[time-nuts] External Frequency Standard Inputs on Counters

Hal Murray hmurray at megapathdsl.net
Fri Apr 3 20:40:59 UTC 2009

> Not terminating could create a null at or near one of them... thus
> resulting in no input signal for that box. Overcoming that would
> require  more drive level than the other boxes wants... 

10 MHz is 100 ns.  The speed of light is 1 ft per ns.  (Yes, coax is slower.  
I'm just looking for the ballpark.)

So if you have several instruments in a rack with short chunks of coax 
between them, they will all see (close to) the same signal.  If the source is 
in the same rack, everybody sees (close to) the output of the driver.

I'm assuming we are talking about a sine wave.  With an edge, you will get 
reflections which can lead to double triggering.

These are my opinions, not necessarily my employer's.  I hate spam.

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