| 摘要 |
PROBLEM TO BE SOLVED: To improve encoding efficiency and sound quality by adaptively encoding an input digital audio signal consisting of plural frames. SOLUTION: A delay circuit 130 stores a 1st signal-to-mask ratio of an i-th frame in a memory built in a delay circuit and supplies a delayed signal-to-mask ratio for an (i-1)th frame to a 2nd cognitive parameter measuring instrument 140 synchronously with the 1st signal-to-mask ratio for the i-th frame. A bit allocation/quantization block 150 to which a 2nd signal-to-mask ratio for respective sub-bands of the 1st frame is supplied from the instrument 140 adaptively finds out a bit for each sub-band and generates corresponding bit allocation information. A digital signal sample in each sub-band is quantized in accordance with the bit allocation information, and the digital signal sample and the bit allocation information are simultaneously supplied to a formating circuit 160, which formats the input data and sends the formated data to a transmitter. |
