Study On The RF Predistortion System

As the development of all kinds of communication systems, requirement about linearity of power amplifier on it becomes a more and more serious problem. This paper begins with the importance of linearized power amplifier, and then introduces the development of linearization techniques home and broad, after it, some common linearization techniques, such as feedback, feed-forward and digital pre-distortion have also been introduced. At last the technology of pre-distortion is deeply discussed.In the second chapter, the nonlinear characteristic of power amplifier is analysed, especially on AM-AM and AM-PM conversion and their influence on the third-order inter-modulation(IM3) .The third chapter talks about the configuration and characteristic of GaAs FET and the principle that how it works, whereafter the author introduces the design course of a Ku band GaAs FET power amplifier. Lastly simulation results and test results are showed.Finally this paper introduces technique of banlanced pre-distortion. Based on the analyzation of its basic theory and a real target, this paper presents a new kind of balanced circuit that implements the distortion function. The results are discovered after simulation and optimization. In the experiment, the author got close results to the simulation ones.