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

[Matthias Welwarsky]

On Montag, 9. März 2020 14:44:59 CET Poul-Henning Kamp wrote:
> --------
> 
> 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 ?

This is one of the areas where a GPSDO simulator can be a great tool.

BR,
Matthias