[time-nuts] GPS W/10KHz

[Hal Murray]

ailer2 at t-online.de said:
> you don't need 10kHz to build a GPS disciplined oscillator. GPSDOs are build
> with control loop response times in the range of some hours, so the loop
> will be absolutely happy with a 1PPS input. 

Right.  But it's not simple to build an analog low pass filter with a cutoff 
frequency of 1/100 seconds.

The modern approach is to use a small processor and a DAC.  The hard part is 
getting enough effective bits out of the DAC.  The archives are full of 
suggestions about which chip to use.

For a home brew setup, you can trade bits for tuning range if you are willing 
to fiddle an analog pot occasionally when your crystal drifts out of tuning 
range as it ages.

-- 
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