[time-nuts] PicTic Data
sar10538 at gmail.com
Sun Aug 15 12:05:40 UTC 2010
On 15 August 2010 17:01, Stanley Reynolds <stanley_reynolds at yahoo.com> wrote:
> Thanks for looking at my data that was what I was fishing for all along :-)
> I was looking at the article:
> "A Small Dual Mixer Time Difference (DMTD) Clock Measuring System W.J. Riley "
> Richard posted
> And thinking it would be nice to do the DSS and Mixer boards to go with the
> pictic II.
I have been speaking to Bill Riley about doing this myself and he has
sent me all the board designs, software, etc. to enable one to be
built. I can ask him if he is OK if I distribute this if you wish.
> Or changing the Pictic II to use the Acam TDC GP2 Time to Digital Converter; 2
> channel w/65 ps resolution now under $30. as Bruce suggested a while back.
> My wants sure exceed my cans ;-)
> ----- Original Message ----
> From: John Miles <jmiles at pop.net>
> To: Discussion of precise time and frequency measurement <time-nuts at febo.com>
> Sent: Sat, August 14, 2010 11:25:44 PM
> Subject: Re: [time-nuts] PicTic Data
>> John glad you are getting good results and have something to
>> compare to. Back to
>> me who doesn't have any knowns but lots of guessing. Attached is
>> a run with a
>> box cover over the pictic, run is shorter ~ 800 seconds but the
>> box does look
>> like it helps.
>> I need to do a lot more testing but sometimes I just get excited :-)
> I imported your .txt file alongside the traces I captured. Assuming it was
> taken with 1 Hz on both START and STOP, it looks like the attached.
> You're getting the exact sort of results that I see if I feed both the START
> and STOP inputs at 1 Hz. My guess is that the onboard oscillator limits the
> performance in that case, since it has a lot of time to drift during the
> measurement if the two pulses occur close to 1 second apart. Even the 5370B
> looks much worse if driven with 1 Hz on both inputs than it does with 1 Hz
> at START and 10 MHz at STOP.
> So I think you're basically up and running OK. When I get around to trying
> a better clock, I'll also go back and see if the 1-pps x2 performance
> It would be great if the next spin of the board could include sine-to-CMOS
> shapers for the input channels as well as an external clock input, for
> people who are working directly with RF signals as opposed to 1-pps.
> -- john, KE5FX
>> ----- Original Message ----
>> From: John Miles <jmiles at pop.net>
>> To: Discussion of precise time and frequency measurement
>> <time-nuts at febo.com>
>> Sent: Sat, August 14, 2010 10:19:46 PM
>> Subject: Re: [time-nuts] PicTic Data
>> A few preliminary measurements here (I'm working on getting some software
>> support together):
>> -- john, KE5FX
>> > -----Original Message-----
>> > From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com]On
>> > Behalf Of Stanley Reynolds
>> > Sent: Saturday, August 14, 2010 7:12 PM
>> > To: Discussion of precise time and frequency measurement
>> > Subject: Re: [time-nuts] PicTic Data
>> > My guess as to what the data may indicate is performance of the
>> > 10 Mhz 20PPM
>> > PICTIC internal oscillator, need to repeat test with precision
>> > 10Mhz and auto
>> > calibrate off. Fatness of the line/width maybe PICTIC error. Note
>> > graph seems to
>> > show me leaving the room and returning via the outside door. Not
>> > sure what the
>> > ~100 sec oscillations are, need to check a/c cycle time.
>> > Stanley
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Steve Rooke - ZL3TUV & G8KVD
The only reason for time is so that everything doesn't happen at once.
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