> This is just a free running PRS10 wired to a TAPR TICC, I thought that I would > run some stand alone tests before I brought my GPSDO in line too.
Ok, good idea to do a stand alone test. The plateau, though, is interesting and I wouldn't quite have expected that in a 1PPS vs 10 MHz self-test. Let's look into that. > The PRS10 is the source for the 10MHz as well as reading the 1PPS output from > it. Ah, ok, that would explain the unusually low MDEV beyond tau 1000. Since you're essentially comparing the oscillator with itself you would expect the MDEV numbers to be [far] lower than the performance of an actual frequency standard. Once you fire up your GPSDO and use that as a reference, your PRS10 ADEV/MDEV numbers will look more appropriate. /tvb ----- Original Message ----- From: Chris Burford To: 'Tom Van Baak' ; 'Discussion of precise time and frequency measurement' ; 'Discussion of precise time and frequency measurement' Sent: Sunday, October 14, 2018 8:07 PM Subject: Re: [time-nuts] PRS10 MDEV Tom, This is just a free running PRS10 wired to a TAPR TICC, I thought that I would run some stand alone tests before I brought my GPSDO in line too. The PRS10 is the source for the 10MHz as well as reading the 1PPS output from it. Chris ----------------------------------------- From: "Tom Van Baak" To: "Discussion of precise time and frequency measurement" Cc: Sent: Sunday October 14 2018 9:45:46PM Subject: Re: [time-nuts] PRS10 MDEV Chris, Thanks for sharing the plot. What instrument are you using to make the measurements? And what frequency reference is being used? Is this a free-running PRS10, or is it locked to GPSDO with some time constant? Is that same GPSDO being used as a reference for your measurements? The plateau looks very much like GPSDO behavior and the slide into e-14 and e-15 territory looks like you're measuring a PLL. /tvb ----- Original Message ----- From: "Chris Burford" <[email protected]> To: <[email protected]> Sent: Sunday, October 14, 2018 7:07 PM Subject: [time-nuts] PRS10 MDEV > Hello All, > I've collected several data sets over the last few days from my RFS > and I'm puzzled by what I'm seeing. A link to the plot is here: > https://drive.google.com/open?id=10Kk8Cqx7es0SXf2H5AldiQkBo8nIfNMT /> > I'm looking at the averaging periods from about 100 thru 400 tau and > noticed a "plateau" or a brief level off period and then it proceeds > down and right again. Is this flat area a function of the averaging > algorithms for the MDEV or is it something else? > I have spent considerable time in reading "Techniques for Frequency > Stability Analysis" by W.J. Riley and a host of other publications > (NIST, etc) in preparation for this. I would enjoy hearing from any > readers that may have some insight as to what I'm seeing and or > possible causes. > Thanks for reading. > Chris > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com /> > and follow the instructions there. _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com /> and follow the instructions there. _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
