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

Daniel Kabs daniel.kabs at gmx.de
Fri Feb 17 08:49:40 UTC 2006

Richard B. Gilbert wrote:
>> Hal Murray wrote:
>>> What sort of accuracy are you expecting?
>> I hoped to measure the time drift within (or better than) 1 PPM
> To what purpose?  The drift will vary with the temperature and you are 
> not planning to operate these devices at a controlled temperature. <...>

I'd like to calibrate the system clock, i.e. correct the frequency 
offset (at a fixed temperature and with certain accuracy, say 5 PPM).

I also want to measure how the time drift varies with temperature.

To do this, I think, I'll have to find out to what uncertainty I can 
measure the time drift of my system clock and how I can improve on this.

I know, I can always resort to running NTP on my system configured for a 
reliable time server and then read the drift file. As this process takes 
some time (at least one day for reasonable convergence) and I wanted to 
compare with other methods of measurement I am also trying to determine 
the time drift using offset readings.


More information about the questions mailing list