Rick, while the discussion was about the frequency control loops of GPSDOs and not the temperature control loops of their OCXOs your answer applies as well to what I have been asking. That was what I thought of when I talked about "3rd ore more order plls".
Best regards Ulrich Bangert > -----Ursprungliche Nachricht----- > Von: [email protected] > [mailto:[email protected]] Im Auftrag von Richard > (Rick) Karlquist > Gesendet: Donnerstag, 3. September 2009 17:47 > An: Discussion of precise time and frequency measurement > Betreff: Re: [time-nuts] Crystal aging > > > > > Maybe! But for the sake of clarity: I have been asking how > > HP/Symmetricom manage to handle the regulation loop appearantly > > WITHOUT time constant adaption/switching and with a fixed time > > constant that seems to be much too high to start with for a > cold OCXO. > > > > Best regards > > Ulrich Bangert > > > > One answer might be the use of a second integrator. The > HP5061 used an analog second integrator, which was quite non > trivial to implement at the time. The 5071 also uses a > second integrator, which is of course digital. The oven > control loop of the E1938A uses first and second integrators > (PID + I^2) to get the best of both worlds. None of these use > switched time constants. > > Rick Karlquist N6RK > > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
