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[1991] Conference Record. IEEE Instrumentation and Measurement Technology Conference

14-16 May 1991

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Displaying Results 1 - 25 of 121
  • A review of near-field antenna measurements at NIST

    Publication Year: 1991
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (34 KB)

    Summary form only given. The authors present the theory underlying probe-corrected near-field antenna measurements from which the far-field gain, pattern, and polarization may be determined. This theory allows for the rigorous compensation for the effect of a probe which does not measure the field at a point, but rather from an average over the aperture of the probe weighted by the characteristics... View full abstract»

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  • Conference Record. IEEE Instrumentation and Measurement Technology Conference (Cat. No.91CH2940-5)

    Publication Year: 1991
    Request permission for commercial reuse | PDF file iconPDF (38 KB)
    Freely Available from IEEE
  • Sorting biological objects with microwave resonant cavities

    Publication Year: 1991, Page(s):40 - 43
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (296 KB)

    It is shown how microwave resonators can be used as sensors for sorting dielectric objects. Differences in volume or mass can be distinguished among objects of irregular shape but of uniform dielectric properties. Moisture content, or other permittivity-dependent qualities can also be distinguished independent of mass or volume when objects are of uniform shape. Fundamental principles of the shape... View full abstract»

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  • Extending the dynamic range of scalar network analyzer measurements

    Publication Year: 1991, Page(s):35 - 39
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (304 KB)

    A set of techniques is described that extends the measurement dynamic range of scalar network analyzers to over 100 dB, without compromising accuracy or functionality. The current limitations of scalar analyzers are also described. Some or all of these techniques can be applied by the instrument user. Or, alternatively, Ferretec has combined all of these techniques into a single instrument, the Fe... View full abstract»

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  • Adaptive software for wattmeter calibration

    Publication Year: 1991, Page(s):476 - 482
    Cited by:  Papers (4)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (384 KB)

    A methodology is presented which is based on an adaptive software that increases the performances of a measurement system devoted to the characterization of industrial wattmeters working in presence of significant distortions in current and voltage signals and/or low values of cos Φ. The system is a two-channels standard waveform including power outputs (mas. 150 Vrms for the voltage channel a... View full abstract»

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  • High speed, error corrected, vector S-parameter measurements

    Publication Year: 1991, Page(s):27 - 34
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (416 KB)

    Techniques are presented that have been successfully utilized in a high-speed vector network analyzer to reduce multistate device test times without reducing measurement confidence or accuracy compared to conventional network analyzers. The technique utilizes conventional S-parameter measurement practices applied in an integrated instrumentation and computer environment. This integrated test stati... View full abstract»

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  • Novel detector and difference clock circuits for generator frequency error monitors

    Publication Year: 1991, Page(s):192 - 197
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (400 KB)

    All detectors are subject to error in difference detection. Where this detection error is integrated by a clock, it may run up to a few seconds, defeating the whole purpose of the clock. A description is presented of an error-free detector circuit which overcomes this problem. In this design, a detector circuit continuously compares the generator clock and the standard clock. Based on the comparis... View full abstract»

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  • A switched-capacitor interface for capacitive pressure sensors

    Publication Year: 1991, Page(s):468 - 473
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (308 KB)

    A switched-capacitor interface of a capacitive pressure sensor is developed which provides linear digital outputs. It consists of a sample/hold circuit followed by a charge-balancing analog-to-digital converter. Two linearization methods based on the hyperbolic relation between the sensor capacitance and pressure are investigated in order to accommodate them to the basic interface configuration. I... View full abstract»

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  • A time domain analysis of a calibration error model

    Publication Year: 1991, Page(s):22 - 26
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (284 KB)

    Two calibration approaches are examined to compare the error coefficients in signal flow models in the time domain. Ideally, the same error-coefficients should be obtained from both calibration approaches. For the most part, the calculated error coefficients are essentially the same. The only major difference occurred in the source-match term near the time t=0 point. A potential reason fo... View full abstract»

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  • Embedded instrumentation for evaluation task sharing performance in a distributed computing system

    Publication Year: 1991, Page(s):222 - 226
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (548 KB)

    Current trends in performance measurement on distributed computers are briefly reviewed. An example of application level performance measurement on a distributed computing system using software based instrumentation techniques is considered. Embedded software instrumentation for measuring the performance of a decentralized adaptive task sharing algorithm in a distributed computing system is descri... View full abstract»

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  • Measurement and evaluation of two-phase flow parameters

    Publication Year: 1991, Page(s):185 - 191
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (360 KB)

    The authors' use of fuzzy theory for identification of two-phase flow patterns and flow imaging based on signals from traditional transducers of flow measurement is briefly summarized. The application of the fuzzy identification theory makes it possible to describe the real flow patterns of two-phase flow more accurately and objectively. The flow pattern judgment is based on an original signal (pr... View full abstract»

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  • Experimental determination of stress in magnetic recording thin film disks

    Publication Year: 1991, Page(s):398 - 404
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (460 KB)

    An experimental program is described to help understand and explain the stress state in Cr and CoCrPt thin films sputtered on ceramic (canasite) substrates. Thin film magnetic recording disk substrates are used with production process equipment. A measurement technique is developed. The effect of Cr thickness and sputter preheat on stress in the Cr layer is determined. Stresses in equal thickness ... View full abstract»

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  • Active tactile perception of 3D surface geometric profiles

    Publication Year: 1991, Page(s):464 - 467
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (304 KB)

    A tactile probe is presented which was designed specifically to respond to a 3D geometric profile stimulus (measurand). In order to improve the tactile probe's compliance to the explored object surface, the authors have used an instrumented passively compliant wrist to attach the probe to the manipulator. It was found that special attention has to be paid in choosing the dimensions of the tactile ... View full abstract»

