Odp: [sdiy] Call for opinions: Walsh Module

[harrybissell]

How about one DAC, with a S/H demultiplexer (a la your favorite analog
polysynths, ProV etc).  Then take an inverting opamp, and have the Walsh

output toggle two transmission gates (4016 ?).  You could do with just
ONE
voltage source if symmetry around 0V is not needed.

I call it 1/2 quad opamp, 1/2 quad transmission gate, two resistors...
should
come in under $1 for sure !

H^) harry

Roman wrote:

> How about common multiplying DACs?
> Feed reference input with audio sugnal and you have
> digitally controlled fader.
>
> R.
>
> ----- Original Message -----
> From: Tim Ressel <madhun2001 at yahoo.com>
> To: Seb Francis <seb at is-uk.com>
> Cc: <synth-diy at dropmix.xs4all.nl>
> Sent: Wednesday, September 11, 2002 12:49 AM
> Subject: Re: [sdiy] Call for opinions: Walsh Module
>
> > Seb,
> >
> > Thanks, but I need digital potentiometers, not rotary
> > encoders. Think programmable fader.
> >
> > --TR
> >
> > --- Seb Francis <seb at is-uk.com> wrote:
> > > Tim Ressel wrote:
> > >
> > > > Ouch! I just looked at the prices of digital pots.
> > > Oy!
> > > >
> > >
> > > ALPS STEC16B 16mm rotary enoders 24 sine pulse per
> > > revolution
> > > CPC 87p each for 5+
> > > (SW01640 / SW01641 / SW01642 / SW01643)
> > >
> > > Just get a PIC + Mux to read them and your away ...
> > >
> > > Seb
> > >
> > >
> >
> >
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