| 摘要 |
PURPOSE:To reduce quantization noise and deterioration in sound quality even from a signal with a large tonality such as the signal of a trumpet sound. CONSTITUTION:The device is provided with band division filters 11, 12 decomposing a digital signal into plural frequency band components, MDCT circuits 13-15 obtaining signal components in a block having a definite time width and a definite frequency width, nonlinear processing circuits 40, 41, 42 applying nonlinear processing to an MDCT coefficient, and an adaptive bit coding circuit 18 quantizing the signal component for each block to implement information compression and providing outputs of both the signal component whose information is compressed and information compression parameters required for compressing the information for each block, and the nonlinear processing circuits 40, 41, 42 make a quantized value zero with a signal to noise ratio as to samples with smaller signal to noise ratio or increase the spectrum value when the signal tonality in the floating block in the high efficiency coding is high. |
