[ntp:questions] Measure clock accuracy, Store to a text file, Expected Oncore M12T accuracy?

Mario Behn behn at mirsl.ecs.umass.edu
Fri May 26 15:02:27 UTC 2006


I want to measure how well my PC time is synchronized to UTC (e.g. true
time). I have a oncore as a reference clock on an embedded system, which
has now graphic libraries installed, so I won't use MRGT or so as I found
as one suggestion.

So I would like to write out the estimated accuracy and the
estimated standard deviation (= jitter?) to a simple ascii file, which I
then can download and plot with matlab or so. 

Now I few questions:

1.) Should I include more then the estimated accuracy and the
estimated standard deviation? What about Allan variance (by the way what
is that is the importance of this parameter) ?

2.) What is the easiest way to perform this measurement? I know there are
many files like /var/log/ntpstats/clockstats, which seem to already
include some of this data? However I don't know whether thats the way to

3.) Well finally after have got the measurement, I need to interpret it
and decide whether it is reasonable for my system. Now I have a VIA EPIA
MII 6000 with 600 Mhz C3 processor and running Red Hat 9.0 with a 2.4.32
kernel and the corresponding pps kit. I have the synergy system smart
antenna based on the oncore M12T receiver. What accuracy can I expect?

So thats for now, any ideas and comments are highly appreciated.

Thanks -- Mario

More information about the questions mailing list