Lock -in amplifier based on virtual Instrumentation

Abstract

When a slowly varying voltage is detected the main problem is the noise especially when it is several times greater than the signal itself. A lock-in amplifier is used to measure the small signals in presence of noise. The aim of this paper is to do a digital lock-in amplifier based on virtual instrument language LabVIEW and later on, it will replace a practice of a subject from the Physics’ degree as a very useful teaching tool. This project is distributed with two experimental parts; the first one works by simulating the signals, reference and input signal, having some parameters to select, even the option if noise is wanted for the simulated input signal. The second one captures signals from external sources making it more realistic