[time-nuts] External Frequency Standard Inputs on Counters

Ed Palmer ed_palmer at sasktel.net
Fri Apr 3 06:51:42 UTC 2009

I see that on many counters (e.g. SR620, HP 5370, HP 5372) the external 
frequency standard input has an impedance of 1Kohm.  Why such a high 
value?  Are they implying that it's acceptable to daisy-chain a single 
reference to multiple devices like an old 10Base2 ethernet network?  
Should such a link be terminated in 50 ohms like a 10Base2 network?


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