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New solutions of converters for measurement of current-mode filters
Štork, Petr ; Kubánek, David (referee) ; Jeřábek, Jan (advisor)
This bachelor’s thesis describes some new solutions of differential converters that convert voltage to current and vice versa. Such converters are necessary for measurement of frequency filters in a current mode due to absence of instruments able to mesure signals with current as signal carrier. The goal is to design such converters that should influence gauged frequency properties in a current mode as little as possible. Converters will consist of operative amplifiers with current feedback. Converters designed this way are tested using simulations from PSpice programme, where particularly wideness of band of individual solutions is tested. Simulated solutions that are the most suitable ones are practicably re-enacted and gauged. These resuls of measurement and simulations are compared.
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Tremolo effect with high modulation frequency range
Pazdera, Michal ; Dvořák, Jan (referee) ; Kubánek, David (advisor)
This work was created while designing the dynamic modulation effect „tremolo“. Because there are certain conditions (wide modulation frequency range, precise input of parameters and precise indication), this work is going to be constructed mainly of searching the right components and schematics, especially wide range frequency oscillator with a period from seconds to the frequency of hundreds of hertz, possible digital frequency counter, which serves as a precise indicator, but we will also talk attenuators, amplifiers, driving circtuits or a power circuit. Possible equations, schematics/circuits and their improvements can be found here through simulators Falstad (ideal circuits) and LTspice (real ciruits), also graphs, sheets, calculations. In the end there is also a short description of the two famous tremolo effects from BOSS and Schaller manufacturers. The design was constructed on breadboard, measured into the protocol and experimentally tested using soundcard. Based on those measurements, a model laboratory task for students has been made.
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Audio signal dynamic compressors
Král, Vítězslav ; Kubánek, David (referee) ; Koton, Jaroslav (advisor)
The aim of this bachelor thesis is to get acquainted with the problems of analog compressors dynamics of the audio signal and practically verify one selected diagram. It deals with individual functional blocks compressor dynamics and shows examples of their implementation. Explains the characteristics of analog compressors and clearly justifies their importance. The thesis also describes the different topologies of analog compressors. Also discusses dynamic processors as such and summarizes their distribution by elementary principle and functionality.
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Design of an AD converter for sensor applications
Bečková, Zuzana ; Kubánek, David (referee) ; Jeřábek, Jan (advisor)
Diplomová práce obsahuje stručný teoretický základ pro designéra/ku A/D převodníku v technologii CMOS a přehled architektur A/D převodníků používaných v automobilovém průmyslu. Volba vhodné architektury pro konkrétní aplikaci byla zásadním úkolem zpra- covaným v semestrálním projektu předcházejícím tuto práci a je rovněž součástí této práce. Analýza v Matlabu, ze které by mělo vyplynout, je-li třeba zahrnout do architek- tury podblok Sample and Hold, je také součástí práce. Klíčovou částí práce je dokumen- tace návrhu jednotlivých podbloků A/D převodníku – operačního zesilovače, kompará- toru a R-2R D/A převodníku – a ověření jejich funkčnosti. V závěru práce je ověřena funkčnost A/D převodníku jako celku.
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Battery Management Systems for LiFePO4 Accumulators
Sejkora, Petr ; Krajsa, Ondřej (referee) ; Kubánek, David (advisor)
This thesis is about BMS systems for the protection, management and supervision of battery-assemblies serial combination of multiple cells. Next part of the thesis is about facilities for an elementary protection of individual cells before overcharging and undervoltage. Draft shall take into consideration the simplicity, low idle power, security function, modifiability for use with other threshold voltages and low cost design. Function is verified by simulating the operation and measuring.
