A lock-in amplifier uses phase-sensitive detection to improve the
signal-to-noise ratio in cw experiments. Using phase-sensitive detection requires that the analytical signal be modulated at some reference
frequency. The lock-in-amplifier then amplifies only the
component of the input signal at the reference signal, and filters out all other frequencies, i.e., noise. In the
fluorescence detection example illustrated below, the analytical signal (the fluorescence) is modulated by chopping the optical excitation
source (the laser ) at the reference
frequency.
Use of a lock-in amplifier in fluorescence detection
Related Topics:
- Index of detection electronics
- Introduction to electronics
- Introduction to data acquisition
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