Hi Volker, Universal counters like 53132A or SR620 or CNT-91 do quite well for making measurements of GPSDO. Over minutes or hours they easily measure down to the 1e-12, 1e-13, and 1e-14 level. But yes, for short averaging times the noise of the counter is probably greater than the instability of your GPSDO so the measurements from the counter are not useful.
Similarly, for long averaging times beyond hours or days the instability of your frequency reference is probably greater than the instability of your GPSDO so the measurements are also not useful. To make higher-resolution phase measurements use advanced commercial time interval instruments like Wavecrest DTS*, or Symmetricom TSC 5110/5120, or TimePod 5330A (http://www.miles.io/). On the cheap, you can also homebrew your own phase meter using several methods. For example, see: http://tf.nist.gov/phase/Properties/main.htm http://www.wriley.com/A%20Small%20DMTD%20System.pdf http://www.ke5fx.com/tpll.htm /tvb ----- Original Message ----- From: "Volker Esper" <ail...@t-online.de> To: "Discussion of precise time and frequency measurement" <time-nuts@febo.com> Sent: Friday, November 02, 2012 8:32 AM Subject: [time-nuts] A counter for phase measures Dear fellows, I'm searching for a counter that allows me to make automated measure series. Of course, Allan Deviation is an important thing to determine when experimenting with or developing GPSDOs (what I intend). So it seemed to be a nice thing to measure phase deviation with a counter (HP 53132A or SR-620 or so). When experimenting with that stuff I discovered, that all my equipment would not be adequate to determine Allan Deviations beyond 10e-11 (or so). The question is, can any counter deliver that precision / low noise to make such measurements possible? Or does it have to be a more sophisticated technique, such as cross spectrum analysis? Thanks a lot in advance Volker (I guess you recognize, that I am just a newbie to that all) _______________________________________________ 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.
