[time-nuts] Ugly Frequency Dividers

[Normand Martel]

This morning, i've just remembered another weird
frequency divider i say on a chronorecorder (a device
used to adjust mechanical watches) a few years ago...

The frequency dividers stages (three or four, i'm not
sure) were unijunction transistor based staircase
generators using the charge pump/reservoir principle
to divide the input frequency by an integer "N"
factor. Interinstignly, the "N" factor was adjustable
using a potentiometer.

Again here, just as with the ring counter, no glitch
problem here, as with the binary dividers, but the pot
had to be carefully adjusted so it is in the middle of
the correct "N" range, this way, the counter can
resist  aging.

Interinstignly, since it uses the charge
pump/reservoir principle instead of the well hnown
gated monostable, this counter is relativey (within a
reasonable measure) frequency independant.

Again, just as the all-transistor ring counter, i do
not have the schematic, but i know the owner of the
chronorecorder, and next time i'll see him, i'll ask
for a look inside the device to sketch a schematic.

BTW, i do not know the jitter response of such a
counter, but i can eassilly imagine that it is very
poor (slow transitions), but since it smells analog, i
like it!! ;-)

73 de Normand VE2UM
Montreal, Qc, anada



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