How to set automatically unknow trigger levels?

What do you mean with "the next time", how much delay between itterations? How fast does the signal change?

It would seem that two DACs controlled by a micro could the set the input levels for the comparators depending upon how fast this all has to work.

Why use a mainframe computer when an analog integrator will work?

robert

Sure, and by what signal ist the integrator controlled ? Meaning what is the input of the integrator ? There might be multiple trigger density maxima between the voltage boundaries.

Rene

Mainframe? The OP didn't even describe an algorithm explaining how the levels would be chosen, how do you know that an integrator will suffice?

Basically what you want looks a little like this:

U1 IN-------!+\ D1 U2 ! >----->!----+-----!+\ ---!-/ ! ! >---+--OUT ! C1 === --!-/ ! ! ! ! ! ! GND --------+ ! ! -------------------------------

If the input goes above the output, the output of U1 swings positive and charges up C1 to bring it to a matching voltage. When the input starts to fall, U1 swings back down, the diode back biases and the output remains at the positive value.

Now all you need is a voltage divider and comparitor to make the signal you want.

This design has some serious problems, however. There is no path for C1 to ever discharge. If the frequency is more than a few KHz, U1's job is near imposible. D1 has to be a very good diode. U2 has to have low bias current but be fast.

Each of these can be solved in specific cases so if we know more about the frequencies etc, we may be able to go further or perhaps just this little push start will have you see how to solve it.

Perhaps...check out the min-max detector, Patent 4315220

Where's Don?

Automatic setting of unknown values is best done in programming using random number generator(s) and praying. Note: can drive anyone loco, including working hardware. BTW this is "design" gathering, try to fit.

Have fun

Stanislaw.