Terje Mathisen <"terje.mathisen at tmsw.no"> wrote: > Martin Burnicki wrote: >> Agreed, too. However, if we are discussing about Garmins with 50 ns >> accuracy then 1000 ns delay is magnitudes worse. > > Garmins never give better than about 1000 ns, i.e. 1 us. >> >> Also, PPS pulses must not necessarily be used only as PPS signals for >> computers. We have also applications where just a piece of hardware is >> synchronized by a PPS signal, in which case 1 microsecond *is* relevant. > > The gold standard seems to be the Oncore timing receivers, they give you > a PPS signal accurate to 100 ns: This is the best they _can_ do since > the PPS signal has to be synchronized to an edge of the internal 10 MHz > crystal. > > For use with NTP we do much better however, since the Oncore knows > exactly how far off the PPS signal is from the true point, and this info > si sent as part of the serial port signal (the "sawtooth correction"), > giving a real measured accuracy in the 15-35 ns range, depending upon > the model.
OK, I should have written "Oncore" instead of "Garmin". Thanks for the details. Martin -- Martin Burnicki Meinberg Funkuhren Bad Pyrmont Germany _______________________________________________ questions mailing list [email protected] https://lists.ntp.org/mailman/listinfo/questions
