短波功放非线性建模及预失真矫正理论研究与实验验证

As a means of reserved minimal communication, the short-wave (SW) communication system is widely used in the department of the army, civil air defense, emergency rescue, and so on. However, the harmonic distortions, inter-modulation distortions and the memory effects of the short-wave power amplifier (SWPA) restrict its development severely. Based on the technology of digital pre-distortion, the project attempts to build a nonlinear behavioral model which is able to characterize the harmonic distortions, inter-modulation distortions and memory effects of the SWPA simultaneously and design one digital pre-distorter for correcting these nonlinearities according to the model. In order to reduce the demand of the analog / digital converter chip sampling rate for capturing the SWPA harmonics, the project intends to propose a "harmonic convergence" method to maximize capturing the high-order harmonics at low sampling rate conditions. In addition, the research group attempts to expand our pre-proposed Generalized Two-Box Cascaded model and Generalized Augmented Hammerstein model into multi-dimensional models for characterizing the harmonics together with their nearby inter-modulation distortions and memory effects. And then we will attempt to establish a digital pre-distorter for simulating and experimentally verifying the nonlinear correction of SWPAs. The project will address key technical issues for researching and developing the next generation SW communication system and optimizing the existing systems, as well as laying a solid foundation for the defense, emergency rescue, maritime strategy and so on. Meanwhile, the project will play an important part in the nonlinear modeling and correcting for the multi-band and multi-mode PAs.

短波通信系统作为军队、人民防空及应急抢险等部门保留的最低限度通信手段被广泛应用。而短波功率放大器的谐波失真、互调失真及记忆效应严重制约着它的发展。本项目立足于数字预失真技术，拟建立一种能够同时表征短波功放谐波失真、互调失真及记忆效应等非线性的行为模型，并根据该模型研究适用于矫正这些非线性的数字预失真器。为了降低谐波捕获对模/数转换芯片采样速率的需求，本项目拟提出一种“谐波聚合”方法，在低采样率条件下最大限度地捕获高次谐波。另外，课题组拟将前期提出的广义串行两厢式模型和广义改进型Hammerstein模型扩展为多维度模型以表征谐波及其附近的互调失真和记忆效应，并建立数字预失真器对短波功放进行非线性矫正仿真和实验验证。本项目研究内容将为新一代短波通信系统的研发和现有系统的优化解决关键技术问题，为国防、应急抢险、海洋战略等奠定坚实基础，同时为多波段多模式功放非线性建模及矫正提供重要的参考价值。

短波通信系统作为军队、人民防空及应急抢险等部门保留的最低限度通信手段被广泛应用。而短波功率放大器的谐波失真、互调失真及记忆效应严重制约着它的发展。本项目围绕着矫正短波功放非线性的关键技术展开研究。在三年的项目执行期内：深入研究了短波功率放大器的非线性特性，针对短波功放的互调失真，谐波失真以及记忆效应进行了细致地分析。搭建了 “谐波聚合”的数据捕获平台并捕获数据，同时设计了一款基于ARM和FPGA 的短波功放数字预失真硬件平台。精确估计并调整带有谐波的功放输入/输出信号的时延问题。研究了多目标优化的模型参数识别算法，建立了带有记忆效应的功放互调、谐波混合行为模型并实验验证，提出模型的建模归一化均方误差NMSE低于-40dB。该项目还针对短波功放的非线性矫正技术进行了研究，经过非线性矫正后，短波功放的非线性改善了30dB以上。.本项目的研究成果可提高短波功放的线性度和效率，减少谐波滤波器的阶数，简化短波电台的散热装置，缩小发射机的体积，增强电台的灵活性和电池续航能力，为新一代短波电台的研发和现有电台的优化提供关键技术。从而为国家海洋战略的发展、国防的建设、军队战斗力的提升以及国家应急抢险等奠定坚实的基础。