Implementation of a field programmable gate array-based lock-in amplifier

A Lock-In Amplifier (LIA), or phase sensitive detector, is an instrument capable of providing high frequency selectivity allowing the user to distinguish a signal of interest from background noise, and has become an important component in the instrumentation for the study of many different physical phenomena. In this work a LIA is implemented using digital signal processing techniques on a field programmable gate array, or FPGA, and is compared against a commercial counterpart with the objective of showing that homebrewed instruments can produce reliable and trustworthy results. For this comparison experimental tests have been performed which are based on the photoacoustic effect, given that LIAs are cornerstones of many techniques based in this and other related effects.