| 摘要 |
PURPOSE:To obtain an optimum filter to noise by transmitting a difference signal output between an input signal and its forecast signal via a circuit section with different spectrum and feeding back negatively an error of input/output of the circuit section to an input. CONSTITUTION:The input signal x(n) is fed to an adder 12 and a forcast device 13, the adder 12 takes difference between the input signal and a signal x(n)' from the forecast device 13 and the difference becomes a difference signal d(n). The signal d(n) is fed to an adder 14, where the difference with a froecast signal e(n)' from the forecast device 15 is taken and the result becomes a signal dd(n) and is fed to a quantizer 16. The difference signal d(n)' quantized from a quantized from a quantizer 16 is extracted from an output terminal 18 as an encoder output and fed to an adder 17, where the difference with the signal dd(n) is taken, the result becomes a quantized error signal e(n), fed to the forecast device 15, and its forecast value e(n)' is fed back to the input. The noise energy of the signal d(n)' is reduced at high frequencies to decrease the audible intensity. |
