Design And Implement Of DPSK Modulation And Demodulation Technology Base On FPGA

With the arrival of the digital information processing era, field programmable gate array (FPGA), as important digital information processing device, have been widely used. The paper presents a scheme to design and implement the DPSK modulation and demodulation base on FPGA and a new direct frequency synthesizer (AD9957), which makes the system digital, compactable, programmable, etc, improving the effectiveness and reliability of information transmission systems.The paper first makes a brief introduction to the background of the program and the research content, the basic principles of the BPSK and DPSK modulation and demodulation are made afterwards with focus on the performance of DPSK modulation and demodulation.Then we introduce the main technical indicators of DPSK modulation and demodulation module with a detailed description of the schemes of the DPSK modulation and demodulation module. The overall design plan of the DPSK modulation and demodulation part, such as the overall interface part of the DPSK modulation and demodulation and the design of chips used in the scheme emphasizes on a new direct frequency synthesizer AD9957 is stated afterwards.We design and simulate the digital filter of hardware design scheme part of the DPSK modulation and demodulation utilizing MATLAB. Afterwards, a simulation of the performances of DPSK direct modulation and smooth phase modulation is done, the simulation results are analyzed as well. The simulation of the performances of DPSK coherent demodulation with pilot inserted and differential demodulation with MATLAB is also made, as well as the peak value of the matching outputs of these two demodulation methods.Afterwards, The paper introduces the FPGA hardware part of Xilinx Company, and the hardware implement of filter base on FPGA. The paper places emphasis on the outputs of the time domain waveforms and spectrums from the oscilloscope and vector analyzer tested. From the time domain waveforms and spectrums it shows that the system has the advantages of stable performance, good flexibility, convenient production debugging, small size and easy to upgrade, which can meet the requirements subject and realize the DPSK modulation and demodulation technology.Finally, the summaries of the paper as well as the outlook for future work.