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Electromagnetic field scanner and its utilization in EMC measurement
Chupáč, Michal ; Číž, Radim (referee) ; Kubánek, David (advisor)
Master’s thesis is focused on making the acquaintance of EMC issues and ways of electromagnetic field scanner RS321 utilization for pre-compliance measurements. First part contains analysis of available equipment’s influence on measurement results on the basis of gathered specification. Next part includes an example measurement used as operational manual for scanner and its controlling program. The most important part is correction evaluation for performed EMI measurement of signal generator using its EMC certification protocol and application of gained correction curve on independent EMI measurement of device tested by EMC testing laboratory. Other possibilities of scanner utilization are mentioned in the next chapters. Last part of the thesis contains suitability evaluation of EMC scanner on the basis of findings from performed measurements.
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Power LED control using ATtiny
Martynek, Tomáš ; Kubánek, David (referee) ; Balík, Miroslav (advisor)
Target of this bachelor’s thesis is to develop suitable DC/DC converter for driving power LED with Atmel Tiny micro. There is PHILIPS white power LED – Luxeon Star/O as the light source used. Micro’s AD converter measures current through this LED. This value is used for current driving using PWM micro output. Whole device is accumulator powered, design allows usage of three AA alkaline batteries instead of NiMH accumulators. During design phase was choosing between 2 and 3 AA batteries power solution. Because of the longest working time, the final solution uses 3 AA batteries – in this configuration works the flashlight about 7 hours. Flashlight can charge NiMH batteries from external constant current power source. Micro controls whole charging process and disconnects accumulators from current source after full charge using method of negative voltage change. Timer method is backup method in case, when negative voltage drop is very small – the charging time is limited to max. 9 hours. Micro can detect bad or non-possible charged cells.
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DC/DC converter 12V/300V
Žurek, Jan ; Hanák, Pavel (referee) ; Kubánek, David (advisor)
This Bachelor´s Thesis is about switch power supplies theory. It contains comparation with power supplies made of linear components and briefly describes principals of each type. Bigger attention is devoted to fly-back engagement, on which´s basic is then in practice designed particular switch power supply. All key components are counted, including initiation of important species interaction, especially of transformator, MOSFET semiconductor triode, output diode, and there are chosen important components, which are subsequently implemented into the particular switch power supply engagement. This blocking engagement turned out to be functionless. That was why I decided to use engagement called half-bridge, which was viable.
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Digital filter for acoustic band, implemented by microcontroller
Hudec, Antonín ; Sysel, Petr (referee) ; Kubánek, David (advisor)
Microcontrollers of the ATmega family are not very suitable for real-time digital signal processing. Although they can reach 20 MIPS with maximum clocking of 20 MHz (most of the instructions are within one clock cycle), ATmega has just one 8bit multiplier unit, which is too little for demanding tasks like real-time digital signal filtration. My objective is to find out whether it is possible to filter digital signal with ATmega. If the answer is yes, what is the maximum sampling rate and what output quality can be achieved.
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RDS-TMC signal processing
Plch, Jan ; Kubánek, David (referee) ; Lattenberg, Ivo (advisor)
At the begining of my work is discourse about basic quality signal RDS, that is transmission by the help of radio signal. Described is way encoding, division to the groups as well as internal rules insider and per informative and preventive part block. Follows description obligatory content of all groups as well as description their content according to insider and version. Next chapter is devoted detailed description content groups news TMC which contain traffic and travelling informations . Described is basic space exploited for track telling. Follows explication obligatory part message and show transmission identifiers on data that are painted user. After it are circumscribed next optional data and their fission to the caregory. Mentioned are also possibilities fission broadcast messages on single-group or multi-gropup and their following management in acceptor. Final part work paies description activities created application servant for signal processing RDS-TMC with explication concurrence and functionality single function.
