[time-nuts] time-nuts Digest, Vol 65, Issue 103
Bob Camp
lists at cq.nu
Sat Dec 26 22:59:42 UTC 2009
Hi
A lot depends on your definition of low power.
To some an EMXO is low power, to other's it's grossly high power. People have indeed rigged up portable rubidiums with battery packs. I would not call them low power, but they are portable.
If the microamp current drain of a quartz watch at a bit over a volt is the standard of low power, then the answer is no. There's nothing lower power than that with better accuracy.
As always the answer is indeed that depends ...
1) How big / heavy / rugged?
2) How long does it operate on it's own?
3) What's the temperature range and the rest of the environment?
4) How accurate do you need?
5) Does it need to be autonomous?
Tough to beat a self winding quartz wrist watch, unless it's not accurate enough to do what you need to do.
Bob
On Dec 26, 2009, at 5:25 PM, Ronald Held wrote:
> Should I assume from these posts that there are no portable low power
> commercial products better than a thermocompensated quartz watch
> working at ~10^-7?
>
> Ronald
>
> On Sat, Dec 26, 2009 at 1:09 PM, <time-nuts-request at febo.com> wrote:
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>> Today's Topics:
>>
>> 1. Re: chip scale atomic clock (Robert Lutwak)
>> 2. Re: Cheap Rubidium (Bob Camp)
>> 3. Re: chip scale atomic clock (paul swed)
>> 4. Re: chip scale atomic clock (Bob Camp)
>>
>>
>> ----------------------------------------------------------------------
>>
>> Message: 1
>> Date: Sat, 26 Dec 2009 12:30:08 -0500
>> From: Robert Lutwak <Lutwak at alum.mit.edu>
>> Subject: Re: [time-nuts] chip scale atomic clock
>> To: Discussion of precise time and frequency measurement
>> <time-nuts at febo.com>
>> Message-ID: <mailman.139.1261850952.18811.time-nuts at febo.com>
>> Content-Type: text/plain; charset="us-ascii"; format=flowed
>>
>> Notwithstanding the performance of one physics package, I think it's
>> safe to say that no-one is holding their breath waiting for a 1e-11 CSAC.
>>
>> That figure (5B) shows the Allan deviation of 10 physics packages
>> (measured with optimal laboratory electronics) and you are correct
>> that the best of the bunch is down around 2-3e-11 at 1-second. At
>> that time, with low-power CSAC electronics, the performance of that
>> same physics package was up around 1e-10 and most were in the 2-3e-10
>> range (see Figure 6), which would have led to a spec somewhere north
>> of there, perhaps 3-4e-10.
>>
>> For your amusement, I just added a more recent paper (from the 2009
>> FCS/EFTF) to my WWW site. Figure 3 in that paper shows some more
>> recent results with (newer, better, and lower power) electronics but
>> similar physics package architecture. These days, typical CSAC
>> instability is in the range of 8-10e-11 @ 1second, which might lead
>> to a spec in the 1-3e-10 range.
>>
>> -RL
>>
>>
>> At 11:41 AM 12/26/2009, you wrote:
>>> Hi
>>>
>>> I *knew* I'd seen a chart somewhere that was getting close to
>>> 1x10-11 at 1 second for the best of the group.
>>>
>>> It's figure B on page 7 of your FSM 2008 paper.
>>>
>>> Bob
>>>
>>>
>>> On Dec 26, 2009, at 10:36 AM, Robert Lutwak wrote:
>>>
>>>> I pay pretty close attention to what people in this field are
>>> saying, and I've never heard anyone say "we'll get to 1e-11 short
>>> term stability at 1 second real soon now."
>>>>
>>>> 1e-11 at 1 second is the XPRO spec (and 2X better than LPRO or
>>> PRS10). There are good (physics) reasons why those units all draw
>>> 100X more power than a CSAC.
>>>>
>>>> CSAC is intended for portable battery-powered operation. Surely
>>> your basement has the space and wallplug power to support an LPRO.
>>> (p.s. don't cool the damn thing, heat it).
>>>>
>>>> The cats were much happier during the CsIII development (see
>>> http://home.comcast.net/~rlutwak). It was bigger and warmer. Any
>>> Cat-Nuts out there who can help me find one with significantly lower SWAP?
