[ntp:questions] Idea to improve ntpd accuracy
Hal Murray
hmurray at megapathdsl.net
Sun Feb 28 04:18:38 UTC 2016
> I thought of that too but rejected it as way too machine-specific. Because
> the clock PLL does not track frequency ramps feed-forward could be very
> effective (e.g. order of magnitude). To make this work however, you need to
> first discover which one of many potential temperature sensors on the MB
> are most closely correlated with frequency, then measure a rough linear
> gain from temperature to PPM. Seemed too hardware-instance-specific to me,
> but perhaps there's a way...
You want to measure the temperature of the crystal.
Several/many years ago, Linux used to use the RTC/TOY clock for the main
timekeeping. Now, the main CPU clock is used. You want to get a temperate
probe on that.
Mark Martinec has a wonderful web page on that.
NTP temperature compensation
https://www.ijs.si/time/temp-compensation/
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