A new speech modification method by signal reconstruction

The authors propose a new speech modification algorithm using short-time Fourier transform (STFT) synthesis. This algorithm is developed using the criterion that the mean-square-error signals between the STFT spectra of the estimated and the modified should be minimized. The most important and unique ideas of the algorithm are liftering that passes all cepstra except cepstra in the pitch frequency region, and phase control by a signal reconstruction algorithm and window-shift adjustment. Listening tests for uniform and nonuniform pitch modification reveal that the proposed algorithm can synthesize high-quality speech and that it is applicable to a synthesis-by-rule system. >