David J Taylor wrote: > Uwe Klein wrote: > >> David J Taylor wrote: >> >>> Richard B. Gilbert wrote: >>> [] >>> >>>> You can try it and see what happens! The results may be >>>> sufficiently good for your purposes. You will almost certainly not >>>> get microsecond accuracy. If you are willing to settle for +/- 10 >>>> milliseconds you can almost certainly get that. >>> >>> >>> >>> Richard, >>> >>> My first tests show within a millisecond or so: >>> >>> http://www.satsignal.eu/ntp/NTP-on-Windows-serial-port.html#usb >>> >> >> Do I see a (sawtoth) beat signal between "true" time and the >> nominally 1ms polling interval from the usb bus? >> >> uwe > > > Uwe, Hi Dave,
> > I don't think so. If you mean the sawtooth on the left, peaking at 1600 > the first day and 0800 the second, that's pure temperature variation. Yes, that's what caught my eye. > PC Narvik was not switched to USB/serial until about 1530 on day 2. OK, > There is an increased fine-grain variation in the offset after the > change, but the jitter reported by NTP has dropped from 110-140 > microseconds to about 45 microseconds after the switch from LAN-sync to > USB-serial-ref-clock. > > There are more performance graphs here: > http://www.satsignal.eu/mrtg/performance_ntp.php > http://www.satsignal.eu/mrtg/daily_ntp-p.html Thanks. uwe _______________________________________________ questions mailing list questions@lists.ntp.org https://lists.ntp.org/mailman/listinfo/questions
