Method of speech synthesis by means of concentration and partial overlapping of waveforms

Abstract

Method for speech signal synthesis by means of time concatenation of waveforms representing elementary units of speech signal, in which: at least the waveforms associated to voiced sounds are subdivided into a plurality of intervals, corresponding to the responses of the vocal duct to a series of excitation impulses of the vocal cords, synchronous with the fundamental frequency of the signal; each interval is subjected to a weighting; the signals resulting from the weighting are replaced with a replica thereof shifted in time by an amount that depends on a prosodic information; and the synthesis is carried out by overlapping and adding the shifted signals. In each interval of original signal to be reproduced in synthesis, an unchanging part is identified, which contains the fundamental information and which is reproduced unaltered in the synthesized signal, and the operations of weighting, overlapping and adding involve only the remaining part of the interval.