[sdiy] Walsh Generator & demo board

[Grant Richter]

I was lucky enough to talk with a professor at UW-Kenosha who wanted to
build a large Walsh array in the 70's. This unit was to have the
coefficients set by a DAC controlled by a PDP-11. (I don't know what
happened to it, I just talked with him about the design).

This was his approach: Instead of using potentiometers for summing, use the
Walsh function to gate a voltage into a summer instead. So the Walsh
function controls a CD4066 (or equiv.) which is gating a voltage between +/-
1 "unit" into the summer. This is the same mathematically as the pot, but
saves a lot of wiring.

So now the coefficients are just voltage sources and you can use fixed
resistors, pots, DACs, LFOs or sequencers to set up the coefficients.

> From: Tim Ressel <madhun2001 at yahoo.com>
> Date: Sun, 10 Mar 2002 18:52:44 -0800 (PST)
> To: Synth-Diy <synth-diy at dropmix.xs4all.nl>
> Subject: [sdiy] Walsh Generator & demo board
> 
> To all,
> 
> I have this Xilinx CPLD design I did for a Walsh
> generator. It takes a clock in, and produces 15 sin
> and cos Walsh functions. I am considering offering it
> for sale, along with a little demo PCB which has a 8
> (or more?) input mixer for summing the Walsh
> functions. There are working prototypes for all this.
> All thats needed is for me to get off my ample
> posterier and do the layout.
> 
> So like, I'm wondering how many people are interested?
> I have not added up the costs, but I'm guessing in the
> $40-50 Dollar (US) range. Maybe less; i'm not trying
> to get rich off of this.
> 
> Anyone interested raise your hand.
> 
> --TR
> 
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