| The process of informationization has been accelerating in modern society, this greatly promotes the rapid development of digital communication system. The digital modulation technology is one of the key technologies in digital communication system, it can directly affect the performance and quality of digital communication system. Frequency shift keying (FSK) is an important digital modulation method standardized by ITU (International Telegraph Union), it is widely used in communications with small amount of data, low data rate and short-distance transmission.FPGA technology develops rapidly recent years. It applies more and more widely in the electronic engineering design due to many great features, such as FPGA can be programmed flexibly and erased repeatedly. A design of FSK digital modulation system based on FPGA and Direct Digital Synthesizer (DDS) technology is proposed in this thesis.The background and significance of research, the brief introduction to the techniques of digital modulation, FPGA and DDS are firstly introduced in this thesis. After that, the theory and principle of technologies involved in this project are analyzed. Based on this theoretical analysis, the detail design of FSK digital modulation system is discussed, the system function is simulated and verified by software. Finally, system is run in the FPGA experiments board, tested and debugged under actual hardware environment. The result shows that, system goal is well achieved, the design of system can be applied in communication projects.Based on FPGA, the FSK digital modulation system designed in this project is with following advantages: less FPGA resources are needed, can be effectively accomplished by one economic FPGA and low cost. At the same time the design can be modularized and easily ported to other FPGA-based digital communications system, so it is also with the strength of strong portability and well applicability. |
