[sdiy] Full wave rectifier for audio

[James Patchell]

Take a look here:

http://www.oldcrows.net/~patchell/archives/idealdiode.html

It is a tutorial...I hope...on using precision diode circuits.


At 10:29 PM 1/14/2006 +0000, you wrote:
>Hi,
>
>I'm working on a full wave rectifier (as the front end of a noise gate 
>level detector), but I'm having trouble finding a simple circuit that 
>works well.  I'd like it to be done with max 2 opamps plus a few extra 
>components.  Anyone know of a suitable circuit that will work over a wide 
>signal range (i.e. from less than a diode drop up to ~10Vptp)?
>
>The nearest I have so far is this:
>http://burnit.co.uk/sdiy/stuff/full_wave_rectifier.gif
>(it intentionally has a gain of 2, but this isn't absolutely necessary)
>
>But the problem with this is the circuit itself tends to slightly 
>positively bias the input signal resulting in the positive halves of the 
>wave being slightly higher than the negative halves.  This effect is 
>dependent on the impedance of the driving circuit - if I slap an opamp 
>voltage follower on the input the problem goes away .. but I don't really 
>want to use another opamp if I can help it.
>
>Any ideas how to fix this circuit, or is there another circuit that will 
>do what I want?
>
>Seb
>
>

         -Jim
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