用于水微电导测量的锁相放大器的设计  

Design of Lock-in Amplifier in Measuring of Water Mill-conduction

作　　者：江光灵[1] 田裕鹏[1] 

机构地区：[1]南京航空航天大学自动化学院

出　　处：《计算机测量与控制》2007年第6期786-789,共4页Computer Measurement &Control

摘　　要：电导率的检测是工业在线成分分析中的一个重要方法,在对于水的电导率检测中,由于信号很小,采用普通的检测方法无法从噪声中提取有用的检测信号,利用相关检测原理,设计了一种应用于水的电导率检测的锁相放大器,给出了信号驱动电路、前置放大、移相电路、开关式相敏检波等电路的实际的电路,并从理论上给予分析,作为电路参数选择的依据,从而能进一步提高整个测量系统的信噪改善比。The conductivity test is the important way, by which the potency of liquid is analyzed. But the conductivity of water is very low, and the noise value of signal is high than the signal value, so we can＇t detect it by the normal way. A design way of Lock-In Amplifier in measuring of water mill-conduction is introduced by correlation theory. Signal-driven circuit, pre-amplifier circuit, phase shaft circuit and switched PSD circuit are given. From the point of theory the analysis are illustrated. If the parameters of the circuit are turned properly, the circuit ANIR is improved.

关 键 词：电导率检测 微弱信号 锁相放大器 噪声抑制 

分 类 号：TP274[自动化与计算机技术—检测技术与自动化装置]