[ntp:questions] Re: Accuracy of ACTS reference

David L. Mills mills at udel.edu
Sat Nov 5 01:49:00 UTC 2005


Thank you for composing in plain ASCII, which is much easier for me to read.

I've had ACTS running here for the better part of a year. Accuracy and 
jitter depend on the interval between calls. At 18 hours the residual 
offset and jitter are in the 5-10 ms range. At 36 hours twice that. 
Indiviudual measurements during a single call are much better, usually 
less than a millisecond. The reduced accuracy between calls is due to 
oscillator wander and different call routing for succeeding calls.


BigHug wrote:
> Hi, there:
> We try to set up a NTP server with ACTS reference. However, the offset
> and jitter are pretty high. The offset will be up to 60ms and jitter up
> to 40ms. And it keeps lost the syncronization. Try different servers,
> phone lines, ntpd's and cables, but it still doesn't help. We think
> that it might be the noizy phone line. Anyway, how accuracy should we
> expect by using ACTS, under 5ms offset and jitter or more?
> Thanks for any help.

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