基于朱氏广义采样定理的射频功放行为建模

Behavioral modeling of RF power amplifiers with Zhu's general sampling theorem

利用朱氏广义采样定理,在降低ADC采样率情况下,对射频功放进行非线性行为建模和数字预失真研究.以20 MHz的WiMAX信号作为射频功放的输入,通过矢量信号源和矢量信号分析仪组成的测试平台采集功放的输入和输出信号,并利用有记忆多项式模型和朱氏广义采样定理进行模型验证和预失真仿真分析.实验结果表明,在采样率为功放输入信号带宽的2倍和8倍时,有记忆多项式模型归一化均方误差保持一致,均达到-41 dB左右,并且经过预失真仿真,功放相邻信道泄漏功率比改善都达到10 dB以上.

With Zhu＇s general sampling theorem（ZGST）,nonlinear behavioral modeling and digital predistortion（DPD） of RF power amplifiers（PAs） are studied when the sampling rate of ADC is reduced.The input and output signals of the RF PAs excited with a 20 MHz WiMAX signal are sampled on a test bench including a vector signal generator and a vector signal analyzer.Model validation and DPD simulation and analysis are conducted by the memory polynomial model and ZGST.Experimental results show that the memory polynomial model can give the same normalized mean square error（NMSE） of about-41 dB by 2 times sampling and 8 times oversampling,and over 10 dB adjacent channel leakage ratio（ACLR） improvement can be achieved in simulation of DPD.