[sdiy] simple "level separator"?

[Ian Fritz]

Hi --

I have a waveshaper that works (part of it) in a similar way.  It uses a 
compartor to detect when the signal is above a voltage-controlled 
threshold, and a FET switch to short the signal to ground when it 
isn't.  The circuit isn't exactly what you are asking for, but you can use 
the same idea.

http://home.earthlink.net/~ijfritz/sy_cir6.htm

Good luck, and let me know if you have question about how to adapt it to 
your application.

   Ian


At 05:49 AM 4/30/2003, VINTVOLT wrote:
>Hi,
>I'm in need of a simple circuit that would be used to separate high and
>low
>levels from a signal. It's transfer function should be like this:
>
>
>     ^out
>     |         /
>     |        /
>     |       /1:1
>     |      |
>     |      |
>     |      |
>sym  ======---------->in
>           thr
>
>
>where the threshold should be adjustable, so very similar to a noise
>gate,
>but without any time constants. It should be instantaneous.
>I searched the web, but could not find any simple circit. I thought
>about
>using a fet in the audio-path with the gate connected to the output of a
>comparator. would that work?
>
>--
>Carles Vila Deutschbein
>Departament d'Acústica -Engingeria La Salle