Hi, alkope...@googlemail.com wrote: > Hi > I have 2 ntp servers running Linux with LinuxPPS patch. Number one > uses a Meinberg PCI511 v1.00 as time source, number two uses a > Meinberg GPS170PCI v1.10. > On both machines ntp is configured to use the Meinberg refclock > (127.127.8.0) and furthermore the Meinberg PPS outputs are connected > to the serial interfaces and use the atom driver (127.127.22.0). > The strange thing is, that there is always a delay of 1-4 ms between > the refclock and the pps signal. In my opinion they should arrive at > the exact same time.
The PCI511 card decodes the AM signal from DCF77 only. Due to the characteristics of the AM signal the accuracy of the PCI511 card is only in the range of a few milliseconds, while the GPS card provides an accuracy better than 1 microsecond. So what you observe is not an NTP problem but just due to the limited accuracy of the PCI511 card which is sufficient for many standard applications. However, if you really want high accuracy you should rely on a GPS time source. Martin -- Martin Burnicki Meinberg Funkuhren Bad Pyrmont Germany _______________________________________________ questions mailing list questions@lists.ntp.org https://lists.ntp.org/mailman/listinfo/questions
