[time-nuts] 10 MHz clock distribution for the lab

[Charles P. Steinmetz]

Russ wrote:

>The HP 5334B has a 1k Ohm input impedance shunted by <20 pf it 
>wouldn't hurt to terminate this input

This is pretty typical for reference inputs on test equipment.  The 
idea is that one 50 ohm source can feed a number of instruments using 
nothing but a series of Tee connectors, with the far end of the cable 
terminated in 50 ohms.  The 1k loads will cause little disturbance on 
the 50 ohm line.

If best isolation and delay matching are required, the source should 
feed a good DA and there should be equal-length runs of coax from the 
DA to each instrument, with proper terminations.  Generally, this is 
required only for measurement inputs -- it is rarely necessary for 
the references of different instruments to be phase coherent (and 
different instruments are likely to have quite different internal 
reference delays).

Best regards,

Charles