一个高抗干扰数字自动控制增益的声发射监测系统

An Acoustic Emission Monitoring System with Digitally Controlled Variable Gain Amplification

工业现场工况监测常常面临两个主要问题:微弱检测信号需要根据实时状况自动变增益放大;在恶劣强电磁场环境下,检测信号能否屏蔽掉绝大部分干扰,传递到计算机进行进一步处理。针对这两个问题,开发了一个高抗干扰数字自动控制增益的声发射监测系统,可适合于强电磁场环境,自动地调整前置放大器的增益。该系统包含一种大动态变化范围的新型数控可变增益放大电路、电源管理电路、模拟信号光纤传输电路和数字信号光纤传输电路。介绍了系统结构、电路原理及实验结果。

There are two major issues in weak signal gain must be automatically set-up according to real time detection of industrial processes. One is that signal signals so as to avoid saturation or insufficiency; another is anti-interference, especially in a very strong electromagnetic field. An acoustic emission detection system with digitally controlled variable gain and anti-interference in a strong electromagnetic field is developed. The system consists of an impedance match circuit, a novel variable gain amplifier （ VGA）, a power management, an analog optical fibre transmitter and several digital optical fibre transmitters. The structure of the system is described and the experimental results are demonstrated.