| 摘要 |
<p>Provided is a parameter decoding device for a CELP-type encoded speech signal which performs parameter compensation process so as to suppress degradation of a main observation quality in a prediction quantization. The parameter decoding device includes amplifiers (305-1 to 305-M) which multiply inputted quantization prediction residual vectors x n-1 to x n-M by a weighting coefficient ² 1 to ² M . The amplifier (306) multiplies the preceding frame decoding LSF vector y n-1 by the weighting coefficient ² -1 . The amplifier (307) multiplies the code vector x n+1 outputted from a codebook (301) by the weighting coefficient ² 0 . An adder (308) calculates the total of the vectors outputted from the amplifiers (305-1 to 305-M), the amplifier (306), and the amplifier (307). A selector switch (309) selects the vector outputted from the adder (308) if the frame erasure coding B n of the current frame indicates that 'the n-th frame is an erased frame' and the frame erasure coding B n+1 of the next frame indicates that 'the n+1-th frame is a normal frame'.</p> |
