Envelope follower for my vocoder...

[danial stocks]

> > I have looked at env follower from Craig Anderton's book, DR. Q, the
> > polyfusion, etc.
> > I looked at some half wave rectifiers.
> >
> > It seems they are just :   signal----diode-----cap to
> > ground------resistor-----cap to ground-----output
> >
>
>I'd consider little preamp before diode, also simple RC filter
>for ripple could be subed with opamp filter.

If you gonna go as far as putting op amps before/ after the diode to buffer 
against the probs of using the diode so you can ditch the op amps.. ? I'd 
stick with the 1/2 wave precision rectifier: 1opamp, can tailor the gain, 
attack time, decay time very easily, dont have the vtg drop prob of using a 
discrete diode on its own..
HPF before the diode doesnt really do anything except damp the low frequency 
response...
The reason sometimes use a full wave rect is to aviod ripple probs at low 
freq's with out unneccessarily long filter response times.. ie the filter 
response time can be halved for the same val of ripple..
Cheers,
Dan

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