数字预失真技术在空间通信系统中的应用研究  

The study of digital-predistortion technology for space communication systems

作　　者：陆宇颖 梁显锋[1] 

机构地区：[1]中国科学院空间科学与应用研究中心,北京100190 [2]中国科学院大学研究生院,北京100049

出　　处：《电子技术应用》2014年第8期54-57,共4页Application of Electronic Technique

摘　　要：针对空间通信中非恒定包络调制信号的传输对功率放大器的高线性度和高效率的需求,提出了一种应用于空间通信系统的数字预失真器方案。基于FPGA硬件平台、结合Matlab软件的仿真结果,采用最小二乘算法拟合出非线性功放归一化输入/输出功率特性曲线的反函数实现的数字预失真器,使得非恒包络调制信号经非线性射频功放后具有良好的线性特性。数字预失真器实现了60MHz中频输出、最大码率为1 Mb/s时,将预失真前EVM值为4.71%的SRRC-OQPSK调制信号变换为EVM值为9.09%的信号,经非线性功放后调制信号的EVM值小于5%。A digital Predistorter proposal scheme for space communication systems is presented to achieve high linearity and high efficiency power amplifier for non-constant envelope modulated signal transmission in space communications. Based on FPGA hardware and the simulated results of Matlab software, a digital predistortier realized by the inverse functions of the normalized in- put-output power characteristic fit curves of the power amplifier by the least-squares algorithm was used to realize better linearity characteristics of non-constant envelope modulated signals passed non-linear RF power amplifiers. EVM value of the modulated signals passed power amplifiers is less than 5% in which EVM value of SRRC-OQPSK modulation output signal with intermediate frequency in 60 MHz and maximum code-rate in I Mb/s was transformed from 4.71% to 9.09% by the digital predistorter.

关 键 词：空间通信 预失真技术 查找表 SRRC—OQPSK 

分 类 号：TN830[电子电信—信息与通信工程]