[time-nuts] Basic regenerative-divider questions
Enrico Rubiola
rubiola at femto-st.fr
Sat Sep 29 10:55:49 EDT 2007
Dear all,
I worked on low-noise regenerative dividers long time ago.
See my home page http://rubiola.org , click on "more journal articles"
22. E. Rubiola, M. Olivier, J. Groslambert, Phase noise in the
regenerative frequency dividers (PDF, 670 kB),
IEEE Transact. Instrum. Meas. vol.41 no.3 pp.353-360, June 1992. ©IEEE.
Notice that you can divide by 4 with a single divider,
using the 3rd harmonics internally generated by the double balanced
mixer.
Dividing 80 MHz, you feed a 20 MHz back to the mixer.
A 60 MHz signal is generated by the mixer.
80 MHz - 60 MHz = 20 MHz, here you go.
Another issue is the correction of the phase noise of a digital divider
using a double-balanced mixer.
Read this *smart* article
D. Huffman, Extremely low noise frequency divider,
Microwave Journal November 1985, pp. 209--210
Very best,
Enrico
On 29 Sep 2007, at 3:02 , 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
>
>
>
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Enrico Rubiola
professor of electronics
web: http://rubiola.org
e-mail: rubiola at femto-st.fr
FEMTO-ST Institute
32 av. de l'Observatoire
25044 Besancon, FRANCE
voice: +33(0)381.853940 (E.Rubiola)
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fax: +33(0)381.853998
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