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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
  • Coherence multiplexing of fiber-optic pressure and temperature sensors based on highly birefringent fibers

    Publication Year: 2000 , Page(s): 392 - 397
    Cited by:  Papers (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (172 KB)  

    In this paper, we present several coherence-based configurations of sensor systems that have been designed and studied specifically for multiplexing of white-light interferometric pressure and temperature transducers based on highly birefringent optical fibers. The first discussed is a serial system that may be composed of up to four pressure (range 0-20 MPa) and temperature (range -50°C-+50°C) sensors powered by a single broadband laser source. An electronically scanned interferometer based on a Wollaston prism with a step-delay line and a CCD array was used as a decoding unit. To increase the number of multiplexed sensors we also proposed a mixed serial-parallel configuration in which two serially connected sensors for measuring pressure and temperature are further arranged in parallel branches powered by several independent sources. The absolute system accuracy is about 0.5% of full scale. In addition to the full characterization of all multiplexed pressure sensors against a primary pressure standard, system response to fast temperature changes, to connecting additional cables, to input-output replacing, and to exchanging sources is also presented View full abstract»

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

    Publication Year: 2000 , Page(s): 256 - 259
    Cited by:  Papers (5)
    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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  • A synchronized two-phase sinewave generator for AC metrology system compensations

    Publication Year: 2000 , Page(s): 320 - 324
    Cited by:  Papers (7)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (120 KB)  

    A slave audio two-phase sinewave generator, which can be directly synchronized to a master generator, is described here. It can be used in ac metrology setups to provide additional “compensation” signals, traditionally derived with expensive multidecade inductive voltage divider networks. The generator is based on two direct digital synthesis (DDS) chips, programmed via the parallel printer PC interface; their clock is provided by a phase-locked loop circuit, which ensures frequency and phase synchronization of the DDS outputs with the master generator. The synchronization reference signal can be provided via an optical link reference channel, which avoids interference and ground loops. In its present implementation, the output voltage is Vpeak =10 V, frequency range 500 Hz-4 kHz. Total harmonic distortion is contained to -65 dB, and amplitude stability is better than 500 μV/V over 24 h View full abstract»

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

    Publication Year: 2000 , Page(s): 260 - 264
    Cited by:  Papers (5)
    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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  • Speech/voice-band data classification for data traffic measurements in telephone-type systems

    Publication Year: 2000 , Page(s): 413 - 417
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (124 KB)  

    A noise-insensitive technique for the discrimination between speech and voice-band data transmissions over a telephone-type system is presented. The proposed procedure combines together the evaluation of some meaningful parameters extracted from the observed speech or data communication signal, with an analysis of the statistical moments associated with these parameters. In this way, the discrimination capability associated with the extracted parameters is enforced by the moment analysis that better exploits the time-varying properties of speech signals. Experimental results, that show the good behavior of the classifier in terms of probability of error with respect to signal-to-noise ratio, are reported and discussed View full abstract»

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  • Calculable coaxial resistors for precision measurements

    Publication Year: 2000 , Page(s): 210 - 215
    Cited by:  Papers (5)
    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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  • Testing microwave devices under different source impedance values-a novel technique for on-line measurement of source and device reflection coefficients

    Publication Year: 2000 , Page(s): 285 - 289
    Cited by:  Papers (4)  |  Patents (1)
    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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  • Real-time 3-D spatial-temporal dual-polarized measurement of wideband radio channel at mobile station

    Publication Year: 2000 , Page(s): 439 - 448
    Cited by:  Papers (56)
    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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  • Frequency-weighting filter selection for H2 control of microgravity isolation systems: A consideration of the “implicit frequency weighting” problem

    Publication Year: 2000 , Page(s): 265 - 269
    Cited by:  Papers (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (116 KB)  

    Many space-science experiments need an active isolation system to provide them with the requisite microgravity environment. The isolation systems planned for use with the International Space Station (ISS) have been appropriately modeled using relative position, relative velocity, and acceleration states. In theory, frequency-weighting design filters can be applied to these state-space models, in order to develop optimal H2 or mixed-norm controllers with desired stability and performance characteristics. In practice, however, since there is a kinematic relationship among the various states, any frequency weighting applied to one state will implicitly weight other states. These implicit frequency-weighting effects must be considered, for intelligent frequency-weighting filter assignment. This paper suggests a rational approach to the assignment of frequency-weighting design filters, in the presence of the kinematic coupling among states that exists in the microgravity vibration isolation problem View full abstract»

