视频对数放大器动态范围的提高  

Improvement of Video Logarithmic Amplifier Dynamic Range

作　　者：俞红珊[1] 刘宇刚[1] 祝敏[1] 

机构地区：[1]贵州师范大学机电工程学院,贵阳550059

出　　处：《化工自动化及仪表》2010年第5期64-67,71,共5页Control and Instruments in Chemical Industry

摘　　要：视频对数放大器是一种采用限幅放大器串联级联或并联求和结构逐级检波构成的交流对数放大器,对交流高频信号具有很强的压缩能力,但其动态范围一般不超过100 dB。利用串联级联和并联求和两种结构的对数放大器的优化组合及改进设计可设计出更大动态范围、宽频带、响应速度快及高精度的对数放大器。本文采用三个单片串联级联对数放大器组成并联求和结构大动态范围对数放大器,其动态范围高达140 dB,是单片级联对数放大器的2.5倍。Video logarithmic amplifier is an AC logarithmic amplifier which composed of limiting amplifier cascaded in series or parallel summation structure sequential detection.It has a strong compression for AC high-frequency signal,but the dynamic range is not more than 100 dB.A logarithmic amplifier with a larger dynamic range,broadband,fast response and high-precision can be designed by using series cascading or parallel summation two structures optimization combination and improvement design.Three monolithic series cascade structure logarithmic amplifiers were adopted to compose parallel summation logarithmic amplifier which had the large dynamic range up to 140 dB,and it is 2.5 times of monolithic cascaded logarithmic amplifier.

关 键 词：限幅放大器 动态范围 串联级联 并联求和结构 串联级联对数放大器并联求和结构 

分 类 号：TN722[电子电信—电路与系统]