| 摘要 |
PROBLEM TO BE SOLVED: To obtain pleasant sound quality by improving the sound quality when reproduction is performed with an encoded sound signal. SOLUTION: The mask level ML of the sound signal is set. The peak of the sound signal is detected. Frequencies f3 (=n×f1) and f4 (=n×f2) which are (n) times as high as the peak frequencies (f1 and f2) are set. It is discriminated whether or not the sound pressure at the frequency f3 which is (n) times as high as peak frequency f1 is sound pressure which is almost 1/n time as high as the sound pressure d1 at the peak frequency f1. When the sound pressure f3 is 1/n time as high as the sound pressure d1 at the peak frequency f1, the mask level in a band including the peak frequency f3 is corrected from the mask level MLa to 0. The frequency f4 (=n×f2) is also set similarly. Sound signals above the mask level are quantized and compressed data are outputted.
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