The definition of SDH transmission system The full name of SDH transmission system is Synchronous Digital Hierarchy.It is a kind of transmission system,like the PDH-the Pseudo-synchronous Digital Hierarchy.SDH specifies digital signal frame structure,multiplex,transfer rate level,type of interface and so on and so forth.SDH transmission system was evolved by PDH transmission system, it has incomparable advantages to PDH system.It is a brand-new transmission system different from PDH.Compared with PDH,SDH have made fundamental changes on technical system. Working ways of SDH transmission system Characteristics of SDH transmission system The reasons that SDH transmission system can develop rapidly are related to its own characteristics: 1.Electrical interface STM-1 is the first level of the SDH,also called basic synchronization transmission module,what the bit rate is 155.520Mb/s. STM-N is the Nth level of SDH synchronous transmission module that bit rate is N times of STM-1(N=4n=1，4，16，64，256). 2.Optical interface The electrical signal scrambler only. OAM function is strong-that’s why the line coding doesnt need to add redundancy code. Compatibility,which decides the costing.It can be compatible with the existing PDH completely and hold all kinds of new business.Formed the global uniform standard of digital transmission system, improve network reliability. 3.SDH implements a multiplexing features and simplifies the DXC(digital cross connect) to reduced the back-to-back interface multiplexing equipment.Which improves business transparency of network. 4.Adopted more advanced inserted multiplexer (ADM), digital cross connect (DXC), network self-healing function and restructuring function.It makes contribution for automation,intelligent network,channel utilization and reduce vascular fees and the survivability of network. 5.A variety of network topology that enhanced network supervisor, operation management and automatic configuration function, optimize the network performance, but also make the network flexible, safe and reliable operation. 6.Easy to use in a variety of network technology, supports ATM or IP transmission. 7.SDH is strictly synchronous, thus ensuring the entire network is stable and reliable, and easy to reuse and adjustment. 8.The function of transmission and switching for different levels and all kinds of topology structure network. 9.Can be used to twisted pair or coaxial cable.Suitable for used as a main channel, also can make feeder channels
Posted on: Sat, 08 Mar 2014 13:22:07 +0000
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