反馈式自动增益控制电路分析  

Analysis of Feedback Automatic Gain Control Circuit

作　　者：李建强[1] 戚红雨 LI Jiangqiang;QI Hongyu(The 54th Research Institute of CETC,Shijiazhuang 050081,China;Unit 96902,PLA,Beijing 100015,China)

机构地区：[1]中国电子科技集团公司第五十四研究所 [2]中国人民解放军96902部队

出　　处：《无线电工程》2018年第12期1096-1099,共4页Radio Engineering

基　　金：国家自然科学基金青年科学基金资助项目(61701368)

摘　　要：结合工程实际需求,对反馈式自动增益控制(AGC)电路进行了分析。介绍了AGC电路的组成部分,在时域和频域上建立了AGC电路的数学模型,对核心的环路滤波器进行了建模和分析,得到了简化后的传递函数,据此对AGC电路的稳定时间进行了详细分析,得到了AGC输出电平变化小于10%、小于1 d B和AGC控制电压变化小于终值10%三种情况下AGC稳定时间的数学表达式。理论计算与实测结果的符合度较高,可以对AGC电路参数的选择提供参考。Based on the actual requirements of some projects,the feedback Automatic Gain Control(AGC)circuit is analyzed.The AGC circuit is usually composed of variable attenuator,amplifier,coupler,power detector and loop filter.Firstly,the AGC circuit models are established in time domain and frequency domain.Secondly,the loop filter is modeled and analyzed as the core component of AGC circuit.The simplified transfer function of loop filter is obtained,based on which the stability time of AGC circuit is analyzed in detail.The mathematical expressions of AGC circuit stability time under three conditions are obtained when the change of AGC circuit output level is less than 10%and less than 1dB as well as the change of AGC circuit control voltage is less than 10%of its final value.The theoretical results are in higher conformity with with the experimental ones and can provide the references for selection of AGC parameters.

关 键 词：自动增益控制 反馈 环路滤波器 稳定时间 

分 类 号：TN850.3[电子电信—信息与通信工程]