Low-Cost, High-Performance Lock-in Amplifier for Pedagogical and Practical Applications

Xu, Xicheng; Suganuma, Yoshinori; Dhirani, Al-Amin

doi:10.1021/acs.jchemed.9b00859

Cited by 7 publications

(2 citation statements)

References 22 publications

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“…An uncooled configuration provides advantage in weight and portability for drone-based operation of the SiPM-based photon counting delayed fluorescence biosensor. An ultra-low-cost signal multiplier would be built to lock-in [ 57 ] delayed fluorescence signal and remove interference from spurious light present even at nighttime.…”

Section: Discussionmentioning

confidence: 99%

A SiPM-Enabled Portable Delayed Fluorescence Photon Counting Device: Climatic Plant Stress Biosensing

Pietro

Mermut

2022

Biosensors

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A portable and sensitive time-resolved biosensor for capturing very low intensity light emission is a promising avenue to study plant delayed fluorescence. These weak emissions provide insight on plant health and can be useful in plant science as well as in the development of accurate feedback indicators for plant growth and yield in applications of agricultural crop cultivation. A field-based delayed fluorescence device is also desirable to enable monitoring of plant stress response to climate change. Among basic techniques for the detection of rapidly fluctuating low intensity light is photon counting. Despite its vast utility, photon counting techniques often relying on photomultiplier tube (PMT) technology, having restricted use in agricultural and environment measurements of plant stress outside of the laboratory setting, mainly due to the prohibitive cost of the equipment, high voltage nature, and the complexity of its operation. However, recent development of the new generation solid-state silicon photomultiplier (SiPM) single photon avalanche diode array has enabled the availability of high quantum efficiency, easy-to-operate, compact, photon counting systems which are not constrained to sophisticated laboratories, and are accessible owing to their low-cost. In this contribution, we have conceived, fabricated and validated a novel SiPM-based photon counting device with integrated plug-and-play excitation LED, all housed inside a miniaturized sample chamber to record weak delayed fluorescence lifetime response from plant leaves subjected to varying temperature condition and drought stress. Findings from our device show that delayed fluorescence reports on the inactivation to the plant’s photosystem II function in response to unfavorable acute environmental heat and cold shock stress as well as chronic water deprivation. Results from our proof-of-concept miniaturized prototype demonstrate a new, simple and effective photon counting instrument is achieved, one which can be deployed in-field to rapidly and minimally invasively assess plant physiological growth and health based on rapid, ultra-weak delayed fluorescence measurements directly from a plant leaf.

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Section: Discussionmentioning

confidence: 99%

A SiPM-Enabled Portable Delayed Fluorescence Photon Counting Device: Climatic Plant Stress Biosensing

Pietro

Mermut

2022

Biosensors

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“…When a voltage excitation is applied to a displacement transducer, the output voltage amplitude changes as the position of the inductive core changes. To obtain the relationship between the inductive core displacement and the output signal, a conditioning circuit based on the AD630 balanced conditioner/demodulator was used [ 21 ]. First, the displacement transducer output signal was amplified using an operational amplifier, then it was processed by the AD630 circuit, and finally, a low-pass filter was used to obtain the DC signal [ 22 ].…”

Section: Structure and Operating Principle Of A Dual-coil Inductive D...mentioning

confidence: 99%

Effect of the Coil Excitation Method on the Performance of a Dual-Coil Inductive Displacement Transducer

et al. 2023

Sensors

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A dual-coil inductive displacement transducer is a non-contact type measuring element for measuring displacement and is widely used in large power equipment systems such as construction machinery and agricultural equipment. However, the effect of the coil excitation method on the performance of dual-coil inductive displacement sensors has not been studied. This paper investigates the impact of different coil excitation methods on the operating performance of displacement transducers. The working principle, electromagnetic characteristics, and electrical characteristics were analyzed by building a mathematical model. A transducer measurement device was used to determine the relationship between core displacement and coil inductance. Three coil excitation methods were proposed, and the effects of the three coil excitation methods on the amplitude variation, phase shift, linearity, and sensitivity of the output signal were studied by simulation based on the AD630 chip as the core of the conditioning circuit. Finally, the study’s feasibility was demonstrated by comparing the experiment to the simulation. The results show that, under the uniform magnetic field strength distribution in the coil, the coil voltage variation is proportional to the inductive core displacement. The amplitude variation is the largest for the dual-coil series three-wire (DCSTW) and is the same for the dual-coil series four-wire (DCSFW) and dual-coil parallel differential (DCPD). DCSFW has an enormous phase shift. DCSTW has the best linearity. The research in this paper provides a theoretical basis for selecting a suitable coil excitation, which is conducive to further improving the operating performance of dual-coil inductive displacement transducers.

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Fully-digital low-frequency lock-in amplifier for photoluminescence measurements

Pollastrone

Piccinini

Pizzoferrato

et al. 2023

Analog Integr Circ Sig Process

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Lock-in amplifiers, used in several experimental physics applications, are instruments performing quadrature demodulation, which is useful when signals are affected by much noise. Generally, commercially-available lock-in amplifiers are very accurate, but expensive, especially if their operating range includes radiofrequencies. In many applications, high precision is not necessary for the measurements, but it is preferable to have low-cost, low-weight, compactness and a user-friendly graphical unit interface. In this paper, we describe a new fully-digital low-frequency lock-in amplifier developed at ENEA C.R. Frascati Laboratories for photoluminescence experiments based on an innovative low-cost architecture and processing algorithms. The hardware, firmware and software developed for the whole photoluminescence measurement set-up is presented. The present lock-in was first characterized with synthetic electrical sine wave signals and white noise. A dynamic reserve of 43 dB and a noise figure in the range of 25–44 dB were estimated. These results show compatibility with several measurement applications, such as photoluminescence, and the adequacy of the resolutions with respect to the hardware costs. Finally, preliminary results of photoluminescence measurements are presented.

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Low-Cost, High-Performance Lock-in Amplifier for Pedagogical and Practical Applications

Cited by 7 publications

References 22 publications

A SiPM-Enabled Portable Delayed Fluorescence Photon Counting Device: Climatic Plant Stress Biosensing

A SiPM-Enabled Portable Delayed Fluorescence Photon Counting Device: Climatic Plant Stress Biosensing

Effect of the Coil Excitation Method on the Performance of a Dual-Coil Inductive Displacement Transducer

Fully-digital low-frequency lock-in amplifier for photoluminescence measurements

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