electro harmonix frequency multiplexer

[Magnus Danielson]

From: Martin Czech <czech at Micronas.Com>
Subject: electro harmonix frequency multiplexer
Date: Wed, 30 Aug 2000 13:26:38 +0200 (MET DST)

> I recently came across this frequency divider (well, why multiplexer?!).
> It basically converts the frequency to an octave lower,
> in order to convert guitar into "bass".
> I saw a scope screenshot, sine in and (almost) sine out.
> 
> ? Huuh ?
> 
> Is this simply done via band limiting the ff output or is there
> some magic inside this effect box that I don't understand yet?
> 
> Are there any schmatics?

Hmm... even if the theory of this device seems to be covered allready, this
just spawned me with the idea of doing another non-linear curcuit which would
have the same effect.

Take an input signal (assume sine waveform), have an envelope follower to
detect the peak envelope, add this signal to the original signal 1:1. Then,
take this signal and send it through a square-root curcuit. The output waveform
will now be a sine being an octave down from the input sine. Naturally, this
will be a possibly interesting source of distorsion ;D

In essence one could say that this is a form of modified RMS detector, somewhat
simpler. It should be easy enougth to do in pure analog curcuitry.

Naturally you can apply this trick many times to get further sub-tones.

Cheers,
Magnus - feeling a bit non-linear