Hello everyone,

I'm trying to accurately count reed switch closures on the end of a cable that
is 20 metres in length. The pulses occur at a rate of about 4 per second and
are feed to the input port of a PIC for processing.

The best that I have been able to achieve is a variation of 2.5% in the count
and that was through the use of a Schmitt Trigger (74LS13 with the inputs
tied together).

Should I expect an accuracy better than 2.5%? How do commercial satellite dish
trackers, for example, achieve an accurate count?

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Regards,
Phil.

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