| 摘要 |
PURPOSE:To lower cost of the titled system and to optionally dispose a monitoring camera between nodes without increasing an optical fiber for transmission by using one encoder in common for encoding video signals from plural monitoring cameras. CONSTITUTION:When it is desired to sec the video of a monitoring camera at a node arranged at the center for traffic monitoring, etc. a request for transmission is transmitted from the center to respective nodes 2. The control part 6 of the node 2 receives the signal, selects the video signal from the monitoring camera 1 corresponding to a video switcher 3, and controls to transmit the signal to an encoding part 4. At the same time, the control part 6 controls a multiplexing part 5 to multiplex the signal in the slot of a multiplexing signal string designated by the center. An optical repeater part 7 converts this multiplexing signal string to an optical signal of a wavelength of lambda1, and transmits it out to an optical fiber 8. Thus transmitted optical signal is demultiplexed and demodulated at the center, accordingly the video signal desired to be transmitted is displayed on a monitoring TV. When it is desired to view video signals from the monitoring camera 12 between nodes, the same case as above tapes place, then a video signal from the camera 12 is converted to an optical signal of a wavelength of lambda2(lambda1not equal to lambda2) by an optical transmitter 10, transmitted to a two-wave use optical multiplexing and demultiplexing device 91, and transmitted through a fiber 8 by means of double wavelength multiplex transmission. |
