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composite conductor with the power cable. It is a non-conductive medium, in which the alternating electromagnetic wave does not produce the induced electromotive force, which will not have nothing to do with the signal noise. This is to make it parallel to the power lines and electrical lay near the railway, it will not be electromagnetic interference. This is for the strong electrical fields (such as power transmission lines and electrified railway) communications systems in particular. Fiber diameter
2.4 thin, light weight, soft and easy to lay the fiber core diameter is very small, about 0.1mm, the multi-core optical fiber cable composed of very small diameter, 8-core cable cross-section diameter of about 10mm, the standard coaxial cable to 47mm. This use of fiber optic cable as the transmission channel, the transmission system footprint is small, crowded underground pipeline to solve problems, save the underground pipeline construction investment. In addition, the fiber weight, flexible, fiber optic cable is much lighter than the weight of the aircraft, spacecraft and satellites can reduce the use of optical fiber communications aircraft, ships, spacecraft weight, appears to be more meaningful. Also, the fiber soft and can be around, easy to bundle, to get the high density of small diameter fiber optic cable.
外文文献阅读及翻译
2.5 security performance requirements of communications systems is one of the important security is good. However, with the development of science and technology, electronic means of communication can easily be intercepted, as long as open wire or cable in the vicinity of a special receiver to get open wire or cable can transmit information, not to say the wireless communication.