[time-nuts] uncertainty calculations
hmurray at megapathdsl.net
Sun Apr 16 00:46:22 EDT 2017
time at radio.sent.com said:
> * You might have any possible phase relationship between the two
> signals. If they are exactly related by a 10^7 ratio, it's possible
> for the 1 PPS edges to exactly coincide with the 10 MHz edges.
> Depending on the type of gating circuit, you will have jitter and
> possibly metastability resolving whether which edge occured first. ...
> * To stay away from such problems, most precision counters add a small
> amount of controlled jitter (phase modulation) to the clock. ...
My experience with metastability is that it's really hard to make it happen.
Are the clock and data in a good lab setup really stable enough to make
metastability a problem?
How much does the added jitter screw up measurements where it isn't needed?
These are my opinions. I hate spam.
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