前馈式数字AGC系统设计与FPGA实现  

Feedforward digital AGC system design and FPGA implementation

作　　者：谢锡海 盖海涛 XIE Xihai;GAI Haitao(School of Communication and Information Engineering,Xi’an University of Posts and Telecommunications,Xi’an 710121,China)

机构地区：[1]西安邮电大学通信与信息工程学院

出　　处：《中国科技论文》2019年第11期1198-1203,共6页China Sciencepaper

基　　金：陕西省自然科学基金资助项目(2018JQ6093)

摘　　要：针对反馈式数字自动增益控制(automatic gain control,AGC)信号调整速度慢、输出信号存在冲击现象的问题,设计了一种基于平均能量的前馈式数字AGC系统。首先对输入信号进行预处理,降低信号强度的差距;接着利用预处理后的信号进行平均能量计算得到判决因子,引入牛顿迭代算法计算增益系数,简化数字逻辑系统的实现;最后采用前馈的控制方式调整预处理后的信号得到输出信号,并使用MATLAB软件对设计系统进行仿真。结果表明,与基于幅度和平均能量的反馈式AGC系统相比,基于平均能量的前馈式数字AGC系统的输出信号更加平稳,稳态响应速度提升了近2倍,且降低了输出信号的冲击现象。基于现场可编程门阵列(field-programmable gate array,FPGA)对设计系统进行数字电路设计,进一步验证了基于平均能量的前馈式数字AGC系统的适用性。A feedforward digital automatic gain control system based on average energy was designed to solve the problem of slow adjustment of feedback digital automatic gain control(AGC)signal and impulse of output signal.Firstly,the input signal was preprocessed to reduce the gap of signal strength.Then,the average energy of the preprocessed signal was calculated to get the decision factor,and the Newton iterative algorithm was introduced to calculate the gain coefficient,which simplified the implementation of digital logic system.Finally,the output signal was obtained by adjusting the pretreated signal with feedforward control.The design system was simulated with the software of MATLAB.The results show that compared with the feedback AGC system based on amplitude and average energy,the output signal of the feed-forward digital AGC system based on average energy is more stable.The steady-state response speed increases by nearly two times,and the output signal reduces the shock phenomenon.Based on field-programmable gate array(FPGA),the digital circuit of the design system is designed,which further verifies the applicability of the feedforward digital AGC system based on average energy.

关 键 词：自动增益控制 牛顿迭代法 现场可编程门阵列 信号冲击 平均能量 

分 类 号：TN850.3[电子电信—信息与通信工程]