envelope generators

[Arnim X. Sauerbier]

>First, all parameters have to be voltage controlled.  Build 10 or
>12-bit DACs for each of the parameters.  The manual knobs on the front
>would simply bump the values going into the DACs up and down (one
>would likely want coarse and fine knobs).  No pots, just something to
>drive a digital counter, but they would *look* like pots.

Yup, I recall hearing about knobs that would close a contact repeatedly 
if you spun them to the left, and close another contact if you spun them 
to the right.  One full turn would trigger the thing maybe 60 times.  The 
faster you turn, the faster the contact is switched on and off.  Perfect 
for driving a digital increment/decrement-by-one circuit.  Remember the 
video game "tempest"?

>Each module would also have a maximum fixed number of input and
>outputs.  These i/o's could either be analogue, going through an
>addressible crossbar switch, or could be bussed, digital control
>"signals".  I would think 12 bits would be enough for the latter.
>For the crossbar, think of the VCS3 pin matrix, but with the pins
>being under software control.

This seems too difficult unless you make audio signals analog, and 
control signals digital. 

Well, maybe you COULD digitize control and audio signals, but then your 
audio signal will go through so many AD/DA conversions, it'd get noisy, 
right?  And speaking of noise, how do you prevent the RF from all those 
digital lines from raising a racket?   I'm no electronics whiz... just 
asking some basic questions.

>A quick tap on a switch would make all the ports that are "patched
>together" flash, while holding down the button would let you set a
>patch.

Cool.

>o	you could have purely digital modules interacting with purely
>	analogue ones (e.g., run a control voltage to your S/PDIF
>	module, out to your Mac where you run it through a room
>	simulator and looper digitally, and then back into the
>	analogue domain).

Cool!

>o	you could use your computer to prototype or implement any sort
>	of processing you wanted, and use it like any other module in
>	the rack.

Way Cool!!

> What say?

Want!
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Arnim Sauerbier