Speech formant frequency and bandwidth tracking using multiband energy demodulation
The AM-FM modulation model and a multiband analysis/demodulation scheme is applied to speech formant frequency and bandwidth tracking. Filtering is performed by a bank of Gabor bandpass filters. Each band is demodulated to amplitude envelope and instantaneous frequency signals using the energy separation algorithm. Short-time formant frequency and bandwidth estimates are obtained from the instantaneous amplitude and frequency signals and their merits are presented. The estimates are used to determine the formant locations and bandwidths. Performance and computational issues (frequency domain implementation) are discussed. Overall, the multiband demodulation approach to formant tracking is easy to implement, provides accurate formant frequency and realistic bandwidth estimates, and performs well in the presence of nasalization.