CAJ | 학술논문

针对传统固定步长 LMS 算法预失真收敛速度较慢和非线性改善不足以及 RLS 算法预失真复杂度较高，对一种基于变步长 LMS 算法的多项式预失真技术进行了研究。通过仿真分析该算法的性能，发现该算法在不较大增加算法复杂度情况下收敛速度较快，能较好地改善带内非线性失真。构建了基于 DSP和FPGA的短波发射机硬件平台以验证算法的有效性，通过双音信号测试功放输出，表明基于该算法的多项式预失真系统对三阶互调降低23.3 dB，五阶互调降低15 dB，有效地改善了功放的非线性。
침대전통고정보장 LMS 산법예실진수렴속도교만화비선성개선불족이급 RLS 산법예실진복잡도교고，대일충기우변보장 LMS 산법적다항식예실진기술진행료연구。통과방진분석해산법적성능，발현해산법재불교대증가산법복잡도정황하수렴속도교쾌，능교호지개선대내비선성실진。구건료기우 DSP화FPGA적단파발사궤경건평태이험증산법적유효성，통과쌍음신호측시공방수출，표명기우해산법적다항식예실진계통대삼계호조강저23.3 dB，오계호조강저15 dB，유효지개선료공방적비선성。
Aiming at the low convergence speed and the insufficient nonlinearity improvement of traditional constant-step LMS(Least Mean Square) predistortion algorithm, including the high complexity of RLS algorithm predistortion, the polynomial predistortion technology based on variable-step LMS algorithm is studied and researched. Simulation and analysis on algorithm performance indicate that the speed of the algorithm is fairly fast and the nonlinear distortion within frequency band could be improved with no obvious increase of algorithm complexity. A HF (High Frequency) transmitter hardware platform based on DSP and FPGA is built up, thus to testify the algorithm efficiency. The test on dual-tone signal output of PA (Power Amplifier) indicates that IMD 3 (Third-Order Intermodulation Distortion) decreases by 23.3 dB while IMD5 descends by 15 dB in the algorithm predistortion system, and the efficient improvement of nonlinearity for power amplifier could thus be realized.