John, That's a good start towards answering my question. Given my set-up of GPS referenced NTP server, how would I integrate a frequency reference into the system?
Keith > As a relative newbie to the who time-nut scene, I'm still working on > > the big picture of how all the hardware fits together. I've > > successfully put together a FreeBSD box with a Garmin 18 LVC as an NTP > > server and am getting consistent microsecond accuracy. I've been > > looking at the next step of adding a stable oscillator to the system. > > I'm not seeing how to integrate this into the system. > > The way I understand it, the oscillator is there to provide a very > > stable frequency reference, regardless of the type used --> VXCO, > > rubidium, cesium, etc. What I'm not seeing is how you link the > > frequency reference to UTC. For NTP, I'm guessing that you'd have to > > sync a PPS pulse with a known time source such as GPS. Am I on the > > right track? Pointers to references appreciated. > > 73, Keith > >Hi Keith -- > >Frequency isn't linked to UTC; phase is. What you're doing with an >external oscillator is simply providing the computer with a stable clock >frequency. The PPS signal from the GPS provides the phase information >that tells NTP when the second marker is. The stable clock frequency >just makes it easier for NTP to hold the second marker at the proper point. > >Even if the reference frequency is inaccurate (and that may be the >question your asking), NTP is still better off as it can correct for a >frequency offset more easily than it can a clock that is erratic. > >Hope this helps. > >73, >John _______________________________________________ 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.