[time-nuts] New Subscriber, DIY GPSDO project (yes, another one)

[Poul-Henning Kamp]

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In message <1593455.IjMom2WFaZ at linux-5fgm.suse>, Matthias Welwarsky writes:

>> Backing up a bit …. the objective is not to minimize overshoot or
>> keep the loop from oscillating. The issue here is optimizing the noise
>> output of the combination of GPS + OCXO when combined via
>> the control loop. It’s a very different objective ….
>
>Absolutely. The GPS will introduce a ton of noise and the objective for the 
>control loop is mainly to keep the influence of this noise away from the GPSDO 
>output for small tau. You want the GPS only have an influence for large tau, 
>ideally only countering the aging of the LO.

Has anybody ever played seriously with separate frequency and phase
adjustments ?

I'm thinking 24h (to minimize GPS periodicities) frequency measurement
and adjustment, with a continuous very weak proportional phase adjustment
to come with measurement noise and rounding errors ?

-- 
Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
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