A Survey of Low-cost Lock-in Amplifiers for Sensor Applications

Sensors working in low frequency range are often subject to flicker noise and produce a noisy output signal. Therefore, it is necessary to retrieve the expected low frequency signal eliminating the unwanted noise. Lock-in amplifiers have been used as an effective signal recovery technique in the past. Custom made lock-in amplifiers have become an integral part of sensor applications. This article takes a detailed look at the existing models of lock-in amplifiers that have been developed for sensor applications. We plan to build and deploy a marine IoT of environment monitoring stations on fishing vessels using ultra low-cost sensors. Towards this, we intend to develop extremely cost-effective lock-in amplifiers with targeted functionality for sensor applications. Based on our survey in this article, we draw some inferences on the components to be used and the approach to be adopted to accomplish our goal.