Thesis (D.Sc.)(Zoology)--University of Pretoria, 1991. / Available on the Internet via the World Wide Web.

This thesis investigates the design and implementation of wireless communication system over the GNU Radio. Wireless applications are on the rise with advent of new devices, therefore there is a need to transfer the hardware complexity to software. This development enables software radio function with minimum hardware dependency. the purpose of this thesis is to design a system that will transmit compressed data via Software Defined Radio (SDR). Some parameters such as modulation scheme, bit rate can be changed to achieve the desired quality of service. in this thesis GNU (GNU’s not unix) radio is used while the hardware structure is Universal Software Radio Peripheral (USRP). in order to accomplish the goal, a compression technique called H264 (MPEG_4) encoding is applied for converting data into compressed format. the encoder was implemented in C++ to get compressed data. After encoding, the transmitter reads the compressed data and starts modulation. After modulation, the transmitter put the packets into USRP and sends it to the receiver. Once packets are received they are demodulated and then decoded to recover the original data.

GNU Radio and OSSIE (Open-Source SCA (Software communication architecture) Implementation-Embedded) are two open source software toolkits for SDR (Software Defined Radio) developments, both of them can be supported by USRP (Universal Software Radio Peripheral). In order to compare the performance of these two toolkits, an FM receiver over GNU Radio and OSSIE are tested in my thesis, test results are showed in Chapter 4 and Chapter 5. Results showed that the FM receiver over GNU Radio has better performance, due to the OSSIE is lack of synchronization between USRP interface and the modulation /demodulation components. Based on this, the SISO (Single Input Single Output) communication system over GNU Radio is designed to transmit and receive sound or image files between two USRP equipped with RFX2400 transceiver at 2.45G frequency. Now, GNU Radio and OSSIE are widely used for academic research, but the future work based on GNU Radio and OSSIE can be designed to support MIMO, sensor network, and real time users etc.

<p>At the Department of Technology and Built environment at the University of Gävle there was an interest to study GNU Radio, which is an "open source radio project. The project is based on that most of the radio signal processing is made in an ordinary PC. The idea behind this degree project was that in a laptop there are several radio transmitters/receivers that takes space, generates heat and transmit in varied frequency band etcetera.</p><p> </p><p>All these radio transmitters/receivers could be replaced with a Software Defined Radio system. It means that one common, general radio hardware is used to different communications such as: WLAN, Bluetooth, GPRS, 3G etcetera. The waveform is generated in the software, which makes the system very flexible. To transmit and receive radio signals a USB-based hardware is required, for example from Ettus Research LLC.</p><p> </p><p>During this degree project two PC:s was used for the signal processing and the signal transferring. The operating system that was used on the computers, were the Linux based Ubuntu 8.04. To generate the signals, to modulate/demodulate the signals and to get the communication on the sound cards in/out-port working, the different packages in the GNU Radio software was used and for programming the high level language, Python, was used.</p><p> </p><p>In this degree project a lot of experiments where made, for example a sine wave was generated in computer 1 and the signal was amplitude modulated and transferred to computer 2, through the sound card. In computer 2 the signal was demodulated and filtrated, before it was saved to the hard drive. When the signal was saved on computer 2, it could be sent out on the sound card and be studied on an oscilloscope. This transfer between the computers was made with a stereo cable, but also with a radio link equipment on the University of Gävle.</p><p> </p><p>The result of this degree project was satisfying, because the signal was possible to modulate, transfer, demodulate and save. In the wire transfer a lot of noise was generated on to the signal, mostly because of the sound cards. When the wireless transfer was made it appeared more noise, because of the quality of the receiver, the transmitter and the antennas.</p><p> </p><p>This work can be developed to more advanced systems.</p> / <p>Vid Högskolan i Gävle på institutionen för Teknik och Byggd miljö (ITB) fanns ett intresse att undersöka GNU Radio, som är ett open source radio-projekt. Projektet bygger på att den största delen av radiosignalbehandlingen sker i en vanlig PC. Idén som låg till grund för detta examensarbete var att det i en laptop finns ett stort antal radiosändar- och mottagarkretsar som tar plats, genererar värme och sänder på olika frekvensband med mera.</p><p> </p><p>Alla dessa radiosändar- och mottagarkretsar skulle kunna ersättas med ett Software Defined Radio-system. Vilket innebär att en gemensam, generell radiohårdvara används för olika kommunikationer som: WLAN, Bluetooth, GPRS, 3G med flera. Vågformerna genereras i mjukvaran, vilket gör systemet mycket flexibelt. För att kunna ta emot och sända radiosignaler behövs en hårdvara. Denna hårdvara har bland annat Ettus Research LLC tagit fram, med USB-anslutning.</p><p> </p><p>Under examensarbetet har två stycken PC använts för behandling av signaler, samt överföring mellan dessa. Operativsystemet som användes på datorerna var det Linuxbaserade Ubuntu 8.04. För att generera signaler, modulation/demodulation av dessa signaler samt för att få kommunikation med ljudkortets in-/utgång att fungera, användes de olika paketen i mjukvaran GNU Radio och för programmering användes högnivåspråket Python.</p><p> </p><p>I detta examensarbete utfördes ett flertal experiment, bland annat genererades en sinussignal i dator 1 och signalen amplitudmodulerades och överfördes till dator 2 via ljudkortet. På dator 2 demodulerades denna signal och filtrerades, innan den sparades på hårddisken. Signalen kunde sedan skickas ut på ljudkortet och studeras med ett oscilloskop. Överföringen mellan datorerna gjordes med en stereokabel, men också med en radiolänkutrustning som fanns på Högskolan i Gävle.</p><p> </p><p>Resultatet var tillfredställande då signalen kunde moduleras, överföras samt demoduleras och sparas. I den trådbundna överföringen uppstod mycket brus i signalen, till största delen berodde detta på ljudkorten. När den trådlösa överföringen gjordes uppstod mera brus, vilket berodde på kvalitén hos mottagare, sändare och antennerna.</p><p> </p><p>Detta arbete kan utvecklas till mer avancerade system.</p>

