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Fully-differential frequency filters with nontraditional active elements
Dvořák, Jan ; Koton, Jaroslav (referee) ; Jeřábek, Jan (advisor)
Bachelor's thesis deals with designs of fully-differential frequency filters which operate in current mode where it is possible to control their parameters by change the transconductance or the amplification. The first part divides and describes in general frequency filters. Furthermore, there are described active elements together with their simple simulation models. The second part describes the design of frequency filter by M-C signal-flow graph and methods of transforming final circuit to fully-differential structure. Next part presents several structures of the second-order filter with their simulations in non-differential and fully-differential forms. Last part presents designs of boards of printed circuits and measurement results of two chosen circuits.
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Frequency filters with untraditional combination of active elements
Filgas, Jaroslav ; Herencsár, Norbert (referee) ; Jeřábek, Jan (advisor)
The Bachelor’s thesis deals with the theory and designing of analog frequency filters of the second order, which operate in current mode and use the untraditional combination of active elements. The filters are designed by means of the autonomous circuits. Active elements used in the design is Multiple Output Current Follower MO-CF, Digitally Controlled Current Amplifier DACA, Generalized Current Mirror and Inverters GCMI, Balanced Operational Transconductance Amplifier BOTA, Inverting Current Conveyor 1st and 3rd Generation ICCI/ICCIII and Universal Voltage Conveyor UVC. The proposed filters work in current mode and their ideal and real models are verified in the simulation environment OrCad. The thesis is structured into five chapters including the conclusion. The first chapter gives the general characteristics of the frequency filters, types of filter functions, types of filters and general equations. The second chapter is devoted to the theory of the active elements. The third charter is about methods of designing and the fourth includes custom designed filters, including their transfer functions and the results verify their functionality in the simulation environment.
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Fully-Differential Frequency Filters with Modern Active Elements
Langhammer, Lukáš ; Dostál, Tomáš (referee) ; Štork, Milan (referee) ; Jeřábek, Jan (advisor)
Tato disertační práce se zaměřuje na výzkum v oblasti frekvenčních filtrů. Hlavním cílem je navrhnout a analyzovat plně diferenční kmitočtové filtry pracující v proudovém módu a využívající moderní aktivní prvky. Prezentované filtry jsou navrženy za použití proudových sledovačů, operačních transkonduktančních zesilovačů, plně diferenčních proudových zesilovačů a transrezistančních zesilovačů. Návrh se zaměřuje na možnost řídit některý z typických parametrů filtru pomocí řiditelných aktivních prvků, které jsou vhodně umístněny do obvodové struktury. Jednotlivé prezentované filtry jsou navrženy v nediferenční a diferenční verzi. Velký důraz je věnován srovnání plně diferenčních struktur s jejich odpovídajícími nediferenčními formami. Funkčnost jednotlivých návrhů je ověřena simulacemi a v některých případech i experimentálním měřením.
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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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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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Analysis of filter structures with controllable amplifiers
Pánek, David ; Langhammer, Lukáš (referee) ; Polák, Josef (advisor)
This bachelor thesis is focused on simulations and practical realizations of already existing frequency filters with modern active components in current mode. New simulation ABM model (Analog Behavioral Model) of DACA (Digital Adjustable Current Amplifier) element was used in the simulations. The first part informs about problems concerning analogue frequency filters. The second part deals with used active components - DACA (Digital Adjustable Current Amplifier), MO-CF (Multiple Output Current Follower), BOTA (Balanced transconductance amplifier) and UCC (universal current conveyor). Four circuits have been chosen and implemented into PCB (printed circuit board) on the basis of simulation results. The first circuit tunes the quality factor with help of DACA component. The second circuit tunes the natural frequency and quality factor with help of DACA components. The third and the fourth circuits are simulated and implemented in differential and also in single ended forms. These circuits tune the natural frequency with help of the same set of current amplification by DACA components. The last part is summary of simulation’s and practical measurement‘s result of this project.
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Frequency Filters with Current Active Elements
Jeřábek, Jan ; Ondráček,, Oldřich (referee) ; Kolka, Zdeněk (referee) ; Vrba, Kamil (advisor)
This doctoral thesis is focused mainly on research of new current active elements and their applications in frequency filters suitable for current-mode. Work is focused on design of new filtering structures suitable for traditional single-ended signal processing and also on structures suitable for fully-differential applications. The thesis contains three designed general conceptions of KHN-type second-order filters. Adjustability of quality factor and pole frequency is provided by controllable current amplifiers that are placed properly in designed structures. Structures also contain second-generation current conveyors, multiple-output current followers, transconductance amplifiers and their fully-differential equivalents. There are lot of possible solutions that could be obtained from general structures, some of them are presented in the work. The thesis also presents several multifunctional and also single-purpose filtering structures of second-order and two variants of n-th order synthetic elements which are suitable to realize higher order filters both in single ended and fully differential type. In each case, functionality of new solutions is verified by simulations and in several cases also by real measurement.
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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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Synthetic Circuit Elements with Higher-Order Immittance with Controlled Current Sources
Popelka, Petr ; Vrba, Kamil (referee) ; Kubánek, David (advisor)
This thesis deals with design and use synthetic circuit elements with higher-order immittance with controlled current sources to implement the frequency filters. Controlled current sources which are derived from the voltage variations are presented. They are current follower, current invertor and current operational amplifier. Low-pass and high-pass filter which are used synthetic elements are simulated on computer. The influence of real properities of active elements and passive elements tolerances on filter functionality is investigated. Selected circuit of frequency filter is realized and measured the frequency characteristic.
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