Cristian Fosalau, Cristian Zet
The paper deals with an automatic method designed to compensate the external magnetic disturbances acting upon a high sensitive magnetic sensor mounted in an ac bridge configuration, whose influences upon the output voltage are comparable to those produced by the quantity to be measured. The method is particularly applied for sensors whose characteristic is non-linear and which cannot be compensated using the classical method of supplying the bridge with a constant current source.
Instrumentation for the Information and Communication Technology Era
· TC4
· 2010
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Milan Smetana, Tatiana Strapacova, Ladislav Janousek, Klara Capova
Pulsed eddy current (PEC) is a new technique of non-destructive material evaluation (NDE). In comparison with other eddy current techniques, PEC uses pulsed excitation that is characterized by wide frequency content and thus the response carries more complex information about a tested object. PEC method is used in many NDE common applications such as inspection of defects, measurement of conductivity and estimation of material thickness. This article deals with the conventional and the pulsed eddy testing method as a new trend in electromagnetic nondestructive evaluation of conductive...
Instrumentation for the Information and Communication Technology Era
· TC4
· 2010
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Ljupco Arsov, Marija Cundeva-Blajer, Alan Šala, Hrvoje Hegeduš, Roman Malaric
In the paper two procedures of inter-laboratory comparisons of the electrical reference standards (resistance and DC voltage) of the Metrological Calibration Laboratory of the Faculty of Electrical Engineering and Information Technologies in Skopje (FEIT), R. Macedonia and the Primary Electromagnetic Laboratory at Faculty of Electrical Engineering and Computing in Zagreb (FER), R. Croatia will be described. An original improved resistance comparison method, developed by R. Malaric is used for the resistance comparison, as well as an expanded model for uncertainty estimation. The improvement...
Instrumentation for the Information and Communication Technology Era
· TC4
· 2010
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Ján Hribik, Peter Novák, Peter Fuchs
A microcomputer-controlled measuring instrument for phase angle measurement in low frequency range is described. It is based on the digital measurement of the time shift between input signals. To avoid the necessity of calculation of the measured phase shift, measurement of the time shift is repeated during a constant time interval to get the average value of the phase shift independent on the period of the input signals. The measured results are displayed on the display of the instrument and can be transferred into a personal computer (PC) which can process and display these results and...
Instrumentation for the Information and Communication Technology Era
· TC4
· 2010
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Dušan Agrež
In this paper, simple algorithms for fast measurement and estimation of the unknown changing frequency, amplitude, and phase difference of the sinusoidal signals from two channels with the same frequency, and other parameters for evaluation of the power quality disturbances are presented. Parameters are calculated from the DFT coefficients around the component peaks. The improvements for reducing the influences of the harmonic components can be the estimation with the three-point interpolation and the Hann window.
Instrumentation for the Information and Communication Technology Era
· TC4
· 2010
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Eduardo Pinheiro, Octavian Postolache, Pedro Girão
Biomedical signals are relentlessly superimposed with interferences and noise. The nonlinear processes which generate the signals, and the interferences, regularly exclude or limit the usage of classical linear techniques, and even wavelet transforms, to decompose the signal. Empirical Mode Decomposition (EMD) is a recently proposed method for analyzing signals from a nonlinear viewpoint. EMD is not defined by a formal mathematical analysis, instead the decomposition is obtained by following an algorithm, requiring experimental investigation, thus being a fully data-driven technique. Hence,...
Instrumentation for the Information and Communication Technology Era
· TC4
· 2010
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Vladimír Pata, Miroslav Maňas, David Maňas, Michal Staněk, Aleksandra Sivtseva
The article describes the problem of dual shooting and evaluation of high-speed time varying phenomena using high-speed camera systems. It describes necessary steps for the preparation of shooting and how to set up the electronic shutter and also focuses on the processes of calibration and final evaluation of the high-speed phenomena. Dual shooting of high-speed phenomena is very modern while still remaining quite an unexplored field and is at present subject of a research at the Institute of Production Engineering ÚTB in Zlín. The published processes particularly for the Chip-Chunk test are...
Instrumentation for the Information and Communication Technology Era
· TC4
· 2010
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Marek Hrúz, Jan Široký, David Maňas
Rapid increase of computational performance of personal computers has enabled employment of automatic hardness measurement in the last decade. It reduces the human factor in measurement and speeds up the measurement process. On the other hand, the automatic measurement often fails, when the specimen surface is not well prepared. Robust image processing algorithm is crucial for the automatic hardness measurement. The article introduces a combination of an advanced image processing technique called Active Shape Modeling (ASM) and a sophisticated model estimation technique called Particle...
Instrumentation for the Information and Communication Technology Era
· TC4
· 2010
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Daniel Belega, Dominique Dallet, Dario Petri
In this paper a criterion for the choice of the optimal window for the amplitude estimation of a sinewave corrupted by a stationary white noise using the energy-based method (EBM) is proposed. The window is chosen by ensuring that the spectral leakage effect on the estimator accuracy is negligible with respect to errors due to noise. The proposed criterion is applied to several different settings, and some interesting conclusions are drawn. The effectiveness of the proposed criterion is validated by means of both computer simulations and experimental results.
Instrumentation for the Information and Communication Technology Era
· TC4
· 2010
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Milos Sedlacek, Zdenek Stoudek
This paper presents an overview of algorithms for one-phase active power estimation using digital signal processing in time domain and in frequency domain and compares properties of these algorithms. Besides comparing already published algorithms also a new algorithm and additional information concerning some known algorithms is included. Results of computer simulations in Matlab and results of measurement by means of computer plug-in boards, both multiplexed and using simultaneous signal sampling is presented. Using new cosine windows designed by iterative algorithm recently published by...
Instrumentation for the Information and Communication Technology Era
· TC4
· 2010
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