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2. Lock-in amplifier - Wikipedia

   en.wikipedia.org/wiki/Lock-in_amplifier

   A lock in amplifier uses a multiplier and a low pass filter to compare a reference signal against a noisy signal. A lock-in amplifier is a type of amplifier that can extract a signal with a known carrier wave from an extremely noisy environment. Depending on the dynamic reserve of the instrument, signals up to a million times smaller than noise ...

3. Homodyne detection - Wikipedia

   en.wikipedia.org/wiki/Homodyne_detection

   Homodyne detection. In electrical engineering, homodyne detection is a method of extracting information encoded as modulation of the phase and/or frequency of an oscillating signal, by comparing that signal with a standard oscillation that would be identical to the signal if it carried null information. "Homodyne" signifies a single frequency ...

4. Optical chopper - Wikipedia

   en.wikipedia.org/wiki/Optical_chopper

   The chopper is used to modulate the intensity of a light beam, and a lock-in amplifier is used to improve the signal-to-noise ratio. To be effective, an optical chopper should have a stable rotating speed. In cases where the 1/f noise is the main problem, one would like to select the maximum chopping frequency possible. This is limited by the ...

5. Phase-locked loop - Wikipedia

   en.wikipedia.org/wiki/Phase-locked_loop

   A phase-locked loop or phase lock loop (PLL) is a control system that generates an output signal whose phase is fixed relative to the phase of an input signal. Keeping the input and output phase in lockstep also implies keeping the input and output frequencies the same, thus a phase-locked loop can also track an input frequency.

6. Ultrasound-switchable fluorescence imaging - Wikipedia

   en.wikipedia.org/wiki/Ultrasound-switchable...

   The image system first dramatically increase the system sensitivity by adopting a lock-in amplifier and a cooled photomultiplier tube(PMT); Then the system use a correlation algorithm to distinguish the USF signal from the background noise; Also, it detects only the change of the fluorescence signal caused by the ultrasound, The modulated ...

7. Stanford Research Systems - Wikipedia

   en.wikipedia.org/wiki/Stanford_Research_Systems

   Stanford Research Systems is a maker of general test and measurement instruments. The company was founded in 1980, is privately held, and is not affiliated with Stanford University. Stanford Research Systems (SRS) manufactures all of their products at their Sunnyvale, California facility. SRS produces scientific and engineering instruments for ...

8. Instrumentation amplifier - Wikipedia

   en.wikipedia.org/wiki/Instrumentation_amplifier

   An instrumentation amplifier (sometimes shorthanded as in-amp or InAmp) is a type of differential amplifier that has been outfitted with input buffer amplifiers, which eliminate the need for input impedance matching and thus make the amplifier particularly suitable for use in measurement and test equipment. Additional characteristics include ...

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