Poul, The PRS10 I have here is free-running, and the ADEV looks similar to the plots TVB made. I think it's the time constant of the Rb steering algorithm, not much one can do about that. Maybe lock a good DOCXO to it with say 200s time constant to filter out the hump..
Bye, Said Sent from my iPad On Aug 23, 2012, at 15:35, "Poul-Henning Kamp" <[email protected]> wrote: > In message <[email protected]>, > "R > ichard H McCorkle" writes: > >> See the chart TVB produced to see the PRS10 hump in published data. >> http://www.leapsecond.com/museum/prs10/ > > I have measured similar data when the PRS10 is fed a 1PPS from a GPS > without sawtooth correction. > > The PRS10 has a 1/256 exponential average filter which can get rid of > most of that noise, and I suspect Tom didn't enable it for that > measurement. > > But even with that filter, the "hanging bridges" leak through at all > relevant timeconstants of the PRS10's internal PLL. > > I tried converting the "negative saw-tooth" and injecting it into > the PRS10 via the serial port, but the results were at best very > mixed. In the end I used the PRS10 to timestamp the 1PPS, pulled > the measurement out via the serial port, and implemented my own > neg-saw corrected PLL in software, which injected the correction > back into the PRS10 via the serial port. > > When you do that, you get much better results, at 2Hz and elsewhere. > > > > -- > Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 > [email protected] | TCP/IP since RFC 956 > FreeBSD committer | BSD since 4.3-tahoe > Never attribute to malice what can adequately be explained by incompetence. > > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
