Journal ArticleDOI
Differential synchronous demodulation for small signal amplitude estimation
TLDR
In this paper, the amplitude demodulation of the difference of two sinewave signals and the common-mode correction of the measurement is performed using a sample-and-hold circuit.Abstract:
A circuit for estimating the amplitude of small signals (in the range of microvolts to a few millivolts) developed initially for an electrical impedance tomography (EIT) data acquisition system is presented. The paper is focused on two points, the accurate demodulation of the difference of two sinewave signals and the common-mode correction of the measurement. The method is oriented for applications in measuring instruments, where a signal source (sinewave oscillator) is assumed to be incorporated. It uses a sample-and-hold circuit, suitably driven, as an amplitude demodulator. One of the advantages of this method is that the realization of the synchronous demodulator (or phase-sensitive detector) does not require a low-pass fitter at the output, resulting in a smaller settling time, that is, in higher speed of measurement. Finally, to improve the accuracy, a self-calibration technique has been developed. >read more
Citations
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Journal ArticleDOI
A CMOS Magnitude/Phase Measurement Chip for Impedance Spectroscopy
TL;DR: In this article, an integrated realization of an alternative method that is less intricate to implement was presented, which was used to measure equivalent RC circuits of the electrode-tissue interface over the frequency range of 100 Hz to 100 kHz.
Journal ArticleDOI
An Integrated Analog Readout for Multi-Frequency Bioimpedance Measurements
TL;DR: In this paper, an integrated analog readout is presented, which employs synchronous detection to perform galvanostatic multi-channel, multi-frequency bio-impedance measurements.
Journal ArticleDOI
A Novel Interface for Eddy Current Displacement Sensors
M.R. Nabavi,Stoyan Nihtianov +1 more
TL;DR: A novel interface concept for eddy current displacement sensors, which consumes less than 12 mW and has an extremely low thermal drift, is proposed and the proposed idea is analytically investigated.
Journal ArticleDOI
Multiscale noise tuning stochastic resonance enhances weak signal detection in a circuitry system
Daoyi Dai,Qingbo He +1 more
TL;DR: In this article, a weak signal detection approach is proposed by combining the multiscale noise tuning SR (MSTSR) circuitry with the traditional synchronous demodulation (SD) detector.
Journal ArticleDOI
A novel differential synchronous demodulator for AC signals
Ramon Pallas-Areny,Oscar Casas +1 more
TL;DR: A novel fully differential (FD) demodulator is presented, which can be used for processing amplitude-modulated (AM) signals obtained from impedance measurements or coming from modulating sensors with differential outputs where a high common-mode rejection ration (CMRR) and low noise are demanded.
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