On Mar 28, 6:45=A0pm, George Herold wrote: =A0
dIf it matters, you can use an AC-coupled monostable to capture the fast rise and generate a 'well-behaved' timing pulse, independent of the slow fall times. For critical work (proportional counters) a delay-line amplifier can do even better. The input pulse and its attenuated/delayed/inverted copy are summed, and if the sum is done carefully, the exponential downward tail of the input exactly cancels against the upward tail of its delay, so all your pulses look like little lumps on a dead-flat background.
Four meters of cat-5 cable with a lower-than-110 ohm terminator generates a negative reflected pulse about 100 ns late (there's four pairs in the cable, and the return pulse goes four lengths, reflects, and comes back four more lengths).