宽带大动态AGC电路设计

摘要

Auto gain control（AGC） circuit is one of the important control circuits of receivers.The working principle and the classification of AGC are analyzed.In order to design broadband and large dynamic AGC circuit,the maim functions and performance indexes of the VGA（Variable Gain Amplifier）ADL5330 and the logarithm ic amplifier AD8318 are analyzed.A kind of broadband large dynamic AGC module is designed by using these two chips.The article provides typical circuit and offers the actuai testing results.Compared to the traditional AGC circuits,the module is simpler and smaller,and has a series of features such as broadband,large dynamic and low noise.%自动增益控制电路是接收机模块中的关键控制电路之一,其作用是改善接收机的动态范围。具体分析了自动增益控制电路的工作原理以及AGC的分类方式。为了设计宽带大动态的AGC电路,分析了可变增益ADL5330和对数放大器AD8318的电路功能和主要性标,并利用这两款芯片设计了一种宽带大动态AGC模块,给出了典型电路及测试结果。与传统AGC电路相该电路结构简单、体积小,且能实现宽带、大动态、低噪声放大等功能。