Low update rate articulatory analysis/synthesis of speech

A pitch-synchronous scheme for analysis/synthesis of speech is presented that uses a parametric model of the time-derivative of the glottal area function. Improved articulatory codebooks are used to start up an analysis-by-synthesis procedure to adapt parameters representing the vocal tract shape and the glottal geometry. The authors also present results of multiframe parameter optimization of articulatory parameters for potential application to low-bit-rate speech coding. In this scheme, they optimize the parameters once for each appropriately selected segment of speech and interpolate to obtain parameter values at intermediate time-instants. They study three different vocal-tract representations for linear and arctan interpolation functions for multiframe parameter optimization. Experiments indicate that multiframe parameter optimization results in some degradation in speech quality as compared to single-frame parameter optimization