Envelope follower schamtic

[Paul Perry]

At 04:31 PM 23/06/97 +0200, Peter Ullrich wrote:
>I found an envelope follower schematic in an old German magazine and put a
>scan on my homepage. You can download the file from:
>
>http://www.geocities.com/SiliconValley/Heights/3586/envfollo.jpg
>

this is ingenious....i cant read german either, but it looks like the first
section acts as an unfiltered full wave rectifier so that the frequencies
are doubled, which makes the filtering more effectiv in the second
section......i wouldn't have thought of that on a million years.....but what
i have thought before is the possibility of using a ne571 or ne572 without
smoothing caps as a nonlinear transform for distortion generation.....

my own search for the perfect envelope gen has ended for the moment. i am
using the full wave detector from page 242 of Jung's IC Op Amp Cookbook 3ed,
with a 3rd order low pass filter after it.....i am a happy man...now for the
perfect pitch extractor!!!!!

paul perry