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Instrumentation and Measurement, IEEE Transactions on

Issue 2 • Date April 1994

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Displaying Results 1 - 25 of 46
  • 10th Annual IEEE Instrumentation and Measurement Technology Conference - IMTC '93

    Publication Year: 1994
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    Freely Available from IEEE
  • The use of DFT windows in signal-to-noise ratio and harmonic distortion computations

    Publication Year: 1994 , Page(s): 194 - 199
    Cited by:  Papers (38)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (432 KB)  

    The discrete Fourier transform (DFT) can be used to compute the signal-to-noise ratio (SNR) and harmonic distortion of a waveform recorder. When the data record contains a non-integer number of cycles of the sine wave, energy leaks from the sine wave and its harmonics to adjacent frequencies. A.L. Benetazzo et al. (1992) describe a windowed DFT method for computing the RMS value of a sine wave from the magnitude of the main lobe of its DFT and recommend the use of minimum energy windows. We present criteria for choosing the DFT window. A constraint for the window coefficients is derived to insure that quantization error does not influence the estimate of the amplitude of a sine wave from the main lobe of its DFT View full abstract»

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  • Holographic pattern measuring system and its application to deformation analysis of printed circuit board due to heat of mounted parts

    Publication Year: 1994 , Page(s): 326 - 331
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (596 KB)  

    A new measuring system, holographic pattern measuring system (HPMS), was developed which is composed of both techniques of holographic interferometry and graphic image processing, and applied to deformation analysis of the printed circuit board (PCB) due to heat of mounted parts. The HPMS was applied to obtain the three-dimensional graphic image pattern of the deformation of-the PCB due to thermal stress with an error of 0.1 μm. In addition, the thermographic pattern was obtained by using a thermography system, and a comparison was made of the fringe pattern (holographic pattern) obtained by the HPMS and the thermographic pattern of the PCB surface due to thermal stress. We found that the holographic pattern was different from the thermographic pattern. The results showed that it was difficult to estimate the thermal deformation of the PCB from the thermographic pattern View full abstract»

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  • Simultaneous hydrostatic pressure and temperature measurement employing an LP01-LP11 fiber-optic polarization-sensitive intermodal interferometer

    Publication Year: 1994 , Page(s): 337 - 340
    Cited by:  Papers (4)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (336 KB)  

    A fiber-optic LP01-LP11 polarization-sensitive intermodal interferometer is proposed to simultaneously measure hydrostatic pressure and temperature using the same sensing element. In analogy to the case of strain sensing it was found that the experimental parameters TP and TT describing the 2π phase shifts in the interferogram are significantly different for the X- and Y-polarizations of two polarization modes. This represents a fundamental phenomenon which can be put to use for simultaneous two-parameter sensing. The results obtained are found to be in agreement with a recently developed Muller-Stokes formalism describing polarization effects in the case of two-mode interference by means of spatial Stokes parameters. Initial calibration of the two-parameter simultaneous pressure-and-temperature sensor has been performed up to 100 MPa using a primary pressure standard (deadweight tester Harwood DWT-35) View full abstract»

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  • Linearizing average transfer characteristics of ideal ADC's via analog and digital dither

    Publication Year: 1994 , Page(s): 146 - 150
    Cited by:  Papers (11)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (324 KB)  

    This paper is a continuation to the previous work by M.F. Wagdy (see ibid., vol. 38, p. 850-855, Aug. 1989). It further investigates the effect of various dither forms, i.e., with different probability density functions (PDF's), on the average observed transfer characteristics of ideal A/D converters (ADC's). First the deviation of the ADC characteristics from the ideal straight line is evaluated for analog dither forms using the concept of nonlinearity spectra developed in the above work. Second, two cases of digital (discrete) dither are investigated, one with rectangular envelope and the other with triangular one. Effects of dither peak-to-peak values and number of PDF impulses are investigated. The paper provides a quantitative basis for replacing analog dither with the easier to implement digital dither View full abstract»

