Power Amplifiers' Model Assessment and Memory Effects Intensity Quantification Using Memoryless Post-Compensation Technique
Power Amplifiers' Model Assessment and Memory Effects Intensity Quantification Using Memoryless Post-Compensation Technique
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DOI：
10.1109/tmtt.2008.2006809
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发表时间：
2008-11
影响因子：
4.3
通讯作者：
O. Hammi;S. Carichner;B. Vassilakis;F. Ghannouchi
中科院分区：
文献类型：
--
作者：
O. Hammi;S. Carichner;B. Vassilakis;F. Ghannouchi
提出了一种新的记忆效应功率放大器静态非线性特性的表征方法。采用二次采样技术在不改变波形特性的前提下减小测试信号的带宽。这消除了放大器的记忆效应，而不影响其静态行为。无记忆AM/AM和AM/PM特性作为载波频率的函数进行测量。这指出了放大器的静态非线性的频率依赖性对其在宽带信号驱动下的行为的贡献。一个无记忆的后补偿技术，然后介绍了几个行为模型的性能进行准确评估。事实上，它被证明，直接比较的测量输出的设备的测试与估计输出不提供可靠的评估模型的性能。相反，无记忆后补偿有效地区分这些模型的性能。为了提供一个全面的方法模型验证和原型性能评估，记忆效应强度指标。这些指标应用于评估目前在300 W的峰值功率Doherty放大器驱动的各种多载波宽带码分多址信号的记忆效应。
A novel approach for power amplifiers static nonlinearity characterization in the presence of memory effects is presented. A subsampling technique is used to reduce the bandwidth of the test signal without changing the waveform characteristics. This cancels the memory effects of the amplifier without affecting its static behavior. Memoryless AM/AM and AM/PM characteristics are measured as a function of the carrier frequency. This points out the contribution of the frequency dependency of the amplifier's static nonlinearity to its behavior under wideband signal drive. A memoryless post-compensation technique is then introduced to accurately assess the performance of several behavioral models. In fact, it is demonstrated that direct comparison of the measured output of the device-under-test with the estimated output does not provide reliable assessment of the model performance. Conversely, memoryless post-compensation efficiently differentiates the performance of these models. To provide a comprehensive approach for model validation and prototype performance evaluation, memory effects intensity metrics are introduced. These metrics are applied to evaluate the memory effects present in a 300-W peak power Doherty amplifier driven by various multicarrier wideband code division multiple access signals.