可變增益放大器的设计112029.doc

商洛学院 本科毕业论文（设计） 题　　目：　　　基于模拟开关的可变增益放大器的设计 　　　　　　 学生姓名：　　 刘涛 　　　 学号： 院（系）：物理与电子信息工程 专业：电子信息工程　 入学时间：　 2010　 　　年　　 　9　　月 导师姓名：　 赵杰 　　 职称/学位：　 　 导师所在单位：　物理与电子信息工程系　 　　　  基于模拟开关的可变增益放大器的设计 摘 要 模拟开关是一种三稳态电路，它可以根据选通端的电平，决定输人端与输出端的状态。当选通端处在选通状态时，输出端的状态取决于输人端的状态;当选通端处于截止状态时，则不管输人端电平如何，输出端都呈高阻状态。模拟开关在电子设备中主要起接通信号或断开信号的作用。由于模拟开关具有功耗低、速度快、无机械触点、体积小和使用寿命长等特点，因而，在自动控制系统和计算机中得到了广泛应用,起着变化增益、调整信号动态范围、稳定信号功率的作用。文章综述了CMOS集成可变增益放大器的研究情况;给出了可变增益放大器的定义、应用、分类和主要指标,描述了多种开环和闭环放大器的结构,分析了相应的增益控制方法及其优缺点;说明了在CMOS工艺下实现放大器增益按指数变化的几种途径。最后,介绍了用于无线数字通信,具有宽带、高线性、低电源电压等高性能可变增益放大器的设计实例。 关键词：模拟开关 ；放大器;可变增益放大器 A Design of Variable Gain Amplifier based on analog switch Abstract Analog switch is a kind of three monostable circuit, it can according to the strobe terminal, determines the input terminal and the output terminal of the state. Elected through end in gating state, state dependent output to input end state; elected through end in a closed state, no matter how input level, output in a high impedance state. The main switch on signal or analog switch off signal in electronic equipment function. Because the analog switch has the advantages of low power consumption, high speed, no mechanical contact, small volume and long service life, therefore, in the automatic control system and the computer has been widely used in the Variable gain amplifier (VGA) is an analog circuit, which varies gain, adjusts signal dynamic range and stabilizes signal power. An overview of CMOS integrated variable gain amplifiers is made .The definition of VGA and its function, classification and specifications are elaborated. Different open-and closed-loop VGA’s are described, and the advantages and disadvantages of gain control strategies are analyzed. Approaches to achieving exponential gain in CMOS technology are explained. Finally, examples of high performance VGA’s used in wireless digital communication are introduced, which mainly focus on