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Proposal of the fractal order filtering structures
Uher, Jiří ; Dvořák, Jan (referee) ; Langhammer, Lukáš (advisor)
This thesis deals with the fractional (1+)-order filters. The proposed filters operate in the current-mode. The derivation of the filters has been achieved using a third-order aproximation of the coresponding fractional-order transfer functions. It also describes active elements such as universal current conveyor, current follower and operational transconductance amplifier. In the end of this thesis some new circuit solutions of the fractional-order filter are proposed. Then the proposed filters are realized and experimentally measured.
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Fractional-order filter structures
Lefler, Filip ; Langhammer, Lukáš (referee) ; Dvořák, Jan (advisor)
Semestral thesis deals with fractional-order frequency filters. There is descripe proposal of the filter, their simulations and practical realizations. The first part is focused at the introduction to a frequency filters. The following is chapter which explore various proposals fractional-order frequency filters. The next chapter describes used activ elements in this thesis. Then there is briefly described a method of the signal flow graphs. The following is a description of the theoretical design of lowpass and highpass frequency filter, where order of the filter is between the first and second. Another part deal with the design and simulation of the four circuits. There are two curcuits consists of transconductance amplifiers (BOTA) and two curcuist consists of current followers. The last part of the thesis deals with practical realization of the two fractional-order filters.
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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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Non-linear circuit structures with active current elements
Langhammer, Lukáš ; Lattenberg, Ivo (referee) ; Koton, Jaroslav (advisor)
This thesis deals with non-linear curcuit structures with current active elements. In its introduction this work deals with a description of the current conveyor. Further the text pays attention to the possiblities of the circuits for modification signals in analogue technology. First are described circuits of diode limiters and transducer. Great attention is paid to the amplifiers with current active parts. In conclusion are realized circuits of universal precise full-wave rectifiers using operational amplifier and current conveyor and made comparisons.
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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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Design of new V/I and I/V converters for the measurement of current-mode filters
Jarník, Lukáš ; Polák, Josef (referee) ; Langhammer, Lukáš (advisor)
This master’s thesis deals with problems of analog differential converters, which are used in measuring circuits working in the current mode. The aim of this thesis is to propose a new voltage to current and current to voltage converter, that should influence measured frequency properties as little as possible. Commercial active elements are use to design converters. Active components are compared on the basis of properties as bandwidth and slew rate. Designed converters are simulated in Orcad PSpice program. Converters, of the best behavior are practically implemented and measured. Measured and simulated values are compared.
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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.
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Creation of laboratory exercises in the NS3 enviroment
Štefančík, Matej ; Langhammer, Lukáš (referee) ; Polák, Josef (advisor)
Diploma thesis provides an introduction to the ns-3 network simulator. It describes the basic abstactions and components of the instrument. This work further discusses the theory, which was applied during simulation creation. The concept of unicast, the issue of IP addressing and routing in networks are specificaly analyzed. The practical part is focused on the creation of four laboratory tasks within the scope of Advanced Communication Techniques. The first task is dedicated to the the issue of static unicast routing in the network. It clarifies the impact of metrics on the process of routing. The following task compares the different types of ICMPv4 and ICMPv6 messages. The third task discusses additional functions of the ICMPv6. Specifically, it focuses on five different types of ICMPv6 messages defined by NDP (Neighbor Discovery Protocol) and their role in the network traffic. The last task focuses on ensuring the quality of services (QoS) in wireless networks, by setting priorities and thereby dividing the traffic into different classes. Attention is focused on parameters such as throughput, delay and jitter.
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Universal precision rectifiers with current active elements
Ryšavý, Lukáš ; Jeřábek, Jan (referee) ; Langhammer, Lukáš (advisor)
In this thesis new circuit solutions of universal precision rectifiers with current active elements are proposed. Based on the knowledge of current active elements, universal precision rectifiers and adverse impacts on these circuits new circuit solutions are proposed. These circuits are then simulated and compared with the known circuits of precision rectifiers. In concusion two original circuits and two proposed circuit solutions based on original ones are implemented, their properties are experimentally measured and their function are verified. The main active element in the original circuit are the OPA or THS, the proposed circuits are used the OPA and THS and the universal current conveyor, which offers a wide range of application use and realization of different variations of active current elements.
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Nonlinear circuits using current active elements
Langhammer, Lukáš ; Kubánek, David (referee) ; Koton, Jaroslav (advisor)
This thesis deals with non-linear curcuit structures with current active elements. In its introduction this work deals with a description of the current active elements, such as current conveyor, transconductance operational amplifier and current follower. Further the text pays attention to the possiblities of the circuits for modification signals in analogue technology. First are described circuits of diode limiters and transducer. Great attention is paid to the amplifiers with current active elements. Are propřed simulated and practically realized circuits of universal precise full-wave rectifiers using operational amplifier and current conveyor and made comparisons of known and proposed circuits. The paper also discussed other circuit structures using of current active elements, such as multiplier, divider, a triangular signal generator and oscillators.
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