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Nonlinear circuits using current active elements
Langhammer, Lukáš ; Kubánek, David (referee) ; Koton, Jaroslav (advisor)
This thesis deals with non-linear curcuit structures with current active elements. In its introduction this work deals with a description of the current active elements, such as current conveyor, transconductance operational amplifier and current follower. Further the text pays attention to the possiblities of the circuits for modification signals in analogue technology. First are described circuits of diode limiters and transducer. Great attention is paid to the amplifiers with current active elements. Are propřed simulated and practically realized circuits of universal precise full-wave rectifiers using operational amplifier and current conveyor and made comparisons of known and proposed circuits. The paper also discussed other circuit structures using of current active elements, such as multiplier, divider, a triangular signal generator and oscillators.
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Electronically controllable frequency filters with current active elements
Suchánek, Tomáš ; Lattenberg, Ivo (referee) ; Kubánek, David (advisor)
The aim of the thesis is to study the possibilities of the electronic frequency ?lter com- posed of active elements operating in current mode. The main opportunities lie in the change control parameters, most are marginal or quality factor frequency. As the active elements are considered especially CC (Current Convejor), controllable current ampli?er DACA (Digitally Adjustable Current Ampli?er) or combination with the current tracker MO-CF (Multiple Output Current Follower). Another part will focus on the management of the above parameters using digital potentiometers and choosing the appropriate ?lter structure. The ?nal task was to digital control parameters using a PC and measuring its properties.
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Utilization of CDTA and CFTA elements in electrical circuits and frequency filters
Kotlán, Petr ; Herencsár, Norbert (referee) ; Kubánek, David (advisor)
Thesis deals about active component in current mode, CDTA (current differencing transconductance amplifier) and CFTA (current follower transconductance amplifier). CDTA compares two input currents. Outcome current comes trough added terminal Z to load. Caused voltage is transfered to output current by transconductance g. Output surrents shall be possitive (terminal X+) or negative (terminal X-). In contrast to CDTA, CFTA has one current input. Components were used in filters and oscillators. Some filters of second order realized simultaneously low, hight and nad pass were designed. Then, the transfer of filters with diverse topology with opperational amplifier to filter with CDTA and CFTA was shown. Some oscillators were designed. Designed circuits were simulated. Transistor models of CDTA and CFTA were created to purpose of simulation. This components can be realized by AD844 and MAX435. There are shown the conclusions of AC analysis of filters and transission analysis of oscillators. The thesis contains practical realization of second order frequency filter also. Device was made like a PCB by smd. CFTA was realized by components AD844 and MAX435.
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Application of modern active blocks in harmonic oscillators
Votýpka, František ; Kubánek, David (referee) ; Slezák, Josef (advisor)
This work deals with using modern active functional blocks in electronic circuits. These blocks have better features than classical operational amplifiers and are characterized especially by working in current mode. Therefore these blocks can be used in higher frequencies. Using those blocks it is possible to design e.g. electronically variable-frequency filters of types low-pass filter, high-pass filter, band-pass filter, etc. Then it is also possible to easily realize electronically variable-frequency oscillators. This work is focused on some of these blocks, their basic characteristics and principles. Also three oscillators with current conveyors of second generation are designed. Its made simulation, sensitivity and tolerance analysis and magnitude stabilization. Everything is performed in OrCAD PSpice program. These made oscillators are electronic tunable in the band frequency ones of MHz.
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Utilization of signal-flow graphs in design of the fully-differential filters
Žůrek, Radomil ; Kubánek, David (referee) ; Jeřábek, Jan (advisor)
The dissertation deals with the design of fully differential frequency filters using the signal flow graphs. It presents the procedures for designing frequency filters, focusing on the active elements such as multiple-output current followers (MO-CF) and digitally adjustable current amplifiers (DACA), which work in a current mode. It is theoretically discussed the issue of designing the M-C graphs, which are the graphic analogy of voltage and current incidence matrices. There are also presented three designs of 2nd order frequency filter circuits using the indirect method of design by M-C graphs and one circuit design using the direct method. The results of each simulation and measurement are presented in a module frequency characteristics. Finally, there is a summary of M-C graphs characteristics and applicability.
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