At the Department of Technology and Built environment at the University of Gävle there was an interest to study GNU Radio, which is an "open source radio project. The project is based on that most of the radio signal processing is made in an ordinary PC. The idea behind this degree project was that in a laptop there are several radio transmitters/receivers that takes space, generates heat and transmit in varied frequency band etcetera.   All these radio transmitters/receivers could be replaced with a Software Defined Radio system. It means that one common, general radio hardware is used to different communications such as: WLAN, Bluetooth, GPRS, 3G etcetera. The waveform is generated in the software, which makes the system very flexible. To transmit and receive radio signals a USB-based hardware is required, for example from Ettus Research LLC.   During this degree project two PC:s was used for the signal processing and the signal transferring. The operating system that was used on the computers, were the Linux based Ubuntu 8.04. To generate the signals, to modulate/demodulate the signals and to get the communication on the sound cards in/out-port working, the different packages in the GNU Radio software was used and for programming the high level language, Python, was used.   In this degree project a lot of experiments where made, for example a sine wave was generated in computer 1 and the signal was amplitude modulated and transferred to computer 2, through the sound card. In computer 2 the signal was demodulated and filtrated, before it was saved to the hard drive. When the signal was saved on computer 2, it could be sent out on the sound card and be studied on an oscilloscope. This transfer between the computers was made with a stereo cable, but also with a radio link equipment on the University of Gävle.   The result of this degree project was satisfying, because the signal was possible to modulate, transfer, demodulate and save. In the wire transfer a lot of noise was generated on to the signal, mostly because of the sound cards. When the wireless transfer was made it appeared more noise, because of the quality of the receiver, the transmitter and the antennas.   This work can be developed to more advanced systems. / Vid Högskolan i Gävle på institutionen för Teknik och Byggd miljö (ITB) fanns ett intresse att undersöka GNU Radio, som är ett open source radio-projekt. Projektet bygger på att den största delen av radiosignalbehandlingen sker i en vanlig PC. Idén som låg till grund för detta examensarbete var att det i en laptop finns ett stort antal radiosändar- och mottagarkretsar som tar plats, genererar värme och sänder på olika frekvensband med mera.   Alla dessa radiosändar- och mottagarkretsar skulle kunna ersättas med ett Software Defined Radio-system. Vilket innebär att en gemensam, generell radiohårdvara används för olika kommunikationer som: WLAN, Bluetooth, GPRS, 3G med flera. Vågformerna genereras i mjukvaran, vilket gör systemet mycket flexibelt. För att kunna ta emot och sända radiosignaler behövs en hårdvara. Denna hårdvara har bland annat Ettus Research LLC tagit fram, med USB-anslutning.   Under examensarbetet har två stycken PC använts för behandling av signaler, samt överföring mellan dessa. Operativsystemet som användes på datorerna var det Linuxbaserade Ubuntu 8.04. För att generera signaler, modulation/demodulation av dessa signaler samt för att få kommunikation med ljudkortets in-/utgång att fungera, användes de olika paketen i mjukvaran GNU Radio och för programmering användes högnivåspråket Python.   I detta examensarbete utfördes ett flertal experiment, bland annat genererades en sinussignal i dator 1 och signalen amplitudmodulerades och överfördes till dator 2 via ljudkortet. På dator 2 demodulerades denna signal och filtrerades, innan den sparades på hårddisken. Signalen kunde sedan skickas ut på ljudkortet och studeras med ett oscilloskop. Överföringen mellan datorerna gjordes med en stereokabel, men också med en radiolänkutrustning som fanns på Högskolan i Gävle.   Resultatet var tillfredställande då signalen kunde moduleras, överföras samt demoduleras och sparas. I den trådbundna överföringen uppstod mycket brus i signalen, till största delen berodde detta på ljudkorten. När den trådlösa överföringen gjordes uppstod mera brus, vilket berodde på kvalitén hos mottagare, sändare och antennerna.   Detta arbete kan utvecklas till mer avancerade system.

