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Instrumentation & Measurement Magazine, IEEE

Issue 4 • Date Dec. 2001

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Displaying Results 1 - 10 of 10
  • Accelerated stress testing handbook -guide for achieving quality products [Book Review]

    Page(s): 69
    Save to Project icon | Request Permissions | PDF file iconPDF (40 KB)  
    Freely Available from IEEE
  • Author index

    Page(s): 70 - 71
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    Freely Available from IEEE
  • Subject index

    Page(s): 71 - 76
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    Freely Available from IEEE
  • Fitting transducer characteristics to measured data

    Page(s): 26 - 39
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2790 KB) |  | HTML iconHTML  

    There are no rules to select the best curve-fitting method for a given set of data. This problem is of great importance in measurement applications. Optimizing analog and digital methods for a transducer's characteristic interpolation or linearization is a field where constant research is being done, particularly since auto-calibration and self-test of intelligent transducers is a topic of major interest. We present an overview of classical methods for data interpolation and least mean squares regression. We make a comparative evaluation of the relative performance of polynomial and artificial neural networks approximations to measurement data with particular attention paid to the reduction of the required calibration set dimension to obtain a given accuracy View full abstract»

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  • Line-pantograph EMI in railway systems

    Page(s): 10 - 13
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1788 KB) |  | HTML iconHTML  

    At present, the EN50121 standards are the main reference for electromagnetic compatibility in European railway systems. These standards should improve as technology and testing develops. Therefore, major sources of EMI in a railway environment need to be better understood. This study is complex because many different railway power systems exist in Europe (1.5 kV DC, 3 kV DC, 15 kV 16.7 Hz, 25 kV 50 Hz). European railways are using new control and communication systems, and electromagnetic compatibility problems should be carefully studied and solved View full abstract»

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  • Least-squares fitting of data by polynomials

    Page(s): 46 - 51
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    In the last two columns, we looked at one approach to approximation, interpolating a set of points by piecewise-cubic polynomials forming a cubic spline. We now look at another approach - one that involves fitting a curve to a set of data without restricting that curve to coincide with the data points. Our focus is on least-squares approximation, and, in particular, least-square fitting of polynomials to data View full abstract»

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  • Computer simulation of a pulse-forming network

    Page(s): 20 - 22
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    Computer simulation allowed research scientists at TRIUMF to achieve the tightest specification to date for a pulse-forming network (PFN). The 66 kV PFN, designed for use by CERN has a measured ripple in the flattop of only ±3%. This is a much flatter pulse than the ±1% ripple that was previously state of the art for these devices. The TRIUMF researchers attribute their ability to achieve this level of performance to using precise computer simulation in the design of the pulse-forming network rather than traditional calculations and mechanical tuning by trial and error. Electromagnetic simulation made it possible to determine a single frequency that could be used to determine the ideal circuit parameters needed to achieve the desired flattop of the pulse. Once the researchers had that information, they were able to optimize the design of the PIN to produce the desired pulse shape. The researchers then used electromagnetic simulation to evaluate the geometry of the pulse-forming network's coil to specify precise manufacturing tolerances View full abstract»

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  • Time domain reflectometry liquid level sensors

    Page(s): 40 - 44
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (361 KB) |  | HTML iconHTML  

    The technique of time domain reflectometry (TDR) has been used by electrical engineers for testing the characteristics of transmission lines and diagnosing faults. Although TDR instruments for testing cable are commonly used today, few instrumentation engineers are aware that the technique can measure liquid levels and fluid interfaces. In this article, I review the theory and principles of time domain reflectometry and present the application of this technology as a liquid level sensor View full abstract»

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  • Continuous monitoring of a capacitor bank

    Page(s): 14 - 19
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (5075 KB) |  | HTML iconHTML  

    We have developed a prototype system for safety assurance of a capacitor bank by combining application-specific and off-the-shelf surveillance technology for remote monitoring. Traditional surveillance technology passively records facility operations, waiting for an event to trigger a physical audit of the collected information. We have implemented a more active approach to remote monitoring and used the Pulsed Field Laboratory as a test bed. We had various sensors continuously collect information about the state of the laboratory and send it to Guardian, a reasoning system developed at LANL. The detection of an anomalous event begins the recording and analysis of the streams of data from the sensors; the system then presents the results to the laboratory personnel in a Web-based multimedia format for immediate interrogation. This facility provides a unique environment for evaluating, developing, and deploying technology that ensures personnel safety and identifies precursor cues to catastrophic equipment failures View full abstract»

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  • Thermal noise in a finite bandwidth

    Page(s): 23 - 25
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (353 KB) |  | HTML iconHTML  

    In a practical circuit, the output noise due to the thermal noise of a resistor will depend on the actual transfer function of the noise source. The bandwidth will never be infinite because the transfer function of either the noise source or the device measuring the output noise will cause limitations. Consequently, the thermal noise voltage of a resistor in a finite bandwidth is maximum for a given resistor value. That maximum thermal noise voltage depends on the stop frequencies and decreases for both smaller and larger resistor values View full abstract»

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Aims & Scope

IEEE Instrumentation and Measurement Magazine contains applications-oriented and tutorial articles on topics in the broadly based areas of instrumentation system design and measurement techniques.

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Editor-in-Chief
Prof. Wendy Van Moer

wendy.w.vanmoer@ieee.org
IandMMagazineEIC@ieee.org