[time-nuts] Basic regenerative-divider questions

Bruce Griffiths bruce.griffiths at xtra.co.nz
Fri Sep 28 21:32:46 EDT 2007


John Miles wrote:
> Submitted for general discussion: I have a need to divide a low-noise 80-MHz
> clock by two, twice, to obtain 40 MHz and 20 MHz outputs, and my current
> thinking is that the quietest way to do this is with a pair of cascaded
> regenerative dividers.  Does anyone have any 'favorite' papers or
> application notes on regenerative divider design/construction?
>
> In particular, what considerations go into determining the bandwidth of the
> post-mixer filter, and how important is the phase-shift network often seen
> in the feedback path?  My overriding concern here is phase-noise
> performance.
>
> -- john, KE5FX
>
>   
John

You can do better than that, a single regenerative divider can be
configured to divide by 4.
A pair of parallel feedback paths (with amplifiers), one tuned to F/4
and the other to 3F/4 are best.
NIST did some work (together with Indian collaborators) on this type of
generalised regenerative divider recently.
Papers are stored on my Windows machine, will boot it up and locate them.

Bruce



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