operation. > of the world with standard mfg practices for house word clock only: > The ovenized can also be the internal clock if there are no external > clocks to synch to in a standalone application Yeah, but a TCXO would be almost as good, and about 1/10th the cost. I still have to ask, why is it so important to have an oven? Ovens buy you long term stability, and better absolute accuracy, neither of which is terribly important in this application. >> This is a baseband sampling application, so phase noise on the >> sampling clock is converted to sidebands on the output > Ah.. I've been wondering about this... Then definitely go get those preprints. Required reading before you fire up the schematic editor again. > I am ultimately looking to use a rubidium for the real long > term system reference and generate house word clocks Why? What would be the benefit to having the absolute accuracy that you get from rubidium? The outputs of a rubidium oscillator are a quartz based circuit, so the short term performance (i.e. jitter or phase noise) is going to be driven by the quality of the quartz circuitry, so the only thing rubidium buys is low long term drift. That has its place and uses, but I'm not sure audio synchronization is one of them. Knock yourself out if you just want it, I like things with ium in the name as much as anyone, but I don't see the functional benefit. > Yah, I was originally going with a $33/each 2 layer PCB So you were going to buy a $250 ovenized oscillator instead of a TCXO, and then scrimp on the PCB? I hope I don't offend your sensibilities, but I would make this box completely differently than the approach you are taking. Implementation is 80% when you are trying to keep noise levels this low, and you can completely screw up a great device with a bad PCB layout, bad power layout design, noisy power supply, etc. > into the PCB, with sharp edges for EMI purposes; then we get into > blind and buried vias perhaps... Buried vias for EMI? Won't make a noticeable difference. For practical purposes vias don't radiate. The loop area through a via is so small compared to your loop area along the rest of the route that vias will be the least of your worries. By the way, what converters were you planning? Those numbers you quoted earlier sound a lot like the new ESS Tech specs. -- Chris Caudle From hmurray at megapathdsl.net Fri Apr 24 08:25:58 2009 From: hmurray at megapathdsl.net (Hal Murray) Date: Fri, 24 Apr 2009 01:25:58 -0700 Subject: [time-nuts] Geocities Shutting Down In-Reply-To: Message from "Max Robinson" of "Thu, 23 Apr 2009 21:37:33 CDT." Message-ID: <20090424082559.4DC22BCE2@ip-64-139-1-69.sjc.megapath.net> > Does this include Angelfire? I think they are a subsidiary of Geocities. Angelfire is part of Lycos. Geocities is part of Yahoo. I don't know of any connection between Yahoo and Lycos. -- These are my opinions, not necessarily my employer's. I hate spam. From phk at phk.freebsd.dk Fri Apr 24 08:55:40 2009 From: phk at phk.freebsd.dk (Poul-Henning Kamp) Date: Fri, 24 Apr 2009 08:55:40 +0000 Subject: [time-nuts] Geocities Shutting Down In-Reply-To: Your message of "Fri, 24 Apr 2009 01:25:58 MST." <20090424082559.4DC22BCE2@ip-64-139-1-69.sjc.megapath.net> Message-ID: <3600.1240563340@critter.freebsd.dk> In message <20090424082559.4DC22BCE2 at ip-64-139-1-69.sjc.megapath.net>, Hal Murr ay writes: I wonder if this is related to the fact that massive amounts of spam have been using geocities for laundering urls recently. If something has been broken badly, closing down rather than fessing up and cleaning up might be a lot cheaper. -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 phk at FreeBSD.ORG | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. From jdb at lartmaker.nl Fri Apr 24 12:08:34 2009 From: jdb at lartmaker.nl (J.D. Bakker) Date: Fri, 24 Apr 2009 13:08:34 +0100 Subject: [time-nuts] femtosecond jitter anyone? In-Reply-To: <0C063B33-62D5-4110-8295-E9EA9E822D3F@twentylogten.com> References: <4CCD1C7E-6952-4FB4-8E1A-3B1A02618BC5@twentylogten.com> <49DD1288.4060103@rubidium.dyndns.org> <18D08480-6725-4251-BE78-145797B6DC31@twentylogten.com> <49DD21D5.6040109@rubidium.dyndns.org> <49DD3B28.4040704@xtra.co.nz><91291C16-6AC8-4BA7-9ADE-B21AC566B024@twentyl ogten.com><49DD4659.1070500@xtra.co.nz> <8DC9EC52-5D5A-43E9-A69E-A244076F0673@twentylogten.com> <2E4EACE099F748BBB079AFF8E5343614@pc52> <0C063B33-62D5-4110-8295-E9EA9E822D3F@twentylogten.com> Message-ID: [Another late reply -- Easter and taxes got in the way] At 09:59 -0400 09-04-2009, Chris Mack / N1SKY wrote: >Imagine this: if you were the mastering engineer for Elvis 50 years >ago, and if today's digital technology was available back then, would >you want to archive the King's record inside Iron Mountain on MP3? >Not really, you would want the most resolution possible for the re- >release onto 32-bit 384kHz whiz-bang chip media in the future. And >cumulative error for successive re-releases over the decade for >frequency drift and re-archival is maybe another concern. What cumulative errors are going to impact digital->digital transfers?? >For example, I am currently using a Rosendahl Nanoclocks (http:// >www.rosendahl-studiotechnik.com/nanoclocks.html) for my house master >word clock and a $6k Eventide Orville for processing of audio. The >Eventide used to measure the Nanoclocks at 88200 Hz... now it >measures 88201 Hz 4 years later... something drifted.... The >Rosendahl uses normal ambient crystals (although they have trimmer >caps) and use 74ACT00 logic to drive the distribution outputs. The >Eventide, I assume uses normal ambient crystals too for the myriad of >DSPs in it.... (What do you mean by 'ambient crystal'? AT cut with minimal df/dT at room temperature?) So your Nanoclock drifted relative to your Eventide. Even assuming that the absolute frequency shift of your converter clock was this much, that translates to a pitch shift of 0.02 cent. Find me *anyone* who can hear that in an ABX test. For that matter, try finding a string instrument that stays within 0.02 cent of its tuning after a minute or two of playing. [snip] >I believe Mr. Lavry for his 127dB ADC uses an OCXO which helps >achieve the specs. http://www.lavryengineering.com/ >productspage_pro_ad122_96mk.html The fact that one good converter uses an OCXO doesn't mean that you have to use an OCXO to build a good converter. The Grimm one mentioned by Chris C gets by just fine without one, for example. JDB. [plus, all things being equal an ovenized oscillator has higher Johnson noise than one running at room temperature] -- LART. 250 MIPS under one Watt. Free hardware design files. http://www.lartmaker.nl/ From max at maxsmusicplace.com Fri Apr 24 18:35:21 2009 From: max at maxsmusicplace.com (Max Robinson) Date: Fri, 24 Apr 2009 13:35:21 -0500 Subject: [time-nuts] Geocities Shutting Down References: <20090424082559.4DC22BCE2@ip-64-139-1-69.sjc.megapath.net> Message-ID: <3F3AABA2DBDF4748B66CD0FD489AECC9@BACKROOM> Good. Thank you. Regards. Max. K 4 O D S. Email: max at maxsmusicplace.com Transistor site http://www.funwithtransistors.net Vacuum tube site: http://www.funwithtubes.net Music site: http://www.maxsmusicplace.com To subscribe to the fun with tubes group send an email to, funwithtubes-subscribe at yahoogroups.com ----- Original Message ----- From: "Hal Murray" To: "Discussion of precise time and frequency measurement" Sent: Friday, April 24, 2009 3:25 AM Subject: Re: [time-nuts] Geocities Shutting Down >> Does this include Angelfire? I think they are a subsidiary of Geocities. > > Angelfire is part of Lycos. > > Geocities is part of Yahoo. > > I don't know of any connection between Yahoo and Lycos. > > > -- > These are my opinions, not necessarily my employer's. I hate spam. > > > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > From W4wj at aol.com Fri Apr 24 18:43:15 2009 From: W4wj at aol.com (W4wj at aol.com) Date: Fri, 24 Apr 2009 14:43:15 EDT Subject: [time-nuts] Yahoo Announcement regarding Geocities Message-ID: _http://www.mediapost.com/publications/?fa=Articles.showArticle&art_aid=1047 56_ (http://www.mediapost.com/publications/?fa=Articles.showArticle&art_aid=104756) **************The Average US Credit Score is 692. See Yours in Just 2 Easy Steps!(http://pr.atwola.com/promoclk/100126575x1221421330x1201417418/aol?redi r=http://www.freecreditreport.com/pm/default.aspx?sc=668072&hmpgID=62&bcd=Ap rilAvgfooter424NO62) From hmurray at megapathdsl.net Sat Apr 25 09:20:16 2009 From: hmurray at megapathdsl.net (Hal Murray) Date: Sat, 25 Apr 2009 02:20:16 -0700 Subject: [time-nuts] OT: 10 MHz data capture, help In-Reply-To: Message from "Tom Van Baak" of "Fri, 10 Apr 2009 13:38:55 PDT." Message-ID: <20090425092017.792BEBCE2@ip-64-139-1-69.sjc.megapath.net> > I have a old data device that is spitting out TTL data at 10 MHz. > There's just a data line (no clock) but the edges clearly indicate an > internal 10 MHz clock. > I'd like to do a continuous capture of the bits, for up to tens of > minutes, into a PC. That comes to about 1 GB of raw data. I can handle > the decoding of the bits in software after the capture is done. This > is a one-time experiment. > What is the best/quickest/easiest way to capture data like this? I've > looked at various USB or LAN logic analyzer and 'scopes but most seem > to work on batches of data. I need a continuous capture. There are two issues with this problem. One is clock recovery. The other is getting a large chunk of data into memory and presumably on to disk. This leads in to a question I've been meaning to ask for a while. I've been looking for a low cost FPGA on PCI board. This might be a wild goose chase, but I think it would be handy for a bunch of time-nut type applications. If I had the board I'm thinking of, you would just plug your data signal into a SMA connector and grab the data. It might take some FPGA hacking, but clock recovery at 10 MHz isn't a big deal and before long we'd have a good collection of FPGA code. What I'm looking for is a FPGA on a PCI card with a front end where I could add my own interface circuitry probably on a daughter card. I'm picturing a connector of some sort on the PCI card, probably standard 0.025 inch pins on 0.1 centers, but I'd be happy with anything low tech and inexpensive. I'd want it as far back from the front panel as is reasonable to leave room for my stuff. I also want a couple of good mounting holes. (and drawings and part numbers...) The daughter cards would be flipped upside down. Cooling would be poor but shouldn't be a problem with low power interface chips. It would get exciting if you wanted to put a fast ADC out there. I'd expect the vendor to make a few popular interface daughter cards available. There are a couple of obvious ones. One is N data lines with a clock on whatever ribbon cable type connector fits on the front panel. Another is several SMA connectors, one going to a clock input on the FPGA. It might make sense to layout something on the front section of the board. As long as that section isn't stuffed it won't get in the way. Whatever is likely to be most popular. Does anybody know of an inexpensive FPGA card like that? There are a handful of reasons why FPGA and PCI don't play together well. The main one is that old 5V PCI can generate 11V spikes from reflections and that is off scale with modern silicon technology, or at least the branch of it used in the FPGAs that I'm familiar with. There is a 3V PCI spec, but (almost?) no mother boards implement it. I think that's mostly a chicken/egg problem. It didn't take off so nobody built cards that depend on it so it didn't take off... Lots of people make cards that run on either 3V or 5V. That's easy. Does anybody know of any mother boards with 3V PCI slots? I think the 66 MHz option for PCI needs them. There are 2 ways that I know of to connect a FPGA to 5V PCI. One is to use FET bus switches. The other is to use some other chip to connect to the PCI bus. One possibility is a PCI-PCI bridge. Another is an older technology FPGA. A 3rd is one of the PLX chips designed to connect to external logic. I think they can all be made to work, but they seem ugly to me. There are a couple more possibilites. One is to cheat. That means putting a scope on your PCI bus and noticing that even though it's a 5V bus, it's only got 3V signals on it. You would have to get out