[time-nuts] Gate propagation delay jitter

Dr Bruce Griffiths bruce.griffiths at xtra.co.nz
Tue Apr 10 18:46:05 EDT 2007


Magnus Danielson wrote:
> From: Enrico Rubiola <rubiola at femto-st.fr>
> Subject: Re: [time-nuts] Gate propagation delay jitter
> Date: Wed, 11 Apr 2007 00:14:01 +0200
> Message-ID: <AD07B1AE-765F-471B-A549-7F09F023EC91 at femto-st.fr>
>
> Enrico,
>
>   
>>> Then we would need to know/measure the jitter of the retiming  
>>> flipflop.
>>>       
>> Expected values
>> microwave: -120 dBrad^2/Hz flicker, -150 dB white
>> RF:                -140 dBrad^2/Hz flicker, -150 dB white
>> Use a double balanced mixer, traditional configuration.
>> A correlation scheme is probably not  necessary.
>>     
>
> So you mean I could toss in a double-balanced mixer and feed it with the
> sampling clock and the output lines, while feeding the flip-flop some lower
> clock? 
>
>   
Magnus

The traditional method is to use a pair of fliflops each dividing the 
clock frequency by 2, one flipflop per mixer input.
Both inputs to the mixer should have the same frequency, so each 
flipflop could be used to resynchronise a lower frequency data input.

Bruce




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