射频功放记忆效应的准确辨识和定量计算

Accurate Identification and Quantitative Calculation of Memory Effects of RF Power Amplifiers

射频功放记忆效应是阻碍采用传统无记忆预失真技术实现射频功放超线性的根源。准确地鉴别射频功放的记忆效应并计算其大小,可以对不同射频功放的记忆效应强弱进行定量比较,以便采用不同的线性化技术对其进行线性化。文中首先讨论如何去除功放时延的影响,以准确提取受实际调制信号激励的射频功放的等效基带特性数据;然后,讨论了采用无记忆预失真技术的记忆效应鉴别方法,提出了基于频谱分析法的记忆效应强度计算方法;最后,通过对受不同调制信号激励的不同类型射频功放的实验测试和计算,证明了所提出方法是一种有效的衡量射频功放记忆效应强弱的手段。

The memory effect of RF power amplifiers is the main reason for preventing a power amplifier from achieving uhra-linearity with traditional memoryless predistortion techniques. It is possible for quantitatively comparing the strength of the memory effects of the different RF power amplifiers by accurately identifying the memory effects and calculating their magnitudes so as to linearize power amplifiers with different linearization techniques. In this paper, it is discussed how to remove the time-delay of a power amplifier in order to extract the equivalent baseband characteristic of the power amplifier excited by practical modulation signal at first. Then the identification approach of the memory effect using the memoryless predistortion techniques is discussed. The calculation method for the strength of the memory effects, which is based on the spectral analysis method, is proposed. Finally, through the experimental test and calculation for the different RF power amplifiers excited by a variety of modulation signals, it is demonstrated that the proposed method is an effective means for evaluating the strength of memory effect of an RF power amplifier.