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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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Design of frequency filters with non-traditional transconductance elements
Gajdoš, Adam ; Vrba, Kamil (referee) ; Jeřábek, Jan (advisor)
The aim of Bachelor’s thesis was to study, design and practically realize controllable frequency filters, working in the current mode, using non-traditional active elements, containing a combination of transconductance amplifiers with current conveyors. Thesis deals in the theoretical part with the basic division of frequency filters, operating modes of circuits and design method of signal flow graphs, which are used for design of the circuits in the practical part. The next section describes all the active elements that are used for circuits realization. In the practical part five circuits are designed with the element VDCC and one circuit with CCTA. Simulation is performed on all circuits using a previously defined model of the real UCC. Last part of thesis describes the design of the PCB and the results of experimental measurements for chosen circuit.
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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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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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Design of frequency filters with non-traditionally combined active elements
Danyi, Ivo ; Koton, Jaroslav (referee) ; Jeřábek, Jan (advisor)
This paper discusses the frequency second-order filters that work in the current mode. As active elements are used VDTA (voltage differential transconductance amplifier) and CCTA (Current Conveyor Transconductance Amplifier) design method as a method is used to graph of signal flow. They are designed and analyzed four frequency filters. The first uses only one element VDTA and is a multifunctional frequency-controllable frequency filter of the second order. The second is composed of two elements, is VDTA fully controllable multifunctional frequency filter of the second order. The third uses one element CCTA represents a multifunctional frequency filter of the second order without control. The fourth element uses a single CCTA and VDTA and is a multifunctional frequency-controlled frequency filter of the second order. All frequency filters are subjec- ted to sensitivity analysis and simulated for ideal and non-ideal active element. Second circuit wiring with two VDTA elements is realized and analyzed the characteristics of this filter.
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Electronic tunable harmonic oscillator
Veselý, Jiří ; Jeřábek, Jan (referee) ; Šotner, Roman (advisor)
This masters project describes properties and primary parameters of active function blocks (OPA, VCA, OTA, CFA, CC) usable in construction of harmonic oscillators. Basic principles of harmonic generators, especially feedback oscillators, are introduced. In next section are presented five particular schematics of harmonic tuned oscillators. For this oscillators are indicated basic formulas, essential qualities performed by simulations and results of sensitivity and tolerance analysis. In the last part of diploma thesis there are selected three circuits which are made and their features are measured.
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Mutlifunctional electronically adjustable KHN filters
Harsa, Jan ; Petržela, Jiří (referee) ; Šotner, Roman (advisor)
In the bachelor thesis some types of KHN filters are analyzed and presented. Filters contain various active elements and they works in the current, voltage and hybrid mode. Great attention is paid to the so-called diamond transistor, which may represent different functional blocks (amplifier with current feedback link, transconductance amplifier and current conveyor) in these circuits. Attention is also paid to the possibility of tuning the filter, which consists in changing the characteristic frequency and quality factor independently. Tuning is achieved by using electronically tuneable active blocks such as voltage controlled operational amplifiers or analogue multipliers. Adjustability is also realized by tuneable passive components (potentiometers). Circuits are tested using the simulation program PSpice. Simulations are performed with professional macromodels, such as model OPA860 or VCA610 (Texas Instruments). In the thesis are results for sensitivity and tolerance analysis, which were gotten with third-level models. The optimization is also resolve for parameters of tuneable filters. The characteristics of the filter operating in voltage mode were verified by measurement.
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Differential and pseudo-differential filtering circuits
Hrbek, Tomáš ; Bečková, Zuzana (referee) ; Jeřábek, Jan (advisor)
This bachelor thesis deals with analog frequency filters operating in differential and pseudodifferential mode. It is focused on active filters second order that use modern active elements. For specific solution is analyzed the ability to control filter parameters. It also deals with the design of fully differential filters and transformations from non-differential filters. The thesis analyzes three specific filtering solutions with which ideal simulations and simulations using third order models are performed. A printed circuit is constructed for one filter solution, its parameters are measured and compared with simulations.
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Analog studio compressor with adustable band-pass filter
Ledvina, Matej ; Kratochvíl, Tomáš (referee) ; Šotner, Roman (advisor)
This thesis deals with design of a dynamic range compressor complemented by an adjustable band pass filter. This device features wider usability than a standard dynamic compressor while simultaniously being able to replace specialized ones. Presented solution utilizes voltage controlled filters of KHN topology to limit the bandwidth of either the processed signal or the controling signal and integrated voltage controled amplifiers for adjustment of dynamics. The design requirements are verified by computer simulation.
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