the scope again every time you wanted to plug in a new card. Ugly. Another option is to use PCI-Express. I'm not sure what is available for low cost FPGAs, but lots of mother boards now include PCI-Express slots. -- These are my opinions, not necessarily my employer's. I hate spam. From sar10538 at gmail.com Sat Apr 25 09:40:39 2009 From: sar10538 at gmail.com (Steve Rooke) Date: Sat, 25 Apr 2009 21:40:39 +1200 Subject: [time-nuts] Characterising frequency standards In-Reply-To: <49E32B95.70904@rubidium.dyndns.org> References: <1231b6a80904070509m5b8bb638gbc088500444254c3@mail.gmail.com> <49DC91B9.6090004@xtra.co.nz> <1231b6a80904080504n4a3a22dcr247fae5df39ed840@mail.gmail.com> <7911976D35924C91A61F679126F77F9E@pc52> <1231b6a80904090500i1cd90f80w7983e03b4978cfa8@mail.gmail.com> <1231b6a80904120206j310d0d66pbb78ea5c4a50c302@mail.gmail.com> <49E1B228.9070106@xtra.co.nz> <1231b6a80904121734v141f37c9t14bb9662328776f2@mail.gmail.com> <49E32B95.70904@rubidium.dyndns.org> Message-ID: <1231b6a80904250240h7cf7edbdwa13a48cda27db9e1@mail.gmail.com> Hi Magnus, 2009/4/14 Magnus Danielson > > Say I have a 1Hz input source and my counter measures the period of > > the first cycle and assigns this to A1. At the end of the first cycle > > the counter is able to be rest and re-triggered to capture the second > > cycle and assign this to A2. So far 2 sec have passed and I have two > > readings in data set A. > > > Strange counter. Traditionally counters rests after the stop event have > occured, since they cannot know anything else.The Gate time gives a hint > on the first point in time it can trigger, the gate just arms the stop > event. There is no real end point. It can however rest and retrigger the > start event ASAP when gate times are sufficiently large. It's just a > smart rearrangement of what to do when to achieve zero dead-time for > period/frequency measurements. I am making period measurements so the gate time does not come into it. My counter can be set to continuously take period readings starting/stopping on a positive or negative edge. Also when my counter finishes a reading it can generate a SRQ allowing me to transfer the measurement to the PC and I can also immediately generate a reset of the counter to take another measurement. Unfortunately it is not possible for the counter to be reset and then trigger again before the last triggering event has finished, IE. an individual trigger event can only be used once per measurement cycle, the same trigger event cannot stop one period measurement and start a second one. All this means that there will always be a one period gap between each period measurement. > You could also use a counter which is pseudo zero dead time in that it > can time-stamp three values, two differences without deadtime but has > deadtime after that. Essentially two counters where the stop event of > the first is the start event of the next. Yes, I could do that but it is extra expense and complication which I do not think is necessary. > > I now repeat the experiment and assign the measurement of the first > > period to B1. The counter I am using this time is unable to stop at > > the end of the first measurement and retrigger immediately so I'm > > unable to measure the second cycle but is left in the armed position. > > When the third cycle starts, the counter triggers and completes the > > measurement of the third cycle which is now assigned to B2. > This is what most normal counters do. So we can agree on this. > For the purposes of my original text, the first data set refers to A1 > > & A2. Similarly the second data set refers to B1 & B2. Reference to > > pre-processing of the second data set refers to mathematically > > removing the effects of drift from B1 & B2 to produce a third data set > > which is used as the data input for an ADEV calculation where tau0 = 1 > > sec with output of tau = 1 sec. > You would need to use bias adjustments, but the B1 & B2 period/frequency > samples is badly tainted data and should not be used.having a deadtime > at the size of tau0 is serious bussness. Removing the phase drift over But for the purposes of how i now think it can be calculated, tau0 will be set equal to 2 x actual period of input source, IE. if f = 1Hz, tau0 = 2 sec. Lets take a look at what we are saying about "badly tainted data" here. The whole purpose of this exercise is to predict the effects of noise on a stable frequency. We have already agreed that a phase/frequency modulation source ate EXACTLY 1/2 of the input source will be masked by this method but we can get round that. So for the rest of the measurement, we have half the data per tau than if there was no missing data. This will have some baring on the accuracy of the result but will only be significant for maximum tau, in almost exactly the same degree that existing ADEV measurements have limited accuracy at maximum tau as there are not enough measurements to provide the statistical probably over that time, IE, if we measure for 100,000 seconds, the calculation for tau = 100,000 will have only one set of values. Remember we are looking at noise here and if for the "missing data" method we take readings for twice the full test time as a "conventional" test, we will have data with the same amount of statistical probability. This "badly tainted data" is just the same unless we have such periodic effects that over the period of the whole test we will always miss them. There is no magic here. the dead time does not aid you since if you remove the phase ramp of the > evolving clock, that of f*t or v*t (depending on which normalisation you > prefer), you have the background phase noise. What we want to do is to > characterize this phase noise. Taking two samples of it back-to-back and > taking two samples with a (equalent sized length) gap becomes two > different filters. Maybe some ascii art may aid: For a 1Hz input I would be able to calculate for tau >= 2 with the unmodified data using tau0 = 2 sec. If I remove the effects of drift, all my data points are the same as measuring for a "conventional" ADEV test provided that I I only calculate for tau = 1 and tau0 = 1. Using the data with the effects of drift removed for calculating for all tau would certainly give incorrect results as it would not show the effects of drift. In a "conventional" measurement of ADEV for tau = 1, successive pairs of data points are used in the calculation and the whole lot averaged. The effects of drift (for any reasonable oscillator we are considering) between any two sequential 1 second period measurements is so small that it does not affect the ADEV measurement. You would only see an incorrect result if you took measurement data points with large periods of time between them, IE. the first and last data points on a 100,000 second run for instance. > __ > __ | |__ > |__| > > y1 y2 y3 > A1 A2 > > A2-A1 = y2-y1 > > vs. > __ > __ __| |__ > |__| > > y1 y2 y3 > B1 B2 > > B2-B1 = y3-y1 Actually we are considering the period of a waveform which is time between successive instances of the waveform moving through the same point in the same direction, IE. it would include the positive and negative half cycles of the waveform. BTW, ASCII art does not work so well on today's proportionate fonts. > Consider now the case when frequency samples has twice the tau of the > above examples > _____ > __ | |__ > |_____| > > y1 y2 > y2-y1 > > These examples where all based on sequences of frequency measurements, > just as you indicate in your caes. > > As you see on the differences, the nominal frequency cancels and the > nominal phase error has also cancled out, so there is nothing to > compensate there. Drift rate would however not be canceled, but for most > of our sources, the noise is higher than the drift rate for shorter taus. Well, if there is a phase error it would cause the positive and negative halves of waveform to differ and therefore not cancel out. But as you so rightly say, and to what I alluded to before, this phase error would be expected to be considerably smaller than the noise in our tests. Now for my "missing data" method, there is twice the amount of time between data points so the phase errors would be doubled in size. This may, or may not now affect the measurement for tau0 = 1 for tau = 1 so I have proposed to remove that phase error by pre-processing the data but ONLY for this one calculation of ADEV for tau = 1, NOT for the other tau. It may be that the phase error is still small compared with the noise and so the data does not need to be processed to remove the drift. That would be proved by performing the calculation with and without the drift removed. But this does not mean that it would then e OK to calculate ADEV for tau >= 1 using tau0 = 1 using the "missing data" method as this WOULD give the wrong indication of the effects of drift. > Time-differences allows us to skip every other cycle thought. > > > In this case the data set is constructed from the measurement of the > > cycle periods of a 1Hz input source where even cycles are skipped, > > hence each data point is a measurement of the period of each odd (1, > > 3, 5, 7...) cycle of the incoming waveform. In this case the time > > between each measurement is 2 sec so ADEV is calculated with tau = 2 > > sec for tau >= 2 sec. This data set is then mathematically processed > > to remove the effects of drift, bearing in mind the 2 sec spacing of > > each data point, and ADEV is then calculated with tau0 = 1 sec for tau > > = 1 sec. > How did you establish the effect of drift? In the case of the data I was using, there actually does not appear to be a great deal of drift and I have made no adjustments to account for it BUT theoretically it could make a difference. > PN - White noise phase WPM, Flicker noise phase FPM, White noise > > frequency WFM, Flicker noise frequency FFM and Random walk frequency > > RWFM. > These are just the names for the various 1/f power noises. They enter > through a myriad of places, white phase noise and 1/f is common to > amplifiers, 1/f^5 is thermal noise onto the same amplifiers. 1/f^2 is > oscillator shaped white phase noise and 1/f^3 is oscillator shaped 1/f > noise. Rubiola spends quite some time on that subject, both in his > excelent book and in various papers. But these are the effects we are measuring here. > Indeed, and this is an important aspect to consider as we have been > > discussing the effects of induced jitter/PN to a frequency standard > > when it is buffered and divided down. Ideally measurements of ADEV > > would be made on the raw frequency standard source (eg. 10MHz) rather > > than, say, a divided 1Hz signal. > Yes and no. There are benefits in dividing it down, you can identify > cycle slips easier and adjust for them, where as one 10 MHz cycle to > another can be a bit anonymous. To get the best performance for ADEV at > 1 s using a 1 Hz signal is not optimum thought. A slightly higher rate > will allow for quicker gathering of high statistical freedom and thus > improved statistical stability as allowed through the overlapping Allan > Deviation estimator as compared to use the non-overlapping Allan > Deviation estimator on the same time-stretch of samples. When running > long runs, sufficient freedom may be achieved even using the > non-overlapping estimator. Agreed, it would be down to what is the maximum rate that the measurement system is able to take readings and record them. 1 second has just been used as an example in this discussion but it is really not that optimal. > A divide down does not have to make significant change to phase-noise, > its effect can be minimized as we have discussed before. Maybe but this topic has in itself generated a lot of discussion and the outcome is that care must be taken with this aspect. This is really the point I was making, we don't want to be measuring noise induced in the buffering and division circuits as this will completely ruin our tests. The 1 PPS signal is also quite historical artifact which is still quite > handy. It allows direct comparision of non-equalent frequencies as the > division ration is adjusted. It is also what comes out of a majority of > GPS receivers. Few GPS receivers evaluate their time offset at a faster > rate than 1 Hz anyway, but 2, 5, 10 and 20 Hz is available. The L1 C/A > signal would allow for a rate of 1 kHz but it would