[sdiy] Digital control

[Blandon Ray]

I found this VCR implementation linked through Ray's page - it's
hosted on Osamu Hoshuyama's site.

http://www5b.biglobe.ne.jp/~houshu/synth/mike_irwin/cmos-vcr.gif

4049s are easy to come by, but digging up the matched transistor pairs
might be a hassle (at least for me, since I haven't built up a huge
DIY component stock yet).

Blandon


On Tue, 1 Mar 2005 14:54:42 +0200 (EET), Antti Huovilainen
<ajhuovil at cc.hut.fi> wrote:
> On Tue, 1 Mar 2005, Johannes Öberg wrote:
> 
> > Mark Verbos: Sorry, I didn't read your post properly, so I didn't
> > notice you wrote they used digital pots. Unfortunately, those are so
> > expensive...
> 
> You can use an OTA to implement voltage controlled resistor. There is an
> example in LM13600 datasheet. I believe you can also use some multiplying
> DACs to make digital potentiometers.
> 
> Antti
> 
> "No boom today. Boom tomorrow. There's always a boom tomorrow"
>    -- Lt. Cmdr. Ivanova
>