[ntp:questions] Can a clock drift be too big for ntpd?
Richard B. Gilbert
rgilbert88 at comcast.net
Thu Oct 25 11:47:34 UTC 2007
Maarten Wiltink wrote:
> "Patrick Nolan" <pln at glast2.Stanford.EDU> wrote in message
> news:slrnfhv6ug.7qo.pln at glast2.Stanford.EDU...
>>[...] I'm amazed that clock radios, plugged into the 60 Hz supply,
>>aren't as good [as wrist watches].
> So am I. Because here at least, they keep a close eye on the number
> of zero crossings in the power plants, and make very sure that it
> comes out right at the end of the day.
I think that power companies almost everywhere count the cycles in the
day. Since most are interconnected, staying in phase is mandatory! So
there are 60*86400 or 50*86400 cycles per day but the difference between
any two consecutive crossings is not guaranteed to be exactly 1/100 or
1/120 of a second. The generators slow down when the load increases or
speed up when the load decreases!
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