On 2010-07-15, Matuschka, Sebastian <[email protected]> wrote: >> I think this isn't a good design. >> >> In my experience, DCF-77 reception is simply not stable enough to >> directly >> use the pulses from the receiver as clock ticks. >> When there are thunderstorms, local interference, and sometimes >> propagation >> problems, there can be spurious extra pulses that you do not want to >> count. Or pulses can be missing. >> >> A good way of using DCF-77 is to collect the 59 pulses that make up a >> minute, average the offset between the pulse start and the local clock >> tick, >> decode the time from the pulse lengths, and then at the end of the >> minute >> decide if all this information is valid and should control the clock >> (adjusting the clock offset/frequency), or should be discarded as a >> whole. >> >> This is also what the DCF-77 drivers in ntpd do. > > Sorry, i forgot to mention an important thing: > The DCF-77 Signal is generated by a precise clock that is connected via > fiber optics to the device the ntpd runs at. > The distance isn't very long, so i can expect that the signal is very > precisely and there is no jitter nor any (relevant) offset. > So, it has not really has anything to do with a normal DCF-77 receiver. > I hope my questions make more sense now :)
And you are using the DCF-77 driver why? Seems like one of the more inapproriate drivers to use. I would have used the shm driver instead. You are also still hiding stuff and expecting us to guess. > > Best Regards > Sebastian _______________________________________________ questions mailing list [email protected] http://lists.ntp.org/listinfo/questions
