DISPOSITIF DE GÉNÉRATION DE SÉQUENCE D'ENVELOPPE COMBINÉE PÉRIODIQUE, PROCÉDÉ DE GÉNÉRATION DE SÉQUENCE D'ENVELOPPE COMBINÉE PÉRIODIQUE, PROGRAMME DE GÉNÉRATION DE SÉQUENCE D'ENVELOPPE COMBINÉE PÉRIODIQUE ET SUPPORT D'ENREGISTREMENT

摘要

An envelope sequence is provided that can improve approximation accuracy near peaks caused by the pitch period of an audio signal. A periodic-combined-envelope-sequence generation device according to the present invention takes, as an input audio signal, a time-domain audio digital signal in each frame, which is a predetermined time segment, and generates a periodic combined envelope sequence as an envelope sequence. The periodic-combined-envelope-sequence generation device according to the present invention comprises at least a spectral-envelope-sequence calculating part and a periodic-combined-envelope generating part. The spectral-envelope-sequence calculating part calculates a spectral envelope sequence of the input audio signal on the basis of time-domain linear prediction of the input audio signal. The periodic-combined-envelope generating part transforms an amplitude spectral envelope sequence to a periodic combined envelope sequence on the basis of a periodic component of the input audio signal in the frequency domain.