I'm not sure what you call that: Basically I was wondering if there is a module that can read the audio input, and output a pitch that can e.g. be patched to an oscillator. Or that you could use to determine tune a guitar that you have plugged in. is there something like that?
There was this "external signal processor" in the korg MS20 that could be used to convert input audio to pitch CV. I know this is not easy (and sometimes impossible) to do if it needs to be fast and accurate, especially if you have distorted waves or even chords or noisy input.