[time-nuts] Sound Cards for locking to GPSDO 10 MHz references

Hal Murray hmurray at megapathdsl.net
Wed Jun 3 13:23:53 EDT 2009


connie.marshall at suddenlink.net said:
> www.k5cm.com/soundcard.htm

Nice, thanks.

>From there:
> Sound card drift over this four hour period is about 250 micro Hertz.
> The temp in the shack was going up during the measurement period.
> Unfortunately I did not track the exact temp rise, but was about
> around 4 to 6 degrees F.

250 micro Hz relative to 1000 Hz is 1/4 ppm.

My memory is that junk PC crystals are ballpark of 1 ppm/degree.  (That's 
probably per degree C rather than F, but that's only a factor of 2.)

So 1/4 ppm for 4 degrees is better than I would have guessed.


-- 
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