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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.
281

Investigation of an optimal utilization of Ultra-wide band measurements for position purposes

Siripi, Vishnu Vardhan January 2006 (has links)
Ultra wideband (UWB) communication systems refers to systems whose bandwidth is many times greater than the “narrowband” systems (refers to a signal which occupies only small amount of space on the radio spectrum). UWB can be used for indoor, communications for high data rates, or very low data rates for substantial link distances because of the extremely large bandwidth, immune to multi-path fading, penetrations through concrete block or obstacles. UWB can also used for short distance ranging whose applications include asset location in a warehouse, position location for wireless sensor networks, and collision avoidance. In order to verify analytical and simulation results with real-world measurements, the need for experimental UWB systems arises. The Institute of Communications Engineering [IANT] has developed a low-cost experimental UWB positioning system to test UWB based positioning concepts. The mobile devices use the avalanche effect of transistors for simple generation of bi-phase pulses and are TDMA multi-user capable. The receiver is implemented in software and employs coherent cross-correlation with peak detection to localize the mobile unit via Time-Difference-Of-Arrival (TDOA) algorithms. Since the power of a proposed UWB system’s signal spread over a very wide bandwidth, the frequencies allocated to multiple existing narrowband systems may interfere with UWB spectrum. The goal of the filters discussed in this project is to cancel or suppress the interference while not distort the desired signal. To investigate the interference, we develop a algorithm to calculate the interference tones. In this thesis, we assume the interference to be narrowband interference (NBI) modeled as sinusoidal tones with unknown amplitude, frequency and phase. If we known the interference tones then it may be removed using a simple notched filter. Herein, we chose an adaptive filter so that it can adjust the interference tone automatically and cancel. In this thesis I tested adaptive filter technique to cancel interference cancellation (ie) LMS algorithm and Adaptive Noise Cancellation (ANC) technique. In this thesis performance of the both filters are compared.
282

Implementation of an FMCW Radar Platform With High-Speed Real-Time Interface

Svensson, Jonny January 2006 (has links)
Acreo AB has developed a radar prototype used for illustrate how the SiGe technology could be used. The radar prototype needs further development with a fast interface and a more integrated design. The beginning of the report describes the radar technique theory and the composing equations. The theoretical background is used to explain each component of the system. The report continues by specifying the target of the next radar prototype. The chosen implementation is motivated and the mode of procedure is described in detail. Test benches were used to verify correct functionality and some limits were found. The report is concluded with test results and recommendations on further enhancements. / Acreo AB har utvecklat en radarprototyp för att illustrera hur SiGe teknologi kan användas. Prototypen behöver vidareutvecklas med ett snabbt digitalt interface och en kompaktare design. Rapporten inleds med att beskriva radarteknikens funktionalitet och de utgörande ekvationerna. Den teoretiska bakgrunden används för att förklara varje komponent som systemet utgörs av. Rapporten fortsätter med att specificera målet med nästa radarprototyp. Den valda implementationen motiveras och tillvägagångssättet beskrivs detaljerat. Testuppkopplingar verifierade korrekt funktionalitet och begränsningar insågs. Rapporten avslutas med en sammanfattning av uppnådda testresultat och rekommendationer på framtida förbättringar.
283

Waveform Development using Software Defined Radio

Sundquist, Thomas January 2006 (has links)
Software Defined Radio (SDR) is a conception of implementing radio functions in computer software, instead of having electronics performing the functions. This thesis aims to compare two different ways of implementing these functions, or waveforms. The Software Communications Architecture (SCA) is an open standard developed by the United States Department of Defense. It uses a CORBA interface environment to make waveform applications interoperable and platform independent. This method of developing SDR is compared to an open-source initiative going by the name GNU Radio. Two waveform applications are developed, one transmitter using SCA, and one receiver using GNU Radio. The analog radio interface is simulated using the sound cards of two regular PCs. The development is done using the C++ and Python programming languages. This thesis examines pros and cons of the two SDR methods, as well as performing studies of Software Defined Radio in general.
284

Modelling and implementation of an MPEG-2 video decoder using a GALS design path.

