Evolution of Lock-In Amplifier as Portable Sensor Interface Platform: A Review

Kishore, Kaushal; Akbar, Sheikh A.

doi:10.1109/jsen.2020.2993309

Cited by 48 publications

(33 citation statements)

References 81 publications

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“…The bandwidth is determined by the lock-in time-constant which depends on the time duration of the measurement. The phase of the signal relative to the reference can be extracted by comparing output between the in-phase and quadrature components of the reference [1,20,21]. SILIA fits a sinusoidal function to the references and locks into each input channel with each reference frequency (Fig.…”

Section: Methodsmentioning

confidence: 99%

SILIA: software implementation of a multi-channel, multi-frequency lock-in amplifier for spectroscopy and imaging applications

Nadgir

Thurston

Larsen

et al. 2021

Meas. Sci. Technol.

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We describe a software implementation of a multi-channel, multifrequency Lock-in Amplifier (SILIA) to extract modulated signals from noisy data distributed over multiple channels of arbitrary number and size. This software implementation emulates the functionality of a multi-channel, multi-frequency lock-in amplifier in a post-processing step following data acquisition. Unlike most traditional lock-in amplifiers, SILIA can work with any number of input channels and is especially useful to analyze data distributed over many channels. We demonstrate the versatility and performance for extracting weak signals in spectroscopy and fluorescence microscopy. We also discuss more general applications and exhibit a method to automatically estimate error from a lock-in result.

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Section: Methodsmentioning

confidence: 99%

SILIA: software implementation of a multi-channel, multi-frequency lock-in amplifier for spectroscopy and imaging applications

Nadgir

Thurston

Larsen

et al. 2021

Meas. Sci. Technol.

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“…Then the DUT complex impedance can be calculated from the output voltage V out . LIA, also known as the phase-sensitive detector, is capable of extracting weak signals from noisy background ( Figure 3 E) [ 98 ]. The output voltage V out , termed as signal under test (SUT), is multiplied by in-phase and quadrature carrier signal V c , whose frequency is the same as that of V in .…”

Section: Device Designs For Sensing Single-cell Impedancementioning

confidence: 99%

Recent Advances in Electrical Impedance Sensing Technology for Single-Cell Analysis

et al. 2021

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Cellular heterogeneity is of significance in cell-based assays for life science, biomedicine and clinical diagnostics. Electrical impedance sensing technology has become a powerful tool, allowing for rapid, non-invasive, and label-free acquisition of electrical parameters of single cells. These electrical parameters, i.e., equivalent cell resistance, membrane capacitance and cytoplasm conductivity, are closely related to cellular biophysical properties and dynamic activities, such as size, morphology, membrane intactness, growth state, and proliferation. This review summarizes basic principles, analytical models and design concepts of single-cell impedance sensing devices, including impedance flow cytometry (IFC) to detect flow-through single cells and electrical impedance spectroscopy (EIS) to monitor immobilized single cells. Then, recent advances of both electrical impedance sensing systems applied in cell recognition, cell counting, viability detection, phenotypic assay, cell screening, and other cell detection are presented. Finally, prospects of impedance sensing technology in single-cell analysis are discussed.

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“…The sample rate and square-wave modulation frequency were set to the default values of 200 kHz and $ 410 Hz, respectively. R 5), long-pass filter (6), mounting plate for long-pass filter (7), mounting plate for amplified photodiode (8), amplified photodiode (9) and PCB (10). (The PCB is shown unpopulated for clarity).…”

Section: Validation and Characterisationmentioning

confidence: 99%

“…6. (a) Exploded-view of detector assembly, showing: LED (1), retaining clip (2), mounting plate for LED and short-pass filter (3), short-pass filter (4), flow-cell assembly (5), long-pass filter(6), mounting plate for long-pass filter(7), mounting plate for amplified photodiode(8), amplified photodiode(9) and PCB(10). (The PCB is shown unpopulated for clarity).…”

mentioning

confidence: 99%

A sensitive and compact optical detector based on digital lock-in amplification

Harvie¹,

Yadav²,

Mello³

2021

HardwareX

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We report a sensitive, fixed-wavelength, lock-in-based optical detector built from a lightemitting diode, two colour filters, a photodetector, a small number of discrete analogue components, and a low-cost microcontroller development board. We describe the construction, operating principle, use and performance of the optical detector, which may be used for both absorption and fluorescence measurements in either a 10-mm pathlength cuvette or a low-volume (<100 ll) flow-cell. For illustrative purposes the detector is applied here to a cholesterol assay based on the enzyme-mediated conversion of (nonemissive) Amplex Red into the fluorescent dye resorufin, providing a detection limit of $ 200 nM -some four orders of magnitude lower than the typical concentration of cholesterol in human serum. (The resorufin molecule itself is detectable down to concentrations of $ 20 nM). The system may be readily adapted to other biomolecules through a simple change of enzyme.

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Evolution of Lock-In Amplifier as Portable Sensor Interface Platform: A Review

Cited by 48 publications

References 81 publications

SILIA: software implementation of a multi-channel, multi-frequency lock-in amplifier for spectroscopy and imaging applications

SILIA: software implementation of a multi-channel, multi-frequency lock-in amplifier for spectroscopy and imaging applications

Recent Advances in Electrical Impedance Sensing Technology for Single-Cell Analysis

A sensitive and compact optical detector based on digital lock-in amplification

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