[time-nuts] Comparing PPS from 2 GPS units
timenuts at triplespark.net
timenuts at triplespark.net
Thu Dec 13 23:06:15 UTC 2012
On Dec 13, 2012, at 4:57 AM, Hal Murray <hmurray at megapathdsl.net> wrote:
> Suppose I want to compare the PPS outputs of 2 GPS units. The problem is
> that I don't know which one will happen first.
>
> If I feed them into the start/stop inputs of a typical timer/freq box, I
> don't know which is which. If I get them wrong, the answer will be
> 0.999999xx seconds rather than the -0.000000xx that I want.
>
> [...]
>
> Do any of the counter/timer boxes have a mode for this? If so, is there
> a buzzword I've overlooked?
>
Counters like the Agilent 53230 actually WILL output negative delays
in this case as long as the delta is still small. This is a quite useful
feature in such cases...
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