In message <2d539724-9c95-497f-8539-36a9840ac...@gmail.com>, Dennis Ferguson wr ites:
>DCF77's AM modulation is a much better fit for what they did, [...] Well, with a footnote about a few details, such as only 1 hour leap-second warning, but yes, it is a very robust signal. >It is also the case the DCF77's phase modulation probably isn't as good >as it could be if the goal is to find it in the noise since it only swings >+/- 15 degrees rather than +/- 90. When they started it, a lot of DCF77 frequency receivers existed and 15 degrees were as much as one particular widespread military model could stay in specs with. That is also why the sign of PM signal follows the bit in the second pulse, so that the average PM code is close to zero in the long run. >Its big advantage might be that it >is high speed, with lots of transitions, so you can probably measure >phase alignment pretty accurately with that. As usual it depends on your averaging period and thus stability of your timebase, but 20 microseconds isn't too hard 1200 km from the transmitter. If you want to measure propagation effects really precisely, DCF77 is your signal :-) -- 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 -- email@example.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.