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Proceedings of the Technical university of Sofia, 1995 -: Recent submissions

Now showing items 381-400 of 853

Title: System for adjustment and test of algorithms for ECG-data processing Author: Iliev, Ivo Tsvetanov; Tabakov, Serafim Dimitrov Date: 2006 Abstract: The paper presents a high-performance system for adjustment and test of algorithms for data processing, embedded in real ECG devices. An additional advantage of the system is the possibility for simultaneous visualization of the applied test signal and the result after processing. This may be a beneficial tool and considerable reduce the ... Library:
TECHNICAL UNIVERSITY - SOFIA
Title: Debugging and diagnostic of sensors connected in a network using microcontroller MSP430 Author: Geshev, Georgi Dotsov; Dimitrov, Emil Nikolov Date: 2006 Abstract: In this paper is examined monitor program for debugging, adjustment and diagnostic of embedded microprocessor system based on TEXAS Instruments MSP430. It is foreseen to work with it while the separate systems are connected to a local network. After a review of the existing monitor programs and analysis of the available resources in the ... Library:
TECHNICAL UNIVERSITY - SOFIA
Title: Power electronic devices for wind turbines Author: Krusteva, Anastassia Petrova; Marinov, Tsvetan; Hinov, Nikolay Luboslavov Date: 2006 Abstract: During the last two decades, the production of wind turbines has grown in size from 20 kW to 2 MW. The electrical part of a wind turbine is becoming more and more important and, it is very important to have this system highly integrated into the overall wind turbine design. Electrical developments include the use of advanced power electronics ... Library:
TECHNICAL UNIVERSITY - SOFIA
Title: Computer simulation of series active power filter Author: Petkova, Mariya Petkova; Antchev, Mihail Hristov; Gurgulicov, Vanjo Tomov Date: 2006 Abstract: The possibility of hysteresis following of a reference sinusoid to control series active power filters as correctors of quality of consumed power from supply network is shown in this paper. This possibility is described using computer simulation. Library:
TECHNICAL UNIVERSITY - SOFIA
Title: Economics reasons to use shunt active power filters Author: Antchev, Mihail Hristov; Zobaa, Ahmed Fahem; Petkova, Mariya Petkova Date: 2006 Abstract: The economics reasons to use shunt active power filters are considered from the point of view of the consumer and producer of electrical power. 3-D diagrams, that give the relationship between load parameters and saving for the consumer and producer of electrical power, are carried out. Experimental results with an estimated saving are given. Library:
TECHNICAL UNIVERSITY - SOFIA
Title: Possibilities of improvement of monitoring and diagnostic process of power electronic devices Author: Veselinov, Vladislav Danchev Date: 2006 Abstract: The present article consider the possibilities of optimization of the control processes on the basis of Digital Parametric Complex. Its main functional centre is presented as a part of conditions for reliability of the analysis of different break-down processes. A summery is made about the influence of the system of control upon the security ... Library:
TECHNICAL UNIVERSITY - SOFIA
Title: Electrical design of single-phase diode rectifiers with active-capacitive load by MATLAB Author: Popov, Evgeniy Ivanov; Pindeva, Liliya Ivanova Date: 2006 Abstract: Single-phase diode rectifiers with active-capacitive load widely applied in different supplying sources pose specific problems to the engineers. The known methods (‘eastern”, based on the assumption that the voltage across the filtering capacitor is almost even and ‘western”) for their electrical design are graphic-analytical and suffer ... Library:
TECHNICAL UNIVERSITY - SOFIA
Title: Response of a NAI(TL) scintillation detector in a wide temperature interval Author: Tsankov, Ludmil Todorov; Mitev, Mityo Georgiev Date: 2006 Abstract: The temperature dependence of a NaI(Tl) scintillation detector's response has been studied in the temperature interval (-300C to +500C). Besides the common temperature drift of the light output and that of the decay time of the scintillator, some other very-long-term factors have been observed which give rise to a remarkable hysteresis of ... Library:
TECHNICAL UNIVERSITY - SOFIA
Title: Reiterated micro contacts Author: Videkov, Valentin Hristov Date: 2006 Abstract: In the present report some micro contacts designs of "dry" type where processes of welding and soldering are not applied are considered. The peculiarities of mechanical contact realization for different structures are discussed. They have been divided into groups according to the plane of the devices. Photos of experimentally made structures ... Library:
TECHNICAL UNIVERSITY - SOFIA
Title: Two-dimensional physical ac-simulation of gaas hbts Author: Palankovski, Vassil; Hristov, Marin Hristov; Philippov, Philipp Ivanov Date: 2006 Abstract: : In this work, results from fully two-dimensional physical device simulation of Gallium Arsenide (GaAs) heterostructure bipolar transistors (HBTs) are presented. Scattering parameters (S-parameters) are directly obtained from small-signal AC-analysis of real devices. A comparison reveals very good agreement with measured data. Library:
TECHNICAL UNIVERSITY - SOFIA