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  • Unified approach to measurand reconstruction

    Publication Year: 1994 , Page(s): 226 - 231
    Cited by:  Papers (29)
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    The basic notions of measurement science are overviewed. A general scheme of measurement is proposed that emphasizes the key role of measurand reconstruction. The problems of measurand reconstruction are classified. Two classes of them, being of particular importance in practical applications, are identified and discussed in more detail. These are the nonlinear reconstruction of a scalar static measurand in the presence of a scalar influence quantity, and the linear reconstruction of a scalar dynamic measurand. Considerations of a tutorial and theoretical nature are illustrated with practical examples View full abstract»

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  • Automatic calibration of a fiber-optic strain sensor using a self-learning system

    Publication Year: 1994 , Page(s): 341 - 346
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (516 KB)  

    This paper describes a fiber-optic strain sensor and a procedure for automatic calibration as applied to the measurement of longitudinal strain. The sensor exploits variation in the intermodal interference pattern in a few-mode birefringent fiber, producing a far-field light distribution varying with the measurand. An array of photovoltaic diodes carries out sampling of the sensor output. A small-size connectionist network integrated within the sensor computes strain values from samples, dealing with the implicit, nonlinear dependencies between the parameter and the sampling data. The automatic calibration method is based on the principle of self-learning. It involves supervised sampling, optimal selection of training inputs, and automated modulation of weights in the neural processor. The method aims at a processor which recombines the photodiode signal into a function fitting the measurand uniformly in the measurement range View full abstract»

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  • Fuzzy methods for multisensor data fusion

    Publication Year: 1994 , Page(s): 288 - 294
    Cited by:  Papers (21)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (632 KB)  

    This paper presents a new general framework for information fusion based on fuzzy methods. In the proposed architecture, feature extraction and feature fusion are performed by adopting a class of (possibly multidimensional) membership functions which take care of the possibility and admissibility of the feature itself. Test cases of one-dimensional and image data fusion are presented View full abstract»

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  • Detecting changes in the condition of process instruments

    Publication Year: 1994 , Page(s): 355 - 358
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (328 KB)  

    By custom, the output from an instrument is a signal representing a measure of the process variable, and instrument performance is usually specified in terms of accuracy, linearity and rangeability. The process operator typically uses the specified performance criteria to assess the operational condition of the instrument based on the premise that degradation in performance essentially reflects malfunction on the part of the instrument. Current developments in intelligent measurement systems place emphasis on local sensor validation schemes to incorporate systematic means for detecting and isolating instrument effects from plant effects. This paper describes a method for detecting and isolating changes in a flow-measuring system using wide-band and unconditioned signals taken directly from the flow-sensing element View full abstract»

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  • Developing linear error models for analog devices

    Publication Year: 1994 , Page(s): 157 - 163
    Cited by:  Papers (25)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (492 KB)  

    Techniques are presented for developing linear error models for analog and mixed-signal devices. A simulation program developed to understand the modeling process is described, and results of simulations are presented. Methods for optimizing the size of empirical error models based on simulated error analyses are included. Once established, the models can be used in a comprehensive approach for optimizing the testing of the subject devices. Models are developed using data from a group of 13-bit A/D converters and compared with the simulation results View full abstract»

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  • The suppression of drift and transient effects for frequency-domain identification

    Publication Year: 1994 , Page(s): 232 - 237
    Cited by:  Papers (6)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (452 KB)  

    The identification of linear system dynamics from measurements corrupted by low-frequency aperiodic noise is discussed for situations where a periodic excitation can be applied to the system. It is shown that, by considering the low-frequency harmonic content of the disturbing noise, accurate elimination of the disturbance can be achieved for typical linear/nonlinear trend characteristics. The removal of transient effects from the initial response of the system to the excitation is also discussed. This is applicable when the experimental time is limited, as can be the case for systems with long time constants. The removal of the transient effects can be coupled with estimation of the drift parameters, thus allowing the effects of both the transients and the drift to be removed simultaneously View full abstract»

