[time-nuts] Comparing Reference Accuracy

Bruce Griffiths bruce.griffiths at xtra.co.nz
Thu May 22 18:33:40 EDT 2008

Stanley Reynolds wrote:
> Disabling all the GPS receivers at the same time would allow a comparison of the hold over of each. As we are also logging the temp and power some changes in these would also help determine how "good" each DO is as far as stability.
> Stanley
You still need a frequency comparison scheme with sufficient resolution 
and low intrinsic noise (perhaps 1E-12 or better at 1sec).
Since the long term average frequencies of the various oscillators are 
not necessarily identical in hold mode, a phase comparison scheme with a 
relatively wide dynamic range is required to avoid frequent phase wrapping.


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