[sdiy] CMOS for linear circuits.

[ryan williams]

Harry,

thanks for the advice!

harrybissell wrote:
> The theremin is a VERY special case.... any interaction bewteen the 
> oscillators will lock them and prevent beating, which will kill the 
> theremin dead !!!

good point, I really should have thought of this. Based on that alone, I
am going to keep these gates on seperate chips just to be sure. I really
want this thing to work when I go to build the second one.

> CMOS 'linear' operation is really a bad idea all in all. If you only
> need ~one~ amplifier and you have a spare gate... maybe.

Ok, but I really liked the idea of a CMOS theremin. I am going to build 
it this way, and if it doesn't work then I guess I will learn more from 
the experience. It sounds like putting those 1MHz oscillators on the 
same board with CMOS VCOs might be a problem. I'm just going to keep 
them away from each other on the board and try to a good layout.

> I don't call most simple RC delays, schmitt trigger oscillators
> etc... "linear" CMOS. I think those are legitimate uses. Its when you
> use feedback that its really 'linear'.

I suppose, I just wrote the title of the message, and then wrote about
something different. I am building CMOS VCOs and VCFs as well, so there
is some of the 'linear'.

-ryan