implementing frequency divider in Max

Apr 2, 2010 at 8:20pm

implementing frequency divider in Max

hi All

I’m trying to implement a frequency divider in Max 5. Something along the lines of

http://www.doepfer.de/a100_man/a115_man.pdf

I was wondering what the easiest way is to produce shifted down copies (e.g F/2, F/4…) of a signal?

Thanks,
Bert

#49496
Apr 3, 2010 at 10:59am

A frequency divider is a bit harder to implement in the digital domain than in the analog.

http://en.wikipedia.org/wiki/Frequency_divider

One trick to get a sub-octave signal is to invert every other cycle of a waveform. I think that’s what those octaver guitar pedals do.
You basically have a comparator, which produces a pulse wave.
This pulse wave gets fed into an divide-by-2 counter to get a pulse with half the frequency, which is then used to invert the original signal.

As this method relies on zero-crossings it will only work well for monophonic signals with a strong fundamental.

If you have the csound book by boulanger handy, have a look at chapter 29 “Efficient Implementation of Analog Waveshaping”. There’s a description of the process with nice diagrams.

If you’re completely lost, I have a patch lying round somewhere, I could share.

cheers,
jan.

#177780

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