Rejean wrote: > On Jun 21, 5:14 pm, "Richard B. Gilbert" <[EMAIL PROTECTED]> > wrote: > >>Rejean wrote: >> >>>I'm trying to use NTP 4.2.0 with red hat 7.3 and a military GPS on a >>>Pentium 1.4 Ghz board. >> >>>If I compare the Linux Time with the GPS time using a oscilloscope. >>>At start time I was getting a time difference of about 20ms then after >>>6h linux time was 150ms ahead. >>>Can i expect to have a time precision to +/-20ms whithout the PPS. >> >>There's no way we can answer that without knowing more about the GPS and >>how time is being transmitted to the Linux system! > > > The GPS is connected through the serial port at 9600 bps > And the ntp.conf is setup to read it. > > >>WITH the PPS, you should have time good to within 50 nanoseconds or >>better! Just how good it will be depends very much on how the interrupt >>system works. If it's low latency, time will be very good. If not, not! > > >
It's probably good to +/-20ms. Using the PPS is clearly several orders of magnitude better. _______________________________________________ questions mailing list [email protected] https://lists.ntp.isc.org/mailman/listinfo/questions
