optical limiter problem

[Barry L Klein]

Years ago I tried to make a compander with these around a Reticon SAD1024/512
or whatever it was.  I never got it quite right.  A couple of naive off the top of my head ideas/thoughts....

Is the response time to small changes of the LED linear?  Perhaps it is more responsive to control voltage changes as the resistance increases.  If so you might be able to do something like setting a minimum audible level threshold whereupon you then initiate a controlled decay of the control signal.  

Another bit of weirdness might be that the signal itself through the photocell changes its resistance or at least its decay rate to high impedance.  That would
be a bit scary wouldn't it... :-)  It was almost 20 years ago but I think I remember wondering if this kind of thing was going on.  Back then I didn't have our fancy current probes and 4 channel digital scopes to be able to tell.

Barry