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Design of frequency filters with active current elements
Hort, Jiří ; Jeřábek, Jan (referee) ; Vrba, Kamil (advisor)
This bachelor's thesis deal with designing frequency filters with current active elements. Preamble is devoted to description of basic properties and division of filters. Next part presents some way of designing frequency filter. The element CMI (Current Mirror and Inverter) seems like optimal possible solution for application working in purely current mode. To design purposes serves generalized version GCMI. This thesis describes way of designing the autonomous circuit based on full admitance nets with one and two active elements CMI. Several autonomous circuits with four or five passive elements are derived from every admitance network. Individual autonomous circuits are then presented in chart with their characteristic equation. In conclusion is shown design of selected multifunction frequency filter working in current mode as in voltage mode together with characterization for its various transmission functions.
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High-order frequency filters using modern active elements
Chrást, Jakub ; Minarčík, Martin (referee) ; Jeřábek, Jan (advisor)
The bachelor thesis deals with the designing of active frequency filters of the second – order which is useful for the construction of cascade high – order filters. These filters were designed by means of autonomous circuits. Multiple current mirror and inverter MCMI, current operational amplifier COA and current differencing transconductance amplifier CDTA were used as active elements. Designing is focused on the circuits using MCMI. Designed filters work in current mode. In the introductory part there are described general characters of frequency filters. The second part includes the methods of construction high – order filters, the third part contains the description of active elements used. The design we can find in the fourth part. The functionality of filters was verified by computer simulation. One of the optimal filters was practically verified by available component UCC 0520. Two other filters were used for the construction of the fourth – order filter.
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Design of frequency filters with active current element
Polášek, Lubomír ; Herencsár, Norbert (referee) ; Vrba, Kamil (advisor)
In my bachelor's thesis I deal with the matter of frequency filters, how to use them, types of transferential functions and various types of approximation that can be used in the design. The next part of my thesis describes various types of active elements, either voltage or current or those working in a mixed mode. My thesis also deals with various techniques that we can use when creating frequency filters. In the final part of my thesis I introduce a scheme of an ideal current amplifier and several possible connexions of autonomous circuits with this element. Several suggestions have been shown, as well as final simulations in a OrCAD software and a possible realization of input and output impedance of a PCA element.
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Design of filters in current, voltage and hybrid modes with OA, using autonomous curcuits
Jašek, František ; Minarčík, Martin (referee) ; Vrba, Kamil (advisor)
This bachelor‘s thesis describes the procedure of design of frequency filters with operational amplifier using autonomous circuit. At first there is the procedure of an inference common and autonomous circuits with operational amplifier, of which they are follow on derived know and unknown engagement of frequency filters in voltage, current and hybrid mode. In all these inference frequency filters were determine a transmission function, according them is evidently about which frequency filters is discussed (low pass, high pass, band pass, band stop). The derived filter circuits are then selected two unknown involvement, which is set out in detail the procedure in the design of the frequency filter. Both suggestion circuits was verified by a simulation which results are noticed in this thesis and sequentially was made an experimental verified by mounting product in SMD. On this product was made a metering of a transmission and phase frequency characterization which was recorded in the graph. In fine there is a description of propriety of suggestion frequency filters for a practically use in this production.
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Frequency filters using voltage conveyors
Dohnal, Pavel ; Vrba, Kamil (referee) ; Minarčík, Martin (advisor)
The topic of this bachelor´s thesis was frequency filters and their realization using voltage conveyors. The main goal of my thesis was design and simulation of frequency filters with voltage conveyors through two different methods. At first there were found filters second order with voltage conveyors using autonomous circuits. These circuits resulted from total admitance net. Then the frequency filters using voltage conveyors were solve through synthetic components. At the beginnig of this project the frequency filters, their characteristics, realizations and types were defined. Then were designed basic properties of current conveyors, from which we can derive voltage conveyors. The voltage conveyors are basic building components of my thesis. There were defined individual types of voltage conveyors and their close specification. There was defined universal voltage conveyor. Through the universal voltage conveyor we can realize all types of voltage conveyors. After the definition of useful species there were designed the frequency filters second order using voltage conveyors with four passive components using the total admitance net. There were found 44 these circuits. Then one of these circuits was selected and this circuit was simulated to lowpass and hipass. Subsequently the other method was used, where were used the synthetic components to creation of filters secon order. The circuits resulted from autonomous circuits, which were produced by the first method. 25 of these autonomous circuits were usable for this method. One of these circuits was simulated to lowpass and hipass.
