High-speed Digital Modulation And Demodulation

Modulation and demodulation are important signal transform links in all the parts of a communication system. The signals be processed in this part deals with the base-band frequency and the radio frequency, some times processes in the intermediate frequency band too, so a high technology content and a high degree of difficulty is involved. The development and application of the high speed digital modulation and demodulation technology can fit the requirement of digital signal processing in so many communication fields. It has so practical significance to the high speed transition of pictures, files and some other types of datas. In this project, the writer developed a digital modulation and demodulation system, which based on the MSK modulation. The work began with the analyzing and calculation in the theory field, then realized the project on the devices. The realizing process involved the software simulating and debugging, the hardware design, and making the complete system work well after downloading the software into the hardware.As a part of the termination in a wireless communication network, the system can work under the control of the whole communication system. The base-band input of the modulation part can has a data rate higher than 640 Kbps, this is a so high rate in wireless communication now. DSP and FPGA are used together to realize the complete digital processing in the system, this satisfied the requirement of the high speed calculation in those communication devices. And it is flexible and can be developed.This thesis focuses on the analyzing and researching of theories and technologies on the digital modulation and demodulation, on the high speed digital processing either. Also, the details of the software and hardware design, especially the new ideals are introduced.