Carolina Luque A., Niclas Björsell
Some test and measurement applications require higher dynamic range for multi-tone signals than a signal generator can generate. Moreover, for other applications it can be interesting to improve the performance of a “low cost” signal generator. The spectral purity of generated signals can be improved by using pre-distorted base-band signals. In this paper, a dynamic grey-box model is described. A pre-distorter is used in order to improve the dynamic range. The results, which are based on measurements, show an improved dynamic range for a three-tone signal of approximately 9 dB and an...
Valeriy I. Didenko, Aleksandr V. Ivanov
The very fast development of sigma-delta analog-to-digital converters is evidently. Therefore analytical methods of their description become more and more important. If the found equations are precise enough, they can be used for verification and validation of modelling and simulation. Analytical equations are also important from the viewpoint of education. As is known, the sigma-delta ADC consists of sigma-delta modulator (SDM) and digital filter. In this paper the quantization noise of modulator is investigated for different forms of input signal. The world known (classical) theory of...
Karel Draxler, Renata Styblíková, Michal Ulvr
This paper describes an innovative procedure for calibrating sets for evaluating instrument current transformer (ICT) errors. The innovation lies in the use of a current source for generating a measured current. There is an adjustable current source at 50 Hz mains frequency with a current transformer on its output. The internal impedance must be sufficiently high to eliminate the methodic error due to calibration. Calibration is carried out by means of a measuring system controlled by a PC through an IEEE 488 bus. Known values of the simulated ratio error and phase displacement are compared...
Exploring New Frontiers of Instrumentation and Methods for Electrical and Electronic Measurements
· TC4
· 2008
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A. Psyllos, C. N. Anagnostopoulos, E. Kayafas
In this work, it is demonstrated that relatively simple image processing functions based on symmetry measurements can be used to obtain high performance vehicle authentication, creating an “image signature” for every vehicle. On that basis, distinctive parts of the vehicle frontal view such as the headlights and the logo area can be segmented. A novel neural network application, properly trained, provides adequate vehicle manufacturer recognition when used in conjunction with a previously developed license plate recognition module. It is also shown that image processing functions based on...
Exploring New Frontiers of Instrumentation and Methods for Electrical and Electronic Measurements
· TC4
· 2008
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Pedro M. Ramos, Tomáš Radil, A. Cruz Serra
This paper describes a new method for detection of some power quality (PQ) disturbances, namely transients and waveform distortions. The proposed algorithm is based on a modified version of the four-parameter sine-fitting algorithm. The sine-fitting algorithm is used to estimate the parameters of the power system’s voltage signal’s fundamental and to extract the transient component of the voltage. The performance of the proposed method is compared with previously developed algorithm and with two commercial PQ analyzers.
Exploring New Frontiers of Instrumentation and Methods for Electrical and Electronic Measurements
· TC4
· 2008
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Vladimír Haasz
New study programmes corresponding to Bologna declaration started in the Czech Republic in 2002 (bachelor study stage), but in electrical engineering generally in 2003. Therefore the first run of master study stage has finished this year. 41 % of bachelor programmes in engineering are oriented more practically, 25 % prefer theoretical background for master stage, about 15 % were prepared as universal and the rest arose by dividing of the first part of long master programme to 2 bachelor programmes – one practically oriented and the other as preparing for master stage. Actual experience...
Exploring New Frontiers of Instrumentation and Methods for Electrical and Electronic Measurements
· TC4
· 2008
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Josef Vedral
ADC testing by means of exponential signal is presented in the article. Time and frequency analysis of the signal is performed and Signal-to-Noise Ratio and Effective Number of Bits is calculated by means of Exponential Fit Test. The approach has been verified on 24-bit Flexible Resolution Digitizer PXI-5922 by National Instruments. Using exponential signal as the digitizer input, the SINAD = 106 dB corresponding to ENOB = 17,3 bits has been achieved. The difference of 1,5 bit was most probably caused by exponential signal frequency spectra decrease. Results comparable with classical...
David Sarrià, Joaquín Del Río, Antoni Mànuel, Jacopo Aguzzi, José Antonio García, Francesc Sardà
An automated acquisition system has been developed to measure the behavioral activity rhythms of marine species. The system has been developed using infrared and computer vision technologies by a distributed topology, different experimentations can be done at the same time if the units are repeated and connected to the main computer. The developed system consists primarily in custom low cost acquisition and illumination units with USB interface that allows the acquisition from different photodiodes sensors and to illuminate with a programmable photoperiod. The main computer controls all the...
Exploring New Frontiers of Instrumentation and Methods for Electrical and Electronic Measurements
· TC4
· 2008
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Arianna Mencattini, Giulia Rabottino, Marcello Salmeri, Federica Caselli,Roberto Lojacono
Breast cancer is the first leading cause of death by cancer for women. To increase the survival rate it is necessary to detect lesions as soon as possible. Most early breast cancer can be diagnosed by detecting microcalcification clusters in mammographic images. The clusters appear as groups of small, bright particles with arbitrary shapes and distribution. Because of human factors such as subjective or varying decision criteria, distraction by other image features, large number of images to be inspected, or simple oversight, some diagnosis are missed.In this paper, we propose a method to...
Exploring New Frontiers of Instrumentation and Methods for Electrical and Electronic Measurements
· TC4
· 2008
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Giulia Rabottino, Arianna Mencattini, Marcello Salmeri, Federica Caselli, Roberto Lojacono
Mammography is the most effective tool now available for an early diagnosis of breast cancer. However, the detection of cancer signs in mammograms is a difficult task owing to the great number of non pathological structures which are also present in the image. It has been shown that in current breast cancer screenings 10%–25% of the tumors are missed by the radiologists. For this reason, a lot of research is currently being done to develop systems for Computer Aided Detection (CADe). Probably, some causes of the false–negative screening examinations are that tumoral masses have varying...
Exploring New Frontiers of Instrumentation and Methods for Electrical and Electronic Measurements
· TC4
· 2008
· Download