Hi One assumption is that you will indeed be capturing / averaging for several days. I'd include some sort of model for sunrise / sunset shifts (might be just "ignore for the next hour"). Another assumption is that your local reference is close enough and stable enough to make a multi day average meaningful.
Bob -----Original Message----- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Poul-Henning Kamp Sent: Friday, March 16, 2012 9:03 AM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] WWVB BPSK Receiver Project? (fwd) In message <b8fa03dc1dd84a588a317b314a6fc...@vectron.com>, "Bob Camp" writes: >Could you generate a "lead" and a "lag" estimate of the signal (in addition >to your "center") and integrate against each of them on the fly? If so you >would need a *lot* less memory. I seem to recall you tried something like >this on the one of the Loran receivers. The reason to use the lead/center/lag model, is that you have a moving signal you need to track, but for timenuts purposes the signal is not going to move more than a few microseconds over an hour, so it is probably a better strategy to just average the heck out of the signal. It is not even clear to me that the phase-coding helps frequency reception at all, I tried it with the very strong phase-coding of DCF77 and there was no statistical significance relative to heavy duty carrier averaging. But it clearly helps a lot with phase-determination, and for that lead/center/lag is the way to go, but you may still want to average for a minute, then resolve the phase using the phase-modulation, rather than run it in real-time. -- 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.
