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Subject: Re: S&H random modulation generation.

From: "gordonjcp" <gordon@...>
Date: 2010-01-05

--- In korgpolyex@yahoogroups.com, Russ <russdaren@...> wrote:

> Isn't this why a lot of random number generators are called quasi random?
> I know on my Moog MG1 if I pull up the random modulation and lopass it just right at certain speeds it is definitely a repeating pattern. I have read elsewhere that the random mod is a S&H circuit. (my aoplogies for bringing up a synth other than the Poly 800, both my polys get used a lot even with a moog and a DX in the studio).

"Pseudo-random". The Moog MG-1 used a single-chip pseudo-random noise generator, the MM5837. Since its output ∗does∗ repeat, then sampling at a low rate would give you a fairly long cyclic pattern. There are a couple of sites out there with replacements for this chip based on cheap off-the-shelf microcontrollers.

Gordon MM0YEQ