Study On Optimization Design Software For High-efficiency Linear Power Amplifier System

With the rapid development of modern high-capacity digital communications technology,which proposes higher and higher demands for the efficiency and linearity of RF power amplifiers.Based on studying optimization design software for high-efficiency linear power amplifier system,in order to optimize the linearity and efficiency of RF power amplifier system, this paper solvessome problems such as accurately controlling the gate bias voltage of Doherty RF power amplifiers,time-delay estimation and alignment, and extracting static nonlinear properties of RF poweramplifiers existing in the solution combined Doherty technology and digital pre-distortionlinearization technology for the high-efficiency linear power amplifier system.To develop high efficiency RF power amplifiers, accurately controlling the gate bias voltageof Doherty RF power amplifiers is an important problem that has to be resolved. In practical work,the gate bias voltage of RF amplifiers will change with the change of the outside temperature,which determines the gate bias of power amplifiers must be adaptive controlled. The optimizationdesign software for high-efficiency linear power amplifier system adopts the gate voltage of poweramplifiers adaptive control technology based on high-accuracy voltage coding algorithm，automatically controls the RF power amplifier so as to accurately, fast obtain the optimal gate biasvoltage over the temperature range, in order to achieve automatic temperature compensation for RFpower amplifiers for optimizing performance for PA system. The software test results show thatthe algorithm which this paper using is accurate, fast and reliable.Because there is the time-delay between the input data and the output data of a poweramplifier, the power amplifier nonlinear characteristics (AM/AM and AM/PM characteristics)cannot be extracted quickly and accurately. Focusing on linear interpolation based time-delayestimation and alignment algorithm, Lagrange interpolation based time-delay estimation andalignment algorithm, cubic spline interpolation based time-delay estimation and alignmentalgorithm, this paper selects cubic spline interpolation based time-delay estimation and alignmentalgorithm which is effectual, fast, and easily hardware achieving. On the basis of cubic splineinterpolation based time-delay estimation and alignment algorithm improving time resolution,aiming at problem of spending more resources and longer processing time while requiring a higherinterpolation rate under long time-delay condition, the paper proposes a two-step algorithm for time-delay estimation and alignment combined coarse time-delay estimation and alignment the finetime-delay estimation and alignment algorithm to solve the problem.The paper uses two methods of extracting static nonlinear properties of RF power amplifiers.In addition to utilizing traditional polynomial method to extract static nonlinear properties of RFpower amplifiers, the paper proposes the improved DEWMA algorithm for extracting static non-linear properties of wideband RF Power Amplifiers. This paper uses digital predistortionlinearization technology based on a lookup table (LUT) to compensate for the static nonlineardistortion of RF power amplifiers. The software test results show that the linearization technologywhich this paper using improve the linearity of RF power amplifiers.