| 摘要 |
PROBLEM TO BE SOLVED: To reduce noise in a coding (compression) process of speech signals, by eliminating frequency components isolated from other frequency components. SOLUTION: In the speech processing device 100, inputted speech signals are divided into frames, the levels of the speech signals are adjusted for every frame based on the maximum value of the amplitudes of the speech signals included in the frame, MDCT (modified discrete cosine transformation) is conducted for the speech signals whose level is adjusted, vector quantization is performed and entropy coding is conducted for the speech signals obtained by the vector quantization and the signals are outputted. When the amount of data of the speech signals obtained by the entropy coding is greater than the amount of target data which are beforehand set, the frequency component, having a band whose energy is equal to or less than a prescribed value, is eliminated from the speech signals; and at the same time, a frequency component, in which the absolute value of the difference in an amplitude value with respect to the adjacent frequency component on a frequency axis is greater than a prescribed value, is eliminated. COPYRIGHT: (C)2006,JPO&NCIPI
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