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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
41

Vysokofrekvenční a mezifrekvenční obvody krátkovlnné radiostanice / HF and IF circuits of shortwave radiostation

Šnajdr, Václav January 2009 (has links)
The study, description, design and implementation of selected blocks of multiband shortwave radio station are dealt with in the thesis. Focus is placed on the concept of multiband shortwave radio stations, with an emphasis on high frequency and intermediate frequency circuits. The first chapter is devoted to description of the transceiver block diagram which is designed as superheterodyne. The design of bandpass input filters, intermediate frequency crystal filters and output filters is described. Simulation results and the measured characteristics of the implemented functional blocks are presented. Furthermore, the amplifier circuits which maintain impedance matching of individual blocks are discussed. SSB signal generation in the transmitter part of radio station and final stage power amplification are depicted.
42

Aktivní elektrické filtry na bázi obvodů se spínanými kapacitory / Active electrical filters based on switched-capacitor circuits

Třeček, Stanislav January 2009 (has links)
This thesis deals with concept of universal frequency filter by application of a switched-capacitor functional block. The concept is based on the theory of switched-capacitor circuits and the theory of a design of classical frequency filters. The printed circuit board was designed based on the filter connection developed by using a software Eagle. The filter was implemented as a laboratory product. This product has been revitalized and the frequency response of all types of filters has been measured. The measured parameters were compared with the parameters set out in the technical documentation of functional block.
43

Composants céramiques 3D innovants pour des applications spatiales de télécommunications millimétriques en bandes Q et V / Advanced technologies for millimeterwave integrated filters in Q and V bands

Drissi, Mohamed Khalil 15 December 2016 (has links)
Ce mémoire est consacré au développement de technologies de filtrage novatrices qui apportent un gain en performance permettant de répondre aux besoins de filtrage pour télécommunications spatiales à moyen et long termes. Il s’inscrit dans le projet ANR ATOMIQ coordonné par Thales Alenia Space ayant comme partenaires le laboratoire SPCTS et la société 3D CERAM. Le premier chapitre est constitué d’une étude bibliographique sur les filtres en bande Q et V ainsi que les technologies de fabrication 3D. Le deuxième chapitre est consacré à l’élaboration d’une nouvelle formulation d’alumine très pure à faible pertes et stable en température. Le troisième chapitre présente une conception de filtres hyperfréquences en bande Q et V à base de cavités résonantes diélectriques. Le quatrième chapitre concerne la fabrication des filtres par usinage en cru ainsi que la présentation des différents démonstrateurs fabriqués par stéréolithographie et moulage basse pression. Il présente aussi des solutions de correction post-fabrication par tir laser. Ce travail est original par l’utilisation de la stéréolithographie céramique 3D ainsi que du moulage basse pression pour fabriquer des filtres hyperfréquences de petites tailles en bande Q et V. / This thesis focus on the development of innovative filtering technologies that enhance the performance to meet the filtering requirements for spacial communications. It is part of the ANR project ATOMIQ coordinated by Thales Alenia Space with partners (SPCTS 3D CERAM). The first chapter consists of a literature review on the Q and V band filters as well as 3D manufacturing technologies. The second chapter is devoted to the development of a new formulation of highly pure, low losses and temperature stable alumina. The third chapter presents a microwave filter design in Q and V band based on a dielectric resonant cavity. The fourth chapter is about the manufacturing of filters and presentation of various demonstrators manufactured by stereolithography and low pressure molding. It also provides a post-production correction solutions based on laser shoots. This work is original because, to the best of our knowledge, 3D ceramic stereolithography and the low pressure molding have not been used to produce small sizes Q and V band microwave filters.
44

MIKROPÁSKOVÉ FILTRY S VYUŽITÍM NARUŠENÉ ZEMNÍ PLOCHY / MICROSTRIP FILTERS USING DEFECTED GROUND STRUCTURE

Vágner, Petr January 2009 (has links)
The thesis deals with the microstrip filter design using defected ground structure (DGS). The difference between standard asymmetric microstrip technique and DGS is in using the structures etched in the microwave substrate ground plane. The DGS resonant characteristics are then used in filter design. The thesis consists of three factual parts. The first one (chapter 4) introduces the use of the DGS resonators in the lowpass filter design. It involves experimental analysis of one type of the lowpass filter. The second part (chapter 5) deals with a novel microstrip lowpass filter design method using DGS. The proposed method is verified by simulations and several samples are realized and measured. Finally, the third part (chapters 7 and 8) deals with the bandpass filter design using specific defected ground structure as a resonator. The resonators are used in a coupled resonator structure. Filters of various orders and resonator configurations are designed and simulated. A combination of the DGS resonators and half-wavelength microstrip resonators is introduced as well. Selected samples are realized and measurement results are compared with simulations.

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