Measuring pitch and formant frequencies for a speech understanding system

Abstract

We present new techniques for the measurement of pitch period and formant frequencies. Individual pitch periods are estimated by finding local maxima in the power spectrum averaged over a frequency band that includes a formant. A spectral analysis is then performed for each pitch period over a data interval that is of shorter duration than the estimated pitch period. The pitch synchronous spectral analysis followed by post detection smoothing - preferably carried out over both time and frequency - leads to a spectrogram from which formant trajectories can be estimated by simple algorithms.