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

Now showing items 221-240 of 853

Title: Electro-optical device parameters modeling Author: Asparuhova, Katya Konstantinova; Аспарухова, Катя Константинова; Djamiykov, Todor Stoyanov; Джамийков, Тодор Стоянов Date: 2008 Abstract: This paper presents electro-optical device parameters modeling for OrCad Pspice simulator. Electro-optical parameters of photodiodes, LEDs and laser diodes like total output power, spectral sensitivity, optical power vs. current are modeled using ABM method. The modeled relations are fitted using MATLAB which is resulting in good accuracy. ... Library:
TECHNICAL UNIVERSITY - SOFIA
Title: Behavioral macromodeling of current feedback amplifiers and drive-R – amplifiers Author: Pandiev, Ivailo Milanov; Пандиев, Ивайло Миланов Date: 2008 Abstract: This paper presents new current feedback amplifier and drive-R – amplifier macromodels at behavioral level. They accurately models basic differentialmode electrical characteristics, the offset input voltage and current, the input voltage noise, the output voltage swing, short-circuit current and the input and output impedances. For creating ... Library:
TECHNICAL UNIVERSITY - SOFIA
Title: Behavioral macromodeling of voltage feedback amplifiers Author: Pandiev, Ivailo Milanov; Пандиев, Ивайло Миланов Date: 2008 Abstract: This paper presents a new voltage feedback amplifier macromodel at behavioral level. It accurately models basic differential-mode and common-mode electrical characteristics, the input offset voltage and current, the differential-mode and common-mode amplification, the input voltage noise, the output voltage swing, short-circuit current and ... Library:
TECHNICAL UNIVERSITY - SOFIA
Title: Multifunctional protection relay input module modernization Author: Tuliev, Nikolay Todorov; Тюлиев, Николай Тодоров; Ovcharov, Stefan Jordanov; Овчаров, Стефан Йорданов; Yakimov, Peter Ivanov; Якимов, Петър Иванов; Balkanska, Emiliya; Балканска, Емилия Date: 2008 Abstract: The paper describes the advantages of the modern numerical protection relays. It is proven that the accuracy depends mostly on the input module. Different approaches in design of current and voltage input transducers are mentioned. After studying the parameters and characteristics of the latest integrated circuits of operational amplifiers ... Library:
TECHNICAL UNIVERSITY - SOFIA
Title: Investigation of digital phase detectors Author: Kachakov, Georgi; Качаков, Георги; Mihov, Georgy Slavtchev; Михов, Георги Славчев; Yordanov, Aleksandar; Йорданов, Александър Date: 2008 Abstract: This article deals to describe the simulation and the experimental investigation of the basic types of digital phase detectors and especially acquiring their phase-voltage response. This phase-voltage response represents the output voltage of the phase detector as a function of the phase difference between the digital input sequences. It ... Library:
TECHNICAL UNIVERSITY - SOFIA
Title: Thermal processes in high power LED Author: Todorov, Dimitar; Тодоров, Димитър Date: 2008 Abstract: High Power LED’s have been around for years, primarily concentrated as the lighting source for a variety of applications. Nowadays, LED technology is the leading choice for interior and exterior automotive and lamp street lighting. Although LED light sources offer many advantages, special considerations apply to their use in the application. ... Library:
TECHNICAL UNIVERSITY - SOFIA
Title: Self - tuning of the PID control loops based on the ziegler nichols frequency response method Author: Stoyanov, Eftim; Стоянов, Ефтим; Iovev, Atanas; Йовев, Атанас Date: 2008 Abstract: The Ziegler Nichols frequency response method is widely used for optimal tuning of the PID control systems. There are some difficulties in the method application in the industrial plants. Looking for the limit of stability, there is a danger to make the control system unstable, which may result an industrial accident. To find a limit of ... Library:
TECHNICAL UNIVERSITY - SOFIA
Title: Designing an optoelectronic characterization system for an educational laboratory Author: Djamiykov, Todor; Джамийков, Тодор Стоянов Date: 2008 Abstract: This paper describes a simple, cost-effective parameter analysis system, built of low-cost data acquisition module, easily obtainable components and programmed using a graphical programming environment. The system is designed for educational purpose and can be used for static characterization of ptoelectronic devices, sensors and other ... Library:
TECHNICAL UNIVERSITY - SOFIA
Title: High current source-measure unit based on low cost DAQ Author: Nikolov, Georgi; Николов, Георги Date: 2008 Abstract: The development of a high current source-measure unit based on multifunctional low cost data acquisition board, graphical development environment and a circuit of voltage controlled current source is presented in this paper. Such development is motivated by capability of source-measure units to acquire data, generate I-V curves, and otherwise ... Library:
TECHNICAL UNIVERSITY - SOFIA
Title: Investigation and design of high current sources for B-H loop measurements Author: Nikolova, Boyanka Marinova; Николова, Боянка Маринова; Nikolov, Georgi; Николов, Георги Date: 2008 Abstract: Presented paper describes investigation and design approach for voltage controlled high current sources. The designed circuits are proposed for development of measurement system for B-H magnetic hysteresis analysis. Using the presented circuits and applying the concepts of virtual instrumentation, the laboratory experiments for investigation ... Library:
TECHNICAL UNIVERSITY - SOFIA
