In message <20110916001417.d49d3800...@ip-64-139-1-69.sjc.megapath.net>, Hal Mu rray writes:
>Here is the frequency: > http://www.megapathdsl.net/~hmurray/time-nuts/ppstest/60Hz-freq.png >I don't know where the wobbles are coming from. They might be in my >collection setup. They are very likely resonance-effects in the power grid. Power-grids are not inherently stable things, and most of them have resonance frequencies like that, depending on which generators run and what the impedance are between them. A few grids have operational SPICE-like models to warn them about configurations which are unstable, but in general the thinking that it would be possible to build an analytical model of the grid died with decentral productions uptake a decade ago. Try running a suitably windowed FFT on your data... -- 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.
