Patent US 5,485,543

A method for speech analysis and synthesis for obtaining synthesized speech of a high quality includes the steps of determining a short-period power spectrum by performing an FFT operation on a speech wave, sampling the spectrum at the positions corresponding to the multiples of a basic frequency, applying a cosine polynomial model to the thus obtained sample points to determine the spectrum envelope thereat, then calculating the mel cepstrum coefficients from the spectrum envelope, and effecting speech synthesis, utilizing the mel cepstrum coefficients as the filter coefficients in a synthesizing (logarithmic mel spectrum approximation) filter.