| 摘要 |
PROBLEM TO BE SOLVED: To perform a regeneration of high quality at a low bit rate by band- dividing an input signal and coding it by respective methods suitable to low-pass side and high-pass side SOLUTION: From the input signal from a terminal 101, a high-pass side signal is taken out by a LPF (low pass filter) 102 and a subtracter 106, and this signal is FFT-processed by a FFT(fast Fourier-transformation) circuit 161, and shifted to a low-pass side band by a frequency shifting circuit. The signal reverse-FFT processed by a reverse FFT circuit 163 is transmitted to a LPC(linear predictive coding) reverse filter circuit 171 and subjected to predictive coding processing, whereby the predictive coding processing can be realized at low sampling frequency. |
