Improved CDF predistortion method and experimental results for HF power amplifier

Performance of conventional baseband digital predistortion method for power amplifiers (PAs) degrades severely as the accuracy of loop delay compensation (LDC) decreases. The existing LDC error free method based on cumulative distribution function (CDF) neglects the phase nonlinearity of PA and therefore further application is limited. An improved CDF predistortion method is proposed in this paper, which considers not only amplitude nonlinearity but also phase nonlinearity of PAs. Experiment based on High Frequency (HF) PA is done, and the results show that the proposed method works well in compensating the amplitude and phase nonlinearities of HF PA, and the performance in third-order intermodulation (3IM) of the PA output can be improved by 23 dB, but the improvement of the conventional CDF method is 8 dB.