基于单片机的锁定放大器设计

Design of Lock-in Amplifier Based on Single Chip Microcomputer

文章介绍的电子设计是以TI公司的MSP430单片机最小系统作为控制中心,结合锁定放大器原理实现的微弱信号的检测装置。该设计包括了交流放大器、带通滤波器、移相电路、方波发生器、PSD电路、A/D采样电路和单片机控制电路等。该小系统能将微弱信号幅值从强噪声中检测出来,并通过液晶显示A/D实时采样的幅值,且误差最高能达到1%以下,所能检测到的弱信号幅度能达到20m V以下。

This electronic design is based on the MCU-MSP430 minimum system, and combined with the principle of lock-in amplifier it canaehieve the weak signal detection. The design includes AC amplifier, band pass filter, phase shift circuit, square wave generator, PSD circuit, A/D sampling circuit and MCU control circuit. The system can detect the weak signal amplitude from the strong noise. Through the LCD, it can shows A/D sampling of amplitude and maximum error is less than 1%, and the weak signal amplitude detected can reach less than 20mV.