[ntp:questions] Isolated Network Drift Problem

David Woolley david at ex.djwhome.demon.co.uk.invalid
Wed Nov 26 08:01:10 UTC 2008


Unruh wrote:

> 
> With your 100m setup you really want a buffer amp on the line. At 100m, the
> one way trip is .3ms, with reflections every .6ms which might make the
> system a bit weird. To get rid of the reflections you need a 100ohm
> termination if you use cat5e cable to lengthen the 5m wire on the receiver.

Round trip time for 100m of velocity factor 2/3 cable is approximately:

3 * 2 * 100 / (2 * 3E8)

= 3E2/3E8
= 1 microsecond.




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