The Study Of The PA For The Linearization Techniques And Realization With FPGA

High power amplifier is widely used in the electronic devices, such as communicationsterminals, automatic control equipments, etc. But as a result of its inherent nonlineardistortion character, will cause the in-band distortion and sideband extend of signal spectrum.The in-band distortion will cause IMD, improve the error rate and the ideband extend willcause disturbances to the the adjacent channels. With the rapid development of wirelesscommunication, The QPSK and QAM modulation technique are used in the third generationmobile communications, as well as3G-LTE and fourth generation mobile communicationechnology will use the OFDM modulation technology, they belong to the non-constantenvelope modulation technique With a high PAPR, Which will make the problem of amplifiernonlinear distortion become more severe. Therefore, suppressing nonlinear distortion andimproving HPA efficiency has been concerned as a widespread technical subjects. This articlemainly centers on linearization techniques of PA to launch.First, it introduced several kinds of PAs and analysed their advantages and disadvantages,and detailed the Performance indicators of the power amplifier.Second, This article studied the mathematical models of the PAs deeply, analysed thefactors which cause PAs memory and nonlinear distortion, analysed the various of PAlinearization techniques systematically and compared with each other.Then, the digital pre-distortion technique was studied emphatically based on adaptiveindirect learning algorithm. In the paper, a new Joint and phased processing algorithm waspresented based on RLS-LMS when calculatied the formulas of RLS and LMS algorithm,analyzed their respectiveadvantages and disadvantages. Analysis of the existing amplifiermodel and presented a new model that non-memory and nonlinear systems with saleh insteadto reduce the computational complexity in the choice of the W-H amplifier model. we discussthe effect about the magnification of attenuator in the technical scheme and give the selectionprinciples and the design methods. Done a simulation with Matlab for a input OFDM signalof8MHz band width, and analyzed the simulation results with data, proved the design isfeasible and and advanced.Last, Working principle of FPGA was expounded and given a chart of hardware platformabout digital pre-distortion. Done the analysis of rationality about the FPGA chip, ADC chip,DAC chip and Clock chip were selected. Studied the theoretical knowledge carefully about digital up converter and digital down converting. Taken software programing and actualdebug to the DPD module.