专用视频放大器模块的设计原理

The Design of a Special Video Amplifier Module

专用视频放大器模块集高增益、大动态、低噪声于一体，而且处理的信号比较复杂，在设计上具有相当难度。选择合适的器件是基础，而使器件工作在最佳状态，设计一个良好的信号通道则是关键；同时，一个品质优良的放大器必须要有关键的参数来表征，因此参数的选择、定义以及相关的测试技术极为重要。本文介绍的视频放大器模块总增益高达９０ｄＢ，带宽１０ＭＣ，系统ＡＧＣ控制范围７０ｄＢ，输出幅度１～８Ｖ＿（ｐ－ｐ），噪声电压３０μＶ＿（ｐ－ｐ）。

A special video amplifier incorporates high gain,large dynamic range and low noise in-to one module,and processes complex signals.The design of such a module,therefore,is fairly dif-ficult.Choosing proper devices is essential,but to make them operating at optimal conditions,de-signing a good signal channel is the key.On the other hand,a high quality amplirler must be char-acterized by critlcal parameters.So,the selection and definition of parameters and related test tech-niques are extremely important.Avideo amplifier module with a total gain up to 90dB and a band- width of 10MC is presented in the paper.The automatic gain control(AGC)for the module is in the range of 70dB.Its output amplitude and noise voltage are 1～8V_(p-p) and 30μV_(p-p), respec-tively.