[time-nuts] Why are PPS pulses so narrow? (was: 53132A triggering)
albertson.chris at gmail.com
Sat Sep 17 13:00:35 EDT 2016
On Fri, Sep 16, 2016 at 4:44 PM, Peter Vince <petervince1952 at gmail.com>
> Can I ask why PPS pulses are so narrow? It makes them difficult to see on
> a 'scope, and difficult to detect on a PC. And, as Bob said, far less
> obvious if you trigger off the wrong edge.
None of us can guess the original designer's motivation but...
I think you answered your own question "far less obvious if you trigger off
the wrong edge.". For most cases, except for time nuts, a few
microseconds does not matter. So the GPS PPS works almost as good if you
invert the signal and trip off the wrong edge. Yes it makes such a
mistake hard to find but, I think that was the point.
Redondo Beach, California
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