摘要
介绍一种由信号通道、参考信道和相敏检波三部分组成的锁定放大器,用于实现强噪声干扰下μV级信号幅值的有效检测。其中信号通道由纯电阻分压网络、加法器、交流放大器和带通滤波器组成;参考通道包括移相器和触发整形电路;相敏检波是该锁定放大器的核心元件,检波后经过低通滤波器输出一个直流信号,经MSP430进行AD采样并根据理论推导进行计算,在LCD1602上显示出特定频率的微弱信号的幅值。实验证明在误差范围内,该锁定放大器能在10μV^1m V微弱正弦信号的十倍噪声干扰下检测出被测信号的幅值。
This paper introduces a lock-in amplifier used to detect the amplitude of μV signal under strong noise interference,which is composed of three parts:signal channel,reference channel and phase sensitive detector.The signal channel is composed of divider resistance,adder,AC amplifier,and band-pass filter.The reference channel is composed of phase shifter and trigger shaping circuit.Phase sensitive detector is the core element. After that,the low pass filter outputs a DC signal.MSP430 disposes this signal by AD sampling and calculate based on theoretical derivation.
出处
《工业控制计算机》
2016年第10期137-138,145,共3页
Industrial Control Computer
关键词
相敏检波
锁定放大器
微弱信号检测
强噪声干扰
MSP430
phase sensitive detection
lock-in amplifier
weak signal detection
strong noise interference
MSP430