Response of a lock-in amplifier to noise

Baak, D. A. Van; Herold, G.

doi:10.1119/1.4873915

Cited by 15 publications

(6 citation statements)

References 10 publications

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“…Output error of lock-in amplifiers tends to decrease sharply with respect to data acquisition time and input SNR [2,23,28,29]. We see a similar significant improvement in the SILIA output error with respect to a the number of samples of the input signal (figures 5(a), (b)), and can conclude the necessity of longer data acquisition times and higher sampling rates for more accurate results, especially from data with low SNR.…”

Section: Error Benchmarkingsupporting

confidence: 65%

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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: Error Benchmarkingsupporting

confidence: 65%

“…Output error of lock-in amplifiers tends to decrease sharply with respect to data acquisition time and input SNR [23,2,28,29]. We see a similar significant improvement 5a) as well as phase error (Fig.…”

Section: Fitsupporting

confidence: 64%

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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“…By applying the work described in the documentation of Zurich Instruments [ 37 ], we can review the basics of lock-in amplifier operation. Using the instructions in [ 38 ], we estimated the noise characteristics of our instrument and the lock-in amplifier gain during the measurement process, as well as deriving numerical measurements of the output signal-to-noise ratio relative to the input signals, thus demonstrating the ways in which the lock-in amplifier can improve its signal-to-noise ratio during measurement.…”

Section: Methodsmentioning

confidence: 99%

“…By analysing the operation of the lock-in amplifier, it can be assumed that the noise was not correlated with the signal

, such that they can be analysed separately [ 38 ]. First, we analyse the transfer of

signal through the lock-in amplifier:

where…”

Section: Methodsmentioning

confidence: 99%

Physical Validation of a Residual Impedance Rejection Method during Ultra-Low Frequency Bio-Impedance Spectral Measurements

Vizvári

Gyorfi

Odry

et al. 2020

Sensors

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Accurate and reliable measurement of the electrical impedance spectrum is an essential requirement in order to draw relevant conclusions in many fields and a variety of applications; in particular, for biological processes. Even in the state-of-the-art methods developed for this purpose, the accuracy and efficacy of impedance measurements are reduced in biological systems, due to the regular occurrence of parameters causing measurement errors such as residual impedance, parasitic capacitance, generator anomalies, and so on. Recent observations have reported the necessity of decreasing such inaccuracies whenever measurements are performed in the ultra-low frequency range, as the above-mentioned errors are almost entirely absent in such cases. The current research work proposes a method which can reject the anomalies listed above when measuring in the ultra-low frequency range, facilitating data collection at the same time. To demonstrate our hypothesis, originating from the consideration of the determinant role of the measuring frequency, a physical model is proposed to examine the effectiveness of our method by measuring across the commonly used vs. ultra-low frequency ranges. Validation measurements reflect that the range of frequencies and the accuracy is much greater than in state-of-the-art methods. Using the proposed new impedance examination technique, biological system characterization can be carried out more accurately.

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“…The pump beam should be modulated at that frequency. The lock-in-amplifier then measures the signal at the modulation frequency thus isolating other noises which are at different frequencies resulting in a good signal to noise ratio [14,15]. Most of the femtosecond oscillators operate at high repetition rates (for example ∼ 80 MHz).…”

Section: Introductionmentioning

confidence: 99%

Filtering Noise in Time and Frequency Domain for Ultrafast Pump-Probe Performed Using Low Repetition Rate Lasers

Khatua¹,

Gurung²,

Singh³

et al. 2020

Preprint

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Optical pump-probe spectroscopy is a powerful tool to directly probe the carrier dynamics in materials down to sub-femtosecond resolution. To perform such measurement, while keeping the pump induced perturbation to the sample as small as possible, it is essential to have a detection scheme with high signal to noise ratio. Achieving such high signal to noise ratio is easy with phase sensitive detection based on lock-in-amplifier when a high repetition rate laser is used as the optical pulse source. However such a lockin-amplifier based method does not work well when a low repetition rate laser is used for the measurement.In this article, a sensitive detection scheme which combines the advantages of boxcar which rejects noise in time domain and lock-in-amplifier which isolates signal in frequency domain for performing pump-probe measurements using low-repetition rate laser system is proposed and experimentally demonstrated. A theoretical model to explain the process of signal detection and a method to reduce the pulse to pulse energy fluctuation in probe pulses is presented. By performing pump-probe measurements at various detection conditions the optimum condition required for obtaining transient absorption signal with low noise is presented. The reported technique is not limited to pump-probe measurements and can be easily modified to suite for other sensitive measurements at low-repetition rates.

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Response of a lock-in amplifier to noise

Cited by 15 publications

References 10 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

Physical Validation of a Residual Impedance Rejection Method during Ultra-Low Frequency Bio-Impedance Spectral Measurements

Filtering Noise in Time and Frequency Domain for Ultrafast Pump-Probe Performed Using Low Repetition Rate Lasers

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