Hi What you are looking at appear to be sawtooth jumps. Simply put, the module is looking at the closest edge on the TCXO to do it’s timing. When the device drifts, it can “slip” to another cycle. If you watch the PPS out, there are also artifacts that result from this process operating in a non-ideal fashion. Lots of details on that in the archives.
Bob > On Apr 25, 2018, at 8:56 PM, Gabs Ricalde <[email protected]> wrote: > > The NAV-TIMEUTC message of the u-blox LEA-6T has a fractional seconds > field, which is the receiver clock offset estimate and can be used to > measure the internal TCXO. Attached are the ADEV and frequency > difference plots (blue traces). For comparison, I also have PPS logs > from a TL-WR703N NTP server (pink traces) with ntpd stopped. > > I'm wondering why the LEA-6T has that kind of frequency jumps. > <ADEV.png><freq.png>_______________________________________________ > 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.
