scholarly journals Methods for Detection of Bioimpedance Variations in Resource Constrained Environments

Sensors ◽  
2020 ◽  
Vol 20 (5) ◽  
pp. 1363
Author(s):  
Eiko Priidel ◽  
Paul Annus ◽  
Andrei Krivošei ◽  
Marek Rist ◽  
Raul Land ◽  
...  
Keyword(s):  
Measurement System ◽  
Dynamic Range ◽  
Current Paper ◽  
Variable Component ◽  
Noise Levels ◽  
Static Component ◽  
Wideband Noise ◽  
Constrained Environments ◽  
Electrical Bioimpedance ◽  
Lock In

Changes in a certain parameter are often a few magnitudes smaller than the base value of the parameter, specifying significant requirements for the dynamic range and noise levels of the measurement system. In case of electrical bioimpedance acquisition, the variations can be 1000 times smaller than the entire measured value. Synchronous or lock-in measurement of these variations is discussed in the current paper, and novel measurement solutions are presented. Proposed methods are simple and robust when compared to other applicable solutions. A common feature shared by all members of the group of the proposed solutions is differentiation. It is achieved by calculating the differences between synchronously acquired consecutive samples, with lock-in integration and analog differentiation. All these methods enable inherent separation of variations from the static component of the signal. The variable component of the bioimpedance can, thus, be acquired using the full available dynamic range of the apparatus for its detection. Additive disturbing signals and omnipresent wideband noise are considered and the method for their reduction is proposed.

scholarly journals Hardware Design of a High Dynamic Range Radio Frequency (RF) Harmonic Measurement System

Instruments ◽  
2018 ◽  
Vol 2 (3) ◽  
pp. 16 ◽  
Author(s):  
Ram Narayanan ◽  
Kyle Gallagher ◽  
Gregory Mazzaro ◽  
Anthony Martone ◽  
Kelly Sherbondy
Keyword(s):  
Radio Frequency ◽  
Measurement System ◽  
High Power ◽  
Nonlinear Distortion ◽  
Dynamic Range ◽  
Low Level ◽  
Rf Systems ◽  
Nonlinear Distortions ◽  
Circuit Elements ◽  
Rf Circuit

Radio frequency (RF) circuit elements that are traditionally considered to be linear frequently exhibit nonlinear properties that affect the intended operation of many other RF systems. Devices such as RF connectors, antennas, attenuators, resistors, and dissimilar metal junctions generate nonlinear distortion that degrades primary RF system performance. The communications industry is greatly affected by these unintended and unexpected nonlinear distortions. The high transmit power and tight channel spacing of the communication channel makes communications very susceptible to nonlinear distortion. To minimize nonlinear distortion in RF systems, specialized circuits are required to measure the low level nonlinear distortions created from traditionally linear devices, i.e., connectors, cables, antennas, etc. Measuring the low-level nonlinear distortion is a difficult problem. The measurement system requires the use of high power probe signals and the capability to measure very weak nonlinear distortions. Measuring the weak nonlinear distortion becomes increasingly difficult in the presence of higher power probe signals, as the high power probe signal generates distortion products in the measurement system. This paper describes a circuit design architecture that achieves 175 dB of dynamic range which can be used to measure low level harmonic distortion from various passive RF circuit elements.

Ultra-Wideband Chaos Life-Detection Radar with Sinusoidal Wave Modulation

2017 ◽  
Vol 27 (13) ◽  
pp. 1730046 ◽  
Author(s):  
Hang Xu ◽  
Ying Li ◽  
Jianguo Zhang ◽  
Hong Han ◽  
Bing Zhang ◽  
...  
Keyword(s):  
Dynamic Range ◽  
Vital Signs ◽  
Radar System ◽  
Ultra Wideband ◽  
Thick Wall ◽  
Sinusoidal Wave ◽  
Echo Signal ◽  
Range Resolution ◽  
Life Detection ◽  
Lock In

We propose and experimentally demonstrate an ultra-wideband (UWB) chaos life-detection radar. The proposed radar transmits a wideband chaotic-pulse-position modulation (CPPM) signal modulated by a single-tone sinusoidal wave. A narrow-band split ring sensor is used to collect the reflected sinusoidal wave, and a lock-in amplifier is utilized to identify frequencies of respiration and heartbeat by detecting the phase change of the sinusoidal echo signal. Meanwhile, human location is realized by correlating the CPPM echo signal with its delayed duplicate and combining the synthetic aperture technology. Experimental results demonstrate that the human target can be located accurately and his vital signs can be detected in a large dynamic range through a 20-cm-thick wall using our radar system. The down-range resolution is 15[Formula: see text]cm, benefiting from the 1-GHz bandwidth of the CPPM signal. The dynamic range for human location is 50[Formula: see text]dB, and the dynamic ranges for heartbeat and respiration detection respectively are 20[Formula: see text]dB and 60[Formula: see text]dB in our radar system. In addition, the bandwidth of the CPPM signal can be adjusted from 620[Formula: see text]MHz to 1.56[Formula: see text]GHz to adapt to different requirements.