require really good > signal conditions. Indeed although it has been suggested that 10MHz ocxos be divided down to around 1 Hz so they can be measured by sound cards in the past. > For high resolution work, the PPS is not that good, since beating two 10 > MHz would give you some 5-7 decades of better resolution if you can > handle the problems with slow slopes. Are you proposing measuring phase differences here as for ADEV this would surely add the noise of both sources into the mix which would be undesirable. >> For short measurement times quantisation noise and instrumental noise > >> may mask the noise from the source but they are still present. > > > > Well, these form the noise floor of our measurement system. > Some of them we can control, though better triggering devices, as > learned the hard way and investigated by many. I guess it would be possible to measure the system against itself with something like a short delay from it's own internal timing source. > Other ways to handle it is to use cross-correlation techniques where two > independent system noises sees the same signal, in which case only the > input source noise correlate and the system noise effect can be > partially canceled out. If you could measure the same signal with multiple systems, it would be possible to cancel out the noise effects of the measuring system. > There are systematic noise problems also, such as lack of zero dead > time, resolution, interpolator distorsion etc. Indeed. Thanks for your input on this, it's really enabled me to focus more. Cheers, Steve > > Cheers, > Magnus > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > -- Steve Rooke - ZL3TUV & G8KVD & JAKDTTNW A man with one clock knows what time it is; A man with two clocks is never quite sure. From jmiles at pop.net Sat Apr 25 11:26:28 2009 From: jmiles at pop.net (John Miles) Date: Sat, 25 Apr 2009 04:26:28 -0700 Subject: [time-nuts] OT: 10 MHz data capture, help In-Reply-To: <20090425092017.792BEBCE2@ip-64-139-1-69.sjc.megapath.net> Message-ID: > It might make sense to layout something on the front section of > the board. > As long as that section isn't stuffed it won't get in the way. > Whatever is > likely to be most popular. > > Does anybody know of an inexpensive FPGA card like that? Tom eventually went with a USBee SX board. The manufacturer doesn't say, but I'm guessing there's a fair bit of RAM on those boards, because they claim to support continuous streaming at 24 megabytes/second with no data loss. As it turned out he had a clock line available for the NRZ bitstream, so he didn't have to sample at 20 MHz. I fooled around a bit with a Xylo USB board and was able to recover a clocked bitstream at 10 MHz, but with only the 512-byte FIFO on the FX2, there's not much time for Windows to go out to lunch. It's probably possible to synthesize a large-enough FIFO in the gate array to make the process reliable. > There are a handful of reasons why FPGA and PCI don't play > together well. > The main one is that old 5V PCI can generate 11V spikes from > reflections and > that is off scale with modern silicon technology, or at least the > branch of > it used in the FPGAs that I'm familiar with. KNJN has been selling their "Dragon" PCI board ( http://www.knjn.com/?pg=cat&src=3 ) for awhile, and it looks like they just glued the Spartan-2 chip to the bus. Looks simple enough, if not especially inexpensive. They have a habit of not fully documenting their hardware in a way that allows you to build standalone applications with it, though. If inspired to do anything with their hardware, make very sure the documentation is adequate for the job. -- john, KE5FX From tvb at LeapSecond.com Sat Apr 25 15:11:54 2009 From: tvb at LeapSecond.com (Tom Van Baak) Date: Sat, 25 Apr 2009 08:11:54 -0700 Subject: [time-nuts] OT: 10 MHz data capture, help References: <20090425092017.792BEBCE2@ip-64-139-1-69.sjc.megapath.net> Message-ID: <7A2CEBAD485740879C114AD8D2C465F6@pc52> > There are two issues with this problem. One is clock recovery. The other is > getting a large chunk of data into memory and presumably on to disk. > > This leads in to a question I've been meaning to ask for a while. I've been > looking for a low cost FPGA on PCI board. This might be a wild goose chase, > but I think it would be handy for a bunch of time-nut type applications. Let me give you an update. First, thanks to all of you with suggestions on my original data capture question. As John mentioned I looked at a lot of alternatives with a special eye towards USB 'scope and logic analyzer products, eventually trying out the USBee SX. I found a clock edge to go with my NRZ data so that made my problem easier (avoiding having to oversample the data). I was quite amazed at the performance of the USBee device. Even on a tiny netbook PC it will stream 8-bit logic samples at 10 MHz (24 max) with no dropouts into available memory (which on my netbook is usually over half a gigabyte, giving over 50 seconds of continuous capture). I'm still working on the PC software to decode this mass of data (maybe even in real-time) and working on longer runs, but mostly I was pleasantly surprised how easy it is to obtain high rates over USB2.0. I was worried that I'd have to go with some expensive or very complicated PCI-card based acquisition. So Hal, give USB2.0 some consideration before you settle on PCI. /tvb From sometimesyoufeellikeanut at twentylogten.com Sun Apr 26 14:25:19 2009 From: sometimesyoufeellikeanut at twentylogten.com (Chris Mack) Date: Sun, 26 Apr 2009 10:25:19 -0400 Subject: [time-nuts] femtosecond jitter anyone? In-Reply-To: References: <4CCD1C7E-6952-4FB4-8E1A-3B1A02618BC5@twentylogten.com> <49DD1288.4060103@rubidium.dyndns.org> <18D08480-6725-4251-BE78-145797B6DC31@twentylogten.com> <49DD21D5.6040109@rubidium.dyndns.org> <49DD3B28.4040704@xtra.co.nz><91291C16-6AC8-4BA7-9ADE-B21AC566B024@twentyl ogten.com><49DD4659.1070500@xtra.co.nz> <8DC9EC52-5D5A-43E9-A69E-A244076F0673@twentylogten.com> <2E4EACE099F748BBB079AFF8E5343614@pc52> <0C063B33-62D5-4110-8295-E9EA9E822D3F@twentylogten.com> Message-ID: <5968A0FC-57E9-4414-9FA1-A0490210BBF9@twentylogten.com> Folks, thanks for your input and sanity checking. To recap... Having never worked with crystals before (only 2 and 10 GHz stuff in GaAs power amp RFIC design for cell phone and the like using lab RF generators or Vitesse / AMCC asics with clock recovery already done by someone/something else back in the 1990s), I am revamping this design moving away from an OCXO and seeing what the design holds for TCXOs and the like. A 4 layer board is going to be several hundred dollars due to the size of the board and I would like to get as close to ideal on the first shot (yes indeed there will probably be another spin)... Since I only have experience in the 2+ GHZ region I was originally concerned about via stubs with reflection induced effects, having no "feel" for this low frequency region. I am having issues trying to get the simulator programme for the LMK04000 to synch to 44.1kHz and generate 11 / 12 MHz. One idea I suppose: I am looking at preceding the LMK04000 with the Si5326 which is a narrow band part compared to the wideband Si5319 to get 44kHz up to 10MHz... Then the LMK04000 can take 10MHz from this or 10MHz from an external source outside the box and get it to the final 11 / 12 MHz for distribution internal to the box to the converters. The Si5326 can also provide an "internally derived" 10MHz from its reference port, so that all design criteria for clocking is satisfied (internal clocking mode and external synch to 44.1kHz or 10M external). I can use a 3rd overtone crystal to provide the reference port frequency on the Si5326.... Regarding spurs in the near carrier region... Yes. these datasheets are a bit of a black box, and every time I look at them they give up another layer of the onion... I wonder about the tiny spurs on the LMK04000 near 100 Hz on their data (granted different carrier frequency, 250MHz). Does anyone have any experience with these chips or have a better suggestion; is there even an issue with these small spurs? Cheers, -chris From phk at phk.freebsd.dk Mon Apr 27 12:38:07 2009 From: phk at phk.freebsd.dk (Poul-Henning Kamp) Date: Mon, 27 Apr 2009 12:38:07 +0000 Subject: [time-nuts] rolling time... Message-ID: <96259.1240835887@critter.freebsd.dk> Kind of cute... http://www.core77.com/blog/object_culture/clock_n_roll_13266.asp -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 phk at FreeBSD.ORG | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. From EWKehren at aol.com Mon Apr 27 12:44:44 2009 From: EWKehren at aol.com (EWKehren at aol.com) Date: Mon, 27 Apr 2009 08:44:44 EDT Subject: [time-nuts] Austron Line Drivers Message-ID: In an ongoing quest to clean out excess equipment from my attic I found an Austron 1295D with eight Quad G703 one Quad TTL, one Framed T1 synthesizer and one Select Rate Synthesizer. Does any one have information on these parts? There has been recently conversation in this group on line drivers and Austron was mentioned. Is there any interest and how would you want me to go forward. Ebay is an option and the question than is should it be posted as a complete unit or as individual parts to make it more available to multiple users. Thanks Bert Kehren, Miami WB5MZJ **************A Good Credit Score is 700 or Above. See yours in just 2 easy steps! (http://pr.atwola.com/promoclk/100126575x1220572846x1201387511/aol?redir=http://www.freecreditreport.com/pm/default.aspx?sc=668072&hmpgID=62&bcd= Aprilfooter427NO62) From rk at timing-consultants.com Mon Apr 27 15:06:07 2009 From: rk at timing-consultants.com (Rob Kimberley) Date: Mon, 27 Apr 2009 16:06:07 +0100 Subject: [time-nuts] Austron Line Drivers In-Reply-To: References: Message-ID: <43E2119D31B4450D8E966BE678F1E164@robinHP> I recently cleared out all my old manuals (including many 1295D manuals). I know for sure that the ones you mention here were amongst them. They went to Ron Smith here in the UK. You may want to check with him. Rob Kimberley -----Original Message----- From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On Behalf Of EWKehren at aol.com Sent: 27 April 2009 13:45 To: time-nuts at febo.com Subject: [time-nuts] Austron Line Drivers In an ongoing quest to clean out excess equipment from my attic I found an Austron 1295D with eight Quad G703 one Quad TTL, one Framed T1 synthesizer and one Select Rate Synthesizer. Does any one have information on these parts? There has been recently conversation in this group on line drivers and Austron was mentioned. Is there any interest and how would you want me to go forward. Ebay is an option and the question than is should it be posted as a complete unit or as individual parts to make it more available to multiple users. Thanks Bert Kehren, Miami WB5MZJ **************A Good Credit Score is 700 or Above. See yours in just 2 easy steps! (http://pr.atwola.com/promoclk/100126575x1220572846x1201387511/aol?redir=htt p://www.freecreditreport.com/pm/default.aspx?sc=668072&hmpgID=62&bcd= Aprilfooter427NO62) _______________________________________________ time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. From EWKehren at aol.com Mon Apr 27 16:52:28 2009 From: EWKehren at aol.com (EWKehren at aol.com) Date: Mon, 27 Apr 2009 12:52:28 EDT Subject: [time-nuts] Austron Line Drivers Message-ID: Thanks. Bert In a message dated 4/27/2009 11:07:46 A.M. Eastern Daylight Time, rk at timing-consultants.com writes: I recently cleared out all my old manuals (including many 1295D manuals). I know for sure that the ones you mention here were amongst them. They went to Ron Smith here in the UK. You may want to check with him. Rob Kimberley -----Original Message----- From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On Behalf Of EWKehren at aol.com Sent: 27 April 2009 13:45 To: time-nuts at febo.com Subject: [time-nuts] Austron Line Drivers In an ongoing quest to clean out excess equipment from my attic I found an Austron 1295D with eight Quad G703 one Quad TTL, one Framed T1 synthesizer and one Select Rate Synthesizer. Does any one have information on these parts? There has been recently conversation in this group on line drivers and Austron was mentioned. Is there any interest and how would you want me to go forward. Ebay is an option and the question than is should it be posted