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  • Measurement-the parametric approach

    Publication Year: 1991, Page(s):259 - 262
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (372 KB)

    It is shown how parametric models of observations may lead to precise and well-defined measurement results. Parametric model fitting transforms the available observations into a few estimated parameters. A further advantage of a parametric model of the observations is the possibility to enhance the precision of the fitting procedure by incorporating a priori knowledge. This concerns knowledge of b... View full abstract»

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  • Stochastic modeling of calibration drift in electrical meters

    Publication Year: 1991, Page(s):530 - 536
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (356 KB)

    The drift in the calibration bias in an instrument can be modeled as a stochastic process, specifically, as the Wiener process. The probability distribution of this Wiener model can be found conditioned upon calibration at some time t1. Bounds on the drift of the bias after calibration can be found as a function of time based upon an estimate of the parameter α, of the Wi... View full abstract»

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  • VXI evaluation testbed

    Publication Year: 1991, Page(s):17 - 19
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (188 KB)

    The scope of this work includes a system description of the VXI testbed and its intended usage and a description of problems, concerns, and recommendations to date. A description is also given of the approach being taken to get on line with VXI as quickly as possible. It is shown that the VXI testbed is proving to be a very useful tool. Not only does it provide a vehicle for training personnel in ... View full abstract»

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  • Process data chemometrics

    Publication Year: 1991, Page(s):608 - 612A
    Cited by:  Patents (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (528 KB)

    Data are gathered in many chemical processes at a very high rate. Unfortunately, much of that data is not often used unless a major problem has occurred. A technique in which data can first be analyzed to determine what is normal variability in the process and a model or models developed which define in a compact way that variability are presented. The information in the models is then used to mea... View full abstract»

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  • Effect of noise on real-time parameter estimation of multifrequency signals

    Publication Year: 1991, Page(s):217 - 221
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (376 KB)

    An investigation was conducted of the noise influence on the accuracy of a frequency-domain procedure suitable for the real-time estimation of multifrequency signal parameters. Imposing very weak assumptions about the statistical description of the noise, simple and accurate expressions for the variances of the estimators are established. They allow both the evaluation of the resulting accuracy an... View full abstract»

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  • A method of improving the resolution and accuracy of rotary encoders using code compensation technique

    Publication Year: 1991, Page(s):183 - 184
    Cited by:  Papers (4)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (176 KB)

    A method for improving the resolution and accuracy of incremental type rotary encoders using a phase encoding and code compensation system is described. Applying this system to an optical incremental encoder whose scale pitch is 1/36000, a rotation resolution of 1/920000 and a better than ±1/300000 rotation (±0.0012°) precision are obtained. The system can also be used for a prec... View full abstract»

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  • Some theorems on Walsh transforms of quantizer differential and integral nonlinearity

    Publication Year: 1991, Page(s):55 - 61
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (416 KB)

    Methods of diagnosing component tolerances of quantizers are derived, based on the assumption of known and available data about a quantizer's nonlinearities. Two of the methods are direct and are based on the Householder orthogonalization, applied to an overdetermined equation system containing data about differential or integral nonlinearities. The remaining two methods are indirect and are based... View full abstract»

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  • Control of particulate magnetic coating properties using dispersion quality measurement

    Publication Year: 1991, Page(s):391 - 397
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (492 KB)

    A description is given of the use of a rheomagnetic instrument which provides an indirect measurement of the dispersion quality of a magnetic ink suspension used for coating application in the manufacture of magnetic disks. The instrument was designed, tested, and put on a pilot line to characterize the relationships between the dispersion quality measurement and functional characteristics of the ... View full abstract»

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  • CMOS chopper amplifier for chemical sensor

    Publication Year: 1991, Page(s):460 - 463
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (264 KB)

    A highly sensitive CMOS chopper amplifier used for an oxygen probe is described. It is integrated in a 2-μm double-poly p-well CMOS process. The chip uses only a single 5-V voltage source, and no external components are needed. It is realized by a current mode chopper technique in order to overcome the low-frequency noise and drift problems. The clock feedthrough generated by the chopper circui... View full abstract»

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  • Parameter correlation of impulse shapes using two-port synthesis

    Publication Year: 1991, Page(s):242 - 246
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (264 KB)

    Equations are derived for determining the time constants of the double exponential impulse from the commonly used parameters for several standard test impulses. A resistor-capacitor (RC) circuit is synthesized that will produce the desired impulse. The prototype network is realized through a computer-aided design (CAD) procedure using Cauer's RC ladder two-port synthesis method. ... View full abstract»

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  • Signal parameter algorithms for trend analysis of digital data acquisition systems

    Publication Year: 1991, Page(s):525 - 529
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (336 KB)

    A description is given of three integrated Fortran routines that calculate a comprehensive set of characterization parameters for any uniformly sampled discrete-time signal. The parameters and algorithms are based on IEEE Standard 194-1977, Pulse Terms and Definitions and IEEE Standard 181-1977, Pulse Measurement and Analysis by Objective Techniques. These subroutines are used extensively for tren... View full abstract»

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  • VXIbus: a military ATE application

    Publication Year: 1991, Page(s):13 - 16
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (352 KB)

    Application of the VXIbus technology in military ATE (automatic test equipment) environment on the A-7 Corsair Avionics System Tester (CAST) program is discussed. In this program, extensive use was made of commercial as well as in-house designed VXI instruments. Firmware was developed, and the VXI systems were integrated into the modular automatic test equipment (MATE) environment View full abstract»

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