elson at pico-systems.com
Fri Feb 3 20:20:41 CST 2017
On 02/03/2017 01:35 PM, Mouse wrote:
>>> the propagation delay as the signal gets to each pin (remember a
>>> foot is about a nanosecond. [...])
> Not really. A foot is about a light-nanosecond, yes, but
> high-frequency signals in copper travel by skin effect, moving
> significantly more slowly - somewhere around .6c, I think it is.
Well, actually, it depends on the impedance. So, 50 Ohm
coax cable is .6 C, twisted pair differential cable is 120
Ohms, and the propagation velocity is a little above .7 I
think. Wires in open space are faster, around .8 or so, but
the signal quality may be poor.
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