| With the development of data communication, the quantity of data and users has alarge leap.The traditional communications method that one signal on one line can notsupply the demand.Multiplexing technique solved the problem,however,it caused a dropof stability,quality and accuracy of signal.To the question above,the paper is to research a protecting system for E1signal.Tocounter the conditions of loss of frame,error code and codeless in the transmission of E1signal,the system is to apply FPGA as the Control Core,and set up two lines for mutualswitching.To approach,system is to increase a spare line closed to the major line,appliesthe powerful capability of data processing and logical judgment to detect the E1signal.As soon as finding the problem of loss of frame,error code and codeless,systemswitches the line,and then transmits the line with good quality to the client.At the beginning of paper,it analysis the background,meaning and current researchstatus,then gives the main research content and index.The next is the research about thestructure of the frame of E1,and put forward the plan that applies FPGA as the controlcore,researching the principle of the core detecting link about frame,error code,codelessand AIS,and finally,gives the design of hardware and software:The design of hardwareinvolves the design of E1interface circuit and the detecting circuits,and expands thesystem from one line to eight lines;The design of software involves the details ofcriterion flow of each detecting link,and the communication between system and hostcomputer, Ethernet.At the end of paper, it progresses some emulation about the detecting of loss offrame, error code and the communication of host computer, Ethernet,to make sure thatwhen finding abnormal situation in the above,the system can direct prompt reaction,andmakes the line switching.And then,it analysis the experimental data,raises a furtherclaim for the system and looks into the future of the system. |
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