摘 要现代社会通信日益发达，对传输网络的要求越来越高，同步数字体系 SDH 作为准同步数字体系 PDH 的替代品而出现，并且不断更新完善以适应市场需求，成为当今光纤传输体系的主流。到目前为止，还没有出现可完全替代 SDH 的新技术，有的只是现有 SDH 技术的进展和补充，这也证明了 SDH 强大的生命力。鉴于 SDH 广泛的应用及未来良好的进展潜力，众多学者展开对 SDH 的讨论，同时也为 SDH 的进展提供了强劲的动力。本次讨论主要是了解 SDH 相关知识，并无高精尖技术方面的讨论。论文主要从 SDH 的产生背景、工作原理出发，介绍了 SDH 的产生、特点以及未来进展（包括多业务传送平台 MSTP 和 IP Over SDH 技术），SDH帧结构，SDH 映射、定位及复用，SDH 同步与定时，SDH 网络结构、网络管理以及网络保护与恢复，并结合应用实例进行讲解，最后介绍了部分 SDH 系统测试内容。关键词：PDH，同步复用，SDH，MSTP,IP over SDHABSTRACTNowadays telecommunication is developing fast, there's higher and higher demand for transmission network. SDH (Synchronous Digital Hierarchy), as a substitute of PDH (Plesiochronous Digital Hierarchy), keeping update to meet the market demand, has become the mainstream optical transmission system. So far, there is no alternative to SDH technology, only the extensions of SDH technology. This also proves SDH has strong vitality.Because of the wide range of SDH applications and good potential on future development, many scholars research on SDH, meantime this provide the development of SDH a strong driving force. This study is to understand basic knowledge of SDH, there is no high-technology research. This paper introduced the generation of SDH, characteristics of SDH and SDH's future development (including the Multi-Service Transport Platform and IP Over SDH technology), SDH frame structure, SDH mapping, positioning and multiplexing, SDH synchronization and timing, SDH network architecture, network management and network protection...
