| 摘要 |
PURPOSE:To improve the transmission quality by providing plural adaptive forecast coding sections having a different processing characteristic, selecting a coding section having the optimum processing characteristic most suited to a present input signal among the coding sections and sending the output quantized value and its code to the reception side so as to change the processing characteristic of a decoder. CONSTITUTION:An evaluation device 2 including a quantized error power calculation section 5 and an optimum quantization decision section 6 uses the quantized error power calculation section 5 to calculate the quantized error power as to quantized error signals ei(n) from adaptive forecast coding sections (1-1)-(1-k). The optimum quantization decision section 6 decides an adaptive forecast coding section 1-opt having the smallest quantized error power to output a code opt representing the adaptive forecast coding section. A multiplexing section 4 multiplexes the output of the adaptive forecast coding section 1-opt selected by a selector 3 and the code opt and sends the result to the reception side. The reception side receiving the signals uses the code opt so as to control the decoding characteristic of a decoder 20 in matching with the characteristic of the adaptive forecast coding section selected by the transmission side.
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