[time-nuts] Fury Realhamradio listing
Dr Bruce Griffiths
bruce.griffiths at xtra.co.nz
Mon Apr 30 01:25:47 UTC 2007
SAIDJACK at aol.com wrote:
> C) I don't believe the Z3801A has 100ps single shot resolution and accuracy
> (for resolution doesn't do anything without accuracy) until someone will
> prove it to me. And even then it would be wasted resolution since the GPS 1PPS
> source noise will totally swamp out any benefit a 100ps resolution would give.
>
Said
The timestamp resolution may well be much greater than needed
particularly if they leveraged an existing well characterised and
debugged design from another product.
This can save time and money over the alternative of developing a time
stamp circuit with just the appropriate resolution.
You have to be more precise in your definition of accuracy. An unknown
but very stable time offset is of little consequence when disciplining
an OCXO, however a scale error is another matter. Thus an interpolator
with an unkown offset of a few nanoseconds which is stable to within a
few tens of picoseconds allows an interpolator with a resolution of say
100ps sec to be useful if its gain is known sufficiently accurately and
the signal being timestamped has sufficient stability.
Bruce
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