Analysis of instantaneous F0 contours from two speakers mixed signal using zero frequency filtering

Instantaneous fundamental frequency (F₀) in voiced speech can be obtained from the sequence of epochs corresponding to the instants of significant excitation. The epoch sequence can be derived using the recently proposed epoch extraction method based on zero frequency filtering. The epoch extraction method is robust against additive noise degradation. But in a multispeaker mixed signal, the degradation is caused due to overlapping impulse-like excitations of two or more speakers. The feasibility of extracting the instantaneous F₀ contours from the two speaker mixed signal using zero frequency filtering is studied in this paper. The present study is based on deriving speaker-specific Hilbert Envelope (HE) signal which emphasizes peaks due to impulse-like excitation of one speaker and suppresses peaks due to other speaker. The epochs from this speaker-specific signal are obtained using the approach based on zero frequency filtering. The results of the proposed method is demonstrated for three different cases of mixed signals of two speakers data.