Simplified Calibration Method for Radiation Temperature Measurement System with Wide Dynamic Range

2019 ◽  
Vol 39 (6) ◽  
pp. 0612003
Author(s):  
马冬晓 Dongxiao Ma ◽  
汪家春 Jiachun Wang ◽  
陈宗胜 Zongsheng Chen ◽  
王冰 Bing Wang ◽  
刘洋 Yang Liu
Keyword(s):  
Temperature Measurement ◽  
Measurement System ◽  
Dynamic Range ◽  
Calibration Method ◽  
Radiation Temperature ◽  
Wide Dynamic Range ◽  
Temperature Measurement System

A Warpage Measurement System with Large Dynamic Range for Boards with Components

2000 ◽  
Author(s):  
Minfu Lu ◽  
Xiaoyan He ◽  
Sheng Liu ◽  
Ampere A. Tseng
Keyword(s):  
Measurement System ◽  
Dynamic Range ◽  
Large Dynamic Range

scholarly journals A CMOS Low Pass Filter for SoC Lock-in-Based Measurement Devices

Sensors ◽  
2019 ◽  
Vol 19 (23) ◽  
pp. 5173 ◽  
Author(s):  
Jorge Pérez-Bailón ◽  
Belén Calvo ◽  
Nicolás Medrano
Keyword(s):  
Dynamic Range ◽  
Current Trend ◽  
Cutoff Frequency ◽  
Oxide Semiconductor ◽  
Constant Current ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Compact Size ◽  
Low Pass ◽  
Lock In

This paper presents a fully integrated Gm–C low pass filter (LPF) based on a current steering Gm reduction-tuning technique, specifically designed to operate as the output stage of a SoC lock-in amplifier. To validate this proposal, a first-order and a second-order single-ended topology were integrated into a 1.8 V to 0.18 µm CMOS (Complementary Metal-Oxide-Semiconductor) process, showing experimentally a tuneable cutoff frequency that spanned five orders of magnitude, from tens of mHz to kHz, with a constant current consumption (below 3 µA/pole), compact size (<0.0140 mm2/pole), and a dynamic range better than 70 dB. Compared to state-of-the-art solutions, the proposed approach exhibited very competitive performances while simultaneously fully satisfying the demanding requirements of on-chip portable measurement systems in terms of highly efficient area and power. This is of special relevance, taking into account the current trend towards multichannel instruments to process sensor arrays, as the total area and power consumption will be proportional to the number of channels.

scholarly journals Implementation of a Cross-Spectrum FFT Analyzer for a Phase-Noise Test System in a Low-Cost FPGA

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Patrick Fleischmann ◽  
Heinz Mathis ◽  
Jakub Kucera ◽  
Stefan Dahinden
Keyword(s):  
Phase Noise ◽  
Cross Correlation ◽  
Dynamic Range ◽  
Low Cost ◽  
Test System ◽  
Low Noise ◽  
Noise Levels ◽  
High Quality ◽  
Cross Spectrum ◽  
The Cross

The cross-correlation method allows phase-noise measurements of high-quality devices with very low noise levels, using reference sources with higher noise levels than the device under test. To implement this method, a phase-noise analyzer needs to compute the cross-spectral density, that is, the Fourier transform of the cross-correlation, of two time series over a wide frequency range, from fractions of Hz to tens of MHz. Furthermore, the analyzer requires a high dynamic range to accommodate the phase noise of high-quality oscillators that may fall off by more than 100 dB from close-in noise to the noise floor at large frequency offsets. This paper describes the efficient implementation of a cross-spectrum analyzer in a low-cost FPGA, as part of a modern phase-noise analyzer with very fast measurement time.

A new highly sensitive broadband ferromagnetic resonance measurement system with lock-in detection

2012 ◽  
Vol 111 (7) ◽  
pp. 07A503 ◽  
Author(s):  
S. Beguhn ◽  
Ziyao Zhou ◽  
S. Rand ◽  
X. Yang ◽  
J. Lou ◽  
...  
Keyword(s):  
Ferromagnetic Resonance ◽  
Measurement System ◽  
Resonance Measurement ◽  
Highly Sensitive ◽  
Lock In

Automated High-Dynamic-Range Three-Dimensional Optical Metrology Technique

2014 ◽  
Author(s):  
Laura Ekstrand ◽  
Song Zhang
Keyword(s):  
Exposure Time ◽  
Measurement System ◽  
High Speed ◽  
Manufacturing Industry ◽  
Dynamic Range ◽  
Three Dimensional ◽  
Optical Metrology ◽  
High Contrast ◽  
Accuracy Measurement ◽  
3D Surfaces

Measuring three-dimensional (3D) surfaces with extremely high contrast (e.g., partially shiny surfaces) is extremely difficult with optical metrology methods. Conventional techniques, which involve measurement from multiple angles or camera aperture adjustments, pose issues for high accuracy measurement in the manufacturing industry because they are difficult to automate and often induce undesirable vibrations in the calibrated measurement system. This paper presents a framework for optically capturing high-contrast 3D surfaces via flexible exposure time variation. This technique leverages the binary defocusing technique that was recently developed at Iowa State University to allow digital fringe projection with a camera exposure time far shorter than the projector’s projection period. Since the camera exposure time can be rapidly adjusted in software, the proposed technique could be automated without mechanical adjustments to the measurement system. Moreover, the exposure times are sufficiently short as to be efficiently packed into a projection period, giving this technique the potential for high speed applications. Experimental results will be presented to demonstrate the success of the proposed method.

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