A robust pitch detector based on time envelope and individual harmonic information using Phase Locked Loops and consensual decisions

A pitch detector system is proposed, based on estimation of time envelope information and individual harmonics frequency determination. The system takes advantage of the fact that both the time envelope of a speech signal and the frequency of its individual harmonics carry information about the pitch. A set of pitch hypotheses are calculated from time envelope signals extracted from different parts of the spectrum. These hypotheses are tested against the information obtained from individual harmonics from the lower part of the spectrum. Hypotheses which reliably match that information are preserved, and a consensual decision is taken between them to obtain the final pitch estimation. In addition, several by-products of the process can be retained in order to perform voiced/unvoiced detection. As every subsystem extracts information from arrangements of Phase Locked Loops the detector is very robust in noisy conditions, compared to the well known get f0 algorithm.