[time-nuts] Why are PPS pulses so narrow? (was: 53132A triggering)

Peter Vince petervince1952 at gmail.com
Sat Sep 17 13:09:56 EDT 2016


Thanks guys - interesting answers all!

     Peter


On 17 September 2016 at 18:00, Chris Albertson <albertson.chris at gmail.com>
wrote:

> On Fri, Sep 16, 2016 at 4:44 PM, Peter Vince <petervince1952 at gmail.com>
> wrote:
>
> > 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.
>
>
>
> --
>
> Chris Albertson
> Redondo Beach, California
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