A note on complexity reduction for linear predictive speech synthesis

Most linear predictive speech synthesis (LPSS) algorithms employ a deemphasis filter with a fixed transfer function subsequent to the time varying LPSS filter. The excitation signal for the LPSS filter is usually a stored waveform sequence, repeated at the pitch period, for voiced sounds or a noise sequence for Unvoiced sounds. In either case the excitation signal is approximately white. A computational savings may be achieved by using an excitation signal whose spectrum reflects the frequency response of the deemphasis filter. A procedure is described for generating such an excitation signal and formal subjective intelligibility test results are presented to demonstrate that no performance degradation occurs when this method is employed.