Pitch detection algorithm

A pitch detection algorithm (PDA) is an algorithm designed to estimate the pitch or fundamental frequency of a quasiperiodic or oscillating signal, usually a digital recording of speech or a musical note or tone. This can be done in the time domain, the frequency domain, or both.

PDAs are used in various contexts (e.g. phonetics, music information retrieval, speech coding, musical performance systems) and so there may be different demands placed upon the algorithm. There is as yet^[when?] no single ideal PDA, so a variety of algorithms exist, most falling broadly into the classes given below.^[1]

A PDA typically estimates the period of a quasiperiodic signal, then inverts that value to give the frequency.