| 摘要 |
PURPOSE:To attain the frequency band separation with high accuracy, by using a single band pass filter, in a frequency band separating circuit extracting a specific frequency component from an analog data. CONSTITUTION:A voice input signal, e.g., an analog signal A having 0-3kHz of frequency is sampled at a sampling pulse signal fs, converted into a pulse amplitude (PAM) signal B, compared with an incorporated reference voltage Vs at a quantizing section 22, converted into a PCM signal and transmitted to a storage section 23. The storage section 23 transmits its content further to a decoding section 24 according to the access externally. The decoding section 24 is constituted with a weighting resistance circuit network taking, e.g., the reference voltage Vs as a reference, restores the PCM signal to PAM signals C, D with plural decoded pulse signals fr1, fr2...frn and transmits them to a BPF25. Thus, a signal f0+ or -m having a prescribed frequency band width is obtained at an output of the BPF25 at all times. |
