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Instrumentation and Measurement, IEEE Transactions on

Issue 2 • Date Apr 2000

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Displaying Results 1 - 25 of 46
  • The sensitivity of a method to predict a capacitor's frequency characteristic

    Page(s): 398 - 404
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (184 KB)  

    A joint effort between the US Naval Academy and the NIST resulted in the development of a method to characterize the capacitance and dissipation factor of a set of commercial standard four terminal-pair (4TP) capacitors. The method depends on network analyzer impedance measurements at high frequencies (40-200 MHz) and a regression of these measurements down to the frequency range of 10 MHz-1 kHz. This paper provides an analysis of the sensitivity of the regression parameters and the high-frequency impedance measurements View full abstract»

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  • Optimization of sensor locations for measurement of flue gas flow in industrial ducts and stacks using neural networks

    Page(s): 228 - 233
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (464 KB)  

    This paper presents a novel application of neural network modeling in the optimization of sensor locations for the measurement of flue gas flow in industrial ducts and stacks. The proposed neural network model has been validated with an experiment based upon a case-study power plant. The results have shown that the optimized sensor location can be easily determined with this model. The industry can directly benefit from the improvement of measurement accuracy of the flue gas flow in the optimized sensor location and the reduction of manual measurement operation with Pitot tube View full abstract»

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  • A finite element-based technique for microwave imaging of two-dimensional objects

    Page(s): 234 - 239
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (596 KB)  

    In this paper, a microwave imaging technique for estimating the spatial distributions of the permittivity and the conductivity of a scatterer, by post-processing electromagnetic scattered field data, is presented. For the description of the direct scattering problem, the differential formulation is applied. This allows the use of the finite element method. During the inversion, the computation of the derivative of the finite element solution with respect to the parameters, which describe the scatterer, is required. This task is performed by a finite element-based sensitivity analysis scheme, which is enhanced by applying the adjoint state vector methodology. The merits of the proposed technique are examined by applying it to both transverse magnetic and transverse electric polarization cases. Finally, the technique is adopted by a frequency-hopping approach to cope with multifrequency inverse scattering problems View full abstract»

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  • New design of optical electric-current sensor for sensitivity improvement

    Page(s): 418 - 423
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (164 KB)  

    A new design of optical electric-current sensor based on the Faraday effect is proposed and demonstrated experimentally. The sensor probe is a precisely cut glass prism with a high reflection coating on the base surface at the far end. Inside the prism, the light beam is allowed to bounce up and down at the critical angle and retrace its path back by the reflection coating. The sensor demonstrated offers a sensitivity of six times higher as compared with conventional designs and suffers from fewer optical losses. The design can also reduce the package size of the sensor probe View full abstract»

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  • A measurement system based on magnetic sensors for nondestructive testing

    Page(s): 455 - 459
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (160 KB)  

    The paper deals with a measurement system based on a low-cost eddy current probe for nondestructive testing (NDT) on conducting materials aimed at reconstructing the shape and position of thin cracks. The magnetic probe is characterized, highlighting good repeatability, linearity, and overall accuracy. A number of different measurement approaches are investigated, in order to choose the most appropriate for NDT applications. A numerical method is then illustrated; it proves to be able to reconstruct cracks starting from noisy measurement data View full abstract»

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  • The influence of electric-field bending on the nonlinearity of capacitive sensors

    Page(s): 256 - 259
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (112 KB)  

    Three-layered electrode structures are often employed in multiple-electrode capacitive position sensors. Even when advanced algorithms and well-designed guarding electrodes are used, the electric-field-bending effect is still one of the major contributors to the nonlinearity of capacitive position sensors. In this paper, the effects of electric-field bending on linearities of five capacitive linear-position sensors have been studied based on a physical model of the capacitive sensor. It is shown that the effect of electric-field bending on linearities strongly depends on the sensor structures, and that it is significantly reduced when advanced sensor structures and algorithms are used. The results are very useful for optimizing the sensor structure according to its application View full abstract»

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  • Broadband versus stepped sine FRF measurements

    Page(s): 275 - 278
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (112 KB)  

    In this paper, the required measurement time to measure a transfer function with a specified accuracy is analyzed. The waiting time that is needed to balance the transient induced errors against the noise errors is calculated. This allows one to decide under what conditions broad-band measurements are faster than stepped sine measurements View full abstract»

