Hi In this case the “phase” is phase correction of the output rather than PLL ….
Bob > On Mar 9, 2020, at 10:58 AM, Matthias Welwarsky <time-n...@welwarsky.de> > wrote: > > On Montag, 9. März 2020 15:04:40 CET Bob kb8tq wrote: >> Hi >> >> If you go that way, just run a pure FLL for the “main loop” and do the phase >> on top of that. Assuming you are disciplining an OCXO, it works pretty well >> …. Even more so if you keep time tagged phase ( to do frequency from phase) >> and can look at some very long tau “frequency” as a section of the loop. > > Not sure about the merit of this. As soon as your LO is close to the "true" > frequency, the phase error will become dominant. Which means the FLL part > will > contribute nothing and the whole thing will effectively become a PLL. > > BR, > Matthias > >> >> Bob >> >>> On Mar 9, 2020, at 9:44 AM, Poul-Henning Kamp <p...@phk.freebsd.dk> wrote: >>> >>> -------- >>> >>> In message <1593455.ijmom2w...@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 ? >> >> _______________________________________________ >> time-nuts mailing list -- time-nuts@lists.febo.com >> To unsubscribe, go to >> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow >> the instructions there. > > > > _______________________________________________ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
