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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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Active Frequency Filter Design Methods Based on Passive RLC Prototype
Pisár, Peter ; Vrba, Kamil (referee) ; Kubánek, David (advisor)
The aim of this diploma thesis is to design active frequency filters based on passive RLC prototype. Three methods of the design of active filters and active functional blocks of electronic circuits working in current or mixed mode are used to this purpose. These blocks allow to process electrical signals with frequencies up to low tens of megahertz. In addition they feature for instance with high slew rate and low supply voltage power. Active high-pass and low-pass 2nd order filters are designed using simulation of inductor by active subcircuit method. Grounded and subsequently floating synthetic inductor is made with the current conveyors in the first case and with the current operational amplifiers with single input and differential output in the second case. This method advantage is relatively simple design and disadvantage is great quantity of active functional blocks. Active filters based on passive frequency ladder 3rd order filter while only one floating inductor is connected, are designed with circuit equation method. In the first design differential input / output current followers are used and in the second case current-differencing buffered amplifiers are used. This method benefits by smaller active blocks number and disadvantage is more complex design of the active filter. Active filter based on passive prototype of low-pass 3rd order filter with two floating inductors is designed with Bruton transformation method. Final active filter uses current operational amplifiers with single input and differential output which together with other passive elements replace frequency depending negative resistor, which arise after previous Bruton transform. This method usage is advantageous if the design consists of larger quantity of inductors and less number of capacitors. High-pass 2nd order filter is simulated by tolerance and parametrical analyses. Physical realisation utilising current feedback operational amplifier which substitute commercially hardly accessible current conveyors is subsequently made. Measurements of constructed active filter show that additional modifications, which allow better amplitude frequency characteristics conformity, are necessary.
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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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Nonlinear circuit structures using current and voltage conveyors
Gabriel, Viktor ; Hanák, Pavel (referee) ; Koton, Jaroslav (advisor)
This thesis deals with the use of active components in nonlinear circuits. First the variants of the current and voltage conveyors are theoretically described. Then the thesis deals with the design of the new curcuit structures with nonlinear components, which comes out from the former known realizations. Several possible solutions of the examined circuit have been designed and the most convenient structure has been selected. The chosen solution has been thoroughly analysed in subsequent diploma thesis to enable comparison of the theoretically designed circuit with the practically realized one.
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Low voltage low power current conveyor CCII
Kadaňka, Petr ; Vávra, Jiří (referee) ; Khateb, Fabian (advisor)
This paper is focused on comparing CCIIs by their construction principle. It researchs differences between gate-driven and bulk-driven approach, and between design based on current mirrors or operational amplifier. Designed current conveyor functionality is verified by SPICE simulation. Main objective of this work is to obtain current conveyor with lowest possible supply voltage and minimal power consumption.
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Analysis, features and applications of available current mode multipliers
Miksl, Jan ; Jeřábek, Jan (referee) ; Šotner, Roman (advisor)
The diploma thesis deals with analysis, validation, measurement of parameters of the commercially available current multiplies (namely the EL2082 and EL4083) and their applications in practice. Control analysis are carried out in OrCAD PSpice program and compared with values from datasheets. Control analysis are focused on AC and DC characteristics of these active blocks. There are discusses the input impedance, the output impedance, the current gain and the possibility of electronic adjusting. The parameters of the elements were verified by measurements. Proposals for circuit applications (selective circuit, oscillator, frequency filter) with EL2082 and EL4083 are presented and analyzed in the program OrCAD. Three oscillator circuit designs are experimentally tested and the results are compared with the theoretical expectations and simulations in OrCAD. The possibility of electronic control for oscillators is examined. Also the sensitivity and the tolerance analysis are carried out. The constructional details of oscillators are presented at the end of this work.
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Multifunctional analog frequency filters
Žůrek, Radomil ; Koton, Jaroslav (referee) ; Minarčík, Martin (advisor)
Main topic of this bachelor thesis are the frequency filters and their application. It presents multifunction frequency filter circuits with focus on active circuit elements like current conveyors (GCC), voltage conveyors (GVC) and transconductance amplifiers (OTA), which operate in both voltage and current modes. Then it presents the outcomes of designing 26 second order frequency filters, all operating in both voltage and current modes. It discusses in theory the problematics of M-C graph design, which is graphics-based analogy of voltage and current incidental matrices. Selected circuit designs are examined as examples with their transfer functions determined and results presented as module frequency characteristics. Individual M-C graphs (signal flow graph) are designed for each filter circuit. In conclusion are summarized the characteristics of M-C graphs and their suitable applications.
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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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Electronically tunable frequency filters
Štěpán, Radim ; Jeřábek, Jan (referee) ; Herencsár, Norbert (advisor)
This bachelor thesis deals with a proposal of electronically controllable filters by means of modern active elemental parts such as current conveyors, transconduct amplifiers or programmable current amplifiers. The suggestion of new connection of frequency filters uses graphic chart of active and passive elements. In the introduction there is described the survey of signal flow graphs, modern active elements suitable for proposal frequency elements. The procedure of proposal of controllable frequency filter based on set typical formula of designed circuit is demonstrated as an example. On a basis of different modifications the designed circuit is made with various types of active elements. Simulation results of the program PCspice confirmed the proper working of the proposal circuits.
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Applications of multi-output active elements in current-mode
Maňas, Stanislav ; Jeřábek, Jan (referee) ; Šotner, Roman (advisor)
Bachelor's thesis deals with analyzing the characteristics of the block in current mode CCII and its applications. The first part is devoted to the theory of CC block, the theory of CCII block his peripheral involvement and exploration properties. The second part is a third model levels and this is carried out sensitivity and tolerance analysis of individual involvement. The third part is a block CCII surveyed as part of participation frequency filters and oscillators. One involvement has been experimentally tested. At the end of each subsection is obtained by a comparison of the characteristics of individual involvement.
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