[time-nuts] Frequency divider design critique request

Bruce Griffiths bruce.griffiths at xtra.co.nz
Fri Jul 11 10:27:53 UTC 2008


Bob Paddock wrote:
>>> There are usually some BNC bulkhead connectors on eBay that terminate
>>> in SMA/SMB/SMC pigtails, which are great for panel mounting.
>>>       
>
> Not directly related to this design, but it made me wonder about something.
>
> If you are building a multiple output system and channel phase to channel phase
> was important, would pigtails like this cause problems due to
> different delay times
> because of slight variations in length?
>
>   
Yes, but matching cable delays to 10ps or even 1ps or better isnt too 
difficult.
The skew between outputs due to propagation delay mismatches between ICs 
and PCB track propagation delay mismatches.
If all flipflops are in the same package then crosstalk between outputs 
will phase modulate the higher output frequencies at all the lower 
output frequencies.

Bruce





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