as a complete unit or as individual parts to make it more available to multiple users. Thanks Bert Kehren, Miami WB5MZJ **************A Good Credit Score is 700 or Above. See yours in just 2 easy steps! (http://pr.atwola.com/promoclk/100126575x1220572846x1201387511/aol?redir=htt p://www.freecreditreport.com/pm/default.aspx?sc=668072&hmpgID=62&bcd= Aprilfooter427NO62) _______________________________________________ time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. _______________________________________________ time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. **************A Good Credit Score is 700 or Above. See yours in just 2 easy steps! (http://pr.atwola.com/promoclk/100126575x1220572846x1201387511/aol?redir=http://www.freecreditreport.com/pm/default.aspx?sc=668072&hmpgID=62&bcd= Aprilfooter427NO62) From magnus at rubidium.dyndns.org Mon Apr 27 18:53:58 2009 From: magnus at rubidium.dyndns.org (Magnus Danielson) Date: Mon, 27 Apr 2009 20:53:58 +0200 Subject: [time-nuts] rolling time... In-Reply-To: <96259.1240835887@critter.freebsd.dk> References: <96259.1240835887@critter.freebsd.dk> Message-ID: <49F5FF46.2030901@rubidium.dyndns.org> Poul-Henning Kamp skrev: > Kind of cute... > > http://www.core77.com/blog/object_culture/clock_n_roll_13266.asp > Very cute. If someone gave me one for my birthday I would be happy. You still have a few hours to pull it of... or a year. :D Cheers, Magnus From david.partridge at dsl.pipex.com Tue Apr 28 14:16:48 2009 From: david.partridge at dsl.pipex.com (David C. Partridge) Date: Tue, 28 Apr 2009 15:16:48 +0100 Subject: [time-nuts] Solartron 7081 ROMs Message-ID: This is a call to anyone who has a Solartron 7081 and has saved a copy of their ROMs (if you haven't you may end up in the same boat as I am - the one that's up the creek without a paddle). One of the ROMs on my earthy processor board has died. It would appear that the ROMs in this 7081 were updated to a high level of firmware at some stage in its life as the total ROM image size is greater than that of a set that was copied by Bill Ezell from his 7081 even though his meter has a higher serial number (461) than mine (180). The ICs in question and the CRC16 checksums (in hex) for my ROM set are: IC430 3238 IC415 C5C0 IC414 1260 <===== It is this one I want IC413 B958 IC412 ED50 If you have saved your firmware ROM images, and the checksums for your ROMs match these, I would be immensely grateful if you could send me the image for IC414 (the middle one of the three). If as a result of reading this message you feel impelled to save your ROM images and find your checksums match these ... Obviously if I can't find a good image of that ROM, I'll just install the older firmware, but one never knows. Cheers, David Partridge From brooke at pacific.net Tue Apr 28 14:40:09 2009 From: brooke at pacific.net (Brooke Clarke) Date: Tue, 28 Apr 2009 07:40:09 -0700 Subject: [time-nuts] Solartron 7081 ROMs In-Reply-To: References: Message-ID: <49F71549.5070001@pacific.net> Hi Dave: I've read that there are some tricks to coaxing the data from memory chips related to reading them under different conditions. It's a lot of work, but it's possible to disassemble the code. That would allow it to be repaired. Have Fun, Brooke Clarke http://www.prc68.com David C. Partridge wrote: > This is a call to anyone who has a Solartron 7081 and has saved a copy of > their ROMs (if you haven't you may end up in the same boat as I am - the one > that's up the creek without a paddle). > > One of the ROMs on my earthy processor board has died. > > It would appear that the ROMs in this 7081 were updated to a high level of > firmware at some stage in its life as the total ROM image size is greater > than that of a set that was copied by Bill Ezell from his 7081 even though > his meter has a higher serial number (461) than mine (180). > > The ICs in question and the CRC16 checksums (in hex) for my ROM set are: > > IC430 3238 > IC415 C5C0 > IC414 1260 <===== It is this one I want > IC413 B958 > IC412 ED50 > > If you have saved your firmware ROM images, and the checksums for your ROMs > match these, I would be immensely grateful if you could send me the image > for IC414 (the middle one of the three). > > If as a result of reading this message you feel impelled to save your ROM > images and find your checksums match these ... > > Obviously if I can't find a good image of that ROM, I'll just install the > older firmware, but one never knows. > > Cheers, > David Partridge > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > From gretchendenisebaxter at gmail.com Tue Apr 28 17:38:45 2009 From: gretchendenisebaxter at gmail.com (Gretchen Baxter) Date: Tue, 28 Apr 2009 13:38:45 -0400 Subject: [time-nuts] Certichron Message-ID: <4fdb424f0904281038n7ef92dc1j117ab1eca8735bb3@mail.gmail.com> Hi, I came across the page of Certichron at www.certichron.com They seem to be positioning themselves as *THE *trusted source for time synchronization. Anyone know of them? Comments? Thanx! Gretchen From dforbes at dakotacom.net Tue Apr 28 17:56:58 2009 From: dforbes at dakotacom.net (David Forbes) Date: Tue, 28 Apr 2009 10:56:58 -0700 Subject: [time-nuts] Certichron In-Reply-To: <4fdb424f0904281038n7ef92dc1j117ab1eca8735bb3@mail.gmail.com> References: <4fdb424f0904281038n7ef92dc1j117ab1eca8735bb3@mail.gmail.com> Message-ID: At 1:38 PM -0400 4/28/09, Gretchen Baxter wrote: >Hi, > >I came across the page of Certichron at www.certichron.com > >They seem to be positioning themselves as *THE *trusted source for time >synchronization. > >Anyone know of them? Comments? > >Thanx! > >Gretchen A brief persual of their website indicates that they are trying to position themselves as the trusted source of time to lawyers, not scientists. I also noticed that the cool 3D clock they show in the upper corner of their home page uses local PC time, not NIST time! (My home Mac is not syncing properly to Apple's time server, so it's a good indicator of a website's time source.) So I don't have much faith in their service, if they can't even get their website's clock right. -- --David Forbes, Tucson, AZ http://www.cathodecorner.com/ From imp at bsdimp.com Tue Apr 28 18:18:06 2009 From: imp at bsdimp.com (M. Warner Losh) Date: Tue, 28 Apr 2009 12:18:06 -0600 (MDT) Subject: [time-nuts] Certichron In-Reply-To: <4fdb424f0904281038n7ef92dc1j117ab1eca8735bb3@mail.gmail.com> References: <4fdb424f0904281038n7ef92dc1j117ab1eca8735bb3@mail.gmail.com> Message-ID: <20090428.121806.-1751000024.imp@bsdimp.com> In message: <4fdb424f0904281038n7ef92dc1j117ab1eca8735bb3 at mail.gmail.com> Gretchen Baxter writes: : They seem to be positioning themselves as *THE *trusted source for time : synchronization. If you were in the time business, would you say you weren't the trusted source of time? Warner From djl at montana.com Tue Apr 28 18:53:38 2009 From: djl at montana.com (Don Latham) Date: Tue, 28 Apr 2009 12:53:38 -0600 (MDT) Subject: [time-nuts] Certichron In-Reply-To: <4fdb424f0904281038n7ef92dc1j117ab1eca8735bb3@mail.gmail.com> References: <4fdb424f0904281038n7ef92dc1j117ab1eca8735bb3@mail.gmail.com> Message-ID: <310f3eed8aa7913fb95d4b3439472afd.squirrel@webmail.montana.com> I might believe this service if it were written in credible English... Don Gretchen Baxter > Hi, > > > > I came across the page of Certichron at www.certichron.com > > > > They seem to be positioning themselves as *THE *trusted source for time > synchronization. > > > > Anyone know of them? Comments? > > > > Thanx! > > > > Gretchen > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > -- Dr. Don Latham AJ7LL Six Mile Systems LLP 17850 Six Mile Road POB 134 Huson, MT, 59846 VOX 406-626-4304 www.lightningforensics.com www.sixmilesystems.com From djl at montana.com Tue Apr 28 18:59:15 2009 From: djl at montana.com (Don Latham) Date: Tue, 28 Apr 2009 12:59:15 -0600 (MDT) Subject: [time-nuts] Certichron In-Reply-To: <20090428.121806.-1751000024.imp@bsdimp.com> References: <4fdb424f0904281038n7ef92dc1j117ab1eca8735bb3@mail.gmail.com> <20090428.121806.-1751000024.imp@bsdimp.com> Message-ID: I have an Austron 2000C to peddle if anyone here is interested before it ebays. In very good shape, works AFIK, lights up, one second light flashes. Don't have a manual. If anyone knows where the manual is found on 'net would you let me know? Google no help... Hope this kind of msg OK with the group, let me know please if it is not. Don -- Dr. Don Latham AJ7LL Six Mile Systems LLP 17850 Six Mile Road POB 134 Huson, MT, 59846 VOX 406-626-4304 www.lightningforensics.com www.sixmilesystems.com From bill at iaxs.net Tue Apr 28 20:06:36 2009 From: bill at iaxs.net (Bill Hawkins) Date: Tue, 28 Apr 2009 15:06:36 -0500 Subject: [time-nuts] Certichron In-Reply-To: References: <4fdb424f0904281038n7ef92dc1j117ab1eca8735bb3@mail.gmail.com> Message-ID: <734D69E0382A4CEF9152D4492B968E45@cyrus> At the bottom of their web page is a link to an article on the limitations of LI GPS as a time source. It says that "reliance on L1 GPS for time-setting is very risky" Sounds like FUD to me. Didn't see anything about their claim to accuracy. Seems like they deliver lawyer time with NTP. An article on network security for process control systems (refinery, power, etc.) comments on the spread of partial knowledge. Governments make laws that are incomplete, plant managers don't want to spend more than they have to, lawyers tell them all they have to do is comply with the law. Result? Engineers can't get money to provide the security they know they need to keep the bad guys out of the system. Maybe that's why SETI can't find any intelligence in the cosmos. Technology soon collapses when common sense isn't enough. Bill Hawkins -----Original Message----- From: David Forbes Sent: Tuesday, April 28, 2009 12:57 PM At 1:38 PM -0400 4/28/09, Gretchen Baxter wrote: >Hi, > >I came across the page of Certichron at www.certichron.com > >They seem to be positioning themselves as *THE *trusted source for time synchronization. > >Anyone know of them? Comments? > >Thanx! > >Gretchen A brief persual of their website indicates that they are trying to position themselves as the trusted source of time to lawyers, not scientists. I also noticed that the cool 3D clock they show in the upper corner of their home page uses local PC time, not NIST time! (My home Mac is not syncing properly to Apple's time server, so it's a good indicator of a website's time source.) So I don't have much faith in their service, if they can't even get their website's clock right. -- --David Forbes, Tucson, AZ http://www.cathodecorner.com/ From pvince at theiet.org Wed Apr 29 19:50:12 2009 From: pvince at theiet.org (Peter Vince) Date: Wed, 29 Apr 2009 20:50:12 +0100 Subject: [time-nuts] Solartron 7081 ROMs Message-ID: <1294.1241034612@uk2.net> I'm sure there was a message on this group a month or two ago, where the bottom line was to read the EPROMs with a slightly lower than usual voltage. Peter Vince On Tue Apr 28 15:40 , Brooke Clarke sent: >Hi Dave: > >I've read that there are some tricks to coaxing the data from memory >chips related to reading them under different conditions. > >It's a lot of work, but it's possible to disassemble the code. That >would allow it to be repaired. > >Have Fun, > >Brooke Clarke >http://www.prc68.com > > > >David C. Partridge wrote: >> This is a call to anyone who has a Solartron 7081 and has saved a copy of >> their ROMs (if you haven't you may end up in the same boat as I am - the one >> that's up the creek without a paddle). >> >> One of the ROMs on my earthy processor board has died. >> >> It would appear that the ROMs in this 7081 were updated to a high level of >> firmware at some stage in its life as the total ROM image size is greater >> than that of a set that was copied by Bill Ezell from his 7081 even though >> his meter has a higher serial number (461) than mine (180). >> >> The ICs in question and the CRC16 checksums (in hex) for my ROM set are: >> >> IC430 3238 >> IC415 C5C0 >> IC414 1260 >> IC413 B958 >> IC412 ED50 >> >> If you have saved your firmware ROM images, and the checksums for your ROMs >> match these, I would be immensely grateful if you could send me the image >> for IC414 (the middle one of the three). >> >> If as a result of reading this message you feel impelled to save your ROM >> images and find your checksums match