>>>>
>>>> -RL
>>>>
>>>> At 10:08 AM 12/26/2009, you wrote:
>>>>> Hi
>>>>>
>>>>> 1x10-11 at 1 second, going down by tau^0.5.
>>>>>
>>>>> That makes them candidates for the basement system ....
>>>>>
>>>>> Bob
>>>>>
>>>>> On Dec 26, 2009, at 9:33 AM, Robert Lutwak wrote:
>>>>>
>>>>>> How "good" do you want?
>>>>>>
>>>>>>
>>>>>> At 09:13 AM 12/26/2009, you wrote:
>>>>>>> Hi
>>>>>>>
>>>>>>> They still seem to be at the stage of "we'll get to good
>>> short term stability at 1 second real soon now".
>>>>>>>
>>>>>>> Bob
>>>>>>>
>>>>>>>
>>>>>>> On Dec 26, 2009, at 8:23 AM, Ronald Held wrote:
>>>>>>>
>>>>>>>> I read about this a while ago. Has anyone seen anything recent about
>>>>>>>> it, notably desktop or even portable units?
>>>>>>>> Ronald
>>>>>>>>
>>>>>>>> _______________________________________________
>>>>>>>> time-nuts mailing list -- 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.
>>>>>>
>>>>>>
>>>>>>
>>>>>> -RL
>>>>>>
>>>>>> -----------------------
>>>>>> Robert Lutwak
>>>>>> Symmetricom - Technology Realization Center
>>>>>>
>>> <mhtml:mid://00000000/mailto:RLutwak@Symmetricom.com>RLutwak at Symmetricom.com
>>> (Business)
>>>>>>
>>> <mhtml:mid://00000000/mailto:Lutwak@Alum.mit.edu>Lutwak at Alum.mit.edu (Personal)
>>>>>> (978) 232-1461 (Desk)
>>>>>> (339) 927-7896 (Mobile)
>>>>>> (978) 927-4099 (Facsimile)
>>>>>>
>>>>>>
>>>>>>
>>>>>> -RL
>>>>>>
>>>>>> -----------------------
>>>>>> Robert Lutwak
>>>>>> Symmetricom - Technology Realization Center
>>>>>>
>>> <mhtml:mid://00000000/mailto:RLutwak@Symmetricom.com>RLutwak at Symmetricom.com
>>> (Business)
>>>>>>
>>> <mhtml:mid://00000000/mailto:Lutwak@Alum.mit.edu>Lutwak at Alum.mit.edu (Personal)
>>>>>> (978) 232-1461 (Desk)
>>>>>> (339) 927-7896 (Mobile)
>>>>>> (978) 927-4099 (Facsimile)
>>>>>> _______________________________________________
>>>>>> time-nuts mailing list -- 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.
>>>>
>>>>
>>>>
>>>> -RL
>>>>
>>>> -----------------------
>>>> Robert Lutwak
>>>> Symmetricom - Technology Realization Center
>>>>
>>> <mhtml:mid://00000000/mailto:RLutwak@Symmetricom.com>RLutwak at Symmetricom.com
>>> (Business)
>>>>
>>> <mhtml:mid://00000000/mailto:Lutwak@Alum.mit.edu>Lutwak at Alum.mit.edu (Personal)
>>>> (978) 232-1461 (Desk)
>>>> (339) 927-7896 (Mobile)
>>>> (978) 927-4099 (Facsimile)
>>>>
>>>>
>>>>
>>>> -RL
>>>>
>>>> -----------------------
>>>> Robert Lutwak
>>>> Symmetricom - Technology Realization Center
>>>>
>>> <mhtml:mid://00000000/mailto:RLutwak@Symmetricom.com>RLutwak at Symmetricom.com
>>> (Business)
>>>>
>>> <mhtml:mid://00000000/mailto:Lutwak@Alum.mit.edu>Lutwak at Alum.mit.edu (Personal)
>>>> (978) 232-1461 (Desk)
>>>> (339) 927-7896 (Mobile)
>>>> (978) 927-4099 (Facsimile)
>>>> _______________________________________________
>>>> time-nuts mailing list -- 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.
