Volt/Octave ADSR

[Grant Richter]

If you charge and discharge a capacitor from current sources rather than
resistors, 
or if you use a capacitor in the feedback loop of and op-amp (the classic
integrator circuit),
the segments will be linear. If you then feedback the output into the
control voltage input
the linear segments can be "bent" either in or out. This allows a linear
envelope to
emulate an exponential envelope quite closely.

A linear envelope is actually preferred over exponential as a general
controller.
You wouldn't want a "pan" envelope to be exponential, for example.
The most time an exponential envelope is required, is for linear VCAs.
Both Buchla and Serge envelope generators are linear.
The Serge "Universal Slope Generator" module uses a CA3080 as a current
controlled integrator.
----------
> From: Tim Ressel <Tim_R1 at verifone.com>
> To: 'synth-diy at mailhost.bpa.nl'
> Subject: Volt/Octave ADSR
> Date: Monday, June 07, 1999 2:46 PM
> 
> Hello list --
> 
> I am building some V/Oct modules, and it occurs to me that with V/Oct you
want
> an ADSR that produces linear ramps rather than exponential curves that
you get
> from charging a capacitor. Does anyone have any info on this concept?
> 
> Thanks
> Tim Ressel