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Methods of acoustic signal sources impedance matching for their further processing
Havelková, Nikola ; Kubánek, David (referee) ; Koton, Jaroslav (advisor)
The purpose of this bachelor thesis is to get acquainted with the theoretical areas related to the issue of impedance matching using the so-called DI boxes. It is mainly the theory of balanced and unbalanced signal, parameters typical for DI boxes (THD, impedance, bandwidth, dynamic range, etc.), knowledge about the transformer, respectively about the coils, or last but not least the issue of operational amplifiers, which is for designing of active DI box absolutely essential. The specifications of the designed DI box based on this theory are subsequently determined and compared with commercially available models. The main target is to achieve better figures or at least get closer to them. Furthermore, the circuit diagram is designed and optimized to achieve predetermined parameters using simulation in the Multisim program from National Instruments. Regarding the resulting specifications of the DI box, a printed circuit board is designed to build a prototype of the device. After its completion, a test gauging using APx525 is done and the results are compared to the target figures.
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Analysis of methods of measurement of fully-differential frequency filters
Kučera, Tomáš ; Kubánek, David (referee) ; Jeřábek, Jan (advisor)
This bachelor thesis focuses on measurements methods of differential frequency -selection filters with active elements in current mode. Firstly it describes differential frequency-selection filters in current mode and conversions from voltage to current mode. Next the thesis deals with measuring of particular voltage converters to differential current and back from differential current to voltage, which is an integral part for measurements of differential frequency-selection filters in current mode. For design of particular converters there was used program OrCAD there and subsequent simulation was executed in program PSpice.
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Influence of Impedance of Input and Output Circuits and Connecting Cables on Audio Signal Transmission
Ďurka, Adam ; Hanák, Pavel (referee) ; Kubánek, David (advisor)
This bachelor thesis deals with the influence of parasitic properties of audio cables as well as input and output impedances of various audio devices for signal transmission between them and also its linear distortion. Using alternative wiring diagrams of these devices, simulations of transmission and linear distortion are performed, and then laboratory jigs for measuring these parameters are designed and implemented. In the next part of the work, the measurements of the transfer between the jigs are performed using the Bode 100 circuit analyzer and the resulting characteristics are compared with the simulated values.
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Design of new active filters, using signal flow graphs
Jašek, František ; Kubánek, David (referee) ; Vrba, Kamil (advisor)
This master’s thesis describes the design of the frequency filters by the help of the graph of the signal flows. There are defined by modern components like GVC (Generalized Voltage Conveyor), GCC (Generalized Current Conveyor), CF (Current Follower), DO-CF (Dual-Output Current Follower), OTA (Operational Transconductance Amplifier), BOTA (Ballanced Operational Transconductance Amplifier) and CFTA (Current Follower Transconductance Amplifier), the graphs of the signal flows, which describe their activity in the thesis. In the other part of the thesis is illustrated the procedure of the design of the frequency filters by the help of the graphs of the signal flows. For the concrete design was selected in the first case as the active component double output current follower and in the second case the CFTA. There are noted all designed circuits of the frequency filters also their characteristic equations in this thesis. The activity of the selected circuits was remitted to the analysis in the simulation program called PSpice. Because the active components, with which was engaged in the design of the filter which doesn’t exist in the real form, that is why the UCC, which is sufficing for attestation of the function of the circuit, was used for the simulation. The simulation was implemented in the frequency range 10 Hz to 10 MHz.
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Synthesis of differential filtering structures with complex active elements
Pánek, David ; Kubánek, David (referee) ; Langhammer, Lukáš (advisor)
This document is focused on already existing single-ended frequency filters with modern active components working in current mode and their modification into fully-differential ended form. After the modification both versions were compared between each other. The first part informs about problems concerning analogue frequency filters. The second part deals with used active components - MO-CF (Multiple Output Current Follower), BOTA (Balanced transconductance amplifier), UCC (universal current conveyor), VDTA (Voltage differencing transconductance amplifier), CDTA (Current differencing transconductance amplifier) and VDCC (voltage differencing current conveyor). Four circuits have been chosen and transformed into their differential form. Two circuits have been chosen and realised into PCB and then practicaly measured in a laboratory. The last part is a summary of simulations and measured results and check of circuits behavior result.
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