[Re: multistage rate level env generators]

[M.Ruberto]

i like this microcontroller idea. it's another thing i've been toying with in
my head - being able to recall env. settings is a nice bonus. 

well here's what i was thinking about. i'm sure there is a flaw in it
somewhere ;). the heart of the circuit would be a dual 8 channel MUX chip. on
each input of MUX1 there would be a voltage divider pot (level) that fed into
another pot in series with the MUX1 input (rate). the output of this MUX is
fed to the usual cap and buffer deal. the 2nd MUX's inputs are connected
directly to the output of each (level) divider pot. take the output from the
second MUX and feed it to a window comparator as the reference (refs hi and
low should be a few tenths of a volt apart). then the comparator's input
connects to the ouput of the buffer. the comparator's output is then used to
trigger a binary counter whose output is cycling the MUX from channel to
channel. i guess the problem is that the circuit can get stuck if one stage is
set to the same level as the next. any ideas, criticisms, complaints?

i'm still gnawing away at making any stage a sustain stage. it's not
impossible, just ugly so far.

-<mike>-

patchell <patchell at silcom.com> wrote:
>     Although I never actually completed it...I did something like that, but
it
> was hybrid.  The core was analog, used an OTA to make the standard voltage
> controlled RC network, it had two inputs, one to control the rate, one to
> control the level it would ramp to.  And there was a window comparator to
tell
> when the output was settled to the level voltage.  The other half was a
micro
> controller.  The parameters were stored in memory.  In theory, I could have
as
> many stages as I wanted....but, I will never know, I abandoned the project
long
> ago.  I keep thinking I will get back to it sometime....maybe.
> 
> "M.Ruberto" wrote:
> 
> > hi,
> >
> > lately i've been thinking about designing a multi-stage rate/level
envelope
> > generator. i think i had this idea once before but never moved on it. i
have
> > some interesting thoughts about how to make it work but before i start
> > protoboarding i thought i'd ask if any of you folks have seen this done
in
> > analog before. if there are designs out there i would like to see them.
> >
> > thanx
> >
> > -<mike>-
> >
> > ____________________________________________________________________
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> --
>  -Jim
> ------------------------------------------------
> * Visit:http://www.silcom.com/~patchell/
> *-----------------------------------------------
> *If you didn't buy a home in Santa Barbara,
> * You didn't pay enough!
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