In the reverse link of tracking and data relay satellite system (TDRSS), as the 30-path frequency-division multiplexing (FDM) signals are fed into the traveling wave tube amplifier (TWTA), severe inter-modulation interference to the 30-element signals emerges. The interference in turn results in the distortion of the 30-element signals as well as the deterioration of digital beam forming (DBF) performance. By advanced mathematical derivation, the present work probes the explanations for magnitude and phase error among the channels derived by the amplitude to amplitude (AM/AM) and amplitude to phase (AM/PM) characteristics of the TWTA. To reduce the impairment due to these nonlinearities, dynamic equalization technique is used in Matlab. Theoretical analysis and simulation results show that the dynamic equalization technique can effectively improve the DBF performance on the earth stations and the power efficiency held by the TDRS power repeater meanwhile.%跟踪和数据中继卫星系统反向链路中,30路频分复用信号通过高功率放大器时,存在严重的互调干扰,导致输出的30路阵元信号严重失真,恶化了星下数字波束形成(digital beam forming,DBF)性能.通过进一步的数学推导,分析高功率放大器的调幅/调幅变换和调幅/调相变换对30路阵元信号间幅相误差的影响机理,提出采用动态均衡技术来补偿非线性失真所引起的DBF性能的恶化,并在Matlab环境中进行了性能仿真.理论分析和仿真结果表明:动态均衡技术在有效提升地面辅助DBF的性能的同时,也提高了转发器的功率效率.
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