AD Env.Gen. Building

[Carlos Vila Deutschbein]

Hi to everyone! 
This is my first posting to this list, so let me introduce myself briefly:
My name is Carlos and I'm from Barcelona (Spain). I'm studying Image&Sound
Engineering here. I'm currently working on a project which involves
building an ADSR Envelope Generator and analyzing it's effect on sound
(not only time domain but also frequency domain). I'm also investigating
on the relationship of different envelope curves for different
harmonics...

Well, to the point:
I have a schematic taken from <http://surf.pangea.ca/~rmiller/ad.jpg>
It is a simple AD EG from Barry Kleins Book. There are a couple of things
I don't quite understand though:

- The only NOR Gates I know work with 0/+5 Volts (CMOS logic?). So, at the
Q output there can be max 5V and that's the voltage towards the capacitor
C3 tends to charge. That fact doesn't fit into my equations because
further on, this voltage is compared to 9.8V at IC A1, which it will never
reach...(?!) In consequence, the decay phase never triggers....

Onother thing: does anybody use circuit simulation software? I use PSpice,
but an old version, which is a hassle, because you have to edit a textfile
instead of drawing the circuit directly. Any ideas?

 I hope someone can help me, electronics in not my strongest point. 
Thanks

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    Carlos Vila Deutschbein
    e-mail: si04697 at salleURL.edu
    www: http://www.salleURL.edu/%7esi04697
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