On Mon, May 21, 2018 2:23 pm, Gary E. Miller wrote: > I look forward to your patch!
My GPSDO doesn't have sawtooth error, so limited interest for me. How much does one of those u-blox modules cost? How would you tell if it made the gpsd performance better? I think that question came up a couple of weeks ago, most of the ways to check time stability involve hardware test equipment logging electrical signals, and there isn't a good way to get an electrical signal generated cleanly from the gpsd software clock. Is there a way to have a timestamp log from another instance of a PPS driver (another meaning the first instance is the one in use by ntpd)? So you could have a PPS driver log timestamps from a really high quality input signal, such that any variation in the timestamps was due to the clock variation and not from the input signal, and then see if the variation in timestamps was less after adding sawtooth correction to gpsd. That's the only idea I can up up with off the top of my head to check whether such a patch would actually improve the clock estimate noticeably. In essence this is like trying to build a GPSDO without being able to see the output of the oscillator directly, so the normal approach to measuring stability with TICC, counters, phase noise analyzers, etc. doesn't really work. -- Chris Caudle _______________________________________________ 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.