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Multifunction frequency filters using GCMI
Voráč, Ladislav ; Minarčík, Martin (referee) ; Jeřábek, Jan (advisor)
At the beginning of my work are the frequency filter possibilities and their use discussed. I continue with the basic theoretical filter characters, their description through the use of the transfer functions, the transfer filter function of the second rank and further possible filter diversification on active and pasive ones. In the next chapter, there is a current mode introduced with its use and reasons why to pick it up. As next are several active current items descriped, that will be used for construction of the frequency filter of the second rank. The most used item for the application in the pure current mode is GMCI, which easily means Generalized Current Mirrors and Inventors. It is obvious already from its name what does it do, mirror reflecting and inverting. The next chapter talks about the concept method of the autonomous circuit, where in several blocks is the process of the frequency filter concept to be found. Last four chapters are focused on the detailed frequency filters concept, with all its active elements and their simulations. One of the circuit was choosen for the practical realization and at the conclusion it shows the comparison of the measured and simulated transfer parameters.
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Frequency filters using current active elements
Homola, Radek ; Lattenberg, Ivo (referee) ; Koton, Jaroslav (advisor)
This master´s thesis is about MO-CF, DCCA and CC frequency filters with current active elements proposal. Current active elements, their features, structure and utilization are shown in introduction. A progress propose of universal filter is described in thesis. With the use of active elements has been established an universal filter with basic parameter changes capability (quality and limit frequency). SNAP software was used in this propose and the characteristics simulation have been done in OrCad-PSpice. For control changes of quality and limit frequency was used active element DCCA. The main circuit board of universal controlled filter was made with the EAGLE software. Created sample was measured for each type of filter, the different quality and limit frequency. These values were compared with simulated values of the filter.
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Design of tunable frequency filters with modern current active elements
Stejný, Jiří ; Herencsár, Norbert (referee) ; Jeřábek, Jan (advisor)
This master´s thesis deals an active elements called digitally controlled current amplifier, multiple-output current follower and its usage in tunable frequency filters. These tunable frequency filters operate in a pure current mode. In the first part of this work are presented the different types of current active elements. Universal current conveyor, multiple-output current follower, digitally controlled current amplifier (UCC, MO-CF, DCCA). In the second part of this work are introduced particular methods of design tunable frequency filters. Special attention is given to using the design method of via autonomous circuits because it is one of the most. In the last part of this thesis are designed and computer-simulated individual multifunction tunable frequency filters with those already active yet elements. These filters were designed via autonomous circuits or modification of existing circuits. The functionality of the proposed filtres have been verified by computer simulation. Snap3 program was used for the symbolic analyse of circuit and OrCad PSpice program was used to simulate the characteristics of multifunction filters.
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Selected frequency filter design methods using non-traditional active elements
Omasta, Zdeněk ; Koton, Jaroslav (referee) ; Herencsár, Norbert (advisor)
This master’s thesis is bent on comparison of four newest method of analog frequency filter design. After the introductory part, a description of properties and internal structure of active elements (Second-Generation Current Conveyor), VG-CCII (Variable Gain Current Conveyor), VCG-CCII (Voltage and current gained second generation current conveyor) a CFTA (Current Follower Transconductance Amplifier) is mentioned. This active elements are used in subsequent design. At the next part, process of frequency filters design by generalized method of filter design flowing from the full admittance network, by extending autonomous circuits, design using the signal flow graphs theory and design with synthetic high-order elements are presented. Thirty nine autonomous circuits are derived from full admittance networks with one and two active elements CFTA. Selected autonomous circuits are used for direct design of frequency filter and for filter design by extending autonomous circuits. Produced structures guarantee the possibility of controlling the quality factor Q0 independently of the characteristic frequency f0. Three frequency filters are designed by method using the signal flow graph theory. Active elements CFTA, VG-CCI and VCG-CCII are used. Full multifunctional frequency filter with conveyors VG-CCII and VCG-CCII guarantee the possibility of controlling the quality factor Q0 and the characteristic frequency f0 independently of the each other. In last part, from 2nd to 5th order low-pass filters by the method using synthetic high-order elements are designed. The behaviour of the selected filters has been verified by simulations in the PSpice program for all of the mentioned methods separately.
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Universal active elements and their usage in frequency filters
Vencálek, Roman ; Kubánek, David (referee) ; Herencsár, Norbert (advisor)
This master’s thesis deals with the advanced universal modern active elements, such as the current and voltage conveyors. The problem with small bandwidth has been fixed due to the quick development in recent years. Current and voltage conveyors are still being researched. The good properties of conveyors promise their possible commercial usage in the future. For the research of current conveyors we can use parts of other integrated circuits and thus get elements with similar properties. This thesis suggests how to make an active filter using the DBTA and FDBTA elements which were created by “combination” of the universal current and voltage conveyor. Simulations were carried out on selected circuits containing the DBTA to verify their properties. It was for finding out about their behaviour in real applications that the circuits were constructed. This enabled the comparison of the results acquired from the simulation programs with the ideal behaviour of the elements and with the models simulating real properties against the values acquired by measurements of the circuits.
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