[time-nuts] GPSDO diurnal variation
Tom Van Baak
tvb at LeapSecond.com
Wed Aug 1 00:39:36 UTC 2012
As you can see, the phase stays within 5 or 10 ns during the day. The frequency stays within 5e-11 with 10 second averaging times; 5e-12 with 1000 second averaging times.
Send me your raw data (off-list) and I'll have a look at it. How sure are you that the 2.5e-11 variation is the GPSDO and not the "precision oscillator", or your comparator?
----- Original Message -----
From: "Bill Dailey" <docdailey at gmail.com>
To: "Time Nuts" <time-nuts at febo.com>
Sent: Tuesday, July 31, 2012 5:27 PM
Subject: [time-nuts] GPSDO diurnal variation
> Does anyone have plots of true frequency variation of their 10 MHz standards over days? I am trying to see if what I am seeing is typical or if I need to get a better antenna/gpsdo tuning/temp control. Right now I am on vacation so am capturing data under much warmer than normal temps (ac turned down) and am seeing 250 uHz deviation with a period of about 24 hours (2.5x10-11). I am trying to look at this in a way that is more intuitive and concrete to me than Allan deviation. I am using a precision oscillator as the comparator and am removing linear drift (stochastic) in excel. It seems surprisingly high.
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