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Tunable ARC frequency filter
Kufa, Martin ; Murina, Milan (referee) ; Sedláček, Jiří (advisor)
This bachelor thesis deals with ARC frequency tunable filters. The introductory chapter generally focuses on the basic terms of the frequency filters, such as the mathematical expression of the transfer function, types of selective filters, tolerant field, etc. The next section describes the actual higher-order ARC filters and cascade sequencing, especially ARC band reject and possibilities of its implementation. Following is a concrete realization of the ARC filter to band reject with suggestions for tuning the frequency components in the frequency range 10 kHz to 100 kHz and retuning quality factor. Finally, this work contains the printed circuit board (PCB) design of the ARC frequency analog and digital filter section for tuning F0 frequency and quality factor Q setting using digital potentiometers. Furthermore, it also outlines the flowchart of the program for digital control.
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USB controlled voltage and current source
Pytela, Ondřej ; Kubánek, David (referee) ; Lattenberg, Ivo (advisor)
This diploma thesis is focused on complete construction of lab source which is controlled and powered by USB in personal computer. Different types of possible solutions are mentioned and finally one of them has been picked up as a best choice, which is developed in the rest of this thesis. Besides hardware construction there is also shown creation of main program for PIC18F14K50 microcontroller and main application that provides controlling of USB source via personal computer.
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Adaptive frequency filter
Dolák, Jan ; Murina, Milan (referee) ; Sedláček, Jiří (advisor)
This thesis deals with passive and active frequency filters and their realization. The mail goal of my thesis was to design, simulate and realize adaptive frequency filter with the possibility of alternating it's parameters. The designed filter should be an active band stop filter of fourth kind with the possibility of alternating it's resonance frequence f0 and it's coefficient of quality Q. At the beggining it was needed to study the theory of frequency filters, types of frequency filters, which are often used in praxis, their properties and ways of their realizations. Use of active filters with operational amplifiers was optimal possibility of their realization. Because of there was given them the biggest attention in this part of the thesis. Then it was searched the most acceptable solution of required band stop filter, witch would have the best properties. Digital potentiometers operated by microcontroller were chosen for setting different values of various parameters. Designed circuits were realized after the decision and adaptation of optimal wirings and then the programme for operating of microcontroller and digital potentiometers was configured. By this way designed circuits were experimentally measured.
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Simulation and realization of laboratory DC power supply
Mach, Ladislav ; Koton, Jaroslav (referee) ; Šotner, Roman (advisor)
The thesis deals with analyses of the laboratory symmetrical supplies with adjustable output voltage. It also describes different kinds of current cut-out circuits and several most frequent supply connection schemes. Analyses (simulation program OrCAD) show the characteristics and behaviour of the mentioned supplies. To set the output voltage, operational amplifier structures or linear three-terminal voltage regulator are very often used. The suggested supply was tested and its parameters compared with the simulations. The value of output voltage and current can be controlled with a computer with a USB port. For controlling of the output voltage and current the digital potentiometers were used and controlled by I2C bus.
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Environment control with microcontroller
Králíček, Martin ; Šebesta, Jiří (referee) ; Fedra, Zbyněk (advisor)
This bachelor project focuses on equipment for environment management and check with help of microcontroller. This equipment should enable us to check and manage home environment for example for goldfish, hamsters, spiders and other small pets. Further on, this project describes individual parts of equipment which the ECM-01 consists of. ECM-01 is consists of general block, feed block, relay block with power supply and sensors. The ECM-01 consists of several functional blocks which are controlled by the main microcontroller. The functional blocks contain measurement transducers and action units. The choice of blocks depends both on individual environment and the user. The user can choose which values he needs to control and measure.
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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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ARC filter for frequency analyser
Janečka, Martin ; Murina, Milan (referee) ; Sedláček, Jiří (advisor)
The aim of this work is to propose and realization an active frequency filter with a 4th grade bandpass for making it possible to electronically tune the resonant frequency in range of 10Hz to 100kHz and adjust bandwidth. The thesis discussed two possibilities of filter connections using cascade synthesis. To choose a better option a filter simulations were made in Pspice. Based on the simulations, the number of components and the possibility of electronic tuning a better option is selected. This circuit is implemented, measured and then compared with simulations.
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Digitally controlled multifunction filter
Hubka, Patrik ; Kubíček, Michal (referee) ; Ševčík, Břetislav (advisor)
he bachelor thesis deals with the modern design of analog filter where the digital potentiometers to control circuit parameters are used. The main purpose of this thesis is to create a fully digitally controlled filter at frequencies above 1 MHz based on LT1568 integrated circuit. The main circuit parameters such as cut-off frequency, gain, filter order and type of approximation function are digitally controlled. Analysis of parasitic effects of digital potentiometers is included. The integrated circuit functionallity is demonstrated by LTspice circuit simulator. Finally, the experimental measurement results for various circuit parameters setting are included.
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Microcontroller-based graphic equalizer
Šmotek, Jiří ; Šebesta, Jiří (referee) ; Dušek, Martin (advisor)
This bachelor's thesis deals with problems of correction of audio-signal by help of equalizer. The first part discusses the fundamental properties of electronic filters. The second part describes graphic equalizer and its schematics. A simulation of this suggested connection is executed in the PSpice software. Furthermore, the circuit diagram is presented and the proposal of PCB design equalizer is realized using the digital potentiometers instead of the classic potentiometers. Following part is then focused on description of a programme for the microcontroller and PC. The last part finally presents the measurement.
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Smart Simulator of Resistive Sensors for Life-Cycle Tests
Pospíšil, Jakub ; Mišurec, Jiří (referee) ; Číž, Radim (advisor)
The document is made as an operating item at evaluating of life tests for connected equipments. There is set of bookcases, thanks to them we can use the equipment simply. The digital potenciometer is used like a stimulator of resistance sensor in this equipment. The equipment is able to communicate with PC. The mikrocontroler ATmega324p is the most important part of the equipment.
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