>>
>>
>>
>> -RL
>>
>> -----------------------
>> Robert Lutwak
>> Symmetricom - Technology Realization Center
>> <mhtml:mid://00000000/mailto:RLutwak@Symmetricom.com>RLutwak at Symmetricom.com
>> (Business)
>> <mhtml:mid://00000000/mailto:Lutwak@Alum.mit.edu>Lutwak at Alum.mit.edu
>> (Personal)
>> (978) 232-1461 (Desk)
>> (339) 927-7896 (Mobile)
>> (978) 927-4099 (Facsimile)
>>
>>
>>
>> -RL
>>
>> -----------------------
>> Robert Lutwak
>> Symmetricom - Technology Realization Center
>> <mhtml:mid://00000000/mailto:RLutwak@Symmetricom.com>RLutwak at Symmetricom.com
>> (Business)
>> <mhtml:mid://00000000/mailto:Lutwak@Alum.mit.edu>Lutwak at Alum.mit.edu
>> (Personal)
>> (978) 232-1461 (Desk)
>> (339) 927-7896 (Mobile)
>> (978) 927-4099 (Facsimile)
>>
>>
>> ------------------------------
>>
>> Message: 2
>> Date: Sat, 26 Dec 2009 12:37:06 -0500
>> From: Bob Camp <lists at cq.nu>
>> Subject: Re: [time-nuts] Cheap Rubidium
>> To: Discussion of precise time and frequency measurement
>> <time-nuts at febo.com>
>> Message-ID: <0CF40F1B-AE56-4F94-8D72-4BFA9BE1E347 at cq.nu>
>> Content-Type: text/plain; charset=us-ascii
>>
>> Hi
>>
>> Unfortunately, I can see the main water tower from my front yard. We don't spend much money heating shower water in the summer.....
>>
>> Bob
>>
>>
>> On Dec 26, 2009, at 12:03 PM, J. Forster wrote:
>>
>>> In most single family houses, the water supply is pretty constant
>>> temperature because the pipes typically run well underground for miles and
>>> miles. Seasonal temperature variations don't usually go down more than a
>>> few feet. The pipes are often deeper.
>>>
>>> -John
>>>
>>> =============
>>>
>>>> Hi,
>>>>
>>>> In most rural or semi-rural areas over here in Canterbury, New
>>>> Zealand, water is provided by a well on the domicile section. Wells
>>>> are drilled into the natural aquifer formed by volcanic ash which we
>>>> live on so it is relatively easy to create a bore hole and take
>>>> advantage of the naturally filtered water from quite a distance below
>>>> the surface. I wouldn't mind betting that this water comes out of the
>>>> ground at a very constant temperature season by season and the amount
>>>> needed to flow over the rb heatsink to hold it steady would not be so
>>>> great as to be able to be wasted back into the drains.
>>>>
>>>> Ths would save all the messing about pumping water down into a bore
>>>> and pumping it back up again. Although I appreciate that not everone
>>>> is in the position to do this but some may already have a water supply
>>>> like this, even for garden irrigation. When I lived out in the sticks
>>>> I had reticulated water on the drip for the house uses but my own bore
>>>> for garden irrigation.
>>>>
>>>> 73
>>>> Steve
>>>>
>>>> 2009/12/25 Bob Camp <lists at cq.nu>:
>>>>> Hi
>>>>>
>>>>> Actually burying a recirculating loop might work pretty well. The gotcha
>>>>> is that going much deeper than 18" would require significant amounts of
>>>>> blasting powder. I suspect the neighbors *might* object ....
>>>>>
>>>>> Bob
>>>>>
>>>>>
>>>>> On Dec 24, 2009, at 3:32 PM, Don Latham wrote:
>>>>>
>>>>>> Actually, couldn't you just squeeze your fish before you eat it? Should
>>>>>> have a lot of mercury in notime, according to the scaremongers.
>>>>>> Also, consider a heatsink buried about 10-15 feet deep. The temperature
>>>>>> at
>>>>>> that depth in the ground does not vary very much at all. The trick to
>>>>>> all
>>>>>> of this is to have a heatsink/source at a constant temp somewhere...
>>>>>> Merry Christams to all the nuts!
