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LNA for the APT signals receiver
Žúrek, Dan ; Urbanec, Tomáš (referee) ; Baran, Ondřej (advisor)
This bachelor thesis is dealing with design, realization and optimization of the LNA (Lownoise amplifier) for receiving of APT signals from the NOAA weather satellites in 137 MHz – 138 MHz frequency band. The first part of this work is aimed on critical parameters of the amplifier and the filter circuits especially on a noise figure and a high selectivity. The next part of this project is about the particular concept and simulation of LNA by using the Ansoft Designer software. The printed circuit board is realized in the Cadsoft Eagle. The final part of this bachelor thesis is dealing with a production of such amplifier together with its measurement and testing in a real operation of receiving APT signals.
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Synthesis of Modern Structures of Frequency Filters
Friedl, Martin ; Hájek, Karel (referee) ; Brančík, Lubomír (referee) ; Sedláček, Jiří (advisor)
Within modern frequency structures, the filter frequency region of up to 10 MHz constitutes a promising research topic that currently attracts intensive attention of specialists interested in the problem. The main reason of this fact consists in that the rapid development of modern technology allows the production of innovated structures of the analog frequency filters required in the defined band. In this context, however, it is also necessary to refine the methods applied in the synthesis and optimization of these structures; such improvement should be carried out with respect to fundamental properties and usability of today's active elements (operational amplifiers with voltage feedback whose Gain Bandwidth Product ranges within units of GHz, operational amplifiers with current feedback, conveyors, transimpedance operational amplifiers). In this thesis, active blocks of synthesis inductors (SIs) and frequency dependent negative resistors (FDNRs) are examined in detail, and the author provides novel formulas to define the basic parameters of the dual circuits. Due emphasis was placed on optimizing the basic building blocks of the second order and defining the variation of their properties caused by the addition of modern active elements. The blocks were analyzed and modified in view of their possible use in higher-order circuits. For active filters of a higher order, simulations were performed to indicate the actual sensitivity of the cascade and non-cascade ARC structures. The following phase of the research comprised mainly the designing of several filters, and this activity was further completed with the verification of the methodology for the synthesis and optimization of higher-order loss ladder filters with modern active blocks. Special attention was paid also to the methods enabling the optimization of such filters, which are invariably based on RLC prototypes. In order to verify the theoretical conclusions, the author materialized a large number of sample optimized filters and measured their parameters. The closing section of the thesis describes the use of the filters in specific applications.
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Active frequency filter using current mode
Paščinský, Jiří ; Dostál, Tomáš (referee) ; Slezák, Josef (advisor)
The aim of this work is design of frequency filter working in current mode. The introduction of the work deals with features and applications of frequency filters. Special attention is paid to the transfer function of the filter. In third chapter different operational modes of electrical circuits and their advantages and disadvantages are discussed. Attention is paid to active blocks suitable for circuits working in current mode. There is description of components AD844 and EL2082 which represent current conveyors of the second generation and are used in the designed filter. The last two chapters deal with design of component values of the frequency filter. The designed circuit was simulated in PSpice and the results were compared with measurments. Also sensitivity and tolerance analysis of the filter were performed.
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Half-mode SIW filter.
Jackovič, Petr ; Láčík, Jaroslav (referee) ; Hubka, Patrik (advisor)
This bachelor’s thesis presents the design of a half mode substrate integrated waveguide band-pass filter by quarter wavelength resonators. This filter is design symestric with quarter resonators are coupled by impedance and admittance inverters. Simulated results shows the HMSIW filter is good performance of low insertion loss, hight quality factor and compact size. In numerical model is good agreement of bandwidth and transmission between simulation and measurement.
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Substrate integrated waveguide filter
Vyskočil, Jiří ; Tkadlec, Roman (referee) ; Láčík, Jaroslav (advisor)
In this thesis is discussed a filter design of a band-pass substrate integrated waveguide filter on the frequency of 5 GHz. It also includes design theory, filter synthesis, filter analysis in the program CST Microwave Studio® and the results of measurement on a vector network analyzer. The analysis results are compared with the measured results. Good agreement between simulated and measured results is observed.
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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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Frequency filter
Suchánek, Tomáš ; Kubánek, David (referee) ; Káňa, Ladislav (advisor)
The main objective of this thesis is to design and implement integration that will be building block for tunable active filters 2nd range of low , high and band pass through the jet structure Sallen - Key. This work first examines the use of different types of frequency filters, the detailed design of the components and selection of a suitable operational amplifiers for participation. Practical part focuses on the production of the finished product, measure its parameters resulting in graphs.In implementing are used software such as simulation programme Micro-cap and layout editor Eagle.
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Visualization of vocal cords movement
Kutálek, Libor ; Sekora, Jiří (referee) ; Rozman, Jiří (advisor)
The aim of this work is to clarify the function of the vocal cords and get familiarized with their investigative methods. In this work we find possible solutions to the peripheral device to illuminate the rapidly vibrating vocal cords using an LED that is less energy exacting than conventional halogen lamps. Then there are solved the problems of processing, signal filtering and finding the natural frequency of vibration of the vocal cords.
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Ultrasound blood flow detector
Kameníček, Robert ; Dlouhý, Jiří (referee) ; Rozman, Jiří (advisor)
My master’s thesis deals with methods of measuring the ultrasonic blood flow blood vessel with a detailed focus on Doppler ultrasound systems, which find application in the diagnosis of superficial vascular and obstetrics. The thesis is described a proposal indicating polydirectional Doppler system with a continuous carrier wave frequency of 4 MHz, the intensity of ultrasound 100 mW/cm2 and diameter D-shaped transducers 8 mm. As a result, the indicator will be able to measure blood flow velocity in the range of 5-40 cm/s, which appears to 3.5 digit display. After describing important theoretical assumptions, the work pays block diagram indicator. Furthermore, it examines the various functional blocks on the requirements imposed on them. It looks at the options of each functional block, and finally describes the implementation of the selected option and including peripheral solutions. Great attention is paid to the power of the indicator, where the power supply will be used 9 V battery. Create a symmetric voltage for operate amplifier and other auxiliary voltage will procure DC/DC converters. In conclusion, the work is located around the perimeter solutions indicator. The following draft for the production of double-sided PCB, its installation and a list of elements. The outcome of the thesis is complete documentation for the implementation of an indicator of blood flow, which allows us to obtain information on throughput vessels, especially the lower and upper limbs.
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