env folower

[Paul Perry]

At 04:47 PM 27/08/98 +0200, Johan Gustavsson <moxie wrote:

>On another note, does anyone have a lead on an external input module
>schemo? I'd like a space with external input, mic preamp, envelope
>follower 

how smooth you want the env follower depends on what you want to do 
with it. 
The common approaches are:
1. precision rectifier folowed by  3rd order40Hz low pass filter

2. peak detector with a zero-crossing reset.

Both these ckts are (or were) on the net somewhere.....

paul perry melb aust
BTW I built #1 using ckts from Jung's "Op Amp Cookbook".
Worked OK for me (enveloped controlled tekkno filter)