[time-nuts] How to measure Allan Deviation?

John Ackermann N8UR jra at febo.com
Sun Oct 22 21:15:12 EDT 2006


Dr Bruce Griffiths said the following on 10/22/2006 07:33 PM:
> Didier
> 
> If you are going to use a PPS divider to divide the oscillator frequency 
> down to 1Hz, you will need to measure the inherent jitter of the divider 
> to ensure that it doesn't degrade the measurement resolution. It may be 
> necessary to resynchronise the divided output using a fast D flipflop to 
> reduce the inherent divider jitter to less than the 20ps resolution of 
> the 5370.

The few experiments I've done indicate that there isn't that much
sample-to-sample jitter in a divider built up out of a reasonable-length
string of 74HC390 dividers, but the temperature stability is horrible.

John



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