Maston ympärille asennetun antenniryhmän säteilykuvion laskeminen

Tämän insinöörityön tavoitteena oli tehdä MATLAB-sovellus, jolla voidaan laskea ja tulostaa yleisradiotoiminnassa käytettävien dipolipaneeliantennien säteilykuvioita. Toinen tavoite oli saattaa tämän työn valvojan Antti Koivumäen vuoden 1980 diplomityön laskenta ja grafiikka modernimmalle tasolle. Aluksi työssä tarkasteltiin yleisiä asioita VHF- ja UHF-taajuuksien lähetystavoista ja lähetinantennityypeistä. Alussa käytiin läpi myös antennijoukon ja -ryhmän käsite. Seuraavaksi tutustuttiin tarkemmin lähetinantennien rakenteeseen ja ominaisuuksiin. Antennien ominaisuuksista tarkasteltiin säteilykuviota, suuntaavuutta, vahvistusta, hyötysuhdetta ja polarisaatiota. Näistä säteilykuvio oli tarkimman tutkinnan kohteena. Säteilykuvion laskeminen esitettiin kaavojen ja havainnoillistavien kuvien avulla. Lopuksi perehdyttiin antennin säteilykuvion laskemiseen tietokoneella, etenkin MATLABilla. Osuudessa tarkasteltiin graafisen käyttöliittymän tekemistä, laskennan suorittamista ja horisontaalisen säteilykuvion esittämistä graafisesti. Työn tuloksena saatiin tehdyksi MATLAB-sovellus, joka laskee elementtiantennin horisontaalisen säteilykuvion annettujen parametrien avulla ja tulostaa sen.

Digital Audio Broadcasting: Technology and Prospects

The subject of the thesis was the digital audio broadcasting technology developed in the Eureka project 147. The research was based on the literature on the subject. At first, some reasons for the digitisation of broadcasting technology were given. Next, the channel multiplexing and channel coding methods employed by digital radio were discussed. The design of these methods is based on certain phenomena related to the propagation of radio-frequency signals, and these phenomena were also described. After that, audio and data transfer mechanisms as well as the structure of digital radio network were explained. Furthermore, digital audio and data services were considered. Finally, the digital radio was examined from marketing and administrative aspects. From a merely technical point of view, the digital radio technology offers several improvements in comparison with analogue technology. However, the digital radio has not become as widespread as it was perhaps originally expected during its development.

NURBS toolbox for Matlab

NURBS are widely used parametric approximation curves or surfaces. NURBS can be applied to the many applications. Examples of these applications are some computeraided design applications and some medical applications. Use of NURBS is very intuitive. The objective of this work was to implement the NURBS toolbox in the Matlab environment. Matlab is a program for many kinds of computational purposes. Matlab is also a programming language. NURBS toolbox implemented in this work offers a user an opportunity to use functions of this toolbox as parts of the user’s own programs. Current version of NURBS toolbox includes functions for NURBS curve and surface evaluation. The toolbox is designed such, that it allows extensions and enhancements in the future.

Comparison and Evaluation of Eddy Current Sensors

In the work eddy current sensors are described and evaluated. Theoretical part includes physical basics of the eddy currents, overview of available commercial products and technologies. Industrial sensors operation was assessed based on several working modes. Apart from this, the model was created in Matlab Simulink with Xilinx Blockset and then translated into a Xilinx ISE Design Suite compatible project. The performance of the resulting implementation was compared to the existing implementation in the Xilinx Spartan 3 FPGA board with the custom made sensor. Additionally, an introduction to FPGAs and VHDL is presented.

Field-Programmable Gate Array Card for Readout and Control of Cryoelectronics

The main goal of the present Master’s Thesis project was to create a field-programmable gate array (FPGA) based system for the control of single-electron transistors or other cryoelectronic devices. The FPGA and similar technologies are studied in the present work. The fixed and programmable logic are compared with each other. The main features and limitations of the hardware used in the project are investigated. The hardware and software connections of the device to the computer are shown in detail. The software development techniques for FPGA-based design are described. The steps of design for programmable logic are considered. Furthermore, the results of filters implemented in the software are illustrated.

Thermal Stress in a Roll-to-Roll Printed Electronics Substrate

The Roll-to-Roll process makes it possible to print electronic products continuously onto a uniform substrate. Printing components on flexible surfaces can bring down the costs of simple electronic devices such as RFID tags, antennas and transistors. The possibility of quickly printing flexible electronic components opens up a wide array of novel products previously too expensive to produce on a large scale. Several different printing methods can be used in Roll-to-Roll printing, such as gravure, spray, offset, flexographic and others. Most of the methods can also be mixed in one production line. Most of them still require years of research to reach a significant commercial level. The research for this thesis was carried out at the Konkuk University Flexible Display Research Center (KU-FDRC) in Seoul, Korea. A system using Roll-to-Roll printing requires that the motion of the web can be controlled in every direction in order to align different layers of ink properly. Between printers the ink is dried with hot air. The effects of thermal expansion on the tension of the web are studied in this work, and a mathematical model was constructed on Matlab and Simulink. Simulations and experiments lead to the conclusion that the thermal expansion of the web has a great influence on the tension of the web. Also, experimental evidence was gained that the particular printing machine used for these experiments at KU-FDRC may have a problem in controlling the speeds of the cylinders which pull the web.

Secure Bluetooth Audio Transmission System

The growing spread of small but powerful mobile devices (such as PDAs, mobile phone, Internet Tablet, etc.) opens up new scenarios in which users can interact with such devices in many environments in order to access the information at different locations. In this thesis, a ubiquitous computing based system called Secure Bluetooth Audio Transmission System is introduced. This system is situated in a large public place (like airport, festival venues, etc.), where voice messages are conveyed from the system to users' Bluetooth headsets in order to inform users the latest flight schedule and other public information. The reliability of the message is secured by adopting an authorization strategy and ECDSA. In order to assess and evaluate the risks and potential weaknesses of the system, an easy-to-use prototype implementation was written and tested. Other possible uses and further research were also considered.

Avalon Media System project update: a Hydra solution for digital audio and video access

Presentation at Open Repositories 2014, Helsinki, Finland, June 9-13, 2014

Audio and Video Repositories at Scale: Indiana University’s Media Digitization and Preservation Initiative

Presentation at Open Repositories 2014, Helsinki, Finland, June 9-13, 2014

Mittausdatan havainnollistaminen MATLAB animaationa

The visualization of measurement data is important in the fields of engineering for research analysis and presentation purposes. A suitable visualization method for scientific visualization is needed when handling measurement data. Visualization methods and techniques will be presented throughout this work. They are the bases of scientific visualization from the abstract visualization process to the applied techniques suited for each situation. This work also proposes a visualization tool using the MATLAB® software. The tool was designed as general as possible to encompass the most needs in terms of measurement data visualization. It offers possibilities for both static and dynamic visualization of the data.