By Topic

Instrumentation and Measurement, IEEE Transactions on

Issue 1 • Date Feb 2000

Filter Results

Displaying Results 1 - 25 of 36
  • Instrument fault detection and isolation: state of the art and new research trends

    Page(s): 100 - 107
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (120 KB)  

    This paper presents the current state-of-the-art of residual generation techniques adopted in instrument fault detection and isolation. Both traditional and innovative methods are described with their advantages and their limits. The improvement of analytical redundancy technique performances for better dealing with high-dynamics systems and/or with online applications is pointed out as the most interesting need to focus the research efforts View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Automatic and accurate evaluation of the parameters of a magnetic hysteresis model

    Page(s): 154 - 160
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (184 KB)  

    This paper presents a method based on both artificial neural networks (ANNs) and on a multidimensional optimization procedure in order to significantly reduce the time taken and to improve the accuracy in evaluating parameters of the Jiles-Atherton model of magnetic hysteresis. The main steps of the method are (1) data acquisition of the experimental hysteresis loop of the magnetic material under test, (2) evaluation of the model's parameters by means of ANN, and (3) parameter accuracy improvement by means of a multidimensional optimization procedure. In order to highlight the method's effectiveness, the results of numerical and experimental tests are also given View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Microwave near-field reflection property analysis of concrete for material content determination

    Page(s): 49 - 55
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (172 KB)  

    One of the most important parameters associated with concrete is its compressive strength. Currently, there is no reliable nondestructive testing technique that is capable of robust determination of this parameter. Concrete is a heterogeneous mixture composed of water, cement powder, sand (fine aggregate), rocks of various size or grade (coarse aggregate), and air (porosity). Water and cement powder chemically combine into a cement paste binder which, in due curing time, produces concrete with its specified compressive strength. Compressive strength of concrete is strongly influenced by its water-to-cement (w/c) ratio as well as its coarse aggregate-to-cement (ca/c) ratio. Therefore, if these two parameters are determined using a nondestructive testing technique, then they may be correlated to the compressive strength. Near-field microwave nondestructive testing techniques, employing open-ended rectangular waveguide probes, have shown tremendous potential for evaluating concrete constituent make-up. In this paper, the results of an extensive set of measurements, using these probes, are presented. The results demonstrate that the statistical distribution of the multiple measurements of the magnitude of reflection coefficient of concrete specimens with various constituent make-ups follows two well-known distributions as a function of frequency. It is shown that for the specimens investigated this distribution is Gaussian at 10 GHz and uniform at 3 GHz. Furthermore, the standard deviation of the measured magnitude of reflection coefficient at 10 GHz is shown to correlate well with ca/c ratio, whereas, the mean of this parameter at 3 GHz is correlated well with w/c ratio. Subsequently, these parameters may be used in conjunction with well established formulae or a look-up table to determine the compressive strength of a given concrete specimen View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • A simple method for measuring the dielectric constant of solids

    Page(s): 66 - 70
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (136 KB)  

    This paper presents a simple method for determining the dielectric constant of a solid material. The method consists of measuring the return loss due to a slab of such material inserted into a rectangular waveguide. The dielectric slab presents a discontinuity inside the waveguide, and the electric field at each interface of the slab is described as a summation of weighted sinusoidal basis functions. The scattered magnetic field on either side of the slab is determined using the modal expansion approach. These weights are solved by using the method of moments on the boundary conditions of continuity of the tangential magnetic field at the interfaces. The component of the electric field (scattered) for the dominant TE10 mode can then be determined in terms of these weights, and from this result the reflection coefficient can be theoretically evaluated. A comparison between the experimentally obtained reflection/transmission coefficient and the theoretical values provide a figure for the dielectric constant of the material View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Automated measurement of optical coherence lengths and optical delays for applications in coherence-modulated optical transmissions

    Page(s): 32 - 36
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (144 KB)  

    The implementation of an automated system for analysis of coherence length of light and for the measurement of optical delays is reported. This type of measurement is very important for designing coherence-modulated optical transmission systems. Such systems have been studied for the last few years as new potential high-speed optical links useful for point-to-point, local area networks, and bidirectional transmissions, at optical wavelengths around 1300 nm. The main characteristics of coherence-modulated transmissions include the need of using low-coherence optical sources and integrated optics lithium niobate (LiNbO3) electro-optic retarders. This paper describes the implementation of an automated system allowing the measurement of coherence lengths of semiconductor optical sources and also optical delays as essential data for designing coherence-modulated optical links. The reported results include characterization of commercial low-coherence semiconductor optical sources and integrated optics coherence modulators View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • A high performance frequency insensitive quadrature phase shifter and its application in reactive power measurements

