Telecommunications – Interference signal transmission
Patent
1994-04-14
1998-07-07
Peng, John K.
Telecommunications
Interference signal transmission
348 14, 348 16, 330275, 330301, 330116, 333 25, H04N 100, H04N 714, H03F 326, H03H 500
Patent
active
057783039
ABSTRACT:
A multiplexed audio-video signal transmission system has a camera-equipped intercom which produces a balanced audio-video signal. A twisted pair-wire connected to the intercom transmits a multiplexed signal of audio signal, video signal modulated to a frequency band not overlapping the audio signal frequency, and DC power. The audio signal and video signal are carried in the pair-wire in opposite phase in a balanced condition, and the DC power is carried between the pair-wire. A relay device is inserted in the pair-wire to refine the video signal. Main line branching device and door branching device are provided to branch out the multiplexed signal to a television equipped control unit 17.
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Kubo Seiichi
Shinozaki Noboru
Matsushita Electric Industrial Co., Inc.
Miller John W.
Peng John K.
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