A high quality 9.6 kbps speech coding system

A 9.6 kbps speech coding system based on a new speech model is presented. In this model, the short-time spectrum of speech is modeled as the product of an excitation spectrum and a spectral envelope. The spectral envelope is some smoothed version of the speech spectrum and the excitation spectrum is represented by a fundamental frequency, a voiced/unvoiced (V/UV) decision for each harmonic of the fundamental, and the phase of each harmonic declared voiced. In speech analysis, the model parameters are estimated by explicit comparison between the original speech spectrum and the synthetic speech spectrum. Preliminary results indicate that high quality reproduction can be obtained with this speech coding system for both clean and noisy speech without the "buzziness" and severe degradation in noise typically associated with vocoder speech.