[time-nuts] Doppler and FMT

Tom Van Baak tvb at LeapSecond.com
Thu Sep 19 20:17:58 EDT 2013


> So it's just a matter of averaging what you can measure
> and assuming that the average will be close?

Two quick comments.

1) A gradual phase drift over time is identical (by definition) to a frequency offset.

2) In general, "averaging" a moving target gets you *less* accuracy, not more.

We learned in school that averaging enhances accuracy. This is true in textbook cases where the mean is constant and where the distribution of error about the mean is symmetrical.

But when working with clocks (time, frequency, stability measurements) this assumption often not true and it's helpful to think of averaging more as a disease than a cure.

/tvb




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