[time-nuts] Basic regenerative-divider questions

Magnus Danielson magnus at rubidium.dyndns.org
Fri Sep 28 22:07:04 EDT 2007


From: "John Miles" <jmiles at pop.net>
Subject: Re: [time-nuts] Basic regenerative-divider questions
Date: Fri, 28 Sep 2007 18:51:58 -0700
Message-ID: <PKEGJHPHLLBACEOICCBJEEKKBJAB.jmiles at pop.net>

> ); SAEximRunCond expanded to false
> Errors-To: time-nuts-bounces+magnus=rubidium.dyndns.org at febo.com RETRY
> 
> 
> > 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.
> 
> Thanks much, Bruce.  I suspected either you or Enrico R. would have some
> knowledge of that.
> 
> Note that I need to end up with 40 *and* 20 MHz, hence the plan to cascade
> two /2 dividers.  If there is a better topology for obtaining both of these
> outputs, it would be good to know.  I'd imagine that a /4 divider running
> alongside a /2 divider would be better from the additive-noise perspective.
> 
> I will probably end up wanting a 10-MHz output as well.  The obvious
> question would be, should that be a separate F/8 + 7F/8 path, or a /2
> divider following the /4 divider?  I haven't seen many references to /8
> regenerative dividers but I suppose they'd be workable.  Availability of
> 8.75 MHz crystals might be what decides that question.

The article in question is...
http://tf.nist.gov/timefreq/general/pdf/1890.pdf
but also
http://tf.nist.gov/timefreq/general/pdf/1800.pdf

See for yourself.

Cheers,
Magnus



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