Rosengren, Kaj January 2006 (has links)
As integrated circuits get smaller, faster and can fit more functionality, more problems arise with wire delays and cross-talk. Especially when using global clock signals distributed over a large chip area. This thesis will briefly discuss a solution to this problem using the Globally Asynchronous Locally Synchronous (GALS) design path. The goal of this thesis was to test the solution by modelling and partially implementing an MPEG-2 video decoder connected as a GALS system, using synchronous design tools. This includes design of the system in Simulink, implementing selected parts in VHDL and finally testing the connected parts on an FPGA. Presented in this thesis is the design and implementation of the system as well as theory on the MPEG-2 video decoding standard and a short analysis of the result.
285

A Synthesizable VHDL Model of the Serial Communication Interface and Synchronous Serial Interface of Motorola DSP56002

Mattam, Swaroop January 2006 (has links)
The design and implementation of a synthesizable model of the Serial Communication Interface and Synchronous Serial Interface, which constitutes the Port C of Motorola DSP56002 is presented in this report. They serves as a full duplex serial interface to other DSPs, processors, codecs, digital-to-analog and analog-to-digital converters and other transducers. The SCI block is able to handle a data rate of 5Mbps in Synchronous mode and 625Kbps in asynchronous mode for a 40MHz clock. It supports five word formats including a multidrop mode for multiprocessor systems. SSI provides a data rate of 10Mbps for the same 40 MHz clock. The design includes a programmable on-chip or external baud rate generator/interrupt timer for the SCI and a clock generator and frame Sync generator for the SSI. The thesis focus on arriving at a full functional description of individual blocks included with Port C from the data sheets and product users manual. From this operational description a behavioural model was developed. The structure and implementation is based on the Motorola DSP56002 with additional support for a variable data-width. The model is written completely in behavioural VHDL with a top-down approach and the model was verified and validated.
286

M.I.M.O Channel Model for High Capacity Wireless Networks and Simulator for Performance Analysis

Alonso, Javier January 2006 (has links)
The wireless communications have suffered, in these last years, one of the greater technological growth within the communications via radio. The application of multiple antennas, as much in transmission as in reception has taken to an impulse of the study of different models from propagation channels. Taking this into consideration, the different types from mentioned models are going to be studied. The work that the ISY department at the Institute of Technology of the Linköping University has proposed is to develop to a propagation channel model, with several antennas in reception and transmission, that one first approach allows a capacity of the channel study, in absence of measures of possible scenarios, as well as the development of a small simulator that allows to analyze its benefits.
287

Undersökning av mätsystem för UMTS (3G) telefoner

Sureshkumar, Meena January 2006 (has links)
Företaget Flextronics AB i Linköping testar moderna mobiltelefoner för tillverkares räkning. Som examensarbete har jag fått företagets uppdrag att utvärdera och förbättra deras testsystem DVT-UMTS (3G). DVT-UMTS är ett komplext system av komponenter, och man misstänker att dessa stör varandra inbördes, vilket i sin tur kan ge felaktiga mätresultat. Beträffande mottagarsidan hos en mobiltelefon tror man att DVT-UMTS p g a störningar, s k intermodulationsprodukter, uppvisar bitfelshalter i testet Rx Out of band blocking. Komponenter som kan tänkas ge störningar är continuous wave-generator och basstationssimulatorn. Antennanslutningen bortses från i undersökningen. Kontroll av CW-generatorn sker med hjälp av lågpassfilter, riktkopplare och dämpare. Kontrollen visar att den är orsak till bitfel men inte ensam orsak. Basstationssimulatorn kontrolleras med hjälp av högpassfilter, riktkopplare och varierade kabellängder. Även denna visar sig ge upphov till bitfel. Bitfel orsakade av intermodulationsprodukter från CW-generatorn kan reduceras med lågpassfilter och dämpare. Motsvarande problem hos basstationssimulatorn kan åtgärdas med högpassfilter och varierade kabellängder. Kvarstående bitfel är acceptabla enligt specificerade krav från det internationella samarbetsorganet 3GPP. Mobiltelefonens sändarefunktion testas med programmet Tx Spurious emission, där otillåtet höga dämpningsnivåer kan ge problem. Dessa nivåer beror av signalvägarna mellan testad enhet och spektrumanalysatorn. Med hjälp av gordon, darlingtontransistor och switch kan signalvägarna optimeras. En alternativ testuppkoppling på DVT-UMTS, innehållande switch med styrprogram, ger dämpningsnivåer innanför specificerade gränser.
288

