[ntp:questions] Re: HowTo calibrate system clock frequency using NTP

Daniel Kabs daniel.kabs at gmx.de
Thu Feb 2 08:53:42 UTC 2006


Richard B. Gilbert wrote:
>> Please see the diagrams on
>> https://ntp.isc.org/bin/view/Support/HowToCalibrateSystemClockUsingNTPDev
>>
> What problem are you trying to solve?

I want to calibrate the system clock on a number of embedded systems. To 
measure the frequeny error, I'm looking for a method that only takes a 
few hours.

I'd prefer to use the frequency value that ntpd writes into the drift 
file but my test (see URL above) showed too slow a convergence. I have 
to add, I ran the test without the "iburst" server option so updating to 
a new ntpd version that supports "iburst" will speed things up.


> If you want to make a one-time correction to your clock frequency, 500 
> ms/day may be a reasonable objective.

It's good to have this recommendation. So 6 PPM is the goal I should 
strive for.


Cheers
Daniel
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Refactor, don't archive! - SamHasler - 28 Aug 2004 - twiki.org




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