Analog -Digital Interface question

Hi everyone,
I am working on a analog - digital circuit design for my Masters thesis. I have an analog signal processing circuit which processes a signal and outputs the strength of the signal as a voltage. I have in mind two voltage levels as my High and Low strength and some intermediate voltage levels for finer accuracy in strengths. The output of my signal processor has a non linear relationship. (ie. it may not be monotic increasing).

I want to use the output voltage of this circuit to be an input to my look up table - LUT (or memory) . The LUT has some digital info stored for some ancillary functions. Can anyone give me any pointers as to how to accomplish this interfacing without using ADC. I dont have much experience in LUTs......so please give me more details! Or if u know of some good sources of information......i would be grateful to the day I die ;-)

Thank you in advance!
Best regds
Kurt

Hi,
Just thought I would post an update.....seems like u have only a couple of options in this situation....one is to use a ring osc to get a digital equivalent (note the equivalent)......but that has some accuracy and consistency issues.....otherwise, just use some sort of selection circuit to choose the signal of greatest strength and process the respective digital info....this is only possible becoz of the nature of my application not as a general case tho!