|
|
Low noise amplifier for UHF band
Horký, Stanislav ; Baran, Ondřej (referee) ; Kasal, Miroslav (advisor)
The subject of this bachelor's thesis is description and design of low-noise RF amplifiers. This work is also focused on design and simulations of amplifier in Ansoft Designer software. In this thesis is in detail described design of amplifier ATF 54143, mainly focused on stability, biasing and noise matching. For the needs of RF applications are described a few types of filters, with his design and realization
|
|
|
Low noise amplifier for UHF band
Horký, Stanislav ; Baran, Ondřej (referee) ; Kasal, Miroslav (advisor)
The subject of this bachelor's thesis is description and design of low-noise RF amplifiers. This work is also focused on design and simulations of amplifier in Ansoft Designer software. In this thesis is in detail described design of amplifier ATF 54143, mainly focused on stability, biasing and noise matching. For the needs of RF applications are described a few types of filters, with his design and realization
|
|
|
Universal Power Sequencer For Rf Power Amplifiers
Waldecker, Miroslav
More often used Galium Nitride (GaN) based Radio-Frequency high power transistors in the various RF PA configurations e.g. Doherty is by their nature easily destroyed, great care must be taken, when powering-up and shutting down this circuits. That means, proper power biasing and sequencing is necessary. The Doherty type RF PA with RF drivers four different gate, drain voltages and time when the individual voltages are turned on or off must be controled. Universal power sequencer and biasing device, which meets this requirements is described in this article.
|
|
|
Low noise amplifier for UHF band
Horký, Stanislav ; Baran, Ondřej (referee) ; Kasal, Miroslav (advisor)
The subject of this bachelor's thesis is description and design of low-noise RF amplifiers. This work is also focused on design and simulations of amplifier in Ansoft Designer software. In this thesis is in detail described design of amplifier ATF 54143, mainly focused on stability, biasing and noise matching. For the needs of RF applications are described a few types of filters, with his design and realization
|
|
|
Power amplifier for shortwave radioamateur bands
Smutný, Štěpán ; Šebesta, Jiří (referee) ; Lukeš, Zbyněk (advisor)
The amplifier is designed in the class AB, for which is typical acceptable efficiency and relatively low quiescent power consumption. As active components, the MOSFETs transistors are used. Their quadratic transfer characteristic allows for a gain control by means of quiescent current setting. The principle of MOSFETs function will be described, along with their utilization in the class AB amplifier. Since the amplifier processes signals in the shortwave band, parasitic capacitances of the transistors reduces gain greatly. Therefore, these capacitances will have to be compensated by positive feedback. First, the function of the amplifier will be verified in PSPICE program, then design or selection of real components (including transformers, heat sink and bias control) will be carried out. By performing measurement on assembled amplifier, we have verified the gain control (doubling the quiescent current increases gain by 3dB). If the quiescent current is set to 1250mA, the gain exceeds 20dB in the range from 1.4MHz to 13.5MHz. Gain at high frequencies was achieved thanks to compensation by positive feedback.
|
|
|
Low noise amplifier for UHF band
Horký, Stanislav ; Baran, Ondřej (referee) ; Kasal, Miroslav (advisor)
The subject of this bachelor's thesis is description and design of low-noise RF amplifiers. This work is also focused on design and simulations of amplifier in Ansoft Designer software. In this thesis is in detail described design of amplifier ATF 54143, mainly focused on stability, biasing and noise matching. For the needs of RF applications are described a few types of filters, with his design and realization
|
|
|
Radniční periodika a komunální volby v České republice: Pomáhají veřejně dotované noviny zastupitelům ke znovuzvolení?
Boháček, Jiří ; Bertoli, Paola (advisor) ; Dušek, Libor (referee)
In the Czech Republic, town halls are allowed to issue printed newspapers to inform the residents about local events. The newspapers are funded from municipal budgets and free for the residents, often delivered directly to the mailbox. Apart from being useful source of information, the newspapers may serve also as a platform for election campaign of the incumbent politicians. This fact was the main reason for the amendment of the Press Act in 2013, directing municipalities to issue unbiased news with enough room for all the political stakeholders. The present study uses various secondary data to examine the effects of town hall newspapers on voting decisions during municipal elections held between 1998 and 2014. Econometric analysis finds significant and positive relationship between presence of a newspaper and performance of incumbent politicians. Comparison of election results from 2014 with previous election years suggest that the Press Act amendment has not had substantial impact on this relationship.
|
|
|
Analýza relaxačních jevů v tokamaku CASTOR vyvolaných nabíjením okrajového plazmatu hluboce vnořenou elektrodou
Brotánková, Jana ; Stöckel, Jan ; Hron, Martin ; Štěpán, Michal ; Peterka, Matěj ; Horáček, Jan ; Ďuran, Ivan ; Spolaore, M. ; Peleman, P.
Transport of plasma to the walls is one of the crucial topics in magnetic confinement fusion research. In tokamak CASTOR, during special regimes with strong biasing of plasma, we can observe relaxation events, corresponding to increasing and collapsing of a transport barrier. High spatially and temporally resoluted arrays of probes enable us to describe these phenomena in details.
|
guest ::