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

    Publication Year: 2000 , Page(s): 418 - 423
    Cited by:  Papers (9)
    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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  • Calibration of a spectrometer using a genetic algorithm

    Publication Year: 2000 , Page(s): 449 - 454
    Cited by:  Papers (7)  |  Patents (2)
    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 high-temperature electronic system for pressure-transducers

    Publication Year: 2000 , Page(s): 365 - 370
    Cited by:  Papers (6)  |  Patents (1)
    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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  • A measurement system based on magnetic sensors for nondestructive testing

    Publication Year: 2000 , Page(s): 455 - 459
    Cited by:  Papers (16)
    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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  • Electromagnetic transducers close to high-temperature plasma in the thermonuclear fusion experiment RFX

    Publication Year: 2000 , 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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  • On the selection of the “best” test waveform for calibrating electrical instruments under nonsinusoidal conditions

    Publication Year: 2000 , Page(s): 382 - 387
    Cited by:  Papers (11)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (116 KB)  

    The paper deals with a test method, based on the generation of signals with known and pre-assigned harmonic content, for calibrating measurement devices to be used under nonsinusoidal conditions. The attention is concentrated on selecting the most suitable waveforms for the characterization of measurement instruments, by considering both the amplitude and the relative phase of the different harmonics. The aim is to identify the situations that cause, more than others do, uncertainty problems while measuring different quantities. This investigation is theoretically performed by means of a number of numerical simulations, in which pre-defined values for each uncertainty source have been added to the voltage and current acquisition channels View full abstract»

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  • A virtual instrumentation system for integrated bearing condition monitoring

    Publication Year: 2000 , Page(s): 325 - 332
    Cited by:  Papers (21)
    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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  • Optimization of sensor locations for measurement of flue gas flow in industrial ducts and stacks using neural networks

    Publication Year: 2000 , 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 new small nano-Kelvin resolution thermometer for low-temperature experiments

    Publication Year: 2000 , Page(s): 253 - 255
    Cited by:  Papers (8)
    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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  • Fuzzy self-organizing hybrid neural network for gas analysis system

    Publication Year: 2000 , Page(s): 424 - 428
    Cited by:  Papers (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (92 KB)  

    The paper presents the gas analysis system applying the self-organizing fuzzy hybrid neural network. The network is composed of the self-organizing competitive fuzzy layer and the supervised multilayer perceptron (MLP) subnetwork, connected in cascade. The characteristic features of this network structure for gas analysis systems are discussed and the results of experiments compared to standard neural solutions based on MLP or classical hybrid network employing the Kohonen layer View full abstract»

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  • Identification of time-variant directional mobile radio channels

    Publication Year: 2000 , Page(s): 357 - 364
    Cited by:  Papers (89)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (556 KB)  

    For the identification of the time-variant, directional structure of the mobile radio channel impulse response (CIR), a broadband vector channel sounder is described. The measurement procedure relies on periodic multifrequency excitation signals, correlation processing, and joint delay-azimuth super-resolution based on the two-dimensional (2-D) unitary ESPRIT algorithm. Problems of imperfect receiver and antenna performance as well as antenna array calibration methods are discussed. Correlation analysis of the directional impulse response records is performed in the time-frequency-spatial domain and the corresponding Doppler-delay-angular domain. Results from measurements in the 5.2 GHz frequency range in an industrial environment are presented View full abstract»

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

    Publication Year: 2000 , Page(s): 371 - 375
    Cited by:  Papers (14)
    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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  • Broadband versus stepped sine FRF measurements

    Publication Year: 2000 , Page(s): 275 - 278
    Cited by:  Papers (19)
    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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  • Measurement of harmonic losses in transformers supplying nonsinusoidal load currents

    Publication Year: 2000 , Page(s): 315 - 319
    Cited by:  Papers (8)
    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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  • Measurement of IC package shielding effectiveness using an integrated antenna

    Publication Year: 2000 , Page(s): 409 - 412
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (80 KB)  

    A novel technique for measuring integrated circuit (IC) package shielding effectiveness is presented. The technique is based on radiated field measurements performed with an integrated circuit antenna in a Gigahertz transverse electromagnetic (GTEM) cell. A thorough test procedure which takes into account all possible field contributions is proposed. The technique is simple to implement, cost effective, and suitable for characterizing IC package shielding effectiveness up to 10 GHz View full abstract»

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  • Quality management for electricity as a processed material

    Publication Year: 2000 , Page(s): 460 - 467
    Cited by:  Papers (8)
    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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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