National Repository of Grey Literature 99 records found  1 - 10nextend  jump to record: Search took 0.01 seconds. 
Circuit realizations of special chaotic dynamical systems
Kaleta, Lukáš ; Langhammer, Lukáš (referee) ; Petržela, Jiří (advisor)
This thesis deals with the circuit synthesis of two given chaotic dynamic systems. The introduction of the work analyses a theory of dynamic systems, a theory of chaos and methods of chaotic circuits synthesis. The practical part contains a derivation of circuits from specified systems of differential equations with an integrator synthesis method and polynomial expansion of resonant circuit equations. Following realization of the circuits is included. The output of the work are the results of numerical integrations of specified systems, simulations of synthesized circuits and measurements on implemented circuits. Results are in a form of state portraits and frequency spectra, ilustrating the induced chaotic phenomena.
Single-Ended Frequency Filter in Practical Realization with Digitally Adjustable Current Amplifier
Polák, Josef ; Langhammer, Lukáš
This paper deals with proposed 2nd order universal frequency filter. In design of this frequency filter, multiple-output current follower (MO-CF) and digitally adjustable current amplifier (DACA) have been used. The frequency filter is proposed with ability to control the pole frequency without disturbing the selected quality factor by parameter of DACA active elements in form of integrated circuit. Design is supported by simulation and also measurement results.
Laboratory exercises in NS3 enviroment for Advanced communication technology course
Vadkerti, Gabriel ; Mašek, Pavel (referee) ; Langhammer, Lukáš (advisor)
This master thesis deals with creating laboratory exercises for students in simulator NS-3, where the IPv4 and IPv6 protocols, unicast and multicast transmission types, quality of services in wireless networks, furthermore protocols TCP and UDP are analyzed. The first section describes the NS-3 network simulator, the Eclipse development environment and the method how to connect them. In the next section protocols IPv4 and IPv6 are presented, the structure of the headers and the technique of fragmentation are described in detail. Based on this a laboratory exercise is created which deals with comparison of protocols IPv4 and IPv6. In the next section the types of transmissions are described, furthermore the multicast transmission type is explained more in detail. In the next practical section the second laboratory exercise is created, which deals with comparison of unicast and multicast transmission types. The subject of the following section is ensuring quality of services in data networks, the EDCA access method is discussed more in detail. In the next section the EDCA access method is implemented in a simulation as a laboratory exercise, in which the impact of the access category of EDCA to different transmission parameters is investigated. The next section deals with protocols TCP and UDP, furthermore with the structure of their headers. In the last section a laboratory exercise is created, in which the properties of the protocols TCP and UDP are compared.
Design and analysis of electronically reconfigurable filtering structures
Kříčka, Tomáš ; Dvořák, Jan (referee) ; Langhammer, Lukáš (advisor)
This bachelor thesis deals with the proposal of analog filters with the ability of the electronic reconfiguration. The main aim was to propose three fully electronically reconfigurable filters using different methods. The work focuses on the use of modern active elements that ensure the electronic reconfiguration. Specifically on operational transconductivity amplifiers, second-generation current conveyors and current amplifiers. The transfer functions are simulated in the Orcad PSpice software, at the ideal and behavioral level. Sensitivity and parasitic analysis is applied to the two proposed filtration structures. Both structures are made on printed circuit boards, which are measured and then their transfer functions are compared with the simulated functions.
Experimental MANET network in NS-3 simulator
Vadkerti, Gabriel ; Langhammer, Lukáš (referee) ; Bartl, Milan (advisor)
This thesis deals with the problem of MANET networks. It presents routing protocols, their types, advantages and disadvantages. The protocols, such as AODV and OSPF, are analyzed in detail. The next section describes the NS-3 simulator and the meaning of its key codes. There are named and explained the most common mobility models and their correct writing into the source code. A MANET network simulation is created and a program for indicating the routes of packets through the network is introduced. The next describes traffic models for data networks. A simple traffic model for NS-3 and a program for graphic representation of this traffic were created. The DCE module for NS-3 is introduced in the last section and a demonstrational program of using Linux stack is created.
Design of laboratory tasks focused on the OLSR protocol.
Pecina, Martin ; Langhammer, Lukáš (referee) ; Kubánková, Anna (advisor)
An ad hoc mobile network is a collection of mobile nodes that are dynamically and arbitrarily located in such a manner that the interconnections between nodes are capable of changing on a continual basis. In order to simplify communication within the network, a routing protocol is used to discover routes between nodes. The primary goal of such an ad hoc network routing protocol is correct and efficient route establishment between a pair of nodes so that messages may be delivered on time. Route construction should be done with a minimum of overhead and bandwidth consumption. This document describes the Optimized Link State Routing (OLSR) protocol for mobile ad hoc networks. The key concept used in the protocol is that of multipoint relays (MPRs). MPRs provide an efficient mechanism for flooding control traffic by reducing the number of transmissions required.
USB battery tester
Andrysík, Lukáš ; Langhammer, Lukáš (referee) ; Lattenberg, Ivo (advisor)
This bachelor's thesis contains construction of battery tester along with primary and secondary cells comparsion. It consists of four parts - the first one focuses on general description of the most commonly used electrochemical cells, their characteristics, advantages and disadvantages. Second one relates to design a custom equipment for testing these cells including software, parts values calculations and common problems with the design. Third part is mainly about mechanical design and PCB manufacture. The last section is devoted to comparsion of several models of cells in terms of capacity and performance under different conditions.
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.
Synthesis of the electronically reconfigurable frequency filters
Michalička, Filip ; Dvořák, Jan (referee) ; Langhammer, Lukáš (advisor)
This diploma thesis deals with design of reconection-less electronically reconfigurable filter structures which have single input and single output using unconventional active elements, which have ability to adjust one of their parameter e.g. gain or transconductance. The first part describes basic parameters of frequency filters, the division of filters by frequency transfer response and used circuit elements, their operational modes, the principle of reconnection-less electronically reconfiguration and the circuit design method MUNV. Second part describes all active elements used in the proposal of filters, their properties and the implementation using existing transistor-level models. The third part contains the design of three reconnection-less electronically reconfigurable filters and the simulations results obtained from simulation programs OrCAD Capture and PSpice. The obtained results were compared with theoretical behaviour. This part also contains results of these analyses: sensitivity, parasitic, Monte Carlo and temperature to determine the behaviour in varied cases.
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.

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1 Langhammer, L.
13 Langhammer, Lukas
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