    Page(s): 161 - 165
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (88 KB)  

    This paper describes a high precision circuit for quadrature phase shifting in which frequency controlled signal amplification is introduced so that the amplitude of the phase shifted signal is not dependent on the frequency of the input signal. The proposed quadrature phase shifting method is aimed at high accuracy reactive power measurements in ac power systems. The implementation of the new phase shifter at the voltage input of a watt/watt hour meter allows for high accuracy var/varh measurements. A prototype of the quadrature phase shifter has been built with magnitude and phase errors within ±15·10-6 and less than 40 μrad, respectively. Its performance was further confirmed when the QPS was used for reactive power measurements View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Far-field antenna pattern estimation from near-field data using a low-cost amplitude-only measurement setup

    Page(s): 71 - 76
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (152 KB)  

    In this paper we report some results on the estimation of the far-field of an antenna by using a low-cost amplitude-only near-field measurement setup. A simple experimental setup is used to measure the intensity of the near-field of the antenna under test on two planes. The measured intensity of the near field is then numerically processed to determine the far-field pattern. The results confirm the validity of the approach View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Laser diode driver with 5-decade range

    Page(s): 2 - 4
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (76 KB)  

    A circuit is described which is capable of controlling the optical output of a laser diode over a 5-decade range under light feedback control. The circuit incorporates a 5-decade exponentially-controlled current source which is temperature compensated over its entire range. The driver operates from a -6-V supply View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • New algorithm for measuring 50/60 Hz AC values based on the usage of slow A/D converters

    Page(s): 166 - 171
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (124 KB)  

    Today digital measuring of utilities AC values is based on application of very fast (flash) A/D converters, along with powerful processors required by such digital processing. This paper presents a new approach based on the use of very slow, high-precision, and inexpensive dual-slope A/D converters. Measurements of voltage and current are performed more than once in a period, so the measured value is reconstructed after n periods. The presented algorithm is of an adaptive type in accordance with the harmonic content of the input signal with modest hardware demands. The assumed stationarity of the electric utilities is validated with an experimental setup, consisting of a fast, high-precision sigma-delta ADC. The necessary synchronization is secured by software measurements of the frequency of the measured signal, Measurements performed in electric utilities in Yugoslavia indicate that the voltage waveform remains unchanged while the required accuracy is maintained View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Experimental and numerical results of optical preamplification in a laser Doppler anemometer receiving head

    Page(s): 10 - 13
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (92 KB)  

    The first application of a fiber amplifier in a laser Doppler anemometer (LDA) system is presented. Using an Nd-doped fiber amplifier as optical preamplifier in a conventional 1064-nm LDA, a small signal gain of 30 and 35 dB signal-to-noise (SNR) enhancement of the LDA radiation are achieved. The amplifier model, numerical, and experimental results are described View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Full-signature real-time corrosion detection of underground casing pipes

    Page(s): 120 - 128
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (236 KB)  

    Corrosion monitoring and early detection of pits and wall thinning for casing pipes are considerably important to gas and petroleum industries since the frequently occurring corrosion at the internal or external parts of those steel casing pipes used in underground gas storage or oil fields causes production and environmental protection problems. In this paper, a new version of the direct current (dc) electromagnetic induction system is introduced in which a sensor system, based on the dc electromagnetic induction instrument, is coupled with an updated data acquisition system. Unlike the conventional dc induction instrument, the new system can achieve a full-signature logging response by providing all the measured flux leakage (FL) signals and eddy current (EC) signals to the computer logging system (CLS) on the surface. To transmit the information represented by large amounts of data acquired by downhole instruments to the CLS on the surface, a wavelet data compression technique has been incorporated. A VLSI integrated circuit (IC) which realizes the wavelet transform has been designed so that the real-time mode can be achieved during the logging operation. The circuit has been designed using CMOS n-well 2-μm technology and has been fabricated by MOSIS View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Magneto-optical current sensor by domain wall motion in orthoferrites

    Page(s): 14 - 18
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (284 KB)  