>>>>>> Don
>>>>>>
>>>>>> Bruce Griffiths
>>>>>>> Magnus Danielson wrote:
>>>>>>>> Bruce,
>>>>>>>>
>>>>>>>> Bruce Griffiths wrote:
>>>>>>>>> At your location, at present, it wouldnt be a significant problem as
>>>>>>>>> long as the basement was unheated.
>>>>>>>>
>>>>>>>> Depends. But having 3 dm snow on the ground helps to keep the ground
>>>>>>>> around the house warmer, as it will insulate against the cold of the
>>>>>>>> open sky. -12.8 C is the lowest so far. Since winter is reoccuring,
>>>>>>>> we
>>>>>>>> build the houses accordingly.
>>>>>>>>
>>>>>>>>> Also good ventilation would help, together with a thin layer of oil
>>>>>>>>> on top of the mercury.
>>>>>>>>
>>>>>>>> Mmm. Yes, didn't think about covering the baths with fluids.
>>>>>>>>
>>>>>>>>> The biggest obstacle would be the cost of the Mercury.
>>>>>>>>
>>>>>>>> Actually, it could be an obstcle just obtaining in those amounts it
>>>>>>>> here within EC, so it would involve some form of approval of some
>>>>>>>> form
>>>>>>>> of excempt since it is mercury is a ROS element.
>>>>>>>>
>>>>>>>> Cheers,
>>>>>>>> Magnus
>>>>>>>>
>>>>>>>>
>>>>>>> Guidline price is around $US600/flask (1 flask = 34.5kg).
>>>>>>> Thus cost for 145 ton would be around $US2.5million.
>>>>>>>
>>>>>>> The Canadians have a liquid mercury mirror telescope about 6m in
>>>>>>> diameter.
>>>>>>> Whilst this doesn't use 145 tons of mercury the surface area would be
>>>>>>> of
>>>>>>> the same order.
>>>>>>>
>>>>>>> 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.
>>>>>>>
>>>>>>
>>>>>>
>>>>>> --
>>>>>> 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.
>>>>>>
>>>>>
>>>>>
>>>>> _______________________________________________
>>>>> time-nuts mailing list -- 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
>>>> A man with one clock knows what time it is;
>>>> A man with two clocks is never quite sure.
>>>>
>>>> _______________________________________________
>>>> time-nuts mailing list -- 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: Sat, 26 Dec 2009 13:01:08 -0500
>> From: paul swed <paulswedb at gmail.com>
>> Subject: Re: [time-nuts] chip scale atomic clock
>> To: Discussion of precise time and frequency measurement
>> <time-nuts at febo.com>
>> Message-ID:
>> <ac803ca80912261001m510f4120s2f3dea9063cfa7e2 at mail.gmail.com>
>> Content-Type: text/plain; charset=ISO-8859-1
>>
>> So when do we see them on ebay?? ;-) Like the low power aspect. instead of
>> 20-40 watts or more
>>
>> On Sat, Dec 26, 2009 at 11:14 AM, Bob Camp <lists at cq.nu> wrote:
>>
>>> Hi
>>>
>>> Not ment as a knock, just a comment that a lot of work is still being done
>>> on getting short term stability closer to a 100~1000X bigger device.
>>>
>>> Bob
>>>
>>>
>>> On Dec 26, 2009, at 10:36 AM, Robert Lutwak wrote:
>>>
>>>> I pay pretty close attention to what people in this field are saying, and
>>> I've never heard anyone say "we'll get to 1e-11 short term stability at 1
>>> second real soon now."
>>>>
>>>> 1e-11 at 1 second is the XPRO spec (and 2X better than LPRO or PRS10).
>>> There are good (physics) reasons why those units all draw 100X more power
>>> than a CSAC.
>>>>
>>>> CSAC is intended for portable battery-powered operation. Surely your
>>> basement has the space and wallplug power to support an LPRO. (p.s. don't
>>> cool the damn thing, heat it).
>>>>
>>>> The cats were much happier during the CsIII development (see
>>> http://home.comcast.net/~rlutwak <http://home.comcast.net/%7Erlutwak>). It
>>> was bigger and warmer. Any Cat-Nuts out there who can help me find one with
>>> significantly lower SWAP?
