[time-nuts] Allan Deviation question

[Azelio Boriani]

I think that no one can say anything on that setup. Anyway, try this: run
the GPSDO 10MHz into the radio and take the measurements. Then run your
signal and let us know the difference. Usually running the reference
against itself (if possible) gives the noise floor of the measurement
setup... if you can't see any difference then maybe the noise is too high.

On Wed, Jul 4, 2012 at 10:23 PM, Bill Dailey <docdailey at gmail.com> wrote:

> I am measuring a 10MHz OCXO.  I am wondering about my methods and their
> effect of Allan Deviation.
>
> SETUP:
>
> I am running the signal into my radio (gps disciplined)  and taking the
> resulting audio and running it to a sound card (oscillator gps disciplined)
> then looking at the result in Spectrum lab.  I am using a sample rate of
> 48kHz and an FFT  length of 32,768 and decimating the signal by 48 to give
> me decent resolution.  The resulting FFT window is 32 seconds.  Then
> looking at the peak frequency or phase every second (can measure both
> instantaneously).
>
> QUESTION:
>
> Does that window time affect my Adev at short time intervals of say 1s to
> 30s or can these numbers be trusted?
>
> Thanks for your time.  Please save esoteric and playful discussions, just
> interested in the ability to trust my measurements.
>
> Doc
> KX0O
>
> --
> Doc
>
> Bill Dailey
> KXØO
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to
> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
>