Richard B. Gilbert wrote: > Karl Denninger wrote: >> Karl Denninger wrote: >> >>> Jason Rabel wrote: >>> >>>> What OS are you running, and what CDMA modem are you using? (Just >>>> curious) >>>> >>>> Also from the info you gave it looks like it is using your CDMA >>>> source, but >>>> seeing the stratum at 16 I don't think you have had NTP run long >>>> enough to >>>> adjust the clock into sync. >>>> >>>> Jason >>> >>> >>> >>> FreeBSD 6 (and 7; I have both here); the modem is a Multitech MTCBA. >>> >> >> Quick update on this.... it appears that while the timecode is being >> stuffed appropriately, the underlying NTPD daemon doesn't like it - >> after a half-hour or so (running with debug turned up) and watching it >> log things, it fails to lock on and resets the time source, dropping >> and restarting the clock. >> >> I assume this means it is unable to get "happy enough" with the >> stability of the timestamps to formulate a "solution", declares the >> clock "broken", and then restarts....... yes? >> >> The obvious question is "can a time source that outputs only with 1 >> second resolution and only when polled generate >> sufficiently-high-quality reference time for the system to use it?" >> >> If the answer is "no", then the curtain needs to be drawn on this >> attempt. If the answer is "yes", then I need to figure out how to >> accomplish getting better input resolution I suspect - perhaps with a >> helper application that polls at a higher rate of speed (e.g. several >> times per second) and "stuffs" timecode events into the receive buffer >> (e.g. via a named pipe or similar) >> > > Subject to correction by someone who knows what he's talking about the > answer is not just "no" but "HELL NO"! > > The resolution of 1 second is a killer. This is going to make the > jitter a function of exactly when each poll is received. I doubt that > ntpd cares very much exactly when a poll is sent. If this device has a > PPS output, it might be useable. . . .
It doesn't, which sucks. Severely. I will contact Multitech and see if there's a solution to this (either in the form of better resolution or a PPS output option somehow.) If not, well, it was a nice try :-> -- Karl Denninger ([EMAIL PROTECTED]) http://www.denninger.net _______________________________________________ questions mailing list [email protected] https://lists.ntp.isc.org/mailman/listinfo/questions
