Study And Realization Of Core Board Of ADM Equipment

Add/Drop Multiplexer equipment is one of the most important network elements of the SDH transmission network, it is rather flexible on the network design. MAN (Metropolitan Area Network) is a highly competitive and open networks, SDH has rich access capacity of business and also been made in full development in the MAN.This paper in view of the needs of the idiographic project,aim at the characteristic of the WAN applications and the SDH network protection mechanisms,proposed a hardware and software solution.The solution assemble line-side optical signal access,high/low Cross-Connection and Synchronization in one board,and provide 1+1 hardware protection.The solution divide the core board in to five modules according to the functions :the linear interface module accomplish the Photoelectric conversion of 2.5Gbit/s and recover the signal,the payload processing module processing the overhead of the SDH signal,the Cross-Connection module accomplish the high/low level Cross- Connection functions and the Multiplex Section protection function,the synchronization module offer clock for all equipment,the control interface function shielding different type of chip interface and provide a unified interface to the control board.This paper focus on the implementation of the linear interface module and the payload processing module.Finally proposed the testing scheme according to the functions required for ADM core board and the SDH system performance parameters ,as well as the test result and analysis are presented. The results showed that the functional requirements of the core board can be completed the function we desired: Cross-Connection,clock switching and Multiplex Section protection.The quality of optical signals is better than the requirement of optical interface paramenters.The signal transmission damage is suppressed by the clock and data receiver retiming function.