Multifrequency Lock-In Detection With Nonsinusoidal References

Hintenaus, Peter; Trinker, Horst

doi:10.1109/tim.2013.2240095

Cited by 15 publications

(6 citation statements)

References 34 publications

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“…Although square waves or other non-sinusoidal waves are used for the detection of resistivity or other types of measurands, [6,9], sinusoidal wave lock-in detection remains the most popular and straightforward contactless resistivity-detection method [4,5,7]. The raw idea behind the MPMC tool proposed in this paper starts from the RSPSC DLIA.…”

Section: Tdm-based Rspsc Dlia Transceivermentioning

confidence: 99%

Carrier-interleaved orthogonal multi-electrode multi-carrier resistivity-measurement tool

Cai¹,

Sha²

2016

Meas. Sci. Technol.

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This paper proposes a new carrier-interleaved orthogonal multi-electrode multi-carrier resistivity-measurement tool used in a cylindrical borehole environment during oil-based mud drilling processes. The new tool is an orthogonal frequency division multiplexing access-based contactless multi-measurand detection tool. The tool can measure formation resistivity in different azimuthal angles and elevational depths. It can measure many more measurands simultaneously in a specified bandwidth than the legacy frequency division multiplexing multi-measurand tool without a channel-select filter while avoiding inter-carrier interference. The paper also shows that formation resistivity is not sensitive to frequency in certain frequency bands. The average resistivity collected from N subcarriers can increase the measurement of the signal-to-noise ratio (SNR) by N times given no amplitude clipping in the current-injection electrode. If the clipping limit is taken into account, with the phase rotation of each single carrier, the amplitude peak-to-average ratio can be reduced by 3 times, and the SNR can achieve a 9/N times gain over the single-carrier system. The carrierinterleaving technique is also introduced to counter the carrier frequency offset (CFO) effect, where the CFO will cause inter-pad interference. A qualitative analysis and simulations demonstrate that block-interleaving performs better than tone-interleaving when coping with a large CFO. The theoretical analysis also suggests that increasing the subcarrier number can increase the measurement speed or enhance elevational resolution without sacrificing receiver performance. The complex orthogonal multi-pad multi-carrier resistivity logging tool, in which all subcarriers are complex signals, can provide a larger available subcarrier pool than other types of transceivers.

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Section: Tdm-based Rspsc Dlia Transceivermentioning

confidence: 99%

Carrier-interleaved orthogonal multi-electrode multi-carrier resistivity-measurement tool

Cai¹,

Sha²

2016

Meas. Sci. Technol.

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“…In particular, this is crucial in the case of the detection of very small signals (and/or related variations) that must be extracted from noise due, for example, to the low concentration of the substance under analysis that interacts with light in transmission, reflection and scattering measurements. The conventional approach used to improve the signal-to-noise ratio of small and noisy signals is based on the standard synchronous demodulation technique for amplitude and phase measurements implemented by lock-in amplifiers [11][12][13][14][15][16][17][18][19]. Generally, this approach is used to detect the amplitude of electrical signals at a fixed modulating frequency and the instrumental achievable sensitivity and resolution depend and are limited by the selected full-scale chosen for the specific measurement.…”

Section: Introductionmentioning

confidence: 99%

High-Sensitivity High-Resolution Optical Phase Shift Detection Technique Using a Si Photodiode Operating in Photovoltaic Mode

2015

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In this paper we report the optimisation of the operating conditions and the maximisation of the performances of the phase shift detection technique allowing to approach the best sensitivity and resolution in terms of light power variations. The system is based on the synchronous demodulation technique and uses a Si photodiode operating in photovoltaic mode biased through a small amplitude sinusoidal modulating signal. Employing a commercial lock-in amplifier for phase measurements and varying the signal modulating frequency, we prove that it is possible to obtain the maximum theoretical phase shift variation range equal to 90° with a resulting sensitivity and resolution equal to 3100°/µ µ µ µW and 3pW, respectively. We demonstrate that these results are more than two orders of magnitude greater than those ones achievable by employing a Si photodiode in photoconductive mode. As a case-example for chemical applications, we apply the proposed technique to detect the variations of the molar concentration of a methylene blue solution by measuring the variations of the transmittance of a laser beam passing through the substance. The experimental findings are compared with those ones achieved by using a commercial spectrophotometer and the conventional amplitude detection technique employing the lock-in amplifier. Despite the achieved results are limited by the fixed phase resolution of the employed lock-in amplifier, the here proposed approach allows to measure molar concentration variations with a resolution of 79pM resulting 1354 times higher than that one obtained using the spectrophotometer and 33 times better than the value achieved with the amplitude detection technique.

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“…In the context of high-precision measurement, Harrison, Player and Sandars (HPS) [6] describe signal modulation with complex, multi-frequency waveforms chosen to be mutually orthogonal. More recently in the context of optical tomography [7][8][9] consider phase-sensitive detection at several frequencies. Careful choice of the frequencies and filter time constants allows the signals to be extracted independently.…”

Section: Introductionmentioning

confidence: 99%

Stochastic multi-channel lock-in detection

et al. 2014

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High-precision measurements benefit from lock-in detection of small signals.Here we discuss the extension of lock-in detection to many channels, using mutually orthogonal modulation waveforms, and show how the choice of waveforms affects the information content of the signal. We also consider how well the detection scheme rejects noise, both random and correlated. We address the particular difficulty of rejecting a background drift that makes a reproducible offset in the output signal and we show how a systematic error can be avoided by changing the waveforms between runs and averaging over many runs. These advances made possible a recent measurement of the electron's electric dipole moment (Hudson et al 2011 Nature 473 493).

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Multifrequency Lock-In Detection With Nonsinusoidal References

Cited by 15 publications

References 34 publications

Carrier-interleaved orthogonal multi-electrode multi-carrier resistivity-measurement tool

Carrier-interleaved orthogonal multi-electrode multi-carrier resistivity-measurement tool

High-Sensitivity High-Resolution Optical Phase Shift Detection Technique Using a Si Photodiode Operating in Photovoltaic Mode

Stochastic multi-channel lock-in detection

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