these ... >> >> Obviously if I can't find a good image of that ROM, I'll just install the >> older firmware, but one never knows. >> >> Cheers, >> David Partridge From stake at btinternet.com Wed Apr 29 20:10:08 2009 From: stake at btinternet.com (Chris Stake) Date: Wed, 29 Apr 2009 21:10:08 +0100 Subject: [time-nuts] Solartron 7081 ROMs In-Reply-To: <1294.1241034612@uk2.net> References: <1294.1241034612@uk2.net> Message-ID: <008a01c9c906$7ec2eb60$7c48c220$@com> Yes, Low supply voltage and slow access time might succeed with those old EPROMS. Best of luck Chris Stake -----Original Message----- From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On Behalf Of Peter Vince Sent: 29 April 2009 20:50 To: brooke at pacific.net; Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Solartron 7081 ROMs I'm sure there was a message on this group a month or two ago, where the bottom line was to read the EPROMs with a slightly lower than usual voltage. Peter Vince On Tue Apr 28 15:40 , Brooke Clarke sent: >Hi Dave: > >I've read that there are some tricks to coaxing the data from memory >chips related to reading them under different conditions. > >It's a lot of work, but it's possible to disassemble the code. That >would allow it to be repaired. > >Have Fun, > >Brooke Clarke >http://www.prc68.com > > > >David C. Partridge wrote: >> This is a call to anyone who has a Solartron 7081 and has saved a copy of >> their ROMs (if you haven't you may end up in the same boat as I am - the one >> that's up the creek without a paddle). >> >> One of the ROMs on my earthy processor board has died. >> >> It would appear that the ROMs in this 7081 were updated to a high level of >> firmware at some stage in its life as the total ROM image size is greater >> than that of a set that was copied by Bill Ezell from his 7081 even though >> his meter has a higher serial number (461) than mine (180). >> >> The ICs in question and the CRC16 checksums (in hex) for my ROM set are: >> >> IC430 3238 >> IC415 C5C0 >> IC414 1260 >> IC413 B958 >> IC412 ED50 >> >> If you have saved your firmware ROM images, and the checksums for your ROMs >> match these, I would be immensely grateful if you could send me the image >> for IC414 (the middle one of the three). >> >> If as a result of reading this message you feel impelled to save your ROM >> images and find your checksums match these ... >> >> Obviously if I can't find a good image of that ROM, I'll just install the >> older firmware, but one never knows. >> >> Cheers, >> David Partridge _______________________________________________ time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. From alan.melia at btinternet.com Wed Apr 29 20:15:36 2009 From: alan.melia at btinternet.com (Alan Melia) Date: Wed, 29 Apr 2009 21:15:36 +0100 Subject: [time-nuts] Solartron 7081 ROMs References: <1294.1241034612@uk2.net> Message-ID: <002901c9c907$472179a0$0900a8c0@AM> Or find the right prommer Peter :-)) Rom read correctly and image returned to David with the right checksum. Alan G3NYK ----- Original Message ----- From: "Peter Vince" To: ; "Discussion of precise time and frequency measurement" Sent: Wednesday, April 29, 2009 8:50 PM Subject: Re: [time-nuts] Solartron 7081 ROMs > I'm sure there was a message on this group a month or two ago, where the bottom > line was to read the EPROMs with a slightly lower than usual voltage. > > Peter Vince > > > On Tue Apr 28 15:40 , Brooke Clarke sent: > > >Hi Dave: > > > >I've read that there are some tricks to coaxing the data from memory > >chips related to reading them under different conditions. > > > >It's a lot of work, but it's possible to disassemble the code. That > >would allow it to be repaired. > > > >Have Fun, > > > >Brooke Clarke > >http://www.prc68.com > > > > > > > >David C. Partridge wrote: > >> This is a call to anyone who has a Solartron 7081 and has saved a copy of > >> their ROMs (if you haven't you may end up in the same boat as I am - the one > >> that's up the creek without a paddle). > >> > >> One of the ROMs on my earthy processor board has died. > >> > >> It would appear that the ROMs in this 7081 were updated to a high level of > >> firmware at some stage in its life as the total ROM image size is greater > >> than that of a set that was copied by Bill Ezell from his 7081 even though > >> his meter has a higher serial number (461) than mine (180). > >> > >> The ICs in question and the CRC16 checksums (in hex) for my ROM set are: > >> > >> IC430 3238 > >> IC415 C5C0 > >> IC414 1260 > >> IC413 B958 > >> IC412 ED50 > >> > >> If you have saved your firmware ROM images, and the checksums for your ROMs > >> match these, I would be immensely grateful if you could send me the image > >> for IC414 (the middle one of the three). > >> > >> If as a result of reading this message you feel impelled to save your ROM > >> images and find your checksums match these ... > >> > >> Obviously if I can't find a good image of that ROM, I'll just install the > >> older firmware, but one never knows. > >> > >> Cheers, > >> David Partridge > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. From gwinn at raytheon.com Wed Apr 29 20:21:24 2009 From: gwinn at raytheon.com (Joseph M Gwinn) Date: Wed, 29 Apr 2009 16:21:24 -0400 Subject: [time-nuts] Solartron 7081 ROMs In-Reply-To: <1294.1241034612@uk2.net> Message-ID: time-nuts-bounces at febo.com wrote on 04/29/2009 03:50:12 PM: > I'm sure there was a message on this group a month or two ago, > where the bottom > line was to read the EPROMs with a slightly lower than usual voltage. Look up "schmoo plots", which are used to determine the temperature by supply voltage region over which a logic device will operate. Often these are contour maps showing highest operating frequency versus temperature and voltage. Joe Gwinn > Peter Vince > > > On Tue Apr 28 15:40 , Brooke Clarke sent: > > >Hi Dave: > > > >I've read that there are some tricks to coaxing the data from memory > >chips related to reading them under different conditions. > > > >It's a lot of work, but it's possible to disassemble the code. That > >would allow it to be repaired. > > > >Have Fun, > > > >Brooke Clarke > >http://www.prc68.com > > > > > > > >David C. Partridge wrote: > >> This is a call to anyone who has a Solartron 7081 and has > saved a copy of > >> their ROMs (if you haven't you may end up in the same boat > as I am - the one > >> that's up the creek without a paddle). > >> > >> One of the ROMs on my earthy processor board has died. > >> > >> It would appear that the ROMs in this 7081 were updated to a > high level of > >> firmware at some stage in its life as the total ROM image > size is greater > >> than that of a set that was copied by Bill Ezell from his > 7081 even though > >> his meter has a higher serial number (461) than mine (180). > >> > >> The ICs in question and the CRC16 checksums (in hex) for my > ROM set are: > >> > >> IC430 3238 > >> IC415 C5C0 > >> IC414 1260 > >> IC413 B958 > >> IC412 ED50 > >> > >> If you have saved your firmware ROM images, and the > checksums for your ROMs > >> match these, I would be immensely grateful if you could send > me the image > >> for IC414 (the middle one of the three). > >> > >> If as a result of reading this message you feel impelled to > save your ROM > >> images and find your checksums match these ... > >> > >> Obviously if I can't find a good image of that ROM, I'll > just install the > >> older firmware, but one never knows. > >> > >> Cheers, > >> David Partridge > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi- > bin/mailman/listinfo/time-nuts > and follow the instructions there. > > The following line is added for your protection and will be > used for analysis if this message is reported as spam: > > (Raytheon Analysis: IP=64.34.164.147; e-from=time-nuts- > bounces+gwinn=raytheon.com at febo.com; from=pvince at theiet.org; > date=Apr 29, 2009 7:52:38 PM; subject=Re: [time-nuts] Solartron7081 ROMs) From brooke at pacific.net Thu Apr 30 02:00:56 2009 From: brooke at pacific.net (Brooke Clarke) Date: Wed, 29 Apr 2009 19:00:56 -0700 Subject: [time-nuts] HP 117 A On eBay Message-ID: <49F90658.5090700@pacific.net> Hi: Tom Becker asked that I let you know he is selling an HP 117A: http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=150342448013 he also has a link to the HP Journal of 1964. http://www.hparchive.com/Journals/HPJ-1964-10.pdf A trivia item at the end of the article you can see a dymec logo (upside down hp logo). -- Have Fun, Brooke Clarke http://www.prc68.com From magnus at rubidium.dyndns.org Thu Apr 30 13:17:08 2009 From: magnus at rubidium.dyndns.org (Magnus Danielson) Date: Thu, 30 Apr 2009 15:17:08 +0200 Subject: [time-nuts] E1938A Message-ID: <49F9A4D4.6030801@rubidium.dyndns.org> Fellow time-nuts (and Rick in particular), I have been looking through the E1938A documentation available from fellow time-nuts. There is some juicy pieces of information, but also some holes. I does not recall having seing a datasheet or users manual, as available for the 10811 devices. I (think) understand what RX and TX is for, the serial port at CMOS/TTL levels, as it hookes directly to the PIC. But I wonder what the Data to PIC, Data from PIC and PIC data ready is meant to do, looks like a second serial port of some sort. Also, I found another article on it which is not on Ricks homepage where various design decisions etc on production is described. I have not bothered to download it from IEEE, but if Rick could make it available that would be a welcome and interesting reading. Cheers, Magnus From quenbob5 at pacbell.net Thu Apr 30 15:05:10 2009 From: quenbob5 at pacbell.net (Bob Q) Date: Thu, 30 Apr 2009 08:05:10 -0700 Subject: [time-nuts] HP 117 A On eBay References: <49F90658.5090700@pacific.net> Message-ID: <000e01c9c9a5$13d20e90$1801a8c0@BOBCEL1R7> Thanks for posting the link to the hp journal article. I wondered what commercial receivers did about the 45 degree phase shift in the WWVB signal. Looks like they just left it alone. I also like the tracking filter idea. And I got to see a face from the past! Bob Q. ----- Original Message ----- From: "Brooke Clarke" To: "Discussion of precise time and frequency measurement" Sent: Wednesday, April 29, 2009 7:00 PM Subject: [time-nuts] HP 117 A On eBay > Hi: > > Tom Becker asked that I let you know he is selling an HP 117A: > http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=150342448013 > he also has a link to the HP Journal of 1964. > http://www.hparchive.com/Journals/HPJ-1964-10.pdf > > A trivia item at the end of the article you can see a dymec logo (upside > down hp logo). > > -- > Have Fun, > > Brooke Clarke > http://www.prc68.com > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. From pete at petelancashire.com Thu Apr 30 15:52:35 2009 From: pete at petelancashire.com (Pete Lancashire) Date: Thu, 30 Apr 2009 08:52:35 -0700 (PDT) Subject: [time-nuts] HP 117 paper ? Message-ID: <8068c4a905e4b8da6f8382422119e2e6.squirrel@petelancashire.com> Does anyone know if the chart paper is still available ? This fall/winter I want to play with the 117 I found, that is after getting an antenna ... not for serious use but would be nice to have at least one roll. -pete From danrae at verizon.net Thu Apr 30 16:28:51 2009 From: danrae at verizon.net (Dan Rae) Date: Thu, 30 Apr 2009 09:28:51 -0700 Subject: [time-nuts] HP 117 paper ? In-Reply-To: <8068c4a905e4b8da6f8382422119e2e6.squirrel@petelancashire.com> References: <8068c4a905e4b8da6f8382422119e2e6.squirrel@petelancashire.com> Message-ID: <49F9D1C3.9050303@verizon.net> Pete Lancashire wrote: > Does anyone know if the chart paper is still available ? > > I got some many years ago from a local electrical wholesaler in LA, the name Granger comes to mind. It wasn't cheap then, something like $40 a box, but it moves slowly :^) Dan From ed_palmer at sasktel.net Thu Apr 30 17:57:36 2009 From: ed_palmer at sasktel.net (Ed Palmer) Date: Thu, 30 Apr 2009 11:57:36 -0600 Subject: [time-nuts] Chart recorder consumables (was HP 117 paper ) In-Reply-To: <8068c4a905e4b8da6f8382422119e2e6.squirrel@petelancashire.com> References: <8068c4a905e4b8da6f8382422119e2e6.squirrel@petelancashire.com> Message-ID: <49F9E690.1050901@sasktel.net> I've thought about buying one of the phase comparators that have a chart recorder, but I've been concerned about the availability of consumables (i.e. paper and ink / pens ). Are these things generally available? Only some models? I see that the HP 117a uses pressure-sensitive paper. How well does it age? Would an old roll still be usable even if you found one? Would old traces fade away? In a previous life I used Gould / Brush 220 chart recorders that used very smooth coated paper and liquid blue ink that was always making a mess. I wouldn't want to get into that again! Ed Pete Lancashire wrote: > Does anyone know if the chart paper is still available ? > > This fall/winter I want to play with the 117 I found, that > is after getting an antenna ... not for serious use but > would be nice to have at least one roll. > > -pete > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > From holrum at hotmail.com Thu Apr 30 19:28:02 2009 From: holrum at hotmail.com (Mark Sims) Date: Thu, 30 Apr 2009 19:28:02 +0000 Subject: [time-nuts] Chart recorder consumables (was HP 117 paper ) In-Reply-To: References: Message-ID: You can sometimes substitute thermal paper for pressure sensitive paper. Try dragging your fingernail across some thermal paper. The combination of pressure and friction should leave a mark. _________________________________________________________________ Rediscover Hotmail?: Now available on your iPhone or BlackBerry http://windowslive.com/RediscoverHotmail?ocid=TXT_TAGLM_WL_HM_Rediscover_Mobile2_042009 From pete at petelancashire.com Thu Apr 30 19:42:39 2009 From: pete at petelancashire.com (Pete Lancashire) Date: Thu, 30 Apr 2009 12:42:39 -0700 (PDT) Subject: [time-nuts] Chart recorder consumables (was HP 117 paper ) In-Reply-To: References: Message-ID: I just checked and the 117 has about 10 feet left. Since it just for show, that should do it for me. But if it is the type of paper I think it is, you should be able to get it for about $8-10 a roll with the exception the printed chart may not be what you want. -pete > > You can sometimes substitute thermal paper for pressure sensitive paper. > Try dragging your fingernail across some thermal paper. The combination > of pressure and friction should leave a mark. > > > _________________________________________________________________ > Rediscover Hotmail?: Now available on your iPhone or BlackBerry > http://windowslive.com/RediscoverHotmail?ocid=TXT_TAGLM_WL_HM_Rediscover_Mobile2_042009 > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > From holrum at hotmail.com Thu Apr 30 19:39:19 2009 From: holrum at hotmail.com (Mark Sims) Date: Thu, 30 Apr 2009 19:39:19 +0000 Subject: [time-nuts] Chart recorder consumables (was HP 117 paper ) In-Reply-To: References: Message-ID: Forgot to mention... most pressure sensitive paper is just a bas paper coated with an opaque wax. The recorder stylus cuts (or melts) through the wax and shows the paper color. On old paper, the wax can become brittle and flake off. I have also seen some 40+ year old paper that still worked well. Paper can be found for most old chart recorders, but can be VERY expensive. For instance the paper used in Tektronix 1502/1503 TDR's can be had for only $36 a roll. It is just thermal paper with a grid. The trick is that it has a timing track punched along one edge. EKG/ECG paper that fits can be had for $1 a roll. To use it, you have to cobble together a signal that simulates the timing track. Without the pulses, the machine thinks that the paper is out or jammed and stops. _________________________________________________________________ Rediscover Hotmail?: Get e-mail storage that grows with you. http://windowslive.com/RediscoverHotmail?ocid=TXT_TAGLM_WL_HM_Rediscover_Storage2_042009 From danrae at verizon.net Thu Apr 30 19:58:06 2009 From: danrae at verizon.net (Dan Rae) Date: Thu, 30 Apr 2009 12:58:06 -0700 Subject: [time-nuts] Chart recorder consumables (was HP 117 paper ) In-Reply-To: References: Message-ID: <49FA02CE.20605@verizon.net> Further to my earlier note, this paper was used in a number of other instruments, Truetime for one. The Box of Rolls I got way back was made by Amprobe. I just found a bit of it I had used as a bookmark, and it has a Catalog Number printed on the edge: 830AV600. Dan From stanw1le at verizon.net Thu Apr 30 22:09:37 2009 From: stanw1le at verizon.net (Stan W1LE) Date: Thu, 30 Apr 2009 18:09:37 -0400 Subject: [time-nuts] Consumables or the Time Nut Message-ID: <49FA21A1.7090105@verizon.net> Hello The Net: while we are on the topic of consumables... Any ideas on how to restore the pens used in a HP buss plotter ? The ink did not run out, it just dried up from old age, and storage. Possible a few drops of a solvent, but what solvent.... ?? Thanks Stan, W1LE FN41sr Cape Cod From dforbes at dakotacom.net Thu Apr 30 22:25:53 2009 From: dforbes at dakotacom.net (David Forbes) Date: Thu, 30 Apr 2009 15:25:53 -0700 Subject: [time-nuts] Consumables or the Time Nut In-Reply-To: <49FA21A1.7090105@verizon.net> References: <49FA21A1.7090105@verizon.net> Message-ID: At 6:09 PM -0400 4/30/09, Stan W1LE wrote: >Hello The Net: > >while we are on the topic of consumables... > >Any ideas on how to restore the pens used in a HP buss plotter ? > >The ink did not run out, it just dried up from old age, and storage. > >Possible a few drops of a solvent, but what solvent.... ?? > >Thanks Stan, W1LE FN41sr Cape Cod Stan, I did this recently. The ink is soluble in, of all things, water! -- --David Forbes, Tucson, AZ http://www.cathodecorner.com/ From bogus@does.not.exist.com Mon Apr 27 04:27:16 2009 From: bogus@does.not.exist.com () Date: Mon, 27 Apr 2009 04:27:16 -0000 Subject: No subject Message-ID: hour plot. /y /y does a 12 hour plot. /y=3D# does same as the 'v' keyboar= d command (sets display to # hours). If you see something interesting in the plot=2C you can click on that poi= nt and the plot will enter scroll mode and either zoom in or out on that po= int. To resume normal operation click on the plot to get your desired zoom= factor (either zoomed in or out) then press the DEL key to exit scroll mod= e. The program implements the zoom and view features by just skipping over ent= ries in the data queue as it draws the plot. It does not attempt to analyz= e or process the skipped over points. =20 ---------------------------------------- _________________________________________________________________ Hotmail=AE has ever-growing storage! Don=92t worry about storage limits. http://windowslive.com/Tutorial/Hotmail/Storage?ocid=3DTXT_TAGLM_WL_HM_Tuto= rial_Storage1_052009= From bogus@does.not.exist.com Mon Apr 27 04:27:16 2009 From: bogus@does.not.exist.com () Date: Mon, 27 Apr 2009 04:27:16 -0000 Subject: No subject Message-ID: hour plot. /y /y does a 12 hour plot. /y=3D# does same as the 'v' keyboar= d command (sets display to # hours). If you see something interesting in the plot=2C you can click on that poi= nt and the plot will enter scroll mode and either zoom in or out on that po= int. To resume normal operation click on the plot to get your desired zoom= factor (either zoomed in or out) then press the DEL key to exit scroll mod= e. The program implements the zoom and view features by just skipping over ent= ries in the data queue as it draws the plot. It does not attempt to analyz= e or process the skipped over points.=20 _________________________________________________________________ Hotmail=AE has a new way to see what's up with your friends. http://windowslive.com/Tutorial/Hotmail/WhatsNew?ocid=3DTXT_TAGLM_WL_HM_Tut= orial_WhatsNew1_052009= From bogus@does.not.exist.com Mon Apr 27 04:27:16 2009 From: bogus@does.not.exist.com () Date: Mon, 27 Apr 2009 04:27:16 -0000 Subject: No subject Message-ID: hour plot. /y /y does a 12 hour plot. /y=3D# does same as the 'v' keyboar= d command (sets display to # hours). If you see something interesting in the plot=2C you can click on that poi= nt and the plot will enter scroll mode and either zoom in or out on that po= int. To resume normal operation click on the plot to get your desired zoom= factor (either zoomed in or out) then press the DEL key to exit scroll mod= e. The program implements the zoom and view features by just skipping over ent= ries in the data queue as it draws the plot. It does not attempt to analyz= e or process the skipped over points.=20 _________________________________________________________________ Insert movie times and more without leaving Hotmail=AE. http://windowslive.com/Tutorial/Hotmail/QuickAdd?ocid=3DTXT_TAGLM_WL_HM_Tut= orial_QuickAdd1_052009= From bogus@does.not.exist.com Mon Apr 27 04:27:16 2009 From: bogus@does.not.exist.com () Date: Mon, 27 Apr 2009 04:27:16 -0000 Subject: No subject Message-ID: e pretty much not repairable. If the case is solid gold and diamonds=2C et= c it may be reasonable to have the mechanism replaced. Your best bet is to= find a replacement on Ebay. My favorite Seiko/Pulsar analog/digital watch= es that sell for $250+ in a store can be had for less than $20 ($5 if you a= re patient). A watchmaker won't even take the back off for that. _________________________________________________________________ Hotmail=AE has a new way to see what's up with your friends. http://windowslive.com/Tutorial/Hotmail/WhatsNew?ocid=3DTXT_TAGLM_WL_HM_Tut= orial_WhatsNew1_052009= From bogus@does.not.exist.com Mon Apr 27 04:27:16 2009 From: bogus@does.not.exist.com () Date: Mon, 27 Apr 2009 04:27:16 -0000 Subject: No subject Message-ID: 24 hour plot. /y /y does a 12 hour plot. /y=# does same as the 'v' keyboard command (sets display to # hours). If you see something interesting in the plot, you can click on that point and the plot will enter scroll mode and either zoom in or out on that point. To resume normal operation click on the plot to get your desired zoom factor (either zoomed in or out) then press the DEL key to exit scroll mode. The program implements the zoom and view features by just skipping over entries in the data queue as it draws the plot. It does not attempt to analyze or process the skipped over points. _________________________________________________________________ HotmailR goes with you. http://windowslive.com/Tutorial/Hotmail/Mobile?ocid=TXT_TAGLM_WL_HM_Tutorial _Mobile1_052009 _______________________________________________ time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. From bogus@does.not.exist.com Mon Apr 27 04:27:16 2009 From: bogus@does.not.exist.com () Date: Mon, 27 Apr 2009 04:27:16 -0000 Subject: No subject Message-ID: pretty much not repairable. If the case is solid gold and diamonds, etc it may be reasonable to have the mechanism replaced. Your best bet is to find a replacement on Ebay. My favorite Seiko/Pulsar analog/digital watches that sell for $250+ in a store can be had for less than $20 ($5 if you are patient). A watchmaker won't even take the back off for that. _________________________________________________________________ HotmailR has a new way to see what's up with your friends. http://windowslive.com/Tutorial/Hotmail/WhatsNew?ocid=TXT_TAGLM_WL_HM_Tutori al_WhatsNew1_052009 _______________________________________________ time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. From bogus@does.not.exist.com Mon Apr 27 04:27:16 2009 From: bogus@does.not.exist.com () Date: Mon, 27 Apr 2009 04:27:16 -0000 Subject: No subject Message-ID: Good, not fantastic. It has the 20(?) year old kernel code from Dave Mills in the kernel sources. You probably have to build your own kernel to get it. It doesn't have anything newer than that. No new features. No new bugs. [My memory could be fuzzy.] -- These are my opinions, not necessarily my employer's. I hate spam. From bogus@does.not.exist.com Mon Apr 27 04:27:16 2009 From: bogus@does.not.exist.com () Date: Mon, 27 Apr 2009 04:27:16 -0000 Subject: No subject Message-ID: in software from a time source in hardware. Attila Kinali -- If you want to walk fast, walk alone. If you want to walk far, walk together. -- African proverb From bogus@does.not.exist.com Mon Apr 27 04:27:16 2009 From: bogus@does.not.exist.com () Date: Mon, 27 Apr 2009 04:27:16 -0000 Subject: No subject Message-ID: panel and flows across the font of A22, the input amplifier and schmitt trigger boards and the front panel board. The rear of A22 also deflects airflow back through thecard cage and the other boards. The crystal oscillator is screened from direct airflow by a sheet aluminium shield. Thus the airflow is quite complex and one would need to monitor the temperatures of a large number of chips and other components to ensure the cooling is appropriate. Since the top and bottom covers also affect the airflow it would be difficult to use a thermal camera to meaningfully monitor chip temperatures. Even if the top and bottom covers were replaced with infrared transparent materials, a thermal vision camera won't have a clear view of all the EECL and ECL chips. Bruce Rick Karlquist wrote: > Hal Murray wrote: > >> How much ECL is used in a 5070? >> > > A bunch > > How tightly are they packed? > > You need a high cooling velocity even if just one chip. > > >> How much of >> the heat goes directly from the chip to the air rather than from chip to >> board to air? >> > > A substantial amount of cooling is from DIP to air, unlike tiny > SMT packages used now. > > >> How much room is there above the chips? Many years ago I saw some neat >> > > Probably not much extra room. > > Rick Karlquist N6RK > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > From bogus@does.not.exist.com Mon Apr 27 04:27:16 2009 From: bogus@does.not.exist.com () Date: Mon, 27 Apr 2009 04:27:16 -0000 Subject: No subject Message-ID: 1. At one time, Ashtech receiver manuals could be downloaded as PDFs from Ashtech's website. Now, some Ashtech receiver manuals appear to be downloadable from . For example, see , , , . 