Updating the EFC more quickly reduces the ADEV, though. I find that the fiddly part of tuning a GPSDO design is balancing the ADEV against phase control. If you want keep an iron fist on the phase, you can only do so by constantly swatting around the frequency.
I won't say that getting more frequent phase feedback is a bad thing, but if you're trying to get the PLL time constant to be longer rather than shorter that it won't help a lot. Sent from my iPhone > On Aug 17, 2016, at 9:57 AM, Peter Reilley <preilley_...@comcast.net> wrote: > > You can get crystal oscillators that have a frequency control signal and are > more > stable than the run of the mill oscillators. Changing the GPS oscillator > would > require modifying a very tightly populated circuit board. Perhaps not > possible. > > What about some of the SDR (software defined radio) projects that aim to > implement GPS functionality? If you used the GPS chipping rate (1.023 MHz) > to dicipline the 10 MHz oscillator then you are less sensitive to crystal > instabilities. > You are updating the crystal one million times a second rather than once per > second. > This is assuming that the chipping rate of the transmitter is just as good as > the > 1 PPS signal. This info from here; > https://www.e-education.psu.edu/geog862/node/1753 > and here; > https://en.wikipedia.org/wiki/GPS_signals > > Even using the 50 bits/sec data rate of the GPS signal would allow updating > the > GPSDO faster than the 1 PPS signal. > > Pete. > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
