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1、摘要摘要 当今社会是信息社会，高度发达的信息社会要求通信网能提供多种多样的电信业务，传输系统是通信网的重要组成部分，传输系统的好坏直接制约着通信网的发展，随着光线通信技术和网络的发展，PDH 的传输体制已经愈来愈成为现代通信网的瓶颈，制约了传输网向更高的速率发展。在技术发展的推动下，美国提出了同步光纤网（SONET)。SDH 网的同步即 SDH 网元时钟的同步，主要是指 SDH 传输网内部与同步有关的问题，包括 SDH 网的同步网结构、SDH网的同步方式、SDH 同步网基准链路以及 SDH 设备的定时工作方式等。SDH网有很大的发展潜力是电信界公认的数字传输网的发展方向，具有远大的商用前景。本
2、论文通过详细介绍SDH原理，介绍了SDH比PDH的优势及其发展前景，讲述SDH设备时钟结构及其工作方式，重点对环型网和链型网结构的SDH 网传送同步网定时信号的方法进行了探讨，包括定时路径结构、定时方式和定时传送方法，讨论了传输系统中引入SDH网后对数字时钟同步网的影响及SDH网本身的同步定时问题研究.关键词关键词 SDH 同步网 同步 定时IAbstractAlong with the SDH is extensive applications in the telecommunications network,people now pay more and more attention t
3、o the SDH is synchronization and timing.AS PHD is time-transparency,.Currently, the transmission link between nodes which in the synchronization networks depends on the PDH transmission system, so some Synchronizations that between the nodes have begun to choose SDH transmission link as Regular tran
4、smission link.on the one hand, when the SDH system transmisst timing signal does not have transparency (the string into the SDH NE clock SEC), therefore, TO using its transmission timing signal ,the SDH transmission system must be asked some certain demands.On the other hand ,The SDH is different to
5、 PDH, PDH synchronization dont need synchronization network, which work systems is quasi-synchronous manner,whereas SDH transmission systems is synchronous manner, which needs synchronization network and all the SDH transmission equipment .Clock frequency of sync can cause the pointer adjustments to
6、 the transmission of digital signals caused by jitter and wander, drifting will cause a large terminal equipment in the terminal equipment .This shows that the SDH transmission system is not only a synchronous signal transmission network bearers but also a objects that need to synchronize the networ
7、k to provide strict synchronization. How to improve the SDH network synchronization and timing performance of the communication network is very important. This thesis details SDH principles, introduced the advantages of SDH over PDH and its development prospects, Tlaking about the SDH equipment cloc
8、ks structure and working methods, emphasis on the ring network and the chain-type network structure of the SDH network timing signal transmission method of synchronization network including timing path structure, timing means and time transfer method, discussed the introduction of SDH network transm
9、ission system after the impact of digital clock synchronization network and SDH network synchronization timing problems of their own. Key words SDH synchronization network synchronization timingII目录目录摘要 .IIAbstract .III前言.1第一章 SDH 的概述.21.1 SDH 的产生与发展.21.2 SDH 的优势.41.3 本文研究内容.5第二章 SDH 的原理及其基本结构.72.1
10、SDH 信号的帧结构.72.2 SDH 的复用结构和步骤.92.3 SDH 的复用结构和步骤.11第三章 SDH 网传送定时信号及同步问题.153.1 SDH 网传送定时信号.153.1.1 SDH 设备时钟结构.153.1.2 SDH 设备时钟工作方式.153.1.3 SDH 传送定时方法.183.2 传输定时信号对 SDH 传输系统的基本要求.193.2.1 对 SDH 同步参考链路模型的要求.193.2.2 对 SDH 终端设备时钟部分的功能要求.213.2.3 对 SDH 系统光中继器的要求.243.3 SDH 网的同步方式.253.3.1 同步方式.253.3.2 SDH 网同步原则.
