Speech formant frequency and bandwidth tracking using multiband energy demodulation

In this paper, the amplitude and frequency (AM-FM) modulation model and a multiband demodulation analysis scheme are applied to formant frequency and bandwidth tracking of speech signals. Filtering by a bank of Gabor bandpass filters is performed to isolate each speech resonance in the signal. Next, the amplitude envelope (AM) and instantaneous frequency (FM) are estimated for each band using the energy separation algorithm (ESA). Short-time formant frequency and bandwidth estimates are obtained from the instantaneous amplitude and frequency signals; two frequency estimates are proposed and their relative merits are discussed. The short-time estimates are used to compute the formant locations and bandwidths. Performance and computational issues of the algorithm are discussed. Overall, multiband demodulation analysis (MDA) is shown to be a useful tool for extracting information from the speech resonances in the time-frequency plane. (C) 1996 Acoustical Society of America.