Food and Entertaining What does a lock-in amplifier do? What does a lock-in amplifier do? A lock-in amplifier performs a multiplication of its input with a reference signal, also sometimes called down-mixing or heterodyne/homodyne detection, and then applies an adjustable low-pass filter to the result. Related Posts:Can an 8-gauge wire handle a 1,000 watt amplifier?What is common gate used for?PDF Rekeying Quick Start Guide - Schlage how to rekey a lock cylinder.How to block channels on smart TVs with step-by- step instructions.