"David I. Emery" <[EMAIL PROTECTED]> wrote: > I see your point, an architecture with the VCXO derived 1 PPS > output NOT coherent with the 10 MHz would be somewhat unnatural and hard > to use in a system and presumably virtually ALL GPSDOs do phase lock the > 10 MHz to the GPS time base rather than just frequency locking to it. > > There are, however, some subtle differences between a loop > optimized to make the best estimate of 10 MHz possible given the OCXO > used and one optimized to make the 1 PPS the best possible approximation > to UTC.
Most GPSDO manuals say that if lock is lost and when lock is recovered recovered it is found that drift is greater than some margin, then the phase relation is not preserved. The system "jumps" to the new phase and there will not be the exact 10M:1 ratio that otherwise exists. Usually this margin is many microseconds of drift, typically accumulated over a day or more. Tim. _______________________________________________ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts