| 摘要 |
PURPOSE:To miniaturize a singing preventing circuit, by PCM-coding the transmission and receiving of voice and transmitting and receiving the voice on a digital line. CONSTITUTION:A band pass filter 5 passes through a voice signal only from the voice signal from a microphone 1 at a band pass filter 5 so as to prevent a fold back noise caused by sampling a switched capacitor comb line filter 6 from entering the pass band, the band is separated at a filter 6, the voice signal is coded at an encoder 7 and transmitted as a PCM signal. Further, a PCM signal transmitted from the opposite terminal is decoded at a decoder 10, converted into an analog signal, the signal is separated into a different band at a switched capacitor comb line filter 9, smoothed at a low pass filter 8 and broadcast from a speaker 2. |
