Amplitude Modulated Signals: The Lock‐in Amplifier
Richard Burdett · Handbook of Measuring System Design · 2005
Abstract By modulating signals that are accompanied by significant noise, it is possible to use synchronous detection to recover the signal. This gives a very narrow bandwidth, thereby significantly increasing the measured signal‐to‐noise ratio. This article deals with this detection method, as commonly implemented by an instrument called a lock‐in amplifier .