Strain amplifying measurement based on digital lock-in

To solve noise interference in data acquisition,the authors applied the theory of digital lock-in amplifying to strain measurement and design a high accuracy strain measuring system.Lock-in amplifying was one of the easiest methods to implement high precision detecting in the environment with severe interference.The paper introduced the detecting principle of the digital lock-in amplifier of stressing bridge based on the theory of analog lock-in amplify and designing of a practical digital lock-in measuring system using amplifier AD8231 and SCM C8051F061,finally gave out the detail of hardware structure.