    A brief review of the latest developments on optical current measurements based on the Faraday effect is presented. In all existing magneto-optical current transformers, the main measured parameter is the polarization state of the light transmitted by a sensor element. A new transformer is described by means of new results concerning the domain wall excitation. The measured parameter is the geometrical position of the boundary between domains with opposite magnetizations. In a wide frequency band, including DC currents, the measurement results are a linear function of the measured current. They are not affected by temperature changes and mechanical factors View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • A current-to-voltage converter for 5 A to 5 V and 30 Hz to 30 kHz

    Page(s): 144 - 150
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (164 KB)  

    A current-to-voltage converter (CVC) is presented, which has three input ranges for nominal input currents of 0.2, 1, and 5 A with frequencies from 30 Hz to 30 kHz. The converter uses an amplifier-aided two-stage current transformer which operates with a very small number of ampere-turns and the primary (measurement) current path of which may be potentially elevated without its error characteristics being affected. The secondary current of 5 mA of the transformer is converted into voltage using an inverting amplifier with a feedback resistor of 1 kΩ. By fine adjustment of its frequency-dependent feedback, small errors and a small error variation are achieved over the whole frequency range. The variation of errors between 20 and 100% of nominal current in each current range is negligibly small. In the frequency range from 30 Hz to 1 kHz, relative errors of less than 10-4±2×10-5 are achieved. From 1 to 30 kHz, the errors increase up to 2×10-4 with ±5×10-5 uncertainty for the in-phase and ±40×10-5 for the quadrature component. The current-to-voltage converter was calibrated by means of a high-quality current shunt, which was especially developed for this purpose View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Calibration of a time-domain network analyzer: a new approach

    Page(s): 178 - 187
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (224 KB)  

    This paper deals with the calibration of time-domain network analyzers operating in the bandwidth dc-20 GHz. After identification and experimental estimation of the error sources, an approach based on a standard TRL (thru-reflect-line) calibration procedure, adapted to bidirectional (two generators and two samplers) time-domain measurement systems for the correction of systematic errors, is developed. Optimal conditions for the minimization of random errors are also carried out. Next, the measurement system dynamic range and repeatability are accurately characterized. Finally, experimental results obtained on coaxial attenuators and a mismatched lossy microstrip line demonstrate the accuracy of the method View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • A noise model for digitized data

    Page(s): 83 - 86
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (72 KB)  

    The paper analyzes the overall conversion error of a noisy digitizer affected by Gaussian noise at its input or generated within the digitizer itself. It is shown that, under mild conditions concerning the ratio between the input noise standard deviation and the quantization step, the overall conversion error can be modeled by a Gaussian random variable uncorrelated with the input sequence. The power of the global conversion error is evaluated in closed formulae together with its degree of variability. Numerical simulations support the proposed analysis View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • A low-current logarithmic LED electrometer

    Page(s): 5 - 9
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (100 KB)  

    A new circuit for measuring low dc currents using an LED-based logarithmic electrometer is presented. The electrometer is designed to measure currents from 1 pA to 0.1 mA. Temperature compensation is achieved using the ratio technique in the temperature range -20°C-70°C. Variations in the scale factor as a function of the input current and the device constant n as a function of temperature are also discussed View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Comparison between thin film and bonded powder phosphors for thermographic sensing in gas turbine engines

    Page(s): 129 - 131
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (96 KB)  

    Measurements of YVO4:Eu in the form of a thin film and bonded powder, before and after testing in a Rolls-Royce gas turbine engine, indicate that the durability of the thin film was markedly better than that of the bonded powder; there was a 500% increase in loss for the bonded powder. Both thin films and bonded powders showed excellent reproducibility for photoluminescent (PL) decay-time temperature measurement. However, for the thin film, the useful temperature range (660-800 K) and sensitivity (18.4 mK-1) were much better than the bonded powder (700-800 K and 14.6 mK-1 ). Evidence here clearly implies that thin films have much better properties for long lifetime thermographic sensing at high temperatures View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Automatic calibration of analog and digital measuring instruments using computer vision

    Page(s): 94 - 99
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (384 KB)  

    This paper presents an automatic calibration system capable of calibrating measuring instruments that do not have a digital interface. Image analysis algorithms are used to automatically determine the instrument reading. It can be used with analog and with digital displays. The maximum uncertainty in the detection of the pointer's position in analog instruments is less than the human eye can discriminate View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Real-time chemical sensing of aqueous ethanol glucose mixtures