>>>>
>>>> -RL
>>>>
>>>> At 10:08 AM 12/26/2009, you wrote:
>>>>> Hi
>>>>>
>>>>> 1x10-11 at 1 second, going down by tau^0.5.
>>>>>
>>>>> That makes them candidates for the basement system ....
>>>>>
>>>>> Bob
>>>>>
>>>>> On Dec 26, 2009, at 9:33 AM, Robert Lutwak wrote:
>>>>>
>>>>>> How "good" do you want?
>>>>>>
>>>>>>
>>>>>> At 09:13 AM 12/26/2009, you wrote:
>>>>>>> Hi
>>>>>>>
>>>>>>> They still seem to be at the stage of "we'll get to good short term
>>> stability at 1 second real soon now".
>>>>>>>
>>>>>>> Bob
>>>>>>>
>>>>>>>
>>>>>>> On Dec 26, 2009, at 8:23 AM, Ronald Held wrote:
>>>>>>>
>>>>>>>> I read about this a while ago. Has anyone seen anything recent
>>> about
>>>>>>>> it, notably desktop or even portable units?
>>>>>>>> Ronald
>>>>>>>>
>>>>>>>> _______________________________________________
>>>>>>>> time-nuts mailing list -- 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.
>>>>>>
>>>>>>
>>>>>>
>>>>>> -RL
>>>>>>
>>>>>> -----------------------
>>>>>> Robert Lutwak
>>>>>> Symmetricom - Technology Realization Center
>>>>>> <mhtml:mid://00000000/mailto:RLutwak@Symmetricom.com
>>>> RLutwak at Symmetricom.com (Business)
>>>>>> <mhtml:mid://00000000/mailto:Lutwak@Alum.mit.edu>Lutwak at Alum.mit.edu(Personal)
>>>>>> (978) 232-1461 (Desk)
>>>>>> (339) 927-7896 (Mobile)
>>>>>> (978) 927-4099 (Facsimile)
>>>>>>
>>>>>>
>>>>>>
>>>>>> -RL
>>>>>>
>>>>>> -----------------------
>>>>>> Robert Lutwak
>>>>>> Symmetricom - Technology Realization Center
>>>>>> <mhtml:mid://00000000/mailto:RLutwak@Symmetricom.com
>>>> RLutwak at Symmetricom.com (Business)
>>>>>> <mhtml:mid://00000000/mailto:Lutwak@Alum.mit.edu>Lutwak at Alum.mit.edu(Personal)
>>>>>> (978) 232-1461 (Desk)
>>>>>> (339) 927-7896 (Mobile)
>>>>>> (978) 927-4099 (Facsimile)
>>>>>> _______________________________________________
>>>>>> time-nuts mailing list -- 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.
>>>>
>>>>
>>>>
>>>> -RL
>>>>
>>>> -----------------------
>>>> Robert Lutwak
>>>> Symmetricom - Technology Realization Center
>>>> <mhtml:mid://00000000/mailto:RLutwak@Symmetricom.com
>>>> RLutwak at Symmetricom.com (Business)
>>>> <mhtml:mid://00000000/mailto:Lutwak@Alum.mit.edu>Lutwak at Alum.mit.edu(Personal)
>>>> (978) 232-1461 (Desk)
>>>> (339) 927-7896 (Mobile)
>>>> (978) 927-4099 (Facsimile)
>>>>
>>>>
>>>>
>>>> -RL
>>>>
>>>> -----------------------
>>>> Robert Lutwak
>>>> Symmetricom - Technology Realization Center
>>>> <mhtml:mid://00000000/mailto:RLutwak@Symmetricom.com
>>>> RLutwak at Symmetricom.com (Business)
>>>> <mhtml:mid://00000000/mailto:Lutwak@Alum.mit.edu>Lutwak at Alum.mit.edu(Personal)
>>>> (978) 232-1461 (Desk)
>>>> (339) 927-7896 (Mobile)
>>>> (978) 927-4099 (Facsimile)
>>>> _______________________________________________
>>>> time-nuts mailing list -- 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: 4
>> Date: Sat, 26 Dec 2009 13:09:06 -0500
>> From: Bob Camp <lists at cq.nu>
>> Subject: Re: [time-nuts] chip scale atomic clock
>> To: Discussion of precise time and frequency measurement
>> <time-nuts at febo.com>
>> Message-ID: <CE6AC93C-5478-4F4A-8494-4BFB106C67BC at cq.nu>
>> Content-Type: text/plain; charset=us-ascii
>>
>> Hi
>>
>> Thanks, that's one I hadn't seen yet. I did not get Besancon this year.
