[time-nuts] advice: frequency calibration to 1 ppm possible without GPSDO?

Rick Karlquist richard at karlquist.com
Thu Feb 17 02:39:27 UTC 2011

beale wrote:
> Hello time enthusiasts!  I'm hoping for your advice on my (perhaps modest,
> by this list's standards) project.
> I would like to make a frequency calibration of a 10 MHz oscillator to 1
> ppm (1E-6) or better, using some basic equipment. I do not have a GPSDO

Divide the oscillator by 10^7 to generate a 1 pulse per second output.
You might be able to tell your frequency counter to measure with a
1 second gate time and take out a gate signal, if the counter provides
it (or add your own).

Compare the phase of this to WWV by recording both with a PC sound
card for 24 hours.  Adjust it until it holds 1/10 of second per day
which is 1 ppm.

Rick Karlquist N6RK

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