[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  
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,


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
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/ 
> time-nuts
> and follow the instructions there.

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)
voice:	+33(0)381.853999 (switchboard)
fax:		+33(0)381.853998

More information about the time-nuts mailing list