Research On Digital Baseband Predistortion Of Frequency Power AmPlifiers

In wireless communication field, the high frequency power amplifier (HPA) is usually nonlinear. In most cases, the HPA is the main cause of the nonlinear characteristics of the system, which has a great negative impact on the performance of the system. How to reduce the effect of the nonlinearity of HPA is really a very important topic. Predistortion is one of the most effective solutions to this problem, which achieves the linearity of the system by putting a module before HPA, whose impact on signals is inverse to HPA's. Predistorter usually has the self-adaptive function, which modifies its parameters so thatpredistorter's nonlinearity keeps inverse to HPA's all the time even when the nonlinearity of HPA changes. Nowadays predistortion technology develops very fast with the achievements of its theory as well as digital processing technology.In Chapter 1, the background of this topic is introduced; Then in Chapter 2 comes the research in the nonlinear characteristics of HPA; Chapter 3 focuses on the currently widely used methods to solve this problem, especially the predistortion technology and theory, In Chapter 4, scheme of the whole system is given, and some information related is also provided; following that in Chapter 5 comes the most important part of this paper, the detailed description of the key modules, which contains the ideas, structure and key points in design. At the end of the paper, simulation result and synthesis result are provided and with a conclusionMain features of this design:Pipeline design, which makes the max frequency reach 153MHz.Support the baseband input with sign and 8-bit wide fraction, which covers the most commonly used digital input.Design can be implemented in a common FPGA.Simulation result and synthesis result indicate that the features of this design met the requirement of practical use.