Ricobom B, Nardi M, Bonfim M
Laboratory of Magnetism, Measurement and Instrumentation, Electrical Engineering Department, Federal University of Parana (UFPR), Curitiba, Brazil.
Rev Sci Instrum. 2023 Jun 1;94(6). doi: 10.1063/5.0145566.
Lock-in amplifiers (LIA) are widely used in laboratory environments to detect low-amplitude signals buried in noise as well as real and imaginary parts of a complex quantity. They are based on the technique of synchronous detection, where the signal of interest is modulated into a desired frequency, sent to the medium or device to be analyzed, and captured by a detector. The detector scheme relies on the concept of phase-sensitive detection, generally resulting in two components: in-phase and quadrature. This article shows a very simple and low computational-cost way to implement a dual-phase LIA, using readily available microcontrollers, running a simple and fast algorithm. Three examples of signal detection are presented (sound wave signal, impedance meter, and weak signal recovery) to point out the flexibility and capabilities of the proposed methodology.
锁定放大器（LIA）在实验室环境中被广泛用于检测淹没在噪声中的低幅度信号以及复数量的实部和虚部。它们基于同步检测技术，即将感兴趣的信号调制到所需频率，发送到要分析的介质或设备，然后由探测器捕获。探测器方案依赖于相敏检测的概念，通常会产生两个分量：同相和正交。本文展示了一种非常简单且计算成本低的方法来实现双相LIA，使用现成的微控制器，运行简单快速的算法。给出了三个信号检测示例（声波信号、阻抗计和弱信号恢复），以指出所提出方法的灵活性和能力。
