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Current amplifier applications in differential frequency filters
Bokůvka, Tomáš ; Kubánek, David (referee) ; Jeřábek, Jan (advisor)
Bachelors’s thesis focuses on selection and analysis of suitable filtering structures working in current mode. In the first part, there is a common description of frequency filters in terms of function and division. The following text discusses the issues of active elements that creates basic construction of these filtering structures. Core of each circuit is formed by digitally adjustable current amplifier DACA, which enables change of amplification. Another used active elements are universal curret conveyor UCC, dual-output current follower DO-CF, multi-output current follower MO-CF, operational transconductance amplifier OTA and balanced-output transconductance amplifier BOTA. In the last part, there are described four chosen applications of frequency filters. There are introduced calculations of passive components a results of simulations. For experimental confirmation there are chosen two fully-differential structures. The end of work contains summary of measurements of these two frequency filters
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Frequency filters with tunable current amplifier
Jemelík, Lukáš ; Lattenberg, Ivo (referee) ; Jeřábek, Jan (advisor)
The bachelor thesis deals with the designing of active frequency filters of the second – order which are make use of active elements. These filters were designed by means of autonomous circuits. Digitally Controlled Current Amplifier DCCA and Multiple Output Current Follower MO-CF were used as active elements. Designed filters works in current mode. The bachelor thesis is divided into five chapters. In the introductory part there are described general characters of frequency filters, the second part contains the description of the active elements, the third part includes the method of construction high – order filters. In fourth part there are described particular circuitry, their transmission functions and confirmation of their functionality in computer software.
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Fully-differential current mode frequency filters
Kubík, Milan ; Koton, Jaroslav (referee) ; Jeřábek, Jan (advisor)
The bachelor thesis focuses on design of fully-differential frequency filters in current mode. First part informs about problems concerning frequency filters and creating differential structures in current mode. Second part deals with used active components - Digitally Controlled Current Amplifier (DCCA) and Multiple Output Current Follower (MO-CF). Key point is own design of differential filters, which is divided into three parts. In the first part of design results there are filters obtained with help of models from FilterPro software. There are presented circuit structures implementing low pass, high pass and band pass frequency filters. At the next part two filters derived from autonomous circuits. These circuits are working as low pass and high pass frequency filters. In the last part are designed two types of integrator type components – loss integrator and lossless integrator. These circuits were used to realize cascade connection achieving three filtering function – band pass 1, band pass 2 and low pass. Final part summarises the thesis and features of designed structures.
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Fully-differential frequency filter designing with current active elements using signal-flow graphs method
Štork, Petr ; Jeřábek, Jan (referee) ; Langhammer, Lukáš (advisor)
This master’s thesis deals with designing of fully-differential current-mode frequency filters using signal-flow graphs method. The first part is focused on a general description of frequency filters, its function and division. Active elements that create these frequency filters, such as multi-output current follower (MO-CF), balanced or multi-output transconductance amplifier (BOTA, MOTA) and digitally adjustace current amplifier (DACA) are described in the following part. Next, problems and various techniques of designing such filters are discussed on a theoretic basis. In the remaining part of the thesis there are six circuits of frequency filters described in detail; these connections are then transferred of passive elements to a proposed connections, with the assistance of a so-called reflection. Calculations of passive form are stated, as well as results of simulations, where nondifferential and differential variations of these designed frequency filters are compared. Finaly, it has been selected some variants of designs, which has been manufactured, then measured out and resulet has been compare between each other.
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Application possibilities of controllable current amplifier
Bradáč, Josef ; Koton, Jaroslav (referee) ; Jeřábek, Jan (advisor)
This thesis deals with the application using digitally controlled current amplifiers DACA (Digitally Adjustable Current Amplifer), which was developed at the Department of Telecommunications FEEC in cooperation with ON Semiconductor in 2010. In introduction is decribed the topic of active filters and oscillators. Farther active current components, besides DACA are described current conveyor UCC (Universal Current Conveyor), current amplifier DO-CF (Dual-Output Current Follower), MO-CF (Multiple-Output Current Follower) and FD-CF (Fully Diferential Current Follower) and operational transconductant amplifier BOTA (Balanced-Output Operational Transconductance Amplifer) and MOTA (Multiple-Output Operational Transconductance Amplifier). The following is a compilation of theories circuits using signal flow graphs, which are designed using a simulated filter circuits to control the cutoff frequency or the quality factor. Then design and simulation with auxiliary oscillator circuit AGC for controlling the oscillation frequency. Simulations are conducted with ideal models and with models that include some real properties. The conclusion of this work is devoted to the printed circuit board design for a selected filter circuit realization and measurement.
