From: Warner Losh <[EMAIL PROTECTED]> Subject: Re: [time-nuts] Re: UTC Date: Wed, 27 Jul 2005 17:19:34 -0600 (MDT) Message-ID: <[EMAIL PROTECTED]>
> > Certainly. But what's your point? I don't see these utilities failing > > if a second slips here or there. The one case where time is critical > > is the power grid, and they keep their own time (Which, IIRC > > approximates UTC). > > The long term average of the power grid in the US is 60.000 Hz. Short > term variations from that can and do happen. Actually, assume that the short-time frequency is most probably anything but 60 Hz (or 50 Hz, depending on where you are). The over and under-production of electricity is the frequency control-means. > It is to make sure that the clocks run on time, on the average. It might be > better to say that the power grid approximates the SI second, since it has no > notion of which second it is (although the control infrastructure for the > grid most likely does). Rather, you have on long term average a frequency control, but no phase control. My oldest counter had in standard edition the 50 Hz or 60 Hz power grid frequency as reference frequency (using a phantastron frequency divider circuit using a pentode and a triode) where as mine has the 100 kHz crystal oscillator reference, when that was a luxuary. ;O) Cheers, Magnus _______________________________________________ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts