[ntp:questions] Jitter versus polling interval

David J Taylor david-taylor at blueyonder.neither-this-bit.nor-this.co.uk
Tue Mar 10 07:47:41 UTC 2009

Danny Mayer wrote:
> David J Taylor wrote:
>> David Woolley wrote:
>>> Danny Mayer wrote:
>>>> Increased polling frequency increases jitter.
>>> I think jitter was being used loosely here, not with the specific
>>> sense of high frequency variations.
>> Yes, my original question referred to looking at a graph of offset
>> plotted over a day (sampling at 5-minute intervals) and trying to
>> judge the amount of short-term oscillation as opposed to the
>> longer-term drifts (e.g. those caused by temperature variations).
> Perform a FFT (Fast Fourier Transform) on the data and look for the
> peaks.
> Danny

A visual inspection is more than adequate in this case, although I agree 
that the FFT could be used for quantitative analysis.


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