F detection by crosscorrelation with a comb function

Abstract

Thanks to the development of fast digital hardware performing real-time spectral analysis on speech data, dependable pitch analysis can be obtained even in the presence of a large amount of noise through the use of new F0 measurement techniques. A new method is presented here, based on the crosscorrelation between the power spectrum of suitably windowed speech data F(ω) and a comb function C(ωp,ω): I(ωp) = ∫ 0∝ F(ω)C(ωp,ω)dω. The comb function detects the possible harmonic structure in the spectrum, so that when C(ωp,ω) is carefully chosen, the crosscorrelation function I(ωp) shows maxima at values of ωp corresponding to the fundamental frequency of voiced speech. The appropriate design of the comb (with an amplitude varying with ω), leads to more appropriate and economical digital hardware compared to the general crosscorrelation approach.