| The topic of this paper is the linearization technology of microwave power amplifier, which is an item of the 10th Institute of China Electronic Technology Group Corporation. This paper mainly concerns in the rejection of adjacent channel power interference (ACPI) in communication system due to the nonlinear distortions of the power amplifier.The research of linearized power amplifier is becoming a hot spot in the amplifier design. A series of patents have been granted for power amplifier linearization abroad, and many mature productions have been presented. At home, however, the research in this field is just at the stage of simulation with software. Furthermore, the study in predistortion linearization is blank for most researchers focus on feed-forward linearization.A novel scheme of adaptive predistortion linearization is proposed in the paper, which is based on the adequate analysis on nonlinear characteristic of power amplifier. The scheme synthesizes the merits of three kinds of linearization methods. The simulation results show the feasibility of the scheme. It is proved to be effective at the same time by fabricating a real predistortion linearization power amplifier. The test results demonstrate the good performance of the linearized amplifier.The application of RF predistortion techniques can handle broader bandwidth and stability. On the other hand, the method of getting the distortion signal by mixer and band pass filter is an improvement to the conventional method on error cancellation loop with complex gain adjustment. In addition, the application of DSP, combined with RF analog circuits, can improve the linearity of the power amplifier explicitly. The above are main features and innovations of the paper.Both the simulation and test results 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. |
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