Les systèmes embarqués prennent une place de plus en plus grande dans le marché actuelavec des dispositifs basée sur des systèmes on-chip. Ces systèmes embarqués ont descontraintes très fortes concernant leurs coût, taille, consommation, fiabilité et dimensions.Dans ce contexte la densité de code d'un processeur devient un critère important.Dans cette thèse l'idée était de prendre un processeur RISC(l'APS3 de la société Cortus)qui a de bonne performance pour le monde embarqué et d'augmenter sa densité de code.Plusieurs méthodes ont été testé :– compression à base de Huffman.– compression à base de dictionnaire.– modification du jeu d'instructions.Les méthodes de compression ont montrée leur limites dans notre cas car soit ellesn'étaient pas compatible avec nos objectifs , soit elles offraient un gain pas assez importantcomparé aux surplus en terme de taille et de cycle en plus lors de l'exécution. Ce qui nousa poussé vers la modification du jeu d'instructions.Le résultat obtenu est une augmentation de la taille du code de 25% dans la phase derecherche et de 20.8% dans la version finale du processeur car il aura fallu faire un compromispour garder une petite taille et de bonnes performances.L'APS3CD est le résultat de cette thèse. il a une surface de 49605m2, une fréquencemaximale de 444 MHZ, un score de 2.16 DMIPS/MHZ et une consommation de12 W/MHZ(UMC90). il offre 20.8% de gain par rapport à l'APS3 et 40% par rapport aucortex-m3 (avec gcc) qui est une référence en terme de densité de code dans le marché.Toutefois le gain obtenu peut être augmente en travaillant sur le compilateur car lecompilateur actuel (gcc) n'utilise pas pleinement les instructions complexes ajoutés (dansquelque cas). Une continuation possible serait de travailler sur un compilateur qui soitmeilleur que gcc qui à la base n'est pas destinée aux systèmes embarqué avec des demandesde densité de code. Un exemple est la différence de taille du code entre gcc etiar ou keil pour les processeurs ARM. / Since the market is moving toward portable devices with a one device System on-Chip(SoC), code density of a processor becomes an important criteria.The idea of this thesis was to improve the code density of the Cortus processor theAPS3, which is an embedded RISC processor with good performances.Several methods were tried :– Huffman compression.– Dictionnary based compression.– Instruction set modification.Compression methods have shown their limits in this case either because they werenot compatible with our goals or did not provided a gain large enough compared to surplusesin terms of size and cycle number when running. This prompted us to modifie theinstruction set.The result was 25% of code density improvement in the research phase and 20.8% ofcode density improvement in the final version of the processor because we had to keepgood perfomances and small size of the APS3.APS3CD is the result of this thesis. It has an area of 49605m2, a maximum frequencyof 444 MHZ, a score of 2.16 DMIPS/MHz and a consumption of 12W/MHZ(UMC90). itoffers 20.8% gain over the APS3 and 40% compared to the cortex-m3 (with gcc) which is arefrence in termof code density in the market.However, the gain can be increased by working on the compiler because the currentcompiler (gcc) does not fully utilize the complex instructions added (in some cases). Apossible continuation would be to work on a compiler better than gcc wich is not designedfor embedded systems applications with code density at the base. An example is the codesize difference between gcc and keil or iar for ARM processors.

From a HF propagation point of view, the ionospheric layers act as partially conducting media (plasma) in which a transmitted radio wave can reflect upon.A way of determining whether a radio wave with a given frequency will reflect from the ionosphere or completely penetrate is to utilize special radar instruments know as ionosondes or chirp sounders. The technique is widely used by amateur enthusiasts and military radio users for monitoring available radio channel links between two remote locations and can often serve as a base for HF radio prognoses.The objective of this Bachelor’s Thesis was to explore, implement and test a single channel receiver for monitoring ionospheric sounders. The implementation is based on Software Defined Radio (SDR) technology and relies on the GNU Chirp Sounder (gcs) open source script program.

Thesis (M.Sc.)(Wildlife Management)--University of Pretoria, 2006. / Includes summary. Includes bibliographical references. Available on the Internet via the World Wide Web.

A two-year study was made of the blue wildebeest Connochaetes taurinus taurinus in Zululand, Natal. Aspects investigated included age determination methods, growth and condition, reproductive physiology, habitat interactions, and population dynamics. Findings were related to suggested management of the species. / Thesis (Ph.D.)-University of Natal, Pietermaritzburg, 1977.

Thesis (Ph. D.)--University of Guelph, 1998. / Includes bibliographical references (leaves 138-162).