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  • Real-time 3-D spatial-temporal dual-polarized measurement of wideband radio channel at mobile station

    Page(s): 439 - 448
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1240 KB)  

    This paper describes a measurement system enabling the complete real-time characterization of the wideband radio channel. The system is based on a wideband radio channel sounder and a spherical antenna array, and it aims to describe the three-dimensional (3-D) spatial radio channel seen by the mobile terminal, including polarization. This information is highly valuable in designing antennas for mobile terminals. The spatial properties of the measurement system are analyzed through test measurements in an anechoic chamber. The system has a 40° spatial resolution and a 17 dB cross polarization discrimination. The values are well above those of a small mobile terminal antenna. The dynamic range in the spatial domain is 12 dB. The measurement is very fast, which makes real-time channel acquisition practical at normal mobile speeds View full abstract»

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  • On the issues of oscillation test methodology

    Page(s): 240 - 245
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (244 KB)  

    In recent years, advances in integration fabrication technologies prompted IC designers to move more analog circuitry onto what had been entirely digital chips, making the verification problem for the entire chip more difficult. This paper presents a detailed case study of using the oscillation test methodology to test an active low pass filter. We highlight some of the difficulties and shortcomings of this testing approach View full abstract»

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  • Average power estimation under nonsinusoidal conditions

    Page(s): 333 - 336
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (152 KB)  

    In this paper, the authors address the problem of estimating the average power of electrical systems under nonsinusoidal conditions. At first, a time-domain-based algorithm is proposed, which smoothes sampled data using suitable coefficients, prior to their numerical integration. Then, the algorithm accuracy is quantified with respect to wide-band noise. Last, simulation and experimental results are presented showing its effectiveness in estimating average power when starting from multifrequency voltage and current samples View full abstract»

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  • A high-temperature electronic system for pressure-transducers

    Page(s): 365 - 370
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (268 KB)  

    This paper describes a high-temperature pressure-transducer interface for resistive Wheatstone bridges. The long-term drift of the smart sensor, i.e., the (pressure) sensor plus its interface electronics, will be determined by the drift of the sensor element only. A three-signal auto-calibration sequence of the interface electronics keeps the transducer interface virtually free of long-term drift. A novel low-drift preamplifier forms an essential element in this system. The high-temperature operation of the transducer interface has been investigated from both an electronic and a packaging point of view. The system has been realized by combining CMOS ASICs with a thick-film packaging technology. The pressure-transducer interface works up to 250-275°C with 15-16 bits accuracy View full abstract»

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  • Quality management for electricity as a processed material

    Page(s): 460 - 467
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (140 KB)  

    The offer provided by an electric utility combines many characteristics of a service together with the continuous delivery of electricity as a product. The quality of electricity as a processed material, resulting from a continuous process and having immediate delivery in continuous flow can he adversely affected by the end-use processes of other customers, as well as by the continuous-process reliability. Hence, the guidelines endorsed by ISO Standard 9004-3 for the quality management of processed materials must be suitably tailored in the case of electricity. Problems that must be dealt with to control the characteristics critical to quality of electricity are discussed. In this connection, measurement activities oriented to quality management are considered, mainly to outline unsolved problems View full abstract»

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  • Interstitial instrumentation for therapeutic ultrasonic heating: modeling the discrete blood vessels

    Page(s): 260 - 264
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (292 KB)  

    Instrumentation for interstitial ultrasound (US) heating is an important emerging technology in thermotherapy of deep seated tumors or those hard to reach by external devices. The instrumentation has special significance in case of radio-and/or chemotherapy resistant lesions. Its efficacy strongly depends on local tissue properties, especially local blood vessels. We evaluate effects of the vessels on temperature distribution elevated from basal by deposition of ultrasound energy. In the proposed model, we take into account several micron diameter vessels in proximity to the US four-applicator array. At large distances from the array, the volume is assigned a modified effective thermal conductivity. Our Finite Element Analysis of the so-defined problem shows that modelling under the assumption of constant, basal temperature across the vessels' lumen leads to erroneous results. The simulations agree best with experiments if fixed nodal temperature is applied at 60% of the lumen. We specify requirements on the array to avoid local underheating that could lead to performance failure of the instrumentation View full abstract»

