Audio band width extending system and method

摘要

A narrow band code book in which parameters of a time region of a narrow band audio signal obtained from patterns of a plurality of audio signals have previously been stored and a wide band code book in which parameters of a time region of a wide band audio signal obtained from the patterns of a plurality of audio signals have previously been stored in correspondence to the code book of the narrow band, and the input narrow band audio signal is analyzed by the narrow band code book and is synthesized by the wide band code book. In this system, an autocorrelation is used on the parameters of the code books, and a signal obtained by up-sampling an linear predictive code residual is used as an exciting source at the time of audio synthesis.