Yes, correct, sometimes the power line goes faster than 60 Hz in which case the zero-crossings occur before you "expect them"; so time error can be negative, on average, as often as it is positive.
You cannot design a PLL that always expects phase error to be unidirectional. The data I provided is time error relative to an ideal 60 Hz; this data can be both positive and negative; and both gaining and losing, as well as both accelerating and decelerating. Welcome to the interesting world of time & frequency, even at 60 Hz. /tvb (iPhone4) On Feb 28, 2013, at 10:42 AM, Daniel Mendes <[email protected]> wrote: > Em 28/02/2013 13:37, Tom Van Baak escreveu: >> Daniel, >> >> I've placed two log files for you under http://leapsecond.com/pages/mains/ >> >> log1932.dat.gz -- timing of every 60 Hz zero-crossing (1.296 million samples) >> log97312.dat.gz -- timing of every 60th zero-crossing (21.6 thousand samples) >> >> Each represents 6 hours of collection time. Units are seconds (elapsed >> time), resolution is 100 ns, granularity is 400 ns. This data was collected >> with a picPET (http://leapsecond.com/pic) using an accurate 10 MHz reference. > > This isn´t very clear to me. First few lines say: > > 0.0000000 > > -0.0000029 > > -0.0000071 > > -0.0000064 > > 0.0000027 > > -0.0000099 > > -0.0000176 > > > Time went backwards? > > > Daniel > > > > > > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
