Re: please explain ring modulators

["Scott Bullerwell" <tanelorn@dimensional.com>]

daniel writes:

> a real ring modulator takes two waveforms and multiplies them together
and
> divides by two giving strange inharmonic overtones

Eh?  If I have two garden-variety sine waves (of the sort I might make with
a synthesizer by plunking around in the middle of the keyboard) one at
440Hz and the other at 200Hz, and I multiply them together I get 88,000Hz. 
Dividing that by two gives 44,000Hz.  That won't sound like much to us, but
it might make the cat sick.   

A ring modulator, in the signal processing definition, is a
sum-and-difference device where an input signal's frequency (say, an
A440Hz) is added to and subtracted from an internal oscillator's frequency
(say, 200Hz), and the sum and difference are output as two tones (in this
case, 640Hz and 240Hz).  (The name, by the way, comes from the arrangement
of diodes in the analog circuit--I built one years ago from plans in Craig
Anderton's book "Electronic Projects For Musicians" and it was a gas!).

Scott Bullerwell
tanelorn@dimensional.com
Boulder, Colorado, USA

----------
From: David Ferguson <breakz@hom.net>
To: Loopers-Delight@annihilist.com
Subject: Re: please explain ring modulators
Date: Wednesday, March 04, 1998 03:58


daniel