Mid-rate coding based on a sinusoidal representation of speech

In this paper a sinusoidal model for the speech waveform is used to develop a new analysis/synthesis technique that is characterized by the amplitudes, frequencies, and phases of the component sine waves. The resulting synthetic waveform preserves the waveform shape and is essentially perceptually indistinguishable from the original speech. Furthermore, in the presence of noise the perceptual characteristics of the speech and the noise are maintained. Based on this system, a coder operating at 8 kbps is developed that codes the amplitudes and phases of each of the sine wave components and uses a harmonic model to code all of the frequencies. Since not all of the phases can be coded, a high frequency regeneration technique is developed that exploits the properties of the sinusoidal representation of the coded baseband signal. Based on a relatively limited data base, computer simulation has demonstrated that coded speech of good quality can be achieved. A real-time simulation is being developed to provide a more thorough evaluation of the algorithm.