[sdiy] generating an s-shaped curve

[Harry Bissell]

OK i'm tring to make a circuit that expands an envelope. I figured out a solution using a diode
breakpoint generator. The curve is the opposite of the tri/sine converter, larger values get progressively
larger, smaller ones get larger in a negative direction

H^) harry
  



----- Original Message -----
From: Donald Tillman <don at till.com>
To: Tim Parkhurst <tim.parkhurst at gmail.com>
Cc: Harry Bissell <harrybissell at wowway.com>, synthdiy diy <synth-diy at dropmix.xs4all.nl>
Sent: Thu, 26 Jan 2012 22:49:21 -0500 (EST)
Subject: Re: [sdiy] generating an s-shaped curve

On Jan 26, 2012, at 7:33 PM, Tim Parkhurst wrote:

> On Thu, Jan 26, 2012 at 12:19 PM, Harry Bissell <harrybissell at wowway.com> wrote:
>> OK let me explain. I want to process a CV, so that there is increasing (non-linear) gain for signals above
>> a break point (maybe +1V) and that has (well) increasing gain going negative below that.
>> 
>> The idea, the 1V signals would be unaffected by the circuit, higher voltages would go progressively higher, and
>> lower voltages would go progressively lower.
>> 
>> I can think of a diode breakpoint generator, but I'm looking for more ideas :^)
> 
> Or perhaps a tri-to-sine shaper?


Or perhaps Harry wants the opposite of a tri-to-sine.  A sine-to-tri?  You could do that with OTA linearization diodes.

Harry, we might need a better description of the curve to help.

  -- Don

--
Don Tillman
Palo Alto, California
don at till.com
http://www.till.com





-- 
Harry Bissell & Nora Abdullah 4eva