一种新型锁相放大器检测电路

A New Type of Lock-in Amplifier Detecting Circuit

锁相放大是微弱信号检测的重要手段.现有的模拟锁相放大器参数稳定性和灵活性差,数字锁相放大器存在运算复杂等问题.为此,提出一种新型锁相检测电路,将传统锁相放大器的优点与Σ- Δ型A/DC的过采样和积分特性结合起来.对该电路作了理论分析,并通过实验证明了该电路比现有锁相放大器具有更好的性能,能实现与微处理器无“缝”数据采集和传输.

Lock-in amplifying (LIA) is one of important means for weak signal detection. However, there are still some problems remained in conventional LIA, such as high circuit parameter dependence and low application flexibility of analogue LIA, and algorithmic complexity of digital LIA. A new type of LIA detecting circuit is presented in this paper, which combines the advantages of conventional LIA with characteristics of over-sampling and integration of Σ-Δ A/DC. It is theoretically analyzed and proved through experiment that this circuit is better in performance than conventional LIA. Another outstanding feature of the circuit is that it collects and transfers data from/to micro-processing unit(MPU) seamlessly.