Dissertations / Theses on the topic 'Radio lines'
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Matarrese, Vincent D. "Tapered radio frequency transmission lines." PDXScholar, 1992. https://pdxscholar.library.pdx.edu/open_access_etds/4329.
Full textJohnstone, G. G. "An investigation into filters utilising coupled transmission lines." Thesis, University of Surrey, 1995. http://epubs.surrey.ac.uk/844257/.
Full textIgnace, Richard. "Asymmetric Shapes of Radio Recombination Lines from Ionized Stellar Winds." Digital Commons @ East Tennessee State University, 2019. https://dc.etsu.edu/etsu-works/5502.
Full textShort-Long, Jessica. "CORRELATION BETWEEN EMISSION LINES AND RADIO LUMINOSITIES OF ACTIVE GALACTIC NUCLEI." UKnowledge, 2018. https://uknowledge.uky.edu/physastron_etds/55.
Full textKryukova, N. V., Evgen Viktorovych Goncharov, and I. V. Polyakov. "Modern monitoring systems of electric power lines." Thesis, NTU "KhPI", 2018. http://repository.kpi.kharkov.ua/handle/KhPI-Press/38909.
Full textBrown, Martin. "High voltage soliton production in nonlinear transmission lines and other pulsed power applications." Thesis, University of Oxford, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.364003.
Full textAlastalo, Ari. "Microelectromechanical resonator-based components for wireless communications : filters and transmission lines /." Espoo VTT, 2006. http://www.vtt.fi/inf/pdf/publications/2006/P616.pdf.
Full textHumphrey, Andrew James. "Quantitative spectroscopy of the ultraviolet and optical emission lines from high redshift radio galaxies." Thesis, University of Hertfordshire, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.421273.
Full textFonseca, Herbert Moreti 1973. "Encoding, application and association of radio frequency identification tags on high speed manufacturing lines." Thesis, Massachusetts Institute of Technology, 2004. http://hdl.handle.net/1721.1/28513.
Full text"June 2004."
Includes bibliographical references (leaves 48-51).
One of the entry points of radio frequency identification technology in supply chain applications is at the manufacturing line, after production, as packaged goods leave for the next link of the network of suppliers, carriers, distributors and retailers. To RFID-enable packaged products, an RFID device needs to be attached to the packaging and an identification number needs to be generated and stored accordingly. Today, a few early adopters of the technology already started to apply RFID tags to some of their cases and pallets and to collect and store the information. These processes however, are still to a large extent done at a slow pace, manually or in an experimental mode, and that may not be suited for large scale applications. To address this issue, this research document focuses on the implementation of an RFID enabled process under strict time and performance constraints, for case packaged goods and pallets. This document reviews the currently published information on the topic and the Auto-ID technology standards. It analyses system integration challenges, proposes a process for case and pallet level encoding, application and association and discusses some of information systems requirements for the implementation. It proposes a framework of options with the requirements and considerations the author believes to be most relevant.
by Herbert Moreti Fonseca.
M.Eng.in Logistics
Цопа, А. И., В. К. Иванов, В. И. Леонидов, Ю. И. Малешенко, В. В. Павликов, Н. В. Руженцев, and А. А. Зарудный. "The research Program of millimetric Radio waves attenuation characteristics on perspective communication lines of Ukraine." Thesis, Proc. of XIII International Conf. Modern problems of Radio Engineering, Telecommunications and Computer Science /TCSET’2016/. – Lviv-Slavsko, 2016. – P. 638-642, 2016. http://openarchive.nure.ua/handle/document/3555.
Full textFu, Hai, J. F. Hennawi, J. X. Prochaska, R. Mutel, C. Casey, A. Cooray, D. Kereš, et al. "THE CIRCUMGALACTIC MEDIUM OF SUBMILLIMETER GALAXIES. I. FIRST RESULTS FROM A RADIO-IDENTIFIED SAMPLE." IOP PUBLISHING LTD, 2016. http://hdl.handle.net/10150/623949.
Full textStuart, Thomas (Thomas Edward Walter). "The measurement of radio frequency complex permeability of thin round wires." Thesis, Stellenbosch : Stellenbosch University, 2003. http://hdl.handle.net/10019.1/53657.
Full textENGLISH ABSTRACT: This thesis is concerned with the measurement of the complex permeability of thin round wires at radio frequencies. This is of interest as such wires are used in various applications, such as absorbing chaff. Iron and nickel alloys are also used for their good tensile properties but have an undesired electromagnetic effect which needs to be characterised. Although little work has been done in this field in recent decades it remains a relevant problem. In this thesis the advantages of accurate wide-band measurements performed by automatic network analysers are applied to the field. The measurement system is a closed coaxial transmission line with a short circuit termination. The centre conductor is the wire of interest. The surface impedance of the wire is related to complex permeability and is measured using low-loss transmission line approximations applied to half-wavelength resonances. The loss associated with complex permeability is separated from conductivity by a D.C. conductivity measurement. A full wave analysis of the coaxial mode was performed and compared to measured values. The maximum error of the propagation constant was found to be 31% at the highest frequencies and was primarily due to length uncertainties. By varying parameters expected error bands around the measured permeability were found. These bands are of the order 1 and demonstrate that the system is sufficiently robust. The measurement of the permeability of two non-magnetic wires was performed and a relative permeability of 1 was found, demonstrating the correct working of the system. A steel wire was measured and compared to measurements found in literature. The permeability dropped as frequency rose as was expected, and an acceptable comparison to other measurements was made as there is no verification standard. Thus a simple measurement system that takes advantage of calibrated automatic network analyser measurements has been developed and demonstrated to work with sufficient accuracy.
