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Modular approach to desing of modern analog devices in CMOS technology
Prokop, Roman ; Ďuračková, Daniela (referee) ; Hudec, Lubomír (referee) ; Musil, Vladislav (advisor)
The presented dissertation thesis deals with modular design of analog circuits in CMOS technology. The goal of the work is to design a set of modular microelectronic building blocks and realize the selected modern active circuits, working primarily in current mode. Nevertheless, the modular approach can be used for design of generally known classical elements, e.g. opamps, as well. As a part of the work, the development of the totally new highly versatile active circuit CCTA has been done, including detailed analysis of utilization and introduction of the most interesting applications. This circuit CCTA, together with relative, already theoretically treated circuit CDTA, has been realized here for the first time, in two different topologies. Final circuits were tested. On the basis of measurement results the library of behavioral models for PSpice was created, including exemplary simulations of the selected applications. Based on the obtained knowledge the brief comparison of voltage mode circuits and current mode circuits was done.
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The Tolerance Analysis of Filters with CDTA
Miksl, Jan ; Jeřábek, Jan (referee) ; Šotner, Roman (advisor)
The bachelor thesis deals with the concept, design, modeling, tolerance and sensitivity analysis of the KHN filter using CDTA. The first part contains theoretical introduction about filters and their general properties. Secondly, the CDTA element, its block structure, schematic symbol as well as its circuit features are defined. Standard KHN filter structure with operational amplifiers is simulated. Results of this simulation are used for comparison with simulations results of CDTA KHN filter structure. The multifunctional CDTA KHN filter structure is simulated using ideal CDTA models, third-level models and models based on professional macromodels of attainable components (AD 844, MAX 435). Then tolerance and sensitivity analyses are explained and described. The following section discusses ways of modifying the structure and design KHN structure with CDTA models 3rd level. In the last chapter the circuit is optimized using PSpice and the attention is focused on achieving the best possible involvement of the typical characteristics of the elements of tolerance. In conclusion, the results of simulations are evaluated, compared the characteristics of circuit before and after optimization, and mention the advantages and disadvantages of filter elements with CDTA.
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Controlled analog frequency filters
Martinek, Pavel ; Koton, Jaroslav (referee) ; Minarčík, Martin (advisor)
In this bachelor’s thesis are described elements frequency filters, especially OTA amplifier, current and voltage conveyor. There're presented possibilities of control frequency-selection filters and components to control, analog multipliers, DA converters, controlled amplifiers and digitally controlled potentiometers. There are discussed some circuits of controlled filters and their possibilities of independent control of parameters f0, Q. Frequency characteristics for mentioned filters are verified simulator programme. The circuits are modified to other type filter and again frequency charakterestics are verified simulator programme PsPice.
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Utilization of CDTA and CFTA elements in electrical circuits and frequency filters
Kotlán, Petr ; Herencsár, Norbert (referee) ; Kubánek, David (advisor)
Thesis deals about active component in current mode, CDTA (current differencing transconductance amplifier) and CFTA (current follower transconductance amplifier). CDTA compares two input currents. Outcome current comes trough added terminal Z to load. Caused voltage is transfered to output current by transconductance g. Output surrents shall be possitive (terminal X+) or negative (terminal X-). In contrast to CDTA, CFTA has one current input. Components were used in filters and oscillators. Some filters of second order realized simultaneously low, hight and nad pass were designed. Then, the transfer of filters with diverse topology with opperational amplifier to filter with CDTA and CFTA was shown. Some oscillators were designed. Designed circuits were simulated. Transistor models of CDTA and CFTA were created to purpose of simulation. This components can be realized by AD844 and MAX435. There are shown the conclusions of AC analysis of filters and transission analysis of oscillators. The thesis contains practical realization of second order frequency filter also. Device was made like a PCB by smd. CFTA was realized by components AD844 and MAX435.
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Application of modern active blocks in harmonic oscillators
Votýpka, František ; Kubánek, David (referee) ; Slezák, Josef (advisor)
This work deals with using modern active functional blocks in electronic circuits. These blocks have better features than classical operational amplifiers and are characterized especially by working in current mode. Therefore these blocks can be used in higher frequencies. Using those blocks it is possible to design e.g. electronically variable-frequency filters of types low-pass filter, high-pass filter, band-pass filter, etc. Then it is also possible to easily realize electronically variable-frequency oscillators. This work is focused on some of these blocks, their basic characteristics and principles. Also three oscillators with current conveyors of second generation are designed. Its made simulation, sensitivity and tolerance analysis and magnitude stabilization. Everything is performed in OrCAD PSpice program. These made oscillators are electronic tunable in the band frequency ones of MHz.
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Modeling of the unconventional functional blocks in Pspice
Zetík, Rostislav ; Brančík, Lubomír (referee) ; Petržela, Jiří (advisor)
This master´s thesis on theme Modeling of the unconventional functional blocks in Pspice deals with the design procedures of electronic elements models and should to help with their create. At the beginning the thesis theoretically describes how the models are created and what possibilities for modeling the program Pspice offers. There are drawn near the individual levels of model and their properties. The second main part of thesis shows practically step by step the design procedures of models of the operational amplifier, current and voltage conveyors, OTA, CDTA, immittance inverter and converter and logarithmic amplifier. There are created the models up to 4.th level, the ideal, resistive, frequency dependent and nonlinear. The basic transmission properties, input and output impedance are modeled this way. The created models with sufficient accuracy correspond to the parameters of the commercial elements. This thesis such shows the possibilities of the program for finding of values for model components like stepping or Optimizer tool.
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