"unruh" <[email protected]> wrote in message
news:[email protected]...
[]
Yes, I was talking about the width of the pulse's rising edge.
It is the risetime that is of first importance for timing. The length of
the pulse
only is important in how the serial port identifies interrupts ( and I
guess the possibility of the pulse been smoothed to nothing if too
short-- but that would show up in the rise time first)
Whether the rise-time is significant would depend on the accuracy
required. I'm assuming that the waveform is rising cleanly and without
ringing, and that the receiver circuit has hysteresis. I'm thinking
microseconds, and a 90m length of should be able to preserve risetimes of
that order. If the OP is looking for sub-microsecond accuracy, then
delays in the PPS signal may be more significant, and the delays in any
TTL-RS-232 convertor circuits etc. would start to matter.
Cheers,
David
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