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Synthesis of frequency filters with ability of the electronic reconfiguration
Theumer, Radek ; Šotner, Roman (referee) ; Langhammer, Lukáš (advisor)
This bachelor thesis deals with proposal of frequency filters providing electronic controllability of its transfer function. The main aim was to propose new filtering structures working in voltage and current mode based on suitable proposal methods. Active elements are implemented by available operational transconductance amplifiers, current amplifiers and conveyors, eventually voltage amplifiers. Four different active controllable filters are presented. Their function is simulated in software PSpice with help of models at transistor level in comparison with ideal behavior (idealized models). Two designed filtering structures were chosen and complemented on parasitic, sensitivity, stability, temperature analysis and Monte Carlo analysis. These circuits were realized on PCB. Measurement results are presented at the end of thesis, including comparison with simulations.
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Transform-based filter design technique based on passive structures
Venclovský, Martin ; Koton, Jaroslav (referee) ; Herencsár, Norbert (advisor)
This diploma thesis deals with transformation of passive elements in filter structures onto substitutes with new active element CFTA. A basic characteristic, types of filters, their frequency characteristics and a form of transfer functions are listed in an introduction. After it is introduced a development of signal flow graphs, single type of graphs and their modifications. There is specified the method Mason-Coates graphs which proves as optimal for analysis circuits. There are listed rules for a correct evaluation and make-up the graphs. Further are described active elements CFTA, CDTA and a current conveyor. There are defined active substitutes to a floating and grounded inductance, a floating capacitor and also a floating and grounded resistor in this thesis. Here, there are also designed substitutes to parallel combinations of floating passive elements. All substitutes use CFTA as an active element and the grounded capacitor as a passive element of substitute. There are presented forms of M-C graphs, transfer functions and equations for calculation passive elements of substitute at created equivalents. Functionality of designed substitutes is always verified on second order passive filters by the help of a PC simulation. There are tabular listed defined equivalents with corresponding signal graphs, transfer functions and equations for calculation capacitor of substitute are here tabular listed too. In this work there are defined two ways of connecting defined substitutes within the scope of one circuit that can be used as a simple connection or integration bounded elements. In the case of usage of the integration bounded elements it is possible to reduce total number used active elements. The usage defined substitutions are verified by way of both methods on known higher order passive frequency filter structures. Third order low pass filter is here realized and scaled in frequency scope from 100 Hz to 100 MHz.
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Design of frequency filters with nontraditional active elements
Jarník, Lukáš ; Herencsár, Norbert (referee) ; Jeřábek, Jan (advisor)
Main topic of this semestral thesis is to design frequency filters with unusual active elements. They are presented active elements as are current conveyors (GCC), voltage conveyors (GVC), transconductance amplifiers (OTA, CFTA), which operate in current mode. Further the thesis contains six designed and simulated circuits with active elements (GCC), (CFTA), (OTA) and (GVC), which are based on according full admittance network. One designed was practically implemented and experimentally verified.
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Versatile autonomous circuit equivalents of floating and grounded passive elements
Štěpán, Radim ; Koton, Jaroslav (referee) ; Herencsár, Norbert (advisor)
This thesis deals with a proposal of versatile autonomous circuit equivalents of floating and grounded passive elements by means of modern active tectonic blocks, such as current and voltage conveyors of all three generations. Current conveyors range as essential tectonic blocks in a current mode. Concerning signal processing, it encompasses a mixed tectonic block. In most cases, these elements may be substituted for presently insufficient operating amplifiers. The voltage conveyor was defined on the basis of duality of current and voltage modes. This element could be selected as a suitable active component for circuits operating in a voltage mode. Implementing the connection, a general autonomous circuit is taken into account. By selecting given admittances, a FDNR (floating frequency dependent negative resistance) element, floating capacitance, floating inductance and ground to floating admittance converter may be implemented. The practical part describes connections which fulfill given requirements. The suggested elements are simulated in comparison with ideal elements and subsequently, they are applied to a frequency filter. The second order filter with a proposed induction coil was practically assembled and experimentally measured in a laboratory. The measured results were compared to simulations received by the use of ideal and real models of current and voltage conveyors.
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Behavioral models of active elements with possibility of independent multi-parameter control
Novotný, Jakub ; Hruboš, Zdeněk (referee) ; Šotner, Roman (advisor)
This thesis is focused on behavioral modelling of active elements with independent multi-parameter electronic control using comercially available components. In a first part of the thesis, CVDIBA, CVDOBA, CVCC and OC elements are discussed. The functionality is verified by simulations using OrCAD PSpice. Used components are diamond transistor OPA860, variable gain amplifier LMH6505, differencing amplifier AD830, low distortion differential driver AD8138, current conveyor EL2082 and current mode four quadrant multiplier EL4083. Four active elements are further built on PCB and measured. Some applications like low pass filter, high pass filter, all pass filter and reconfigurable filter.
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Electronically Configurable Transfer Structures
Langhammer, Lukáš ; Hospodka, Jiří (referee) ; Vávra, Jiří (referee) ; Šotner, Roman (advisor)
Práce se zaměřuje na vývoj a výzkum v oblasti elektronicky rekonfigurovatelných přenosových struktur. Primárním cílem je návrh těchto struktur za užití moderních elektronicky řiditelných aktivních prvků. V práci je prezentováno množství elektronicky rekonfigurovatelných filtračních struktur, jež byly vytvořeny za užití různých návrhových metod. Důraz je dále kladen na možnost řídit některý z typických parametrů filtru pomocí řiditelných aktivních prvků. Práce dále obsahuje několik obvodových návrhů aktivních prvků či stavebních bloků s vhodně řešenou elektronickou řiditelností, tak, aby tyto prvky/bloky mohly být dále použity pro návrh elektronicky rekonfigurovatelných filtrů. Správnost návrhu jednotlivých zapojení je podpořena PSpice a Cadence simulacemi s modely na tranzistorové úrovni. Vybraná zapojení jsou dále realizována za pomocí dostupných aktivních prvků a podrobena experimentálnímu měření.
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Modern active elements and their behavior in linear circuit blocks
Kosztyu, Tomáš ; Jeřábek, Jan (referee) ; Koton, Jaroslav (advisor)
The topic of this master’s thesis was a frequency filters and their realization using modern active elements like UVC, UCC, VFA, CFA and OTA. The base point of this thesis was designed frequency filters with these active elements, when the shape of the transfer function will be identical for all structures and compare the characteristics of active elements. The proposed frequency filters are second order with one or two active elements. In the first part of thesis are discussed basic properties of frequency filters, their properties and distribution. Next are described the general characteristics of active filters and their basic elements such as operational amplifier OTA, VFA and CFA, and recently more frequently used voltage and current conveyor. The second part is the frequency filters designed with these elements is the same transfer function. Subsequently, simulations are done all the filters and obtained the frequency response. Finally, these filters are experimentally made and made practical measurements.
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Universal precision rectifiers with current active elements
Ryšavý, Lukáš ; Jeřábek, Jan (referee) ; Langhammer, Lukáš (advisor)
In this thesis new circuit solutions of universal precision rectifiers with current active elements are proposed. Based on the knowledge of current active elements, universal precision rectifiers and adverse impacts on these circuits new circuit solutions are proposed. These circuits are then simulated and compared with the known circuits of precision rectifiers. In concusion two original circuits and two proposed circuit solutions based on original ones are implemented, their properties are experimentally measured and their function are verified. The main active element in the original circuit are the OPA or THS, the proposed circuits are used the OPA and THS and the universal current conveyor, which offers a wide range of application use and realization of different variations of active current elements.
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