Visuell processreglering

Andersson, Pontus January 2007 (has links)
Examensarbetet handlar om att ta fram en processmodell för nivåreglering och det innehåller flera utmaningar. Vätskesystemets dynamik och balans måste beaktas likväl som lämpliga reglermetoder samt modellens utseende. I den här rapporten behandlas hela händelseförloppet från initialskedet till en färdig produkt redo att visas för en publik. Läsaren får möjlighet att närmare granska de komponenter som modellen är uppbyggd av, ta del av programmeringsarbetet och de omfattande test av modellen som utförts. Flera teknikområden belyses men fokus riktas särskilt på ABB:s styrsystem AC800M/800xA, fältbussteknik och reglerstrategier. PID-regulatorn har under arbetet spelat en stor roll och reglerstrategier som innefattar bl.a. framkoppling och kaskadkoppling analyseras och diskuteras. För att bedöma skillnader i val av reglermetod används grafer från praktiska försök. Rapportens upplägg med flertalet illustrationer och den genomgripande tekniska dokumentationen hjälper läsaren att förstå modellens funktion och uppbyggnad.
289

A Low-Power Implementation of Turbo Decoders

Tang, Weihua January 2007 (has links)
In the 3G standards, wireless communication system can support 2 Mb/s. With this data rate, multimedia communication is realized on handset. However, it is expected that new applications will require even higher data rates in future. In order to fulfil the growing requirement of high data rate, 100 Mb/s is considered as the aim of 4G standards. Such high data rate will result in very large power consumption, which is unacceptable considering the current battery capability. Therefore, reducing the power consumption of turbo decoders becomes a major issue to be solved. This report explores new techniques for implementing low power, small area and high throughput turbo decoders.
290

Undersökning av optimeringsalternativ för elektrostatlackering / Study of optimization options for electrostatic coating

Persson, Daniel, Skansare, Rikard January 2010 (has links)
<p>This report describes a thesis done at the Jönköping University of Technology. The aim of this thesis was to create conditions to optimize an existing automatic electrostatic coating system by changing the technology for dispensing lacquer. To select the technology, a study of different dispensing techniques carried out which concluded that the piezoelectric membrane and electrostatic atomization are the most interesting techniques.</p><p>In order to perform tests with dispensing techniques a demonstrator has been optimized. The controller and PC software of the demonstrator has been programmed to be able to send out PWM signals that control the dispensers. An adapter card was designed to control the piezoelectric membrane and a steering link to the electrostatic atomization has been developed for PWM signals up to 500V.</p><p>The work has laid ground for a demonstrator where further testing of the dispensing technologies can be performed.</p> / <p>Den här rapporten beskriver ett examensarbete utfört vid Jönköpings tekniska högskola. Målet med arbetet var att skapa förutsättningar för att optimera ett befintligt automatiskt elektrostatlackeringssystem genom att byta ut tekniken för dispensering av lack. För att välja teknik har en undersökning av olika dispenseringstekniker genomförts där man kommit fram till att piezoelektriska membran och elektrostatisk atomisering är de tekniker som är mest intressanta.</p><p>För att kunna utföra tester med dispenseringsteknikerna har en befintlig testutrustning (demonstrator) anpassats för ändamålet. Demonstratorns kontrollerkort och PC-program har programmerats om och anpassats för att kunna sända ut PWM-signaler som styr dispenseringen. Ett adapterkort har konstruerats för att kunna styra piezoelektriska membran och en styrkoppling till elektrostatisk atomisering har tagits fram för PWM-signaler upp till 500V.</p><p>Arbetet har lagt grunden till en demonstrator där vidare tester av dispenseringsteknikerna piezoelektriska membran och elektrostatisk atomisering kan utföras.</p>

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