| With the development of wireless communication, microwave power amplifier plays the very important role. In order to improve output power and efficiency, power amplifier always works in the saturated state, which will produce severe non-linear distortion. The nonlinearity creates spectral growth beyond the signal bandwidth, which interferes with adjacent channels. It also causes distortions within the signal bandwidth. The topic of this thesis is the linearization technology of RF power amplifier.To improve the power amplifier efficiency without compromising its linearity, power amplifier linearization is essential. The thesis focus on digital predistortion, which is one of the costs, effective and the most potential technology for RF power amplifier linearization. In this topic, digital predistortion implementations bases on the power amplifier that has a memoryless nonlinearity. Main researches are as follow:(1) Introduce the characteristic of non-linear power amplifier of the major technical and analyze several commonly used mathematical model of power amplifier.(2) Discuss the problems of communication system arising from the nonlinear distortion theoretically and analyze several main types of linearization techniques.(3) A novel program of based on LUT adaptive predistortion linearization is proposed in the paper, which is based on the adequate analysis on nonlinear characteristic of power amplifier. Reason the adaptive digital pre-distortion program in polar form.(4) Design key parts of digital pre-distortion and simulate the program in Matlab software. Simulate the model of power amplifier, and verify the algorithm in this environment.The simulation results show the feasibility of the scheme. The results demonstrate the good performance of the linearized amplifier. The results of simulation demonstrate that the predistortion linearization can improve the power amplifier's linearity distinctly, which is essential to multi-carry communication system and the third generation(3G)mobile communication system in the future. At the end of this paper, it concludes the project, points out the existing problems, and gives some suggestions for later work. |
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