[time-nuts] AC Connector On HP 5061B

Bruce Griffiths bruce.griffiths at xtra.co.nz
Fri Oct 3 16:58:58 EDT 2008


Tom Van Baak wrote:
>> On the DA you will want to ensure all your output cables are of
>> identical length as this will ensure that all signals are in phase at
>> the timebase input(s).   It's a small thing really a fraction of a
>> picosecond but it's there and easily compensated for.
>>     
>
> When does the phase of the timebase input mean anything?
> Most test equipment is happy to have a stable external frequency
> input; the phase is immaterial, no? Can someone give me an
> example when relative phase among various random pieces of
> test equipment is important?
>
> /tvb
>
>   
Tom

Another example of a case where the electrical length of a cable can be 
important is in precision frequency distribution systems.
Trimming the cable to the right length (one way propagation delay equal 
to an odd multiple of half the signal period) for the frequency in use 
minimises the effect of load and source mismatch.

Bruce



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