Hi If you dig into commercial GPSDRb's their loop time constants are *very* long. They crank out to a couple days fairly quickly. In addition they (like a lot of GPSDO's) have lowpass filters in the loop in addition to the basic PLL / FLL structure.
Bob On May 3, 2012, at 6:30 PM, Azelio Boriani wrote: > And maybe the problem is worse: I want also to keep aligned the PPS. To > recover the PPS position (without phase jumps) it is mandatory to slightly > force the 10MHz. Better start the machine and take measures... > > On Fri, May 4, 2012 at 12:20 AM, Brian, WA1ZMS <wa1...@att.net> wrote: > >> At the risk of over simplifying it: Doesn't it all always depend on the >> loop >> BW you pick? >> >> Inside the loop BW you see the noise of the loop's reference. Outside the >> loop BW you see the free running noise of the oscillator. >> At and around the loop's corner frequency you see a combination of both. >> The choice of loop BW depends on what Tau you want >> and what grade of Rb you are trying to improve. >> >> But as PHK said, the article was a bit thin on details. >> >> >> -Brian, WA1ZMS >> >> -----Original Message----- >> From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On >> Behalf Of Azelio Boriani >> Sent: Thursday, May 03, 2012 6:06 PM >> To: Discussion of precise time and frequency measurement >> Subject: Re: [time-nuts] Interesting paper: Don't GPSD' your Rb... >> >> OK, I've read the paper. Why not GPSDiscipline your Rb? GPSDiscipline "cum >> grano salis" but do it. My LPFRS GPS disciplinator hardware is ready. OK, I >> know, the 1E-11 step is too large but I'll try. First I'll take >> measurements >> so that I can think about a disciplining algorithm. Then a hardware >> modification on the LPFRS to get access to the C-field could make it >> better. >> >> On Thu, May 3, 2012 at 11:29 PM, Poul-Henning Kamp >> <p...@phk.freebsd.dk>wrote: >> >>> >>> This is pretty think, but interesting: >>> >>> http://tf.nist.gov/sim/Papers/Trigo_CPEM_2010.pdf >>> >>> -- >>> Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 >>> p...@freebsd.org | 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 -- 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. >> >> >> _______________________________________________ >> 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. _______________________________________________ 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.