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Analysis of differential and non-differential filtering structures with adjustable current amplifier
Dvořák, Jan ; Vrba, Kamil (referee) ; Jeřábek, Jan (advisor)
The master thesis deals with designs of the single-ended and the fully-differential secondorder frequency filters with adjustable parameters. This filters operate in the current mode where main element is the current amplifier DACA (Digitally Adjustable Current Amplifier). The first part describes basic behaviour of frequency filters and distribution according to filter funcion, used parts and structure. The second part of thesis describes the design of the frequency filters by the M-C signal-flow graphs and the transformating single-ended structures to the fully-differential forms. The next part deals with properties of the active elements and their simulation models. The following part describe six circuits of the frequency filters with adjustable parameters and their simulations. Four simulation models with different properties were used for simulating of the DACA in the each circuits. The last part deals with the practical design and measurement of the selected frequency filters.
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Application possibilities of LNVGA programmable amplifier
Sobotka, Josef ; Hanák, Pavel (referee) ; Jeřábek, Jan (advisor)
This thesis deals with the theoretical description of the qualitative characteristics and parameters of some modern active elements, also discusses the theory of signal flow graphs at the level applicable for the following frequency filter design methods. The thesis is also generally discussed the issue with the circuit simulator PSpice modeling theory and voltage amplifiers on the basic 6-levels. The practical part of the work is divided into two parts. The first practical part is dedicated to design four levels of simulation model of components LNVGA element. The second practical part contains detailed theoretical proposals for three circuit structures implementing the frequency filters 2nd order (based on the basic structure of the OTA-C) using signal flow graphs with configuration options of Q and fm based on the parameters of active elements in the peripheral structure and their verification with prepared LNVGA model layers.
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Differential frequency filters with modern active elements
Kubík, Milan ; Vrba, Kamil (referee) ; Jeřábek, Jan (advisor)
The master thesis focuses on design of fully-differential frequency filters with modern active components in current mode. First part informs about problems concerning analogue frequency filters and creating differential structures. Second part deals with methods of create filters and used active components - DACA (Digital Adjustable Current Amplifier) and MO-CF (Multiple Output Current Follower). Own design of differential filters is divided on two parts. In the first part of design results there are filters created with synthetic higher-order elements. There are presented circuit structures implementing the third order low pass filter and high pass filter. In the second part are designed filters with signal flow graphs. The first circuit implementing low pass, high pass, band pass, band rejection and all-pass filter. The second circuit is with help of the same set of current amplification by DACA components tuning of the natural frequency. For this circuit was make sensitivity analysis. In the final part is practical implementation of the differential frequency filter for tuning of the natural frequency and summarises the thesis.
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Design of adjustable fully-differential filters with current active elements
Polášek, Lubomír ; Koton, Jaroslav (referee) ; Jeřábek, Jan (advisor)
The master thesis deals with design of the fully differential frequency filters working in the current mode and is focused on possibilities of the natural frequency and the quality factor adjustment. At the beginning, there is a brief description of frequency filters and active elements (MO-CF, FD-CF and DACA), which are used in the thesis. Furthermore, simplified signal flow graphs design method and transformation of passive and active elements to the differential structures are described. The designs of four differential circuitries which provide possibility of tuning the natural frequency or quality factor by the gain of the DACA element are shown in the thesis. Simulation results made in OrCAD program with help of third-order models are included. The practical implementation of the differential frequency filter for tuning of the natural frequency by the DACA elements is shown in the last chapter.
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Synthetic immittance dipoles using active current elements
Mráka, Michal ; Jeřábek, Jan (referee) ; Koton, Jaroslav (advisor)
This master thesis discusses the design of Synthetic immittance dipoles using active current elements. The introduction presents aktive current elemetns MO-CF and DACA as buildings blocks for analog filters that are able to process signals with frequencies up to ten megahertz. Methods of synthetic elements using active current elements design is described in this thesis.Is resulted from full addmitances net which contains one active current element Subsequently there are designed various types of frequency filters working in current mode. The functionality of designed filters was verified by computer simulation. Selected designed filter were practically verified with commercially available elelments and active element MO-CF. Measurements in the frequency domain were carried on. On all of types of filters are made sensitivity analysis.
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