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  • Slider-disk clearance measurements in magnetic disk drives using the readback transducer

    Publication Year: 1994 , Page(s): 121 - 126
    Cited by:  Papers (14)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (484 KB)  

    A new method is described for noninvasively measuring the mechanical clearance between a recording head slider and the magnetic medium in hard-disk drives. The method is based on the detection of the pulse width of the read transducer output. A variation in clearance produces a proportional variation in pulse width. The proportionality factor can be determined by simulating the spacing loss using a digitized isolated impulse, typical for the respective head-disk combination. Instrumentation is presented that provides an output voltage proportional to the ratio (PWx/T) of the pulse width at x% of the peak amplitude PWx and the period T of the readback signal. This instrumentation measures the absolute slider-disk clearance by evacuating the air from the disk drive. The bandwidth is such that clearance dynamics can also be measured. This allows clearance measurements as well as the detection of undesirable slider-disk interactions, in situ, in fully operational disk drives View full abstract»

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  • Real-time X-ray fan-beam z-axis position measurement

    Publication Year: 1994 , Page(s): 295 - 298
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    Precise control of fan-beam position is important to the production of highest quality CT images; failure to maintain fan-beam orientation can produce image artifacts. This paper describes a special technique which provides accurate real-time measurement of fan-beam z-axis position. A geometrical mask set is used to modify the response of conventional detector cells. Data from the masked detector cells are used to form a self-consistent normalized position signal which is independent of radiological dose View full abstract»

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  • Development of instrument detecting nonmetal foreign bodies in food material

    Publication Year: 1994 , Page(s): 359 - 363
    Cited by:  Patents (7)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (372 KB)  

    In spite of a great deal of effort to prevent mixing foreign bodies in food materials, food manufacturers have still not been able to exterminate them. Nonmetal foreign bodies are very difficult to detect while metal foreign bodies can be detected easily. In this study, we developed a new nonmetal foreign body detection method and instrument. At first, we showed that the phases of the reflected waves from minced fish containing and not containing a few kinds of nonmetal foreign bodies were measured by setting the minced fish between two pieces of electrodes with high-frequency voltages. The results showed that the optimal frequency of the voltage supplied to the electrodes is 10 MHz, and the phase detector needs a precision of 0.1 deg. However, if floating the minced fish fast through the detector like the site in the factory, existing measuring instruments cannot be used because of their sampling speed and of the distortion of the signal. So, we developed a new digital phase-measuring instrument, which had the DSP's (digital signal processors) for calculation of the FFT (fast Fourier transform), are tangent and so on, and which used an adaptive sampling method. The developed instrument made it possible to measure the phase every 5 ms with a precision of 0.1 deg. However, the judgment of the foreign bodies was difficult, because the phase value of the minced fish itself is changeable in the floating experimental condition. So, we dealt effectively with the problem by using a neural network with a backpropagation learning method. The computer simulation results showed that a glass bead (2 mm in diameter), a styrene foam (3×3×3 mm3) and paper (15×15 mm2) could be detected View full abstract»

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  • Active infrared sensors for mobile robots

    Publication Year: 1994 , Page(s): 283 - 287
    Cited by:  Papers (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (408 KB)  

    Sensors based on the ultrasonic, pulse-echo technique for measuring range have been the mainstay for robotic collision avoidance systems. Although these sensors have been successfully applied to both indoor and outdoor mobile robotic applications, certain disadvantages of these systems prompted our investigation of inexpensive sensors that use light to determine the range or presence of targets. A number of commercially available, light-based sensors are analyzed for application in a mobile robotic space application. The objective of the analysis is to develop a cost-effective, light-based ranging sensor for a collision avoidance system for an experimental Mars Rover. This paper presents some results from our investigation View full abstract»