>>
>> I guess my main point is that *if* the physics package is capable of ~2x10^-11 with good electronics, then what ever you get past that is simply mission related. A different system requirement could take the performance closer to that "ideal".
>>
>> Good to see that the RbXO is coming back to life (again). It would have been nice to get it into production back at EG&G.
>>
>> Bob
>>
>> On Dec 26, 2009, at 12:30 PM, Robert Lutwak wrote:
>>
>>> Notwithstanding the performance of one physics package, I think it's safe to say that no-one is holding their breath waiting for a 1e-11 CSAC.
>>>
>>> That figure (5B) shows the Allan deviation of 10 physics packages (measured with optimal laboratory electronics) and you are correct that the best of the bunch is down around 2-3e-11 at 1-second. At that time, with low-power CSAC electronics, the performance of that same physics package was up around 1e-10 and most were in the 2-3e-10 range (see Figure 6), which would have led to a spec somewhere north of there, perhaps 3-4e-10.
>>>
>>> For your amusement, I just added a more recent paper (from the 2009 FCS/EFTF) to my WWW site. Figure 3 in that paper shows some more recent results with (newer, better, and lower power) electronics but similar physics package architecture. These days, typical CSAC instability is in the range of 8-10e-11 @ 1second, which might lead to a spec in the 1-3e-10 range.
>>>
>>> -RL
>>>
>>>
>>> At 11:41 AM 12/26/2009, you wrote:
>>>> Hi
>>>>
>>>> I *knew* I'd seen a chart somewhere that was getting close to 1x10-11 at 1 second for the best of the group.
>>>>
>>>> It's figure B on page 7 of your FSM 2008 paper.
>>>>
>>>> Bob
>>>>
>>>>
>>>> On Dec 26, 2009, at 10:36 AM, Robert Lutwak wrote:
>>>>
>>>>> I pay pretty close attention to what people in this field are saying, and I've never heard anyone say "we'll get to 1e-11 short term stability at 1 second real soon now."
>>>>>
>>>>> 1e-11 at 1 second is the XPRO spec (and 2X better than LPRO or PRS10). There are good (physics) reasons why those units all draw 100X more power than a CSAC.
>>>>>
>>>>> CSAC is intended for portable battery-powered operation. Surely your basement has the space and wallplug power to support an LPRO. (p.s. don't cool the damn thing, heat it).
>>>>>
>>>>> The cats were much happier during the CsIII development (see http://home.comcast.net/~rlutwak). It was bigger and warmer. Any Cat-Nuts out there who can help me find one with significantly lower SWAP?
>>>>>
>>>>> -RL
>>>>>
>>>>> At 10:08 AM 12/26/2009, you wrote:
>>>>>> Hi
>>>>>>
>>>>>> 1x10-11 at 1 second, going down by tau^0.5.
>>>>>>
>>>>>> That makes them candidates for the basement system ....
>>>>>>
>>>>>> Bob
>>>>>>
>>>>>> On Dec 26, 2009, at 9:33 AM, Robert Lutwak wrote:
>>>>>>
>>>>>>> How "good" do you want?
>>>>>>>
>>>>>>>
>>>>>>> At 09:13 AM 12/26/2009, you wrote:
>>>>>>>> Hi
>>>>>>>>
>>>>>>>> They still seem to be at the stage of "we'll get to good short term stability at 1 second real soon now".
>>>>>>>>
>>>>>>>> Bob
>>>>>>>>
>>>>>>>>
>>>>>>>> On Dec 26, 2009, at 8:23 AM, Ronald Held wrote:
>>>>>>>>
>>>>>>>>> I read about this a while ago. Has anyone seen anything recent about
>>>>>>>>> it, notably desktop or even portable units?
