Linearization Correction Of Wideband Power Amplifier

Power amplifier is one of the essential and power hungry devices in communication system.As for power amplifier,power efficiency and linearity are inherently contradictory.High efficiency amplifier will lead to serious nonlinear distortions,which will not only worsen the communication quality of in-band signal,but also generate the out-of-band spectral regrowth,interfering the adjacent channels communications.Currently,digital predistortion is one of the most effective and extensive linearization techniques to overcome the tradeoff between power efficiency and linearity.It has been widely used in all kinds of base stations,wireless routes,satellites and other radio equipment.However,with the development of mobile communication,the signal bandwidth is constantly increased,which challenges the traditional linearization technologies and systemizations.Therefore,this paper focuses on the linearization technology for wideband power amplifier.The main contents are as follows:1.Based on the in-depth research of signal spectrum aliasing,a low speed digital predistortion scheme is proposed to eliminate spectrum aliasing.The proposed scheme can effectively reduce the sampling rate requirement of broadband communication system,thereby improving the capability of digital predistortion to process the wideband signal at a low rate.It can significantly relax the hardware complexity and power dissipation.At present,there are lacks of researching on the signal spectrum aliasing in academia and industry.The proposed scheme provides a novel insight and idea to address the problem.Finally,both the simulation and actual measurement results show the feasibility of the proposed scheme.2.Through the study of numerical point power for the communication signal,this paper puts forward a power control scheme of wideband power amplifier.In the process of linearization,this scheme can effectively operate the power amplifier with stable output power.In addition,compared with the traditional power control method,proposed scheme can achieve low complexity and high precision.3.With the study of the linearization system architecture for wideband power amplifier,the digital predistortion architecture without feedback loop is designed to fundamentally change the linearity architecture.Compared to the traditional DPD system requiring feedback loop,proposed scheme guarantees the performance of communication signal as well as dramatically reduce the hardware consumption costed by the observation path,including sampling operation,ADC,model extraction block etc.Meanwhile,it can also be applied to ultra wide band signal in Millimeter-wave frequency.Finally,the feasibility of the scheme has been verified by the experimental results.