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  • A high-precision RF vector analyzer based on synchronous sampling

    Publication Year: 1994 , Page(s): 306 - 310
    Cited by:  Papers (2)  |  Patents (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (488 KB)  

    An RF/microwave amplitude and phase measurement system of exceptional linearity and stability (0.0001 dB) has been developed. In this system, the signals to be measured are transformed to discrete time digital signals by synchronous sampling and analog-to-digital conversion. These digital signals are then processed by a digital signal processor for vector detection and for computing digital feedback sent to the sampling gates. Digital iterative feedback is used to make the system insensitive to gain variations of the sampling gates. The method resembles that of dc substitution, but with vector capabilities, and is responsible for the high stability of the system. Furthermore, digital processing of the IF signals avoids the various IF imperfections of conventional vector analyzers such as gain range errors and detector circularity errors, which explains the exceptional linearity of the system. It is used as the basis for a high-performance dielectric measurement system working from 10 kHz to 500 MHz View full abstract»

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  • A laser-interferometer measuring displacement with nanometer resolution

    Publication Year: 1994 , Page(s): 332 - 336
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (468 KB)  

    In material science there are certain classes of problems that require strain measurement over base lengths as small as 100 μm and still demand a resolution limit of about 10 microstrains. This paper presents an interferometric strain sensor that is able to cope with that demand. The optical principle is given, and the digital signal processing involved is detailed. Furthermore, some experimental data for crack-tip opening displacement measurements on micro cracks and the measurement of thermal expansion coefficients of copper is given View full abstract»

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  • Quasi-synchronous sampling algorithm and its applications

    Publication Year: 1994 , Page(s): 204 - 209
    Cited by:  Papers (24)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (412 KB)  

    Synchronous sampling is a commonly used method with good performance. However, when perfect synchronization is impossible, or when the signal contains interharmonics, undesirable asynchronous deviations between the sampling and some components of the signal may exist. Consequently, possibly large leakage or truncation errors may occur. Consisting of a quasi-synchronous window to reduce the long-range leakage, and a compensation algorithm to reduce the short-range leakage after normal FFT, the method described in this paper will give much more accurate measurement of many electrical quantities, e.g., spectral content of signal and phase difference between two periodic signals in power networks, than the traditional one View full abstract»

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  • Dither signal effects on the resolution of nonlinear quantizers

    Publication Year: 1994 , Page(s): 139 - 145
    Cited by:  Papers (12)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (380 KB)  

    The consequences of dithering on nonlinear quantizers are analyzed. A model of the nonlinear quantizer is considered, and a model of the same quantizer with dither is proposed. By means of this approach, relationships are given for the total quantization error in the case of discrete binary, uniform, and Gaussian dither signals View full abstract»

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  • Fiber optic CdMnTe magnetic field sensor made by the laser ablation deposition technique

    Publication Year: 1994 , Page(s): 322 - 325
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (304 KB)  

    A Cd1-xMnxTe (CMT) fiber optic magnetic field sensor has been developed with the use of a laser ablation deposition technique: pulsed laser evaporation and epitaxy (FLEE). This method of growth yields high-quality material and due to the low-temperature deposition it enables integration of CMT in optoelectronic systems. A disk-shaped sensor structure of diameter and thickness less than 3 mm and 75 μm, respectively, is incorporated in a fiber optic system. A linear response of the sensor held at room temperature has been measured in the magnetic field up to 0.8 T; however, its usefulness for measurements of the field above 25 T is expected. Due to its small physical dimension and the potential of high-speed operation in the gigahertz range, the sensor can be particularly useful in the measurements of spatial and temporal uniformity of the magnetic field View full abstract»

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  • Nonlinear disturbance errors in system identification using multisine test signals

    Publication Year: 1994 , Page(s): 238 - 244
    Cited by:  Papers (19)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (560 KB)  

