AURAL SIGNAL DECODING METHOD AND DEVICE, AURAL SIGNAL ENCODING/DECODING METHOD AND DEVICE, AND RECORDING MEDIUM

摘要

PROBLEM TO BE SOLVED: To provide a device and a method by which reproduced voice quality is improved with respect to background noise voice in an aural signal decoding device which generates aural signals by driving the filter, that is composed of linear prediction coefficients, by exciting signals. SOLUTION: A smoothing circuit 1320 conducts smoothing of a sound source gain (a second gain) in a noise segment using the sound source gain obtained in the past. A smoothing amount limiting circuit 7200 computes the amount of fluctuation that is represented by dividing the absolute value of the difference between the sound source gain and the smoothed sound source gain by the sound source gain and limits the value of the smoothed gain so that the amount of fluctuation does not exceed a certain threshold value.