> 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 improves. 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 <jmi...@pop.net> > To: Discussion of precise time and frequency measurement > <time-nuts@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): > http://www.ke5fx.com/pictic.htm > > -- john, KE5FX > > > -----Original Message----- > > From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@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 > > > > _______________________________________________ > > time-nuts mailing list -- time-nuts@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@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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