Design And Realization Of Multi-carrier Feed-forward Amplifier With High Efficiency

With the third generation mobile communication popularity, in order to meet theincreasing network bandwidth requirements, the requirements of the correspondingterminal equipment are constantly being improved. Thus the third generation mobilecommunication must constantly improve the spectrum utilization rate. The linearity of theRF power amplifier which is as the last stage of communication system transmitter is alsoput forward higher requirements. The feed-forward power amplifier is a relative idealmethod in improving the linearity in currently, so the study of RF power amplifier formulticarrier and high linearity is a very important topic.This thesis firstly analyzes nonlinear characteristics of the communication system, andthen focuses on analysis of the multi-carrier nonlinear and the nonlinearity of variableenvelope modulation. According to the nonlinear characteristics, this thesis analyzes andcompares three different kinds of linearization techniques, and highlights manyadvantages of the feed-forward technology and influencing factors of the feed-forwardsystem.This thesis focuses on the analysis of the feed-forward system main amplifying linkusing a combination of APD technology, Doherty combiner technology, and powerregression technology. Improve power efficiency based on ensuring the power amplifier.Feed-forward RF circuit design and the part of adaptive control is the difficulty of thethesis. And combined with the index requirements of the current3G communicationsystem, specifically analyzes the working principle of the feed-forward system, nonlinearmathematical model of the communication system, software simulation and test methodand so on. In view of the current communication system for the requirements ofcommunication indicators, propose the minimum power detection for the detection of errorextraction loop detection, and signal extraction circuit using of method MCU read table,design and realize a feed-forward power amplifier in GSM band which output of125W,and IMD3is less than-65dBc, efficiency higher than18%...