2. GPS receivers require firmware updates in order to keep up with changes in the GPS signal structure, NAV message content and format, etc. The latest update posted at is dated July 8, 2003. You may have to pay for a firmware update. 3. Remember that Ashtech was merged into Magellan long ago (in the early 1990's IIRC), and that Magellan was merged into Sagem pretty long ago (circa 1996??). Little or no support may be available for a Z-12 now. 4. That said, the Z-12 was an excellent receiver -- the best available at its time. -Chuck W1HIS =========== -John From bogus@does.not.exist.com Mon Apr 27 04:27:16 2009 From: bogus@does.not.exist.com () Date: Mon, 27 Apr 2009 04:27:16 -0000 Subject: No subject Message-ID: > Sound card drift over this four hour period is about 250 micro Hertz. > The temp in the shack was going up during the measurement period. > Unfortunately I did not track the exact temp rise, but was about > around 4 to 6 degrees F. 250 micro Hz relative to 1000 Hz is 1/4 ppm. My memory is that junk PC crystals are ballpark of 1 ppm/degree. (That's probably per degree C rather than F, but that's only a factor of 2.) So 1/4 ppm for 4 degrees is better than I would have guessed. -- These are my opinions, not necessarily my employer's. I hate spam. From bogus@does.not.exist.com Mon Apr 27 04:27:16 2009 From: bogus@does.not.exist.com () Date: Mon, 27 Apr 2009 04:27:16 -0000 Subject: No subject Message-ID: > Sound card drift over this four hour period is about 250 micro Hertz. > The temp in the shack was going up during the measurement period. > Unfortunately I did not track the exact temp rise, but was about > around 4 to 6 degrees F. 250 micro Hz relative to 1000 Hz is 1/4 ppm. My memory is that junk PC crystals are ballpark of 1 ppm/degree. (That's probably per degree C rather than F, but that's only a factor of 2.) So 1/4 ppm for 4 degrees is better than I would have guessed. -- These are my opinions, not necessarily my employer's. I hate spam. _______________________________________________ time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. From bogus@does.not.exist.com Mon Apr 27 04:27:16 2009 From: bogus@does.not.exist.com () Date: Mon, 27 Apr 2009 04:27:16 -0000 Subject: No subject Message-ID: "Finally, graph mode presents a detailed graph of the EFC (electronic frequency control), TI (time interval value), PU (predicted uncertainty) and the number of satellites being tracked. The cursor readout indicates the time and date, and either the EFC or the TI corresponding to the location of the cursor. On typical Z3801A's, measurements confirm that 1 count of EFC is roughly equivalent to 1 part in ten to the twelve." The event seems to start at about 04:00 30/6/09 and is over at about 16:00 on 30/6/09. There is no indication that there was a complete loss of lock to the birds at that time and the number of sats looks no lower than at other times (OK it's not an ideal number of sats but my antenna is in a temp position at the moment and cannot see all of the sky). There is no actual loss of lock, it shows that the peak deviation at that time was about 35ns but obviously something changed to cause the EFC needing to track away from the "norm" to remain in lock. I think I spent most of that day in bed with the flu that's going on here so it was very quiet. We have been having a fair bit of rain here but it has been over many days, not just this Tuesday. Just thinking now, but these times are in UTC so that would represent about 4pm on Tuesday to 4am on Wednesday, again most of time in bed. 73, Steve > Cheers, > Magnus > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > -- Steve Rooke - ZL3TUV & G8KVD & JAKDTTNW A man with one clock knows what time it is; A man with two clocks is never quite sure. --00163646c2e400e246046dde9d55 Content-Type: image/png; name="export.png" Content-Disposition: attachment; filename="export.png" Content-Transfer-Encoding: base64 X-Attachment-Id: f_fwq5qeyv0 iVBORw0KGgoAAAANSUhEUgAAAlgAAAJYCAYAAAC+ZpjcAAAAAXNSR0IArs4c6QAAAARnQU1BAACx jwv8YQUAAAAgY0hSTQAAeiYAAICEAAD6AAAAgOgAAHUwAADqYAAAOpgAABdwnLpRPAAAjL9JREFU eF7tvVuW3DqvZuvqxenJbkR1qJqzn/fz35J69ku1xCcjnQozEADxgaIUukyP4bGWU7yAEyDwiVJG 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r9i6tu3a/lmMZmtVBfnMedR9U4lz2kIAAq8EssdBU3kpguRvMeyLjd71rG82/sjJUr8YrXtE2BOR kx8bqrGw+UvuqjjLhJNSuNRCo7bz/aWf9oyu6WGfV8jbn3tcR+dTE4PCLROgikDpnYJ5DEZjY2uG a3hl/rcCzcaM6lPaQQACdQKV3ySrjy4Ip0z8/EsQ/RfHM+GRvVDe9s/aZiDWnmCp/TM7kusV30vv YPVEUuXEyBaFqDBWCpN3YpTxq5xyKMW7L8pjQZYJCbu2jFckGHpCsXfiVl27wlXxl2LTnnMp/lVs XiPYe+MjrrIdz3UInIzA2tOl1zu0+MXz9yT/fopkH7f1XlqvtFXm9oSkcirn2fGBEAgfEVYLoXdH HZ02qMUx46HYWC1qmbjLrldESXbaowimTIRFDLOC7RXtbO3qdWVdf/dV/EXeM+caZfiaw8a+eDxb Ryaqsz3CdQhA4IQEZgqsVqT0xJEnZv4Vdv0F8tH3n9QTqIzNQcTVN84Thh4mQwACEIAABCAAgUMT +P8B1HTKUVfZEXkAAAAASUVORK5CYII= --00163646c2e400e246046dde9d55-- From bogus@does.not.exist.com Mon Apr 27 04:27:16 2009 From: bogus@does.not.exist.com () Date: Mon, 27 Apr 2009 04:27:16 -0000 Subject: No subject Message-ID: colored part. What about a propane torch applying just enough heat to allow the copper to drop away ? Bill....WB6BNQ Kit Scally wrote: > James, > > These are "before" photo's ... I think a Dremmel is the tool of choice ! > > Kit > VK2LL > > -----Original Message----- > From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On > Behalf Of Lux, James P > Sent: Sunday, 5 July 2009 8:12 AM > To: Discussion of precise time and frequency measurement > Subject: Re: [time-nuts] Broken Ovenaire OSC 85-50 - crystal failure ? > > On 7/4/09 1:49 PM, "Hal Murray" wrote: > > > > > > >> I've not attempted to butcher a capsule open to determine the cause - > > >> this to my mind is bordering on the sacrilegious but if given > >> absolution from another TimeNut, I may attempt it and photograph the > >> results ... > > > > What have you got to lose? Is it good for anything else? > > > > I probably wouldn't bother unless I had a camera that was good enough > > to get a nice picture in case I found something interesting. (This > > might be a good excuse to get a good camera.) > > > > How would you open the can? I was thinking of using a file, but > > that's likely to setup vibrations which could cause enough damage to > > mask the initial problem. Maybe if it was held in a vice. > > > > > > Clearly, the tool of choice is a plasma cutter, because you don't get > the oxidation you do with the oxyacetylene torch, and it works better on > stainless steel anyway. > > Actually, what about a sharp knife making repeated trips around the edge > (think of a tubing cutter). You get a very clean cut. For the old TO-5 > type cans, I've chucked the device in a suitable drill press (a lathe > would work), and used a utility knife on a suitable rest (e.g. A block > of wood). You probably aren't lucky enough to have a round can, though. > > Or a cutoff wheel or saw blade on a dremel type tool. Both work quite > nicely. > > ------------------------------------------------------------------------ > Name: E1938A xtal.jpg > E1938A xtal.jpg Type: JPEG Image (image/jpeg) > Encoding: base64 > > ------------------------------------------------------------------------ > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. From bogus@does.not.exist.com Mon Apr 27 04:27:16 2009 From: bogus@does.not.exist.com () Date: Mon, 27 Apr 2009 04:27:16 -0000 Subject: No subject Message-ID: reference derived from the reception of NMEA data from the USB GPS receiver. It does not contain a pulse-per-second (PPS) kernel nor high-stability oscillators. The NTS1-GPS is not designed nor intended for use in application where high-precision high-stability UTC time is required. Position information is provided by the NTS1-GPS for reference only" > > Cheers All. > > Dave B > G0WBX. > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-= nuts > and follow the instructions there. > --=20 GDB has a 'break' feature; why doesn't it have 'fix' too? From bogus@does.not.exist.com Mon Apr 27 04:27:16 2009 From: bogus@does.not.exist.com () Date: Mon, 27 Apr 2009 04:27:16 -0000 Subject: No subject Message-ID: e by Hunter S. Thompson, who later popularized the style. http://en.wikipedia.org/wiki/Gonzo_journalism =09 From bogus@does.not.exist.com Mon Apr 27 04:27:16 2009 From: bogus@does.not.exist.com () Date: Mon, 27 Apr 2009 04:27:16 -0000 Subject: No subject Message-ID: different outputs, each module a .1, 1, 5, 10 MHz. Most of the standards that same seller had appeared to be 5 MHz out so I expected a 5 meg input. That same data sheet states under MBF options that most of the modules are 5/10 MHz input but two were dedicated 5 or 10 meg only. Perhaps we got the 5 meg only ! From what you are saying, each port on the MBF module is outputting the same thing, strictly distribution. That's fine, perhaps they meant the MFT would pass .1 to 10 meg. If that's the case we should still be able to modify the input module. My application is the same as yours, not a "time-nut" application! I though it worth the gamble for the cheap price. Phil ----- Original Message ----- From: "Demian Martin" To: Sent: Thursday, July 23, 2009 3:48 AM Subject: Re: [time-nuts] EFRATOM MFTD-AC4 FREQUENCY REFERENCE DISTRIBUTIONAMP - update >I received the unit. The shipping and packing was very good- no peanuts! > > The one I got was different from what I expected. It's a 5 MHz unit with > 20 > outputs. More than I could conceivably need. I looked inside. The supply > is > actually 25V. The input module has an FPGA for some reason, probably to > communicate fault back to a host. The signal is distributed as a low level > square wave on the backplane and amplified through a high gain tuned amp > before going to the output amps. The outputs are all monitored. > > I need to figure out the tuned circuit so I can retune it. Would the > performance be better if I bypass the input module and drive the output > modules with a sine wave? I'm using it as a reference for some > not-too-sophisticated counters and generators so the phase noise will be > much better than those could benefit from regardless. > > Demian Martin > PDS > ------------------------------ >> >> Message: 2 >> Date: Mon, 20 Jul 2009 22:46:44 -0700 >> From: "Demian Martin" >> Subject: [time-nuts] EFRATOM MFTD-AC4 FREQUENCY REFERENCE DISTRIBUTION >> AMP >> To: >> Message-ID: <9A1668B965254471953484D102B6A96C at PDSDesktop> >> Content-Type: text/plain; charset="us-ascii" >> >> >> EFRATOM MFTD-AC4 FREQUENCY REFERENCE DISTRIBUTION AMP >> I just bought this off eBay. I was about to look into >> building one but for >> $50 + $25 shipping I could not justify the effort. They have >> 6 more. Item >> number 290330439821. Probably a deal for the box alone. >> >> Is there anything I should know about it? I'm planning to mount a >> Thunderbolt inside it. There is a decent datasheet on the >> family of products >> here: http://www.freewebs.com/beststuff2u/MFS-207.pdf >> >> Demian Martin > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. From bogus@does.not.exist.com Mon