| 摘要 |
PROBLEM TO BE SOLVED: To improve the quality of a speech when outdoor background noise etc., is superposed in a digital mobile wireless communication system of automobile telephone, mobile telephone, etc. SOLUTION: A speech decoding device has a detecting means of monitoring an encoded signal encoded on a transmission side to decide whether the encoded signal is in a noise section or in speech section, a 1st speech decoding means of decoding the encoded signal decided as the speech section when the detecting means decides that the encoded signal is in the speech section, and a 2nd decoding means of decoding the encoded signal decided as the noise section when the detecting means decides that the encoded signal is in the noise section, and is characterized in that when the encoded signal in the noise section is received, the gain of an adaptive code book used by the 2nd decoding means is set to 0. COPYRIGHT: (C)2005,JPO&NCIPI
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