Title: Computer controlled setup for temperature measurements for thin film deposition Author: Jivkov, Ivaylo; Живков, Ивайло; Dimov, Deyan; Димов, Деян; Aleksandrova, Mariya; Александрова, Мария; Petkov, Julien; Петков, Жулиен; Denishev, Vladimir; Денишев, Владимир Date: 2008 Abstract: Computer controlled module for temperature measurements with thermocouples based on microcontroller PIC18F2620 is developed and tested. It consists of thermocouples, preamplifiyers, microcontroller PIC18F2620 and serial interface unit. The software configures the microcontroller for temperature measurement, implements a temperature calibration ... Library:
TECHNICAL UNIVERSITY - SOFIA
Title: Air pressure measurement using silicon based analog sensor SPD015A Author: Sapundjiev, Petar Vasilev; Сапунджиев, Петър Василев; Mitev, Mityo Georgiev; Митев, Митьо Георгиев; Manoev, Ventseslav; Маноев, Венцеслав Date: 2008 Abstract: The aim оf this work is to examine the properties of analog pressure sensor SPD015A and it’s use in atmospheric pressure measuring system. Special attention has been paid at the problems related with the temperature dependence of the sensor. Two methods for temperature compensation are described: one by using mathematical procedure and ... Library:
TECHNICAL UNIVERSITY - SOFIA
Title: Study of power and ripple factors of controlled thyristor rectifiers Author: Popov, Evgeniy Ivanov; Попов, Евгений Иванов; Pindeva, Liliya; Пиндева, Лилия; Hristov, Sergey Kirilov; Христов, Сергей Кирилов Date: 2008 Abstract: Controlled thyristor rectifiers provide regulatable output d.c. voltage, current and power necessary in many power application by phase control of the moment of turning on the devices. But at the same time the power factor in respect to the supplying mains is decreased that leads to an additional loading of the system for generation and ... Library:
TECHNICAL UNIVERSITY - SOFIA
Title: Small local network for microprocessor controllers Author: Shoshkov, Tsvetan Petkov; Шошков, Цветан Петков; Mihov, Georgy Slavtchev; Михов, Георги Славчев; Manoev, Ventsislav; Маноев, Венцислав Date: 2008 Abstract: This article deals with the matter of developing of a driver for small local field network for microprocessor controllers in information controlling systems. As a basis it is used the structure of a small local network driver, developed in Technical University of Sofia. It is processed to work according to a standard protocol under the ... Library:
TECHNICAL UNIVERSITY - SOFIA
Title: Feasibility assessment of the smart standartized sensors design for vehicle tests and diagnostics Author: Geshev, Georgi Dotsov; Гешев, Георги Д.; Dimitrov, Emil Nikolov; Димитров, Емил Николов Date: 2008 Abstract: The paper examines the basic principles set by the IEEE 1451 standards. A review of the current status of the standards has been made. Some recommendations are given how to design electronic monitor systems with a variety of requirements taken into account. The paper is focused on a vehicle real-time diagnostic systems design. The developed ... Library:
TECHNICAL UNIVERSITY - SOFIA
Title: Research on the metrological characteristics and stability of gamma-dosimeters using SWFM Author: Mitev, Mityo Georgiev; Митев, Митьо Георгиев; Dimitrov, Еmil; Димитров, Емил; Hristova, Diana; Христова, Диана Date: 2008 Abstract: In this work we discuss the problem of precise energy calibration of gamma-dosimeters, using the Spectral Weight Function Method (SWTM). We provide some comparative measurement results for the dose rate, gathered using the aforementioned method and through spectrometric measurements. Library:
TECHNICAL UNIVERSITY - SOFIA
Title: Performance of a station for long term monitoring of the atmospheric ground layer status in urban sites Author: Mitev, Mityo Georgiev; Митев, Митьо Георгиев; Tsankov, Ludmil Todorov; Цанков, Любомир Тодоров Date: 2008 Abstract: The performance of a station for long term atmospheric monitoring situated at the Astronomical Observatory of the Sofia University in Sofia is considered. The ability of the station to register the change in the environmental radiation due to changes in the meteorological status of the atmosphere is demonstrated. The long term efficiency ... Library:
TECHNICAL UNIVERSITY - SOFIA
Title: Test generator for examination of PLL and DDS systems Author: Yordanov, Aleksandar; Йорданов, Александър Date: 2008 Abstract: This paper describes a test generator for examination of digital and analogue phase locked loop and digital synthesizers. In practice very often are used signals with various types of shapes and frequencies. For high precision signals mostly are used PLL and DDS generators. The device described in this paper is based on a digital synthesizer ... Library:
TECHNICAL UNIVERSITY - SOFIA
Title: Generalised equations and algorithm of the subtraction procedure for removing power-line interference from ECG Author: Mihov, Georgy Slavtchev; Михов, Георги Славчев; Dotsinsky, Ivan Asenov; Доцински, Иван Асенов; Levkov, Chavdar; Левков, Чавдар; Ivanov, Ratcho Marinov; Иванов, Рачо Маринов Date: 2008 Abstract: The present work generalises the subtraction procedure, which removes the power-line interference without affecting the components intrinsic to the ECG. It is based on previous investigations, dealing separately with the cases of odd and even multiplicity/non-multiplicity between the sampling rate and the power-line frequency. The study ... Library:
TECHNICAL UNIVERSITY - SOFIA
Title: Implementation of real time power-line interference removal procedure from ECG Author: Mihov, Slavy Georgiev; Михов, Слави Георгиев; Ivanov, Ratcho Marinov; Иванов, Рачо Маринов; Popov, Angel Nikolaev; Попов, Ангел Николаев Date: 2008 Abstract: Presented is the algorithm of the subtraction method for removing powerline interference from ECG signals, in case of powerline frequency variations. The existing MatLab prototype version is adapted for real time execution on DSP and programmable logic (FPGA) platforms. The algorithm is ported and experimented in case of odd sample number ... Library:
TECHNICAL UNIVERSITY - SOFIA