Distributed Access Video Optical Fiber Transmission System

Video optical fiber transmitting technology is a important technology frequently adopted in Long Distance Video Supervisory System and CATV transmitting system, which has many advantages, such as a wide transmission bandwidth,a large quantity of information,low transmission loss,high transmission quality,long transmission distance and high interference free quality. A new structure distributed access video optical fiber transmission system is adopted and a video transmission node is designed for the system to realize multi-video-signal optical fiber transmission in the paper. The structure of the system and the design of the node are applied for national patent of invention.The methods and experiments in the paper are mainly as follows:1. Firstly a distributed access video optical fiber system is designed according to the distributed access video optical fiber transmission theory presented in the paper. The system adopts a combination of frequency division multiplexing and wavelength division multiplexing technique to transmit distributed access video signals in optical fiber.2. A experiment system is designed with three channels frequency modulated video signals multiplexed by frequency division and four channels wavelength division multiplexing according to the system presented above.There are twelve video transmission nodes and one receiving node in the system. Devices are selected and parameters are fixed according to the structure and the features of the system. Parameters such as optical power,carrier-to-noise ratio,composite second order (CSO) and composite triple beat (CTB) distortions are analyzed and calculated.3. According to the experiment system, the optical link and circuits are designed for the video transmission node, in which the circuits design includes photoelectric processing circuits design,frequency division multiplexing circuit design,the drive,modulating and transmitting circuits of the laser design and the system power circuits design.4. In the process of the system design, some key points such as PCB design for the high frequency circuits,the radiated interference of the high frequency signal and impedance matching are solved by emulation,optimization and system debugging.