[ntp:questions] Re: Best way to harness multiple stratum 1 servers

Darryl Otzen "darryl otzen at acterna com" at ntp.isc.org
Fri Apr 7 00:08:44 UTC 2006


John Ackermann N8UR wrote:
> Darryl Otzen said the following on 04/06/2006 06:37 AM:
> 
> 
>>If your Cs and GPS all have a common freqency output signal (2048kHz,
>>10MHz), you can use a phase meter to track any difference between them.
>>This will only be of benefit if you have three or more sources.
>>I have done this with Cs references to keep track the performance of old
>>units.
> 
> 
> I already do time-interval comparisons (using a time interval counter
> and GPIB to log data onto a Linux machine) of the PPS between the Cs and
> GPS (and, soon, each other) so I have pretty good data on their
> performance (see http://www.febo.com/time-freq/plots for the semi-live
> data).
> 
> I'm looking at NTP as an auxiliary method, with the idea of having a
> single network time source that represents the "best" time I can get
> from the ensemble.  I don't *need* to do this, but since the tool is
> there, I thought I'd try to wring as much out of it as possible.
> 
> John
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For comparing Cs oscillators I use an old fashioned analogue phase meter coupled with a chart recorder.
The meter is centre zero with +/- 5 degree FSD.
Once I'm happy with the performance of the analogue outputs of the oscillator I'd start looking at the PPS.
How accurate is your TIC?
Feed the same signal to both inputs, check if there is any unstable measurement error.

dotzen




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