AFRIKAANSE OPSOMMING: In hierdie tesis word die meting van die komplekse permeabiliteit van dun ronde drade by radio frekwensies ondersoek. Hierdie drade word in verskeie toepassings gebruik, waaronder dié van absorberende materiale. Nikkel- en ysterallooie word ook vir hul goeie breekkrageienskappe gebruik. In laasgenoemde gevalle moet die ongewenste elektromagnetiese effekte wat voorkom, gekarakteriseer word. Hoewel baie min werk in onlangse dekades gedoen is, bly die meting van die komplekse permeabiliteit 'n relevante probleem. In hierdie tesis word die voordele van akkurate wyeband metings, soos geneem deur 'n outomatiese netwerk analiseerder, toegepas in dié veld. Die meetopstelling is 'n geslote koaksiale transmissielyn, kortgesluit aan een end. Die middel geleier is die draad van belang. Die oppervlak impedansie van die draad is verwant aan die komplekse permeabiliteit, en word gemeet deur die gebruik van lae verlies transmissielyn benaderings, soos toegepas op halfgolf resonante frekwensies. Die verlies wat met die komplekse permeabiliteit geassosieer word, word van die geleidingsvermoë onderskei deur 'n G.S. meting van die geleidingsvermoë. 'n Volgolf analise van die koaksiale mode is uitgevoer en met gemete waardes vergelyk. 'n Maksimum fout van 31% by die hoogste frekwensie is in die voortplantingskonstante gevind. Hierdie volg primêr uit onsekerhede in lengte. Deur die parameters te varieer kon 'n verwagte foutband rondom die gemete permeabiliteit gevind word. Hierdie bande is van die orde 1 waaruit volg dat die stelsel 'n genoegsame robuustheid toon. Die komplekse permeabiliteit van twee nie-magnetiese drade is gemeet en 'n relatiewe permeabiliteit van 1 is gevind. Hierdie bevestig die korrekte werking van die stelsel. 'n Staal draad is opgemeet en met gepubliseerde meetresultate vergelyk. Soos verwag, verminder die permeabiliteit met 'n verhoging in frekwensie. Hoewel geen verifiëringstandaard beskikbaar is nie, is 'n aanvaarbare vergelyking met ander metings gemaak. Die produk van die navorsing is 'n metingstelsel wat, met behulp van 'n gekalibreerde outomatiese netwerk analiseerder, aanvaarbare akkuraatheid in die meting van die komplekse permeabiliteit van dun ronde drade by radio frekwensies kan verkry.
Shaw, Gargi, G. J. Ferland, and I. Hubeny. "The Validity of 21 cm Spin Temperature as a Kinetic Temperature Indicator in Atomic and Molecular Gas." IOP PUBLISHING LTD, 2017. http://hdl.handle.net/10150/625168.
Full textRussell, H. R., M. McDonald, B. R. McNamara, A. C. Fabian, P. E. J. Nulsen, M. B. Bayliss, B. A. Benson, et al. "Alma Observations of Massive Molecular Gas Filaments Encasing Radio Bubbles in the Phoenix Cluster." IOP PUBLISHING LTD, 2017. http://hdl.handle.net/10150/623241.
Full textBarnes, Peter J., Audra K. Hernandez, Stefan N. O’Dougherty, III William J. Schap, and Erik Muller. "THE GALACTIC CENSUS OF HIGH- AND MEDIUM-MASS PROTOSTARS. III. 12 CO MAPS AND PHYSICAL PROPERTIES OF DENSE CLUMP ENVELOPES AND THEIR EMBEDDING GMCs." IOP PUBLISHING LTD, 2016. http://hdl.handle.net/10150/622167.
Full textGqaza, Themba. "Optimisation of galaxy identification methods on large interferometric surveys." Master's thesis, Faculty of Science, 2018. http://hdl.handle.net/11427/30072.
Full textSchmidt, D. R., and L. M. Ziurys. "New Identifications of the CCH Radical in Planetary Nebulae: A Connection to C-60?" IOP PUBLISHING LTD, 2017. http://hdl.handle.net/10150/626258.
Full textSchmidt, D. R., and L. M. Ziurys. "NEW DETECTIONS OF HNC IN PLANETARY NEBULAE: EVOLUTION OF THE [HCN]/[HNC] RATIO." IOP PUBLISHING LTD, 2017. http://hdl.handle.net/10150/622874.
Full textMisanovic, Zdenka. "Search for young galactic supernova remnants." Thesis, The University of Sydney, 2001. http://hdl.handle.net/2123/795.
Full textMisanovic, Zdenka. "A search for young galactic supernova remnants." University of Sydney. Physics, 2001. http://hdl.handle.net/2123/795.
Full textUrban, Rodney Gordon. "Power line corona noise prediction from small cage measurement." Thesis, Stellenbosch : Stellenbosch University, 2004. http://hdl.handle.net/10019.1/50063.
Full textSome digitised pages may appear illegible due to the condition of the original hard copy.
ENGLISH ABSTRACT: The radio noise (RN) performance of an AC high voltage transmission line is