Hello to the group! Have you ever measured frequency standard (or other precision oscillator) simultanously by time interval method (difference between 1 pps ref and 1 pps DUT) and dual mixer method (e.q. with phase/frequency comparator)? I'm very interested in results. Slawek

Hi You have to measure two different outputs to do what you describe. The PPS measurements are limited to > 1 x10^-10 with most counters at tau = 1 second and 2x10^-11 with some exotic models. The mixer based stuff can get around three orders of magnitude past that at the same tau. Since a practical mixer system involves filtering one would expect some impact from that. The gotcha is the low resolution of the counter approach. You run out of resolution before you can really see anything. All that said, yes, I have measured the same device both ways and the results do agree within the accuracy constraints imposed by the techniques. Bob > On Jan 16, 2018, at 11:58 AM, slawek dabrowski <slawdabr@wp.pl> wrote: > > > Hello to the group! > > Have you ever measured frequency standard (or other precision oscillator) simultanously by time interval method (difference between 1 pps ref and 1 pps DUT) and dual mixer method (e.q. with phase/frequency comparator)? I'm very interested in results. > > Slawek > > > > > > > _______________________________________________ > 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.

I am working to build a small DMTD system based on Bill Riley’s paper. Bill was kind enough to send me a package with updates. In the meantime, I tested an AD8302 phase detector coupled to an HP voltmeter (HP3456 and HP3457), both with the filter set. I believe the HP3456A voltmeter filter limits voltage changes to below 60hz. The results were interesting but I don’t have anything to compare them with though they did look correct from a relative standpoint. For instance, my Cs beam looked better than one Rb unit and my GPSDOs looked better at longer Tau. My HP 10811 looked correct when compared to others. The issue with the AD8302 though is that phase deltas below 3 degrees are inaccurate, actually the plots had flats at those phase deltas. Also, since it reports in degrees, you need to change that back to time which I did in a spreadsheet. Regards, Jerry Jerry Hancock jerry@hanler.com (415) 215-3779 > On Jan 16, 2018, at 8:58 AM, slawek dabrowski <slawdabr@wp.pl> wrote: > > > Hello to the group! > > Have you ever measured frequency standard (or other precision oscillator) simultanously by time interval method (difference between 1 pps ref and 1 pps DUT) and dual mixer method (e.q. with phase/frequency comparator)? I'm very interested in results. > > Slawek > > > > > > > _______________________________________________ > 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.

Hi Slawek, I have tried two versions of DMTD and I think the biggest problem with this method is the fact that two measures made on the same DUT never coincide. The DMTD suffers from time wrap and the measurement results are linked to the time difference presetted by t1 and t2. At the moment I am using the TICC with good results, attached to the noise floor. I think that in order to have a better resolution we need to focus on a recent production error multiplier such as the A7 of Quartzlock or a similar one to be self-constructing. http://quartzlock.com/userfiles/downloads/manuals/A7-A_&_A7-MX_Manual.pdf Luciano www.timeok.it Da "time-nuts" time-nuts-bounces@febo.com A "time-nuts" time-nuts@febo.com Cc Data Tue, 16 Jan 2018 17:58:18 +0100 Oggetto [time-nuts] Time interval measurement vs dual mixer method Hello to the group! Have you ever measured frequency standard (or other precision oscillator) simultanously by time interval method (difference between 1 pps ref and 1 pps DUT) and dual mixer method (e.q. with phase/frequency comparator)? I'm very interested in results. Slawek _______________________________________________ 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.

Hi If the time offset gets to the point that it bothers the measurement, you likely are running to low a difference frequency. It is quite possible (though not easy) to get low parts in 10^-13 running an offset of 8 or 9 Hz at 10 MHz. If you are running very precise signals, then line stretchers can be used to get everything so it hits at the same point. There are NBS papers where they talk about doing exactly this sort of thing. Results were “within a couple of microseconds” as I recall. Bob > On Jan 17, 2018, at 1:44 AM, timeok@timeok.it wrote: > > > Hi Slawek, > I have tried two versions of DMTD and I think the biggest problem with this method is the fact that two measures made on the same DUT never coincide. > The DMTD suffers from time wrap and the measurement results are linked to the time difference presetted by t1 and t2. > At the moment I am using the TICC with good results, attached to the noise floor. > I think that in order to have a better resolution we need to focus on a recent production > error multiplier such as the A7 of Quartzlock or a similar one to be self-constructing. > http://quartzlock.com/userfiles/downloads/manuals/A7-A_&_A7-MX_Manual.pdf > Luciano > www.timeok.it > > > Da "time-nuts" time-nuts-bounces@febo.com > A "time-nuts" time-nuts@febo.com > Cc > Data Tue, 16 Jan 2018 17:58:18 +0100 > Oggetto [time-nuts] Time interval measurement vs dual mixer method > > Hello to the group! > > Have you ever measured frequency standard (or other precision oscillator) simultanously by time interval method (difference between 1 pps ref and 1 pps DUT) and dual mixer method (e.q. with phase/frequency comparator)? I'm very interested in results. > > Slawek > > > > > > _______________________________________________ > 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. > <TICC noise floor.tim>_______________________________________________ > 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.