Sdh Optical Interface Board Design And Lock-in Technique

The High speed, large capacity, high reliability, intelligence and IP application are the trends of SDH optical transmission system, which has the advantage of wide bandwidth and long distance transmission. Developing the advanced and stable working SHD transmitting equipment would form a solid foundation for the next generation communications and Internet. The optical interface board is crucial in SDH system, and the frequency synthesizer unit is especially important for the design of the board, so how to design an excellent optical interface board(OL1ZC8) ,which is in ZXSM-2510 project, is discussed in this dissertation. Tasks are completed as follow:1. The PLL theory is discussed firstly, for it's the basis of design of the frequency Synthesizer. The dissertation begins with the mathematics model of the PLL, and then its linear performance is well analyzed.2. The designs of the PFD, digital filter OCXO and fractional-N counter in the frequency Synthesizer unit are discussed, based on the PLL theory.In order to improve the precision of PLL, some design methods of PFD are given, and its feasibility is validated by the FPGA hardware implement.3. The design of each important module is studied in the 4th chapter. The designs of the CPU MPC852T, FPGA & CPLD in the OL1ZC8 board of the ZXSM-2510 transmission system are performed, and the tests using hardware implement yield a satify results.4. The dissertation ends in the 5th chapter, and gives the prospects of the following research work.