"Greg Mayman" wrote to "Roy J. Tellason" (27 Dec 02  08:07:00)
 --- on the topic of "DIGITAL CLOCKS"

 GM> My TTL data books don't give the output rise or fall times, but
 GM> the since the propogation delay of a 7400 gate is typically 11 nS
 GM> lo-to-hi and 7 nS hi-to-lo, the rise and fall time of the output
 GM> can't be any longer than this, possibly considerably less.

Propagation delay and rise/fall time are different though often related.
Progation delay has to do with the amount of time elapsed from when a
signal is applied to an input and when its effect appears at the output.
The circuit may have very fast rise/fall times yet have a substantial
propagation delay, for example if internally it consists of a series of
logic functions.

 Mike
 ****

... Integrated Circuit (n): a device used to protect fuses.
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