[time-nuts] A counter for phase measures

[Tom Van Baak]

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" <ailer2 at t-online.de>
To: "Discussion of precise time and frequency measurement" <time-nuts at 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)