On a smoothing method by time-axis control with the zero-crossing of speech signal

In the area of speech synthesis techniques, waveform coding with high quality is mainly used for synthesis by analysis. In order to apply waveform coding, a pitch alteration technique is required in prosody control. The spectrum distortion of the pitch alteration method by time-axis control increases exponentially when the alteration rate is increased. In this paper, we propose a new pitch alteration method that uses a smoothing technique. This method changes the pitch period by partially controlling the time-axis of each zero crossing of the speech signal. This is a time domain method that preserves the phase components of the waveform and has little spectrum distortion of 4.3% for 70% pitch change