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Mạng và viễn thông P33

Practical Network Transmission Planning Transmissionmedia exist to convey information across networks. No matter what form the information takes (be voice, video,data, or some other form), the prime requirement that the it is information received atthedestinationshouldas closelyaspossiblematch that originally transmitted. The signal should be free from noise, echo, interference and distortion, and should be of sufficient strength (or volume) asto be clearly distinguishable by the receiver. The reliability of the service is also important. . | Networks and Telecommunications Design and Operations Second Edition Martin P. Clark Copyright 1991 1997 John Wiley Sons Ltd ISBNs 0-471-97346-7 Hardback 0-470-84158-3 Electronic 33 Practical Network Transmission Planning Transmission media exist to convey information across networks. No matter what form the information takes be it voice video data or some other form the prime requirement is that the information received at the destination should as closely as possible match that originally transmitted. The signal should be free from noise echo interference and distortion and should be of sufficient strength or volume as to be clearly distinguishable by the receiver. The reliability of the service is also important. Meeting these objectives requires careful network transmission planning. This chapter covers two aspects of planning first describing the electrical engineering design guidelines usually laid out in a formal network transmission plan and then going on to discuss the general administrative and operational practicalities of lining-up and operating a transmission network. Resource management is crucial to ensure that lineplant and circuits are available when needed that radio bandwidth is available without interference that cables have been laid and satellites put in orbit. 33.1 NETWORK TRANSMISSION PLAN A set of guidelines laying down simple rules for planning and commissioning new line systems or new circuits is usually set out in a formal transmission plan. These guidelines are intended to ensure that the electrical principles of telecommunications theory are adhered to. The transmission plan should include for example stringent rules on the use positioning and strength of amplifiers or regenerators to correct the effects of attenuation. The plan needs to give guidelines on minimization of noise and interference on the use of echo control devices to eliminate echo and on the use of equalizers to rectify frequency attenuation distortion. A good .