Hi
> On Apr 4, 2017, at 10:01 AM, Bo Hansen <timen...@rudius.net> wrote: > > Hi all > > The data can be a bit hard to read in an email. So I will give it another try. > > PC-time | Diff. | GPS-time | Diff. > ... > 011606.005 | 0.992 | 011604 |1 > 011607.013 | 1.008 | 011605 |1 > 011608.005 | 0.992 | 011607 |2 <--- The issue > 011609.013 | 1.008 | 011608 |1 > 011610.004 | 0.991 | 011609 |1 > ... > > I used a terminal program to log the NMEA data to a file and do the PC > timestamp. Calculations were done in a spreadsheet by me. The PC-time is kept > under control by Meinberg and also OK vs. <http://www.time.is> during the > time of observation. > > The PC-timestamp wobble is not the issue. It is a combination of the PC-time > itself and the NMEA wobble. Nobody should expect the NMEA data to come at the > same time every time relative to the 1 PPS. As Björn correctly points out it > is always late and wobbles with processor load. > > Sometimes the 2-something lag can last for many hours - I have seen more than > 48 h. > > The issue is the "seconds jump". The issue is not the relative difference > between the PC-time and the GPS-time but the jump, e.g. using Tac32 reveals > that the TU30 is always ~1200 ms late on in case of the "jump second" ~2300 > ms late. > > I wonder if it has anything to do with the Week 1024 Syndrome? We are roughly 2 years away from the next week 1023 to week 0 GPS rollover point. If you see this multiple times in a 20 year period it is not a 1024 week issue …. Bob > > Indeed the TU30 is a old device. I guess some 30 years if not more looking at > the components. F/W I have no idea. > > The 10 kHz seems unaffected. > > Bo > > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
