| 摘要 |
PROBLEM TO BE SOLVED: To perform bit rate variable voice encoding, to suppress the bit rate of the voice signals of low importance and to improve efficiency of a transmission line. SOLUTION: This voice encoder divides the voice signals into plural bands, allocates a quantization bit number for the respective bands, quantizes the voice signals of the respective bands by the allocated bit number and sends them out. In this case, a bit allocation part 33 (1) calculates an MNR(mask-to- noise ratio) for the respective bands, (2) compares a minimum MNR among the MNRs in the respective bands with a set MNR, (3) increases the quantization bit number of the band corresponding to the minimum MNR by 1 in the case that the minimum MNR is smaller than the set MNR and (4) controls the allocation of quantization bits to the respective bands until the minimum MNR becomes larger than the set MNR. A quantization part 39 quantizes the voice signals of the respective bands by the allocated quantization bit number and a bit rate calculation part 35 takes the quantization bit number allocated to the respective bands into consideration and decides the bit rate for voice data transmission. |