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  • A new small nano-Kelvin resolution thermometer for low-temperature experiments

    Page(s): 253 - 255
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (100 KB)  

    A small, high-resolution paramagnetic susceptibility thermometer was developed using a GdCl3 paramagnetic salt. The device uses a superconducting quantum interference device (SQUID) magnetometer to determine the temperature dependent magnetization of the salt in a magnetic field. The magnetic field is provided by a pair of small samarium cobalt permanent magnet disks situated inside the thermometer housing. This eliminates the need for a heavy, charging solenoid used in a conventional SQUID-based magnetic thermometer system. This thermometer can resolve approximately 10-9 K near the liquid-gas critical point of 3He (~3.31 K). The drift rate of the thermometer was measured to be <2×10-13 K/s. This light weight thermometer (~7 g) is a candidate for use in future low-temperature Space Shuttle and International Space Station experiments View full abstract»

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  • Two methods for the comparison of hand movement signal quality

    Page(s): 388 - 391
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (112 KB)  

    This paper proposes and compares two methods for the automatic detection of force adaptation disturbances from recorded kinematic and kinetic signals of periodic hand movements. Line-oriented spectrum and cross-correlation analysis are examined as methods for the evaluation of periodic acceleration and grip force hand movement signals, thereby opening novel ways for the automatic assessment of force adaptation quality. The results obtained for three representative probands with the two methods are presented in some detail, and an overview of the results obtained with 24 probands is given View full abstract»

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  • Electromagnetic transducers close to high-temperature plasma in the thermonuclear fusion experiment RFX

    Page(s): 290 - 293
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (280 KB)  

    RFX is a magnetically confined fusion experiment in operation since 1992 in Padova, Italy. Analysis of the magnetic field is essential for the safe operation of the machine and the understanding of high-temperature plasma dynamics. Both of these issues require an accurate electromagnetic diagnostic system. In this paper, after a discussion of the problems related to magnetic measurements in fusion experiments, with particular reference to the RFX environment, the probes installed inside the vacuum vessel are described View full abstract»

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  • Measurement of harmonic losses in transformers supplying nonsinusoidal load currents

    Page(s): 315 - 319
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (244 KB)  

    The spread of the load control techniques based on power electronics is causing the increase of harmonic losses in power distribution systems. A digital method for the evaluation of these losses in power transformers, which only requires measurements taken at the transformer output terminals, is discussed. The accuracy of the method, along with the performance of a virtual-instrumentation-based instrument implementing it, is also discussed. The results of some experimental work are reported View full abstract»

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  • Testing microwave devices under different source impedance values-a novel technique for on-line measurement of source and device reflection coefficients

    Page(s): 285 - 289
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (196 KB)  

    This paper describes a new approach for fast and accurate determination of the source reflection coefficient in microwave source-pull measurements. To the authors' knowledge, this is the only technique that allows the simultaneous measurement of the source and the device-under-test input reflection coefficients. A traditional vector network analyzer is used as a four-channel receiver. The calibration procedure is based on a new reflectometer model that extends the traditional error box concept. Experimental results are presented and compared to data obtained with traditional techniques View full abstract»

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  • Comparison of three accurate methods to measure AC voltage at low frequencies

    Page(s): 429 - 433
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (188 KB)  

    Three methods for the determination of the RMS value of AC voltage at low frequencies are compared: the step calibration of a digitally synthesized source, the optimized sampling method, and the AC-DC voltage transfer with a multijunction thermal converter. The three methods agree within 1×10-6 with an uncertainty of 2.5×10-8 in the frequency range from 10 to 100 Hz View full abstract»

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  • Reactive power measurement using the wavelet transform

    Page(s): 246 - 252
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (264 KB)  

    This paper provides the theoretical basis for the measurement of reactive and distortion powers from the wavelet transforms. The measurement of reactive power relies on the use of broad-band phase-shift networks to create concurrent in-phase currents and quadrature voltages. The wavelet real power computation resulting from these 90° phase-shift networks yields the reactive power associated with each wavelet frequency level or subband. The distortion power at each wavelet subband is then derived from the real, reactive and apparent powers of the subband, where the apparent power is the product of the v, i element pair's subband rms voltage and current. The advantage of viewing the real and reactive powers. In the wavelet domain is that the domain preserves both the frequency and time relationship of these powers. In addition, the reactive power associated with each wavelet subband is a signed quantity and thus has a direction associated with it. This permits tracking the reactive power flow in each subband through the power system View full abstract»

