| 摘要 |
A speech signal decoding apparatus includes a decoding section, an error check section, a data memory, a white noise generating section, a switch group, and a frequency region synthesizing filter bank. The decoding section separates a received code string into the 0th to nth sub-band signals and decodes them. The data memory outputs the decoded signals with a delay. The white noise generating section outputs white noise signals of the (m+1)th to nth sub-bands which are level-adjusted in accordance with the average power of the decoded signal of each sub-band. The switch group selects/outputs the decoded signals of the 0th to nth sub-bands when a control signal representing an error is not output, and selects/outputs the delayed and decoded signals of the 0th to mth sub-bands and the level-adjusted white noise signals of the (m+1)th to nth sub-bands when a control signal representing an error is output. The frequency region synthesizing filter bank outputs a reproduced speech signal on the basis of the selected outputs of the 0th to nth sub-bands. A speech signal decoding method is also disclosed.
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