AW: AW: [sdiy] Re: OTA nonlinearities

[Czech Martin]

That's correct. Therefore I added a log input that is added to the expo
control voltage. This works pretty well.

btw.: you get exp{k*Ve + log[Vl]}=exp{k*Ve} * Vl

this way, this means turning the linear input Vl to zero will cancel any
signal.
OTOH turning the expo control input Ve down makes Vl ineffective as well.
This is just a basic equation, in the real case the signs and constants
are different, but it shows what I mean.

Unfortunately you need double tempco cancelation if you want to do any
compensation at all. One for the 2018 expo input, the other for the
loger.

OTOH this circuit performs the same thing as the formant dual vca, but
with only one gain controled element.

So there are technical advantages but the behaviour is a bit odd if
you are not used to a vca with two controls. It is just that the controls
don't add, but multiply.

m.c.

> -----Ursprüngliche Nachricht-----
> Von:	WeAreAs1 at aol.com [SMTP:WeAreAs1 at aol.com]
> Gesendet am:	Mittwoch, 9. Mai 2001 18:21
> An:	Martin.Czech at micronas.com; synth-diy at node12b53.a2000.nl
> Betreff:	Re: AW: [sdiy] Re: OTA nonlinearities
> 
> 
> In a message dated 5/9/01 6:32:17 AM, Martin.Czech at Micronas.com writes:
> 
> << I used SSM2018 with linear and expo controll.  >>
> 
> Hello Martin,
> 
> I thought the SSM2018 had only expo control input.  Was I mistaken?
> 
> Michael Bacich