Phase modelling and its application to sinusoidal transform coding

In the context of a sinusoidal representation for speech waveforms [1-4], it is shown that the excitation sine-wave phases can be modelled as a linear function of frequency, the slope being determined by the onset time of the underlying pitch pulse. An algorithm for estimating the pitch onset time from the original sine-wave parameters is derived. The new phase model has been used to improve the coding efficiency of the sinusoidal transform coder (STC) and for compensating phase errors introduced by the quantization of the sine-wave frequencies.