SIMULTANEOUS ESTIMATION OF VOCAL-TRACT AND VOICE SOURCE PARAMETERS BASED ON AN ARX MODEL

A novel adaptive pitch-synchronous analysis method is proposed to esti mate simultaneously vocal tract (formant/antiformant) and voice source parameters from speech waveforms. We use the parametric Rosenberg-Kla tt (RK) model to generate a glottal waveform and an autoregressive-exo genous (ARX) model to represent voiced speech production process. The Kalman filter algorithm is used to estimate the formant/antiformant pa rameters from the coefficients of the ARX model, and the simulated ann ealing method is employed as a nonlinear optimization approach to esti mate the voice source parameters. The two approaches work together in a system identification procedure to find the best set of the paramete rs of both the models. The new method has been compared using syntheti c speech with some other approaches in terms of accuracy of estimated parameter values and has been proved to be superior. We also show that the proposed method can estimate accurately the parameters from natur al speech sounds. A major application of the analysis method lies in a concatenative formant synthesizer which allows us to make flexible co ntrol of voice quality of synthetic speech.