| 摘要 |
PURPOSE:To improve the amplitude and group delay time characteristics in the PCM signal process system which is applied to a sound recorder or the like, by giving a band limit to the input signal to 1/2-1 times as less as the sampling frequency and then carrying out a sampling with the frequency of double the upper limit frequency of transmission. CONSTITUTION:The BPF22 gives a band limit to the audio input signal to the frequency which is larger than the 1/2 sampling frequency F and smaller than the frequency F. This output is given the A/D conversion 4 and then transmitted to the transmission line 6 after a sampling given with the frequency of double the upper limit frequency. This output is demodulated 7 and then changed from the sampling frequency F to 2F to receive the D/A conversion 27 and then to be delivered after the LPF28. In such way, both the amplitude and group delay time characteristics can be improved. |
