Comprehensive tutorial about the why and how of lock-in amplifiers.

The microphone signals are further amplified and detected using lock-in amplifiers.

A lock-in amplifier is then used to measure deflections found at the modulation frequency.

Recovery of small signals that otherwise would be lost in noise (lock-in amplifier)

Application note detailing how lock-in amplifiers work.

The output is fed into a lock-in amplifier whose reference signal has the same frequency used to modulate the pump.

The high frequency signal is separated using a lock-in amplifier and this signal provides the magnetic information about the surface.

Operation of a lock-in amplifier relies on the orthogonality of sinusoidal functions.

This noise can be avoided by modulation of the signal at a higher frequency, for example through the use of a lock-in amplifier.

For contact potential measurements a lock-in amplifier is used to detect the cantilever oscillation at ω.

The cantilever vibrations are measured by a 4-section photo-diode and evaluated by a lock-in amplifier.

The thermoreflected signal is then measured by a photodiode which is connected to a RF lock-in amplifier.

Lock-in amplifier tutorial from Bentham Instruments.

A lock-in amplifier aids noise reduction by filtering through only the amplitude oscillations that match the probe's vibration frequency.

In a typical setup, the induced voltage is measured through the use of a lock-in amplifier using the piezoelectric signal as its reference signal.

Optical choppers, usually rotating disc mechanical shutters, are widely used in science labs in combination with lock-in amplifiers.

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.

Signal obtained by the AFM (and captured by lock-in amplifier) are actually representations of the cantilever deflection at a specific frequency.

The A.C. component of the tunneling current is recorded using a lock-in amplifier, and the component in-phase with the tip-sample bias modulation gives directly.

By using the expansion signal, the temperature can be extracted as follows: the signal that captured by the lock-in amplifier is converted into the bending of cantilever.

The resulting deflection of the probe cantilever is detected through standard split photodiode detector methods and then demodulated by use of a lock-in amplifier (LiA).

For a sine reference signal and an input waveform , the DC output signal can be calculated for an analog lock-in amplifier by:

When the lock-in technique is applied, care must be taken to calibrate the signal, because lock-in amplifiers generally detect only the root-mean-square signal of the operating frequency.

The high-frequency signal is sent to a lock-in amplifier and correlated with the reference signal sent by the signal generator to form the AFAM image.