Was: Subject: Re: [time-nuts] 60hz west coast electric grid gone berserk albertson.ch...@gmail.com said: > What? Lets assume 80 characters per line at 60Hz that word to a whopping > 4800 bytes per second. For a modern desktop computer moving even a million > bytes per second is trivial. Even 10 times that much is easy. In the 1/ > 60th second between cycles a simple desktop computer can execute well over a > hundred million instructions.
Thanks for the poke. The obvious thing to do was try it. So I collected a half-hour of data. Things are more interesting when you have data for every cycle (as compared to every 10 seconds). Here is the offset from 60 Hz: http://www.megapathdsl.net/~hmurray/time-nuts/ppstest/60Hz.png 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. Here is the step-size between samples: http://www.megapathdsl.net/~hmurray/time-nuts/ppstest/60Hz-step.png The row at 30+ ms is where the collection system couldn't keep up and missed a sample. The top row is where it missed 3 samples. This is zooming in, ignoring the missed-sample cases: http://www.megapathdsl.net/~hmurray/time-nuts/ppstest/60Hz-step-a.png Note that the dots that are not part of the main line/blob come in pairs, one above and one below. I think that means one sample was late, so the previous step is long and the next one is short. These are expanded to show only 2 minutes: http://www.megapathdsl.net/~hmurray/time-nuts/ppstest/60Hz-b.png http://www.megapathdsl.net/~hmurray/time-nuts/ppstest/60Hz-freq-b.png http://www.megapathdsl.net/~hmurray/time-nuts/ppstest/60Hz-step-b.png These are zooming in on the step size: http://www.megapathdsl.net/~hmurray/time-nuts/ppstest/60Hz-step-c.png http://www.megapathdsl.net/~hmurray/time-nuts/ppstest/60Hz-step-d.png The horizontal bars are because I've rounded off to a microsecond someplace. These are zooming in on the offset: http://www.megapathdsl.net/~hmurray/time-nuts/ppstest/60Hz-c.png http://www.megapathdsl.net/~hmurray/time-nuts/ppstest/60Hz-d.png The downward spikes are a delayed sample. The upward spikes are "early" samples. I assume it got lucky and the cache didn't get flushed or something like that. Here is a histogram of the step size: http://www.megapathdsl.net/~hmurray/time-nuts/ppstest/60Hz-hist.png This is a better view of the stuff along the bottom: http://www.megapathdsl.net/~hmurray/time-nuts/ppstest/60Hz-hist-a.png Looks like 5-10 microseconds RMS of noise. That's on a laptop that wasn't doing anything. -- These are my opinions, not necessarily my employer's. I hate spam. _______________________________________________ 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.