| 摘要 |
PROBLEM TO BE SOLVED: To transmit a voice signal and a video image signal in the same transmission path without generating electric feedback. SOLUTION: The television intercom device includes: an entrance terminal 2 for transmitting an FM signal S3 in which the video image signal S1 of a video image picked-up by a camera 21 is modulated, and a voice signal S2 entered from a microphone 22; and a room master unit 3 for demodulating the transmitted FM signal to a video image signal forming a picture on a monitor 31, and making sound of the voice signal through a speaker 33. The entrance terminal includes a superimposing/modulating unit 25 for sampling a voice signal with synchronization with the cycle of the horizontal synchronization signal of the video image signal, and superimposing the voice signal on a front porch unit during a horizontal blinking term of the video image signal and modulating into the FM signal. The room master unit includes a demodulating/reproducing unit 36 for demodulating the FM signal transmitted from the entrance machine, separating a voice signal superimposed on the front porch unit during the horizontal blinking term of the video image signal, and sampling and reproducing them. COPYRIGHT: (C)2006,JPO&NCIPI
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