mixing/modulating

[Byron G. Jacquot]

>If I had two oscillators, for instance a square and a triangle, and I
>wanted to make a more complex waveform by modulating them together, what
>kind of mixer circuit would I use?

There are _many_ routes you can take.

If these are voltage controlled oscillators, you're in luck, because you can
run the audio output from one into the control voltage of the other.  This
can be done without much extra circuitry, maybe an attenuator on the
recieving oscillator's CV input.

Depending on how they're tuned, the sound will change quite a bit.  In
general, if they're at musically pleasant intervals (fifths, octaves, etc),
then they'll sound fairly consonant together.  If they're other intervals,
they'll sound somewhat clangorous.  The effect will also change in intensity
depending on the setting of the attenuator between them.

You could also use an analog multiplier to combine them, which will be more
clangorous.  Motorola make a fairly cheap multiplier if that's the route you
decide to go.  This is the core of a modern day ring modulator.

If both oscillators offer square waves between 0 and 5 V, you could run them
into various 2-input digital gates.  You'll probably find that an
exclusive-or makes a good one.

Byron