Speech synthesis apparatus and speech synthesis method

Abstract

A speech synthesis apparatus and a speech synthesis method, in which a waveform of a desired formant shape may be generated with a small volume of computing operations. A voiced sound generating unit of the speech synthesis apparatus includes n single formant generating units, an adder for summing these outputs to generate a one-pitch waveform, a one-pitch buffer unit, and a waveform overlapping unit for overlapping a number of the one-pitch waveforms as the one-pitch waveform is shifted by one pitch period each time. Each single formant generating unit is supplied with three parameters, namely a center frequency of a formant representing the formant position, a formant bandwidth, and a formant gain and reads out the band characteristics waveform at a readout interval, derived from the bandwidth wn, from a band characteristics waveform storage unit to effect expansion along the time axis. The resulting waveform is multiplied with a sine wave of the center frequency to output a pitch waveform for a formant representing characteristics of a formant.