Detect frequency and lock

[prprog]

I started to read/learn about Phase Lock Loops IC's ...because I want to do this as a musical electronic project -> I will take a violin note (via a mike/transducer-> convert to squared wave -> compared the frequency to a know frequency and if it is "acceptable" to be near output the corrected frequency.

The idea is to generate/synthesize correct frequencies for a "not to correct" frequency.

Is a Phase Lock Loop IC the way to do this?

Thanks,