Title: Wave soldering quality improvement by design of experiment approach Author: Andonova, Anna Vladova; Dinkova, Nely; Marinov, Ivan Date: 2006 Abstract: The investigation deals with quality improvement of wave soldering joints for printed circuit boards (PCB) by using DOE approach. Using DOE pro XL capabilities, DOE and statistic process control an effective way to approach and evaluate wave soldering process development is offered to determine the most essential control parameters in order ... Library:
TECHNICAL UNIVERSITY - SOFIA
Title: Three-dimensional microfabrication of high-aspect-ratio structures using dry negative photoresist Author: Andreev, Svetozar Krastev; Georgieva, Adriana Kirilova; Todorov, Svetlin Stefanov Date: 2006 Abstract: The development of anisotropic, high-aspect-ratio micromachining processes has provided opportunity for the extension of silicon microfabrication capability well into the third dimension. For some applications, however, truly 3D structures are desired, especially those that possess arbitrary surface height profiles, i.e., surfaces with ... Library:
TECHNICAL UNIVERSITY - SOFIA
Title: Production of 3D contact structures using the LIGA method Author: Videkov, Valentin Hristov; MIhaylova, Evelina Aleksandrova; Andreev, Svetozar Krastev; Iordanov, Nikola Stefanov Date: 2006 Abstract: The purpose of this report is finding an alternative method for 3D contact structures production, which is different from traditional silicon technology. The LIGA method showed capability of preparing such structures. For that purpose the technological sequence for LIGA process implementation in making of functional contact is investigated ... Library:
TECHNICAL UNIVERSITY - SOFIA
Title: Ionization chamber based on RF sputtered ITO thin films Author: Boiadjiev, Stefan Ivanov; Marinov, Boris Marinov; Dobrikov, Georgi Hristov; Yordanov, Rumen Stoyanov; Minkova-Rassovska, Milka Markova Date: 2006 Abstract: The present work presents a new type ionization chambers for x-ray dose meters, based on indium-tin oxide (ITO) thin films. ITO attract our attention as promising material with various applications, here in our study as a transparent conducting coating, but also for transparent conductive electrodes in displays, solar cells and many other ... Library:
TECHNICAL UNIVERSITY - SOFIA
Title: Investigation of the effective thermal conductivity of PCB Author: Andonova, Anna Vladova; Kafadarova, Nadja Miteva; Pavlov, Galin Date: 2006 Abstract: The investigation deals with the numerical solution of the 3D heat conduction equatioin and study variation of the effective conductivity of PCB with different component size. Cases with and without a copper layer on the component side and different PCB thicknesses were investigated. It was shown that the effective thermal conductivity of ... Library:
TECHNICAL UNIVERSITY - SOFIA
Title: Class E power amplifier for bluetooth applications Author: Antonova, Olga Jorova; Angelov, George Stoychev; Draganov, Valentin Date: 2006 Abstract: The main purpose of this paper is to present the design of a class E power amplifier for Bluetooth Class 1 application. The power amplifier has to provide 20 dBm output power and as high as possible power efficiency at 1.5V power supply voltage, for 0.35µm CMOS Austria Microsystems (AMS) technology. Library:
TECHNICAL UNIVERSITY - SOFIA
Title: CMOS VCO design Author: Hristov, Marin Hristov; Rashev, Ivan Krasimirov; Arabadzhiev, Dobromir Nikolov Date: 2006 Abstract: In this article , the design of quadrature voltage controlled oscillator (Q-VCO), which covers the Bluetooh requirements is described. A methodology which makes easy the design of oscillators with negative resistance is shown. Standard 0.35um CMOS process was used. The circuit is fully monolithic, and this decreases its price. The oscillator ... Library:
TECHNICAL UNIVERSITY - SOFIA
Title: Capacitors dc-dc converters for RF implementation Author: Brusev, Tihomir Sashev; Goranov, Petar Trifonov; Hristov, Marin Hristov Date: 2006 Abstract: Two separate capacitor’s dc-dc converters for RF implementation are analyzed. The goal of this work is to be skipped the negative effects of the integrated inductors, which can destroy the circuit’s parameters. Simulations results demonstrated in this paper were done with AMS CMOS 0.35 µm process. Presented architectures are suitable for ... Library:
TECHNICAL UNIVERSITY - SOFIA
Title: Efficiency investigation of buck dc-dc converter for rf applications Author: Brusev, Tihomir Sashev; Goranov, Petar Trifonov; Hristov, Marin Hristov; Slavo, Rosen Nikolaev Date: 2006 Abstract: This paper was focused over the efficiency evaluation and optimization of switchmode dc-dc converter for RF applications. AMS CMOS 0.35 µm technology was used for investigations. Effect of different factors over the circuit’s behavior was considerate. Soft-switching control techniques was analyzed and compared with basic regulation’s method ... Library:
TECHNICAL UNIVERSITY - SOFIA
Title: Electrochemical formation of three-dimensional golden microcontacts Author: Yordanov, Nikola Stefanov; Andreev, Svetozar Krastev; Ivanova, Filipina; Arnaudov, Radosvet Georgiev Date: 2006 Abstract: Electroplating of golden layers is often used in the microelectronic devices. This paper reports our experimental results from formation of golden micro - contact elements – bumps with diameter 300µm, developed by UV-LIGA process. The gold-acid-cyanide electrolyte, which is used, has no influence on the dry negative photo-resist (PR). We ... Library:
TECHNICAL UNIVERSITY - SOFIA