Research On Key Techniques Of Digital Predistortion For Broadband Power Amplifier

This paper mainly discusses relative technical problems about linear correction of broadband power amplifier,focuses on researching the nonlinear behavior model of broadband power amplifier under the frame of baseband digital predistortion program of parameterization inverse model structure and verify the effectiveness of the new model with instrument platform.Different from the traditional theoretical derivation,this paper puts forward a new Recursive Optimum-terms Selecting(ROS)and this algorithm reaches simplification to Volterra series through inputting and outputting signal and gets Customer Tailored(CT),Sub-optimal Customer Tailored(SCT)and Integrated Customer Tailored(ICT)which are more fit for the specific working features of power amplifier.Firstly,the paper makes deep research to the common behavior model of nonlinear system and analyzes the work features of classic model using actual signal analysis.It researches Volterra series model and simplified model and orthogonalization of the model,combines orthogonalization and simplified process together and puts forward Recursive Optimum-terms Selecting(ROS).This algorithm sorts the general Volterra series cross term according to the contribution degree and constitute the Customer Tailored(CT)according to the order then analyzes the accuracy degree,stability and adaptability of new model.Secondly,this paper further expands ROS algorithm in order to meet the requirement of modeling of complex nonlinear system.Take simplified Volterra series model as the base model of ROS algorithm so as to get Sub-optimal Customer Tailored(SCT)and analyzes the performance and characteristics of this model through actual signal.This paper also researches sectional model and puts forward the new Integrated Customer Tailored(ICT)through combing sectional model and ROS algorithm and makes analysis to the performance and characteristics of this model.At last,this paper implements linear improvement test to broadband power amplifier under the environment of instrument platform and conducts test separately through two kinds of signals including 8PSK and OFDM and the results represent that the new models suggested all have good performances in the digital predistortion linear program of broadband power amplifier.