1. What are
lock-in amplifiers anyway?
Lock-in amplifiers use the process of synchronous detection to
recover signals that have been buried in noise. They act as extremely narrow
pass band filters with the pass band centre point selected by a reference
signal. For those seeking further information we offer the following
Lockin Amplifier Theory of
Operation. External site produced by M. Stachel of Faculty of Physics
University of Konstanz Germany. Includes theory, diagrams and a Java virtual
Amplifiers as explained by Wikipedia.