Modified group delay functions are beginning to gain significance in the literature for formant
estimation, speaker recognition and speech recognition. In particular, group delay functions
have the property that they possess higher resolution compared to that of the magnitude
spectrum. In this paper, modified group delay functions are used for the estimation and
tracking of two pitches in concurrent speech. The power spectrum of the speech signal is first
flattened to annihilate the system characteristics, while retaining the source characteristics …