Pitch-Synchronous Time-Domain Estimation of Formant Frequencies and Bandwidths

Abstract

A technique for the measurement of vocal-tract formant frequencies and bandwidths during voiced speech is described. A theoretical justification for the method is presented, based on a model of the vocal tract that is linear and stationary over time intervals of the order of one pitch period (approximately 0.01 sec). In brief, the technique consists of selecting a portion of one pitch period of a speech waveform during which the glottis is closed. This finite-duration signal is approximated in a weighted-least-squares sense by a function of the form f̂(t) = ∑ i−1Ne−πBit(ai cos2πFit+ci sin2πFit)+a0, where ai, ci, Fi, and Bi are selected to minimize the weighted-squared error between f̂(t) and the actual speech signal of interest, f(t). Bi and Fi are estimates of the bandwidth and frequency, respectively, of the ith formant. A digital-computer program was used to perform the minimization. The program was used to determine the bandwidths and frequencies of the first four formants of the vowels /i/, /ɔ/, and /ɑ/ in the context b(vowel)t. Two male speakers produced most of the speech waveforms. The technique seems to be most reliable for the first two formants. It yields results that appear to have a smaller variance than those obtained by previously reported methods, although the variance is still substantial.

Pitch-scaled estimation of simultaneous voiced and turbulence-noise components in speech

“…In order to adapt the spacing of the teeth of the comb filter in synchrony with variations in voicing, knowledge of the glottal pulse epochs is required. There have been many TD realizations of this pitch-synchronous method, which have accommodated timing variations by truncation and zero-padding [7], [29], [30], scaling [15], least-squares alignment [27], [31], or dynamic time warping [17].…”

Linear Prediction and Long Term Predictor Analysis and Synthesis

“…Acoustic data transformation into spectral form performed using short-time Fourier analysis of speech wave [1]. However, its application degraded because of nonstationary and quasiperiodic properties of speech wave [2]. Therefore, spectral analysis may not provide an accurate description of speech articulation.…”

A time domain study of speech sounds

“…Pinson (48) has approached the problem of describing The actual spectrograph uses a fixed band-pass filter, and heterodynes the signal up to the frequency of the filter.…”