    The errors introduced into linear system identification by a class of nonlinear distortions are examined. A theoretical framework is presented for the distortion generated by odd-power-nonlinearities when using multisine test signals for frequency-domain identification. It is shown that the distortion is a function of the number of test harmonics, their harmonic values, and their phases. This leads to the definition of a novel class of signals, termed no interharmonic distortion (NID) multisines, with interesting properties. An explanation of previously published practical results is then given. Application of multisines to system testing with a method of compensating for nonlinearities is illustrated with practical results View full abstract»

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  • A highly linear single p-n junction temperature sensor

    Publication Year: 1994 , Page(s): 127 - 132
    Cited by:  Papers (3)  |  Patents (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (404 KB)  

    A temperature sensor based on the use of two forward-biased p-n junctions is known to exhibit good linearity. An alternative sensor configuration, based on the same principle, but employing only one p-n junction is presented in this paper. The forward current through the p-n junction is switched alternately between two fixed values, and the difference between the corresponding voltages is shown to vary linearly with temperature. This scheme eliminates the problems associated with close matching required for the two p-n junction sensors. Experimental results obtained with the proposed scheme are presented. A configuration to exploit the temperature dependence of the p-n junction incremental resistance is also presented View full abstract»

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  • Measurement and simulation of crosstalk reduction by discrete discontinuities along coupled PCB traces

    Publication Year: 1994 , Page(s): 170 - 175
    Cited by:  Papers (7)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (400 KB)  

    Crosstalk among interconnects and printed-circuit board (PCB) traces is a major limiting factor of signal quality in high-speed digital and communication equipment. The paper evaluates coupled surface microstrip transmission lines with periodical loading and coupling. The situation may represent stray coupling and loading of digital buses due to connector pins, plated through holes at connector slots, and stubs as well as the input capacitance of active devices. This paper shows that discrete periodical coupling along coupled surface microstrip transmission lines may be used to reduce far-end crosstalk. An expression is given to calculate the discrete coupling capacitance to achieve optimum far-end crosstalk reduction. The reduction of far-end crosstalk is verified by measurements, and the good agreement between the simulated and measured data is shown. On the other hand, discrete loading does not significantly reduce near-end crosstalk, but will introduce additional ringing in the time domain View full abstract»

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  • Novel hardware and software solutions for a complete linear and nonlinear microwave device characterization

    Publication Year: 1994 , Page(s): 299 - 305
    Cited by:  Papers (11)  |  Patents (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (516 KB)  

    While S-parameter test sets are well suited for linear active device characterization, many problems are still unsolved for a complete large-signal characterization. In this paper a test set, which performs measurements of S-parameter and load-pull characteristics at the fundamental and harmonic frequencies, is used to produce a set of data (constant gain, constant output power, efficiency, and so on), which completely describes the linear and nonlinear transistor behavior. The goal is reached by means of a special design of the test set which quickly makes the measurements with a particular tracking algorithm for load-pull contours. The high speed and the accuracy that can be achieved make the test set particularly useful for production testing of microwave active devices and for power amplifier design View full abstract»

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  • The two-winding transformer: an experimental method to obtain a wide frequency range equivalent circuit

    Publication Year: 1994 , Page(s): 364 - 371
    Cited by:  Papers (37)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (520 KB)  

    A lumped-component equivalent circuit has been developed by our team to model the electric behavior of any two-winding transformer. This circuit is general: its topology is independent of shape, sizes, and technology chosen. Changing the sample results only in a change of numerical values. Moreover, this circuit is suitable in a wide frequency range: from dc up to, at least, one decade beyond the maximum working frequency of the transformer. The aim of this paper is to present an experimental method which allows all the component values of this equivalent circuit to be determined, using only external impedance measurements. The method is illustrated by one example and, to conclude, Bode plots related to the circuit are compared to the experimental ones 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
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alessandro.ferrero@polimi.it
Phone: 39-02-2399-3751
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