Apr 27 04:27:16 2009 From: bogus@does.not.exist.com () Date: Mon, 27 Apr 2009 04:27:16 -0000 Subject: No subject Message-ID: had 4=20 different outputs, each module a .1, 1, 5, 10 MHz. Most of the standards that same seller had appeared to be 5 MHz out so I = expected a 5 meg input. That same data sheet states under MBF options = that=20 most of the modules are 5/10 MHz input but two were dedicated 5 or 10 = meg=20 only. Perhaps we got the 5 meg only ! From what you are saying, each = port on the MBF module is outputting the same thing, strictly distribution. = That's=20 fine, perhaps they meant the MFT would pass .1 to 10 meg. If that's the = case we should still be able to modify the input module. My application is = the=20 same as yours, not a "time-nut" application! I though it worth the gamble for the cheap price. Phil ----- Original Message -----=20 From: "Demian Martin" To: Sent: Thursday, July 23, 2009 3:48 AM Subject: Re: [time-nuts] EFRATOM MFTD-AC4 FREQUENCY REFERENCE=20 DISTRIBUTIONAMP - update >I received the unit. The shipping and packing was very good- no = peanuts! > > The one I got was different from what I expected. It's a 5 MHz unit = with=20 > 20 > outputs. More than I could conceivably need. I looked inside. The = supply=20 > is > actually 25V. The input module has an FPGA for some reason, probably = to > communicate fault back to a host. The signal is distributed as a low = level > square wave on the backplane and amplified through a high gain tuned = amp > before going to the output amps. The outputs are all monitored. > > I need to figure out the tuned circuit so I can retune it. Would the > performance be better if I bypass the input module and drive the = output > modules with a sine wave? I'm using it as a reference for some > not-too-sophisticated counters and generators so the phase noise will = be > much better than those could benefit from regardless. > > Demian Martin > PDS > ------------------------------ >> >> Message: 2 >> Date: Mon, 20 Jul 2009 22:46:44 -0700 >> From: "Demian Martin" >> Subject: [time-nuts] EFRATOM MFTD-AC4 FREQUENCY REFERENCE = DISTRIBUTION >> AMP >> To: >> Message-ID: <9A1668B965254471953484D102B6A96C at PDSDesktop> >> Content-Type: text/plain; charset=3D"us-ascii" >> >> >> EFRATOM MFTD-AC4 FREQUENCY REFERENCE DISTRIBUTION AMP >> I just bought this off eBay. I was about to look into >> building one but for >> $50 + $25 shipping I could not justify the effort. They have >> 6 more. Item >> number 290330439821. Probably a deal for the box alone. >> >> Is there anything I should know about it? I'm planning to mount a >> Thunderbolt inside it. There is a decent datasheet on the >> family of products >> here: http://www.freewebs.com/beststuff2u/MFS-207.pdf >> >> Demian Martin > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to=20 > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there.=20 _______________________________________________ time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. From bogus@does.not.exist.com Mon Apr 27 04:27:16 2009 From: bogus@does.not.exist.com () Date: Mon, 27 Apr 2009 04:27:16 -0000 Subject: No subject Message-ID: urposes. First as an environmental alarm. Second as compensation for temp= erature effects on the system as a whole. As such=2C you want it near whe= re it was. Sticking it on the oscillator would mask a lot of the ambient t= emp changes that it is making adjustments for. Another thing to consider is the difference in the thermal mass / time cons= tant of a DIP package and the SO-8 package. The DIP will respond more slow= ly to temperature changes. It is not known how that might affect the oscil= lator disciplining algorithm. ---------------------------------------- _________________________________________________________________ Windows Live=99 Hotmail=AE: Celebrate the moment with your favorite sports = pics. Check it out. http://www.windowslive.com/Online/Hotmail/Campaign/QuickAdd?ocid=3DTXT_TAGL= M_WL_QA_HM_sports_photos_072009&cat=3Dsports= From bogus@does.not.exist.com Mon Apr 27 04:27:16 2009 From: bogus@does.not.exist.com () Date: Mon, 27 Apr 2009 04:27:16 -0000 Subject: No subject Message-ID: of the two sections in the D310 are not too much like the 310. It looks more like the 500 or 3200 without the final stages. For instance the reference frequencies in the regular 310 come from one SGC module, whereas the D310 uses SGA and SGB. I was surprised when I found that the D310 used different strategies than the 310. So it is a bit different and if you look at the datasheet for the D310, the 0.1 Hz resolution is standard. I certainly expected the 310 and D310 to be based on the same design, but they aren't. Now, back to the GPIB commands. Looking at the GPIB section in the PTS 500 manual, it appears that it uses the command format that I expected. For the extra .1 digit, just add one more digit in the 'F' command. So where did I go wrong? Seems the manual is not quite right in its examples. I was stringing commands together like 'f1234567a0[LF]', the a0 being command for max output level. That's what the manuals show in an example or two, but seems the hardware gets confused if there is more that 1 command with just 1 LF at the end. I think 'f1234567[LF]a0[LF]' is ok. If I send it just 'f1234567[LF]' I get 123456.7 Hz, which is what I expected. With 'f1234567a0[LF]' I get 1.234567 MHz. So it seems the controller wants a LF after each command to not get confused. There may be some finesse points I haven't worked out yet, but I'm on the right track now. ----------- Hi Rex I'm glad to hear you're getting it sorted and that sounds like a really interesting unit, I'm quite jealous:-) I hadn't expected the D310 to be anything more than two standard 310s in the same box so that's another variant to add to the list. Between PTS, Wavetek, and Rockland, there's a variety of units that throw up some interesting similarities, although sometimes with subtle or not so subtle differences , and then there are some quite different, such as the PTS310 and the DDS version of the PTS160. I bought one of the latter a while ago, without realising up front what it was, only to have a small and so far unidentified daughter board, not obviously part of the DDS board itself, detach itself in transit. I put that to one side and never did investigate further, probably time I did, but the PTS160 manual doesn't even acknowledge the existence of that version. regards Nigel GM8PZR From bogus@does.not.exist.com Mon Apr 27 04:27:16 2009 From: bogus@does.not.exist.com () Date: Mon, 27 Apr 2009 04:27:16 -0000 Subject: No subject Message-ID: long term aging. When you want to know what the aging will be over the next 10 years,=20 Allan needs to have 30 or 40 years of data. Not the most practical way. I have found for long term aging, taking data at around once per month = generally does a good job, IF the osc is a "good osc" Not sure if the attached under 60k plot will be seen. It is plot of actual data for 3 of my Osc over a 5 to 9 year time span. = (Ref was GPS) The 10MHz SC10 shows a very consistent -8.3e-11 per day aging rate, = after a two year 'warm up.' The Dana 1992 high stability option shows a less consistent +2e-10 per = day rate,=20 and the 5MHz, a small OXCO, has a Zero aging rate averaged over the last = 6 years, and shows it can be pretty misleading to talk about just aging = rate per year if the stability is not there. warren ******************* ----- Original Message -----=20 From: "John Green" To: Sent: Tuesday, August 04, 2009 6:38 AM Subject: Re: [time-nuts] Allan deviation plots etc > Ulrich Bangert wrote: > my point has not been to judge who has to be interested in what. My = point > has only been to use the right terms for it. Let me give an example: = John > uses the term >=20 >> ...but I am more concerned with ... and stability over time >=20 > Well, stability over time is what exacly is displayed in a = tau-sigma-diagram > of an oscillator. Since only a few words before he is saying that he = is NOT > intersted into Allan Deviation plots, then he is perhaps interested = into > something else? >=20 > Allan deviation plots are interesting and if I had the means to = generate > them, I certainly would. Since I don't, I find it easier to interest = myself > in ways to try to measure oscillator performance in practical terms = with > the equipment at hand. What I would really like is to be able to = produce a > specification in the same form as the oscillator manufacturers. I am = used to > data in that form and while the Allan deviation gives somewhat the = same > data, I rarely see one that gives a clue to stability over a year or = 10 > years. Most of the ones I see seem more concerned with seconds to = hours and > maybe weeks at most. Of course, my method won't give any clue as to = how an > oscillator will perform over years either. > I hope this clears things up a bit. >=20 > ------=_NextPart_000_0788_01CA14DB.2C30A7E0 Content-Type: image/jpeg; name="Long term Osc1.jpg" Content-Transfer-Encoding: base64 Content-Disposition: attachment; filename="Long term Osc1.jpg" /9j/4AAQSkZJRgABAgAAAQABAAD/4B7KSkZYWAATQCnv7e/49vj//v/08vT//v/9+/39+/3//f/d 293+///7/P/4///6///2///+///59/n5///5/////v/6///9//z//P////L///X///739/L///7/ /v/+/vf8+vz//v///v/6+vX///7//v///v///v//+v7//v///v///v///v/8+vz//f/8+vz//v// /v///v///v/9+/39+/3//v///v8BAAEBAAH//v8BAAH//v///f/7+fv//v/7+fsBAAETERP//v// /v///v///v///v///v/k4uT//v///v/e9v//2+L/6Mjsan//+uz/+PD7/P//kZ3/4efhYG7wkZz/ 9v///f/KyP/49Pzz//MJFbz69//p39nb3f/z+//3//n+/+IgFqL++v/18/////v//v/f//Xz8uff 8er7//72/fTW/elIknJxmYVPfGZzmobo9eprgHLC5NK58tj9/////f///v///v///v/+/P7//v/3 9ff6+Pr//v///v///v///v///f///v/9+/3y8PL//v///v///v///v///v//8//65+fw/+f/7Oz/ 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When you want to know what the aging will be over the next 10 years,=20 Allan needs to have 30 or 40 years of data. Not the most practical way. I have found for long term aging, taking data at around once per month = generally does a good job, IF the osc is a "good osc" Not sure if the attached under 60k plot will be seen. It is plot of actual data for 3 of my Osc over a 5 to 9 year time span. = (Ref was GPS) The 10MHz SC10 shows a very consistent -8.3e-11 per day aging rate, = after a two year 'warm up.' The Dana 1992 high stability option shows a less consistent +2e-10 per = day rate,=20 and the 5MHz, a small OXCO, has a Zero aging rate averaged over the last = 6 years, and shows it can be pretty misleading to talk about just aging = rate per year if the stability is not there. warren ******************* From bogus@does.not.exist.com Mon Apr 27 04:27:16 2009 From: bogus@does.not.exist.com () Date: Mon, 27 Apr 2009 04:27:16 -0000 Subject: No subject Message-ID: we were talking about the fairly linear drift in crystal oscillators for which HD handles. If there is a non-stable drift, it's going to be an interesting exercise to be able to process that out of the data easily. Agreed if the drift can be characterized to fit some form function but I would call that a stable drift anyway. I also had the impression, and please correct me if I'm wrong, that the use of the additional adjacent data point in HD calculations resolved the issues with drift at any point in the data stream. Cheers, Steve -- Steve Rooke - ZL3TUV & G8KVD A man with one clock knows what time it is; A man with two clocks is never quite sure. From bogus@does.not.exist.com Mon Apr 27 04:27:16 2009 From: bogus@does.not.exist.com () Date: Mon, 27 Apr 2009 04:27:16 -0000 Subject: No subject Message-ID: devices would do the same job, perhaps a 2N3055 for example?, the hardest part might be matching the shape but where it's mounted would determine how necessary that would be. Second, unless I've missed something somewhere, are you sure it needs replacing? From bogus@does.not.exist.com Mon Apr 27 04:27:16 2009 From: bogus@does.not.exist.com () Date: Mon, 27 Apr 2009 04:27:16 -0000 Subject: No subject Message-ID: was high, but also seem to recall it being pretty close. Have you checked the transistor, or just measured either side of it to see if it seems to be regulating? A voltage a bit high or low on a regulated supply usually indicates just a need for adjustment. If there's no adjustable preset it might indicate the designer didn't consider the absolute value to be that critical anyway. regards Nigel GM8PZR