Study Of High-Speed Multi-Band Modulation And Demodulation Technology Based On FPGA

In modern communication, the demand of communication rate is higher and higher, we can improve the rate of information transmission in the limited frequency band by. the use of multi-band. In order to improve the spectrum efficiency, enhance the anti-interference and secrecy, we can meet the requirements of high speed communication system by using the spread spectrum communication. Therefore, in a digital communication system, the main direction of modulation and demodulation technology we study is developing into high-speed multi-band orthogonal spread spectrum.With the application of digital information technology is becoming more and more widely, the FPGA (Field Programmable Gate Array)plays a more and more important role in the field of digital signal processing.In this paper we use FPGA and Maxim’s zero IF wireless broadband transceiver Max2837to design and realize the high speed of multi-band orthogonal spread spectrum modulation and demodulation system, which can be applied to the wireless audio conferencing system based on CDMA. In this paper, we make a research of multi-band modulation and demodulation technology at a high speed on the basis of the CDMA wireless audio conferencing system.First of all, the paper introduces the background and research content of the project, and introduces the technology and application of the spread spectrum communication and the principle of zero IF orthogonal modulation and demodulation.Secondly, the paper uses FPGA and Max2837to design the high speed multi-band orthogonal spread spectrum modulation and demodulation system, and analyzs the hardware design of wireless conference system, based on CDMA and the key algorithm of the high speed of multi-band spread spectrum modulation and demodulation system in detail, and proposes and analyzes the influence of frequency offset on the orthogonal spread spectrum system.Thirdly, the paper improves the existing technology of the capture of PN code and the synchronization of carrier in spread spectrum communication, and makes a theoretical analysis and FPGA simulation of the improved algorithm, finally the paper uses the hardware platform of FPGA and Max2837to verify the algorithm of the capture of PN code and AFC, and makes hardware implementation and test for the downlink of wireless audio conferencing system based on CDMA to design and realize the high speed of multi-band modulation and demodulation system.Finally, the paper makes a summary and puts forward a prospect.