|
|
Synthesis of differential filtering structures with complex active elements
Pánek, David ; Kubánek, David (referee) ; Langhammer, Lukáš (advisor)
This document is focused on already existing single-ended frequency filters with modern active components working in current mode and their modification into fully-differential ended form. After the modification both versions were compared between each other. The first part informs about problems concerning analogue frequency filters. The second part deals with used active components - MO-CF (Multiple Output Current Follower), BOTA (Balanced transconductance amplifier), UCC (universal current conveyor), VDTA (Voltage differencing transconductance amplifier), CDTA (Current differencing transconductance amplifier) and VDCC (voltage differencing current conveyor). Four circuits have been chosen and transformed into their differential form. Two circuits have been chosen and realised into PCB and then practicaly measured in a laboratory. The last part is a summary of simulations and measured results and check of circuits behavior result.
|
|
|
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.
|
|
|
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.
|
|
|
Electronically reconfigurable frequency filters
Gajdoš, Adam ; Langhammer, Lukáš (referee) ; Jeřábek, Jan (advisor)
The aim of the thesis was design of reconnection-less and electronically reconfigurable filters of SISO type with non-traditional active elements. Adjustability of bandwidth or quality factor is also required. First part of the thesis deals with theoretical analysis of filters, their operation modes and design of frequency filters using Signal-flow graph method aswell. Last but not least, electronical reconfiguration of transfer function and parasitic analysis was discussed. Another part describes active elements used in the practical part of thesis. Behaviors and design of active elements using existing circuits (e.g. UCC,EL2082) are described and their transformation into the Signal-flow graph form too. In the practical part five reconnection-less and reconfigurable filters of SISO type was designed using SNAP program. Simulations were done using Orcad program with ideal and real simulation models of active elements. Last part deals with filter design in EAGLE and experimental measurement.
|
|
|
Automated measurement of circuit characteristics of the current amplifier
Polák, Josef ; Koton, Jaroslav (referee) ; Jeřábek, Jan (advisor)
The aim of my bachelor thesis was to construct a system for measuring DC and AC current measurements of selected characteristics of an amplifier with controllable amplification DACA. It describes the internal structure and the principle of setting the gain of the amplifier. I put together programs for controlling of measurement systems in the program Agilent VEE 9.2. The software communicates with devices via the GPIB bus. For saving and processing data is use Microsoft Excel. With this program Agilent VEE can communicate. With the incurred DC and AC measuring system I carried out measurements at one current amplifier. The measured values are processed into graphs and are given in the last two parts of this work. These measurements shows that the current amplifier operates under the assumptions and myself designed and constructed measurement systems work without problems.
|
|
|
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.
|
|
|
Frequency filters with untraditional combination of active elements
Filgas, Jaroslav ; Herencsár, Norbert (referee) ; Jeřábek, Jan (advisor)
The Bachelor’s thesis deals with the theory and designing of analog frequency filters of the second order, which operate in current mode and use the untraditional combination of active elements. The filters are designed by means of the autonomous circuits. Active elements used in the design is Multiple Output Current Follower MO-CF, Digitally Controlled Current Amplifier DACA, Generalized Current Mirror and Inverters GCMI, Balanced Operational Transconductance Amplifier BOTA, Inverting Current Conveyor 1st and 3rd Generation ICCI/ICCIII and Universal Voltage Conveyor UVC. The proposed filters work in current mode and their ideal and real models are verified in the simulation environment OrCad. The thesis is structured into five chapters including the conclusion. The first chapter gives the general characteristics of the frequency filters, types of filter functions, types of filters and general equations. The second chapter is devoted to the theory of the active elements. The third charter is about methods of designing and the fourth includes custom designed filters, including their transfer functions and the results verify their functionality in the simulation environment.
|
|
|
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.
|
|
|
Filters with current mirrors
Kotlán, Petr ; Herencsár, Norbert (referee) ; Lattenberg, Ivo (advisor)
A second-order frequency-selection filters with current amplifier design is shortly shown in this bachelor's thesis. An autonomous circuit was modified to be conform with all rules of functionality of filters. A few version of autonomous circuit are shown i this text. The circuits were simulated by a program Microcap expecially transient and AC analysis. The current amplifier was replaced by a current mirror or more precisely by a current inverter. A direct-current and his relations to suplied harmonic signal were investigated. A deformation of a harmonic signal is unwanted. This deformation is ussualy created by the transistors in nonlinear mode. This current have to have special ratio to the alternating-current. A sixth-order filter was created by cascade connection of three second-order blocks. This more intricated circuit is correct. A correct rate of characteristic due for low-pass, high-pass and band-pass was shown thanks AC analysis.
|
|
|
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.
|
guest ::
