[ntp:questions] Leap second to be introduced in June
terje.mathisen at tmsw.no
Tue Jan 27 09:27:34 UTC 2015
David Malone wrote:
> Terje Mathisen <terje.mathisen at tmsw.no> writes:
>> The derivatives of sine/cosine are of course +/- cosine/sine, so they
>> stay smooth at all levels.
> The point is that it is not smooth where it joins on to the regular
> passage of time... It is possible to do this in an infinitely smooth
> way, but using the cos formula just gives a few continuous derivatives.
You are of course right.
I can even see how using exponential functions with a totally flat tail
would allow you to get arbitrarily close to the desired smoothness, but
in the real world what we care about is to make the steering something
that the normal ntpd control loop handles without breaking a sweat, i.e.
in the same magnitude as the usual temperature-induced frequency swings.
- <Terje.Mathisen at tmsw.no>
"almost all programming can be viewed as an exercise in caching"
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