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  • Low-cost electrochemical impedance spectroscopy system for corrosion monitoring of metallic antiquities and works of art

    Page(s): 371 - 375
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (252 KB)  

    Electrochemical impedance spectroscopy (EIS) is recognized to be a powerful and noninvasive technique to test the integrity of protective coatings on memorials, but commercial EIS systems are rather costly though versatile devices. This paper describes a low cost and portable EIS system that is based on a compact digital signal processor (DSP) board and embeds the potentiostatic function so that it can be used without requiring an external potentiostat. The software that runs on the DSP is designed to analyze the electrochemical impedance only in a reduced frequency range in order to produce a simple corrosion alert result. The device is equipped with a digital interface and can be connected to a personal computer to carry out a complete frequency analysis and perform a more complex data processing View full abstract»

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  • Robust broadband periodic excitation design

    Page(s): 270 - 274
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (164 KB)  

    This paper considers a rather practical problem arising when inexperienced users misuse the (otherwise well-designed) periodic broadband excitation signals during the measurement or signal processing phase of an identification process. Using a fractional period of the excitation signal instead of full periods may affect not only the precision because of the well-known leakage effect, but may cause a serious loss of information on the measured system as well. The power of the excitation signal in certain frequency bands may be much lower (30-40 db) than it would be expected, and thus the measurement in a noisy environment may give poor result. A solution is presented here to make periodic broadband (multisine) excitation signals more robust against such misuse. The suggested solution is analyzed, and the theoretical results are verified by practical examples View full abstract»

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  • Calibration of a spectrometer using a genetic algorithm

    Page(s): 449 - 454
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (168 KB)  

    This paper is on digital processing of data acquired by means of low-resolution spectrometers. A procedure for calibration of such spectrometers is proposed which provides parameters of operators for correcting effects of imperfect spectrometric hardware. The procedure, based on the use of a genetic algorithm of global optimization, is studied using both synthetic and real-world data, viz, it is used for estimating parameters of three nonlinear operators of data correction: a rational filter (published in a previous paper), a Cauchy filter (CF) (proposed in this paper), and a superposition of two Cauchy filters. The results of study are presented that confirm the practical usefulness of the proposed procedure for calibration of spectrometers and of the proposed Cauchy filter View full abstract»

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  • A virtual instrumentation system for integrated bearing condition monitoring

    Page(s): 325 - 332
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (708 KB)  

    This paper presents the design, optimization, and implementation of a virtual instrument (VI), which is an essential part of an integrated bearing condition monitoring system. The VI is designed using the graphical programming language LabVIEW and is capable of performing on-line measurement functions, including data acquisition, display, and analyses in the time and frequency domains, as well as data archiving. The issues of data length selection and VI real-time capability have been investigated to optimize the VI operation and improve data-processing efficiency. The VI system presents an effective and user-friendly human-machine interface for on-line bearing condition monitoring, which is of critical importance to real-time fault diagnosis and intelligent manufacturing View full abstract»

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  • Calculable coaxial resistors for precision measurements

    Page(s): 210 - 215
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (100 KB)  

    Coaxial straight-wire resistors have been constructed with the purpose of improving comparisons between resistors, capacitors, and inductors in the audio-frequency range. The design is based on the principle that a coaxial line with a cylindrical shield can be described by relatively simple equations for the real and imaginary parts of the impedance. The resistors, with values at and above 100 Ω will be used as transfer standards for characterization of the frequency dependence of standard resistors and of the quantum Hall resistance in the audio frequency range View full abstract»

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Aims & Scope

Papers are sought that address innovative solutions to the development and use of electrical and electronic instruments and equipment to measure, monitor and/or record physical phenomena for the purpose of advancing measurement science, methods, functionality and applications.

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Meet Our Editors

Editor-in-Chief
Prof. Alessandro Ferrero
Dipartimento di Elettrotecnica
Piazza Leonardo da Vinci 32
Politecnico di Milano
Milano 20133 Italy
alessandro.ferrero@polimi.it
Phone: 39-02-2399-3751
Fax: 39-02-2399-3703