- TITLE:
FOREIGN PATENT ACTIVITY IN BULGARIA FOR THE PERIOD 2001-2012
- AUTHOR(S):
R. Georgieva
- ABSTRACT:
The objective of the current study is to reveal the status and the tendencies in the technological development of the legally protected for-eign technological knowledge in different fields and spheres of the International Patent Classification, to study the national identity of the patent holders and to draw some conclusions and prognoses. These goals were achieved through analyses of the foreign patent activity in
Bulgaria for the period 2001-2012, measured by the number of the patent for innovation of foreign holders.
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FOREIGN PATENT ACTIVITY IN BULGARIA FOR THE PERIOD 2001-2012
- TITLE:
RELIABILITY OF ELECTRONIC EQUIPMENT AND THERMOGRAPHIC METHODS
- AUTHOR(S):
A. Andonova, V. Todorova
- ABSTRACT:
Results in the application of advanced thermographic methods effective to conduct diagnosis of electronic equipment and in particular to power conversion devices are presented and discussed.. The application of the thermography as a diagnostic tool is illustrated by examples of LED and PV.
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RELIABILITY OF ELECTRONIC EQUIPMENT AND THERMOGRAPHIC METHODS
- TITLE:
STUDY OF THE TERAIN INFLUENCE ON THE DISTRIBUTION OF THE RADIO FREQUENCY SIGNALS USING DIFFERENT QAM CONSTELLATIONS
- AUTHOR(S):
M. N. Makarov, N. D. Tashkov
- ABSTRACT:
In this paper different digital modulation techniques used in today’s high speed communications are researched. Matlab based simulations for comparison of different QAM constellations are presented. Using mathematical models for signal fading for urban scenario, results for the fading are obtained. The influence of the signal to noise ratio and the modulation type on the size of the covered area has been studied.
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STUDY OF THE TERAIN INFLUENCE ON THE DISTRIBUTION OF THE RADIO FREQUENCY SIGNALS USING DIFFERENT QAM CONSTELLATIONS
- TITLE:
SYNTHESIS AND STUDY OF THE CURRENTS OF ELECTRO DRIVE SYSTEM WITH SINGLE TREE PHASE CYCLOCONVERTER
- AUTHOR(S):
C. Petkov
- ABSTRACT:
The paper presents a way of theoretical synthesis and study about electrical drive system with induction motor and direct frequency converter. The result of the synthesis is nonsinosoidal form of the phase currents for different frequencies. The representative vector of the stator current is found and important conclusions are made. The form of the stator,s current allows a spectral analysis on the Fourier transform, which is an important part of the engineering studies.
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SYNTHESIS AND STUDY OF THE CURRENTS OF ELECTRO DRIVE SYSTEM WITH SINGLE TREE PHASE CYCLOCONVERTER