>>>>>>>>> Ronald
>>>>>>>>>
>>>>>>>>> _______________________________________________
>>>>>>>>> time-nuts mailing list -- 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.
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>> -RL
>>>>>>>
>>>>>>> -----------------------
>>>>>>> Robert Lutwak
>>>>>>> Symmetricom - Technology Realization Center
>>>>>>> <mhtml:mid://00000000/mailto:RLutwak@Symmetricom.com>RLutwak at Symmetricom.com (Business)
>>>>>>> <mhtml:mid://00000000/mailto:Lutwak@Alum.mit.edu>Lutwak at Alum.mit.edu (Personal)
>>>>>>> (978) 232-1461 (Desk)
>>>>>>> (339) 927-7896 (Mobile)
>>>>>>> (978) 927-4099 (Facsimile)
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>> -RL
>>>>>>>
>>>>>>> -----------------------
>>>>>>> Robert Lutwak
>>>>>>> Symmetricom - Technology Realization Center
>>>>>>> <mhtml:mid://00000000/mailto:RLutwak@Symmetricom.com>RLutwak at Symmetricom.com (Business)
>>>>>>> <mhtml:mid://00000000/mailto:Lutwak@Alum.mit.edu>Lutwak at Alum.mit.edu (Personal)
>>>>>>> (978) 232-1461 (Desk)
>>>>>>> (339) 927-7896 (Mobile)
>>>>>>> (978) 927-4099 (Facsimile)
>>>>>>> _______________________________________________
>>>>>>> time-nuts mailing list -- 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.
>>>>>
>>>>>
>>>>>
>>>>> -RL
>>>>>
>>>>> -----------------------
>>>>> Robert Lutwak
>>>>> Symmetricom - Technology Realization Center
>>>>> <mhtml:mid://00000000/mailto:RLutwak@Symmetricom.com>RLutwak at Symmetricom.com (Business)
>>>>> <mhtml:mid://00000000/mailto:Lutwak@Alum.mit.edu>Lutwak at Alum.mit.edu (Personal)
>>>>> (978) 232-1461 (Desk)
>>>>> (339) 927-7896 (Mobile)
>>>>> (978) 927-4099 (Facsimile)
>>>>>
>>>>>
>>>>>
>>>>> -RL
>>>>>
>>>>> -----------------------
>>>>> Robert Lutwak
>>>>> Symmetricom - Technology Realization Center
>>>>> <mhtml:mid://00000000/mailto:RLutwak@Symmetricom.com>RLutwak at Symmetricom.com (Business)
>>>>> <mhtml:mid://00000000/mailto:Lutwak@Alum.mit.edu>Lutwak at Alum.mit.edu (Personal)
>>>>> (978) 232-1461 (Desk)
>>>>> (339) 927-7896 (Mobile)
>>>>> (978) 927-4099 (Facsimile)
>>>>> _______________________________________________
>>>>> time-nuts mailing list -- 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.
>>>
>>>
>>>
>>> -RL
>>>
>>> -----------------------
>>> Robert Lutwak
>>> Symmetricom - Technology Realization Center
>>> <mhtml:mid://00000000/mailto:RLutwak@Symmetricom.com>RLutwak at Symmetricom.com (Business)
>>> <mhtml:mid://00000000/mailto:Lutwak@Alum.mit.edu>Lutwak at Alum.mit.edu (Personal)
>>> (978) 232-1461 (Desk)
>>> (339) 927-7896 (Mobile)
>>> (978) 927-4099 (Facsimile)
>>>
>>>
>>>
>>> -RL
>>>
>>> -----------------------
>>> Robert Lutwak
>>> Symmetricom - Technology Realization Center
>>> <mhtml:mid://00000000/mailto:RLutwak@Symmetricom.com>RLutwak at Symmetricom.com (Business)
>>> <mhtml:mid://00000000/mailto:Lutwak@Alum.mit.edu>Lutwak at Alum.mit.edu (Personal)
>>> (978) 232-1461 (Desk)
>>> (339) 927-7896 (Mobile)
>>> (978) 927-4099 (Facsimile)
>>> _______________________________________________
>>> time-nuts mailing list -- 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 65, Issue 103
>> ******************************************
>>
>
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
>
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