4089 & 4046 frequency multiplier

[mike page]

Anyone tried using a 4089 rather than a 4017 to make a frequency multiplier with a 4046? Would the irregular pulses of the 4089 make the 4046 fail to or struggle to track?

[JovianPyx]

I've used a 4046 to do frequency multiplication, but I did not use either of those two chips for the dividers. Instead, I used 4027 (dual JK flip flop) so that I could make a 50% duty cycle divide by 3 which supplies a musical perfect 5th in relation to the input frequency.

You can find more on my implementation here:
4046 Freq Mult

It's outputs include 1, 1.5, 2, 3, 4, 6 and 12 times the input frequency, all 50% duty cycle.

[Steveg]

The phase comparators on the 4046 need a 50% duty cycle so neither a 4089 or a 4017 is useful. You can use a 4017 followed by a divide by two to get your 50% duty cycle. Some (1) modes of a 4089 have a 50% duty cycle the rest won't be regular even after a divide by 2. Try having a look at the 4018. The 4018 can be a tad difficult to understand but will give you 50% duty cycle for every divider from 2 to 10.

[JovianPyx]

That's true of Phase Comparator I, but Phase Comparator || is an edge detecting system which works on only one edge. One source I read said "leading edge". In practice, my 4046 frequency multiplier works with a narrow pulse input (the discharge pulse from my VCO), but it works properly only with Phase Comparator II. I have a switch and can get some pretty odd woggly stuff with Phase Comparator I, but I find Phase Comp. II more useful.