    Page(s): 114 - 119
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (180 KB)  

    A new high-frequency approach to monitoring component concentration in dielectric solutions is proposed. After appropriate calibration, the volume percentage of an n-component solution can be uniquely determined by measuring the real part of the solution permittivity at n-1 distinct frequencies. A flow-through microstrip bandpass filter sensor has been fabricated to demonstrate the accuracy of the technique when applied to a water-ethanol mixture. The sensor can discriminate 0.35% relative variations in ethanol volume concentration when solution temperature is independently monitored View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • A linear resistance-to-time converter with high resolution

    Page(s): 151 - 153
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (52 KB)  

    A resistance-to-time converter employing a bridge amplifier, an integrator and a comparator is described. While possessing a resolution and linearity of the same order as that of a recently reported resistance-to-frequency converter, the present circuit has the advantage of grounded detecting resistance. Further, no compensation arrangement need be incorporated for maintaining wide-range linearity View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Increasing the performance of arbitrary waveform generators using periodic sigma-delta modulated streams

    Page(s): 188 - 199
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (316 KB)  

    This paper describes a new method to increase the performance of existing arbitrary waveform generators (AWGs). By encoding the digital words using sigma-delta (ΣΔ) techniques, it is possible to decrease the noise floor in a narrow band while keeping the same memory requirements. Calibration techniques to deal with the nonidealities of the AWG are also presented and verified experimentally. Improvements in spurious free dynamic ranges (SFDRs) of over 40 dB will be demonstrated with commercial test equipment View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Design and calibration of a noise measurement system

    Page(s): 77 - 82
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (144 KB)  

    The setup principle and calibration method of a noise measurement system for frequencies from dc to 10 kHz are described. This system measures the current noise power spectral density of some device, and consists of a low-noise current preamplifier, a voltage preamplifier, and a dynamic signal analyzer which implements the fast Fourier transform (FFT). The noise aspects of the whole system can be modeled as a serial noise voltage generator and a parallel noise current generator at the input port, plus a system free of noise. The cross correlation of the two noise generators is an imaginary number because the system input stage is composed of some junction field effect transistors (JFET's). Via the thermal noise measurement of several resistors, we derive the magnitudes of the noise generators in addition to the input impedance and the total system gain. The imaginary cross correlation is obtained by the noise measurement of pure capacitance. With a well-calibrated procedure, we can measure the noise power down to 2×10-27 A2/Hz. Two systems with different input stages were calibrated with the same procedure and the noise measurement results of the various resistance values with the two systems all agree well with theoretical values. One of these with an input stage which has a much smaller noise current generator shows great improvement in the noise measurement of the high-impedance device View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Fuzzy handling of measurement errors in instrumentation

    Page(s): 89 - 93
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (152 KB)  

    This paper focuses on the use of possibility theory and of fuzzy subset theory to deal with the uncertainty of the measurements handled in instrumentation systems. Methods are described for building fuzzy subsets from numerical data coming from imprecise “physical” sensors on the one hand, and handling approximate estimations provided by “human” sensors on the other hand. The propagation of the fuzzy representation of acquired measures in further treatments, such as those involved in performance indicators aimed at controlling manufacturing production, is also considered View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Feasibility of picosecond electrical sampling using GaAs FET

    Page(s): 172 - 177
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (152 KB)  

    A fully MESFET hybrid sampling system has been built and tested. The circuit includes an FET sampling gate, an FET sampling pulse generator, and an FET test step generator. These functions have been studied separately using a large-signal model and picosecond instrumentation. The parameters of each of them are optimized to obtain the best performances. Measurements with the GaAs FET sampler are performed and a time-domain resolution better than 28 ps corresponding to a bandwidth of 12 GHz is obtained. In particular, the measurements performed on the MESFET sampling system are in good agreement with those obtained on the conventional S4 reference sampling head View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Improved design for multistate reflectometer (with two power detectors) for measuring reflection coefficients of microwave devices

    Page(s): 61 - 65
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (136 KB)  

    The optimum-performance criteria originally developed for use with six-port reflectometers may, under certain circumstances, be extended to the design of the multistate reflectometer (which utilizes two power detectors to measure the reflection coefficients of microwave components). Test results-from simulations as well as experiments-have confirmed that the novel WR90 multistate instrument proposed in the present paper is able to yield near-optimum performance over the entire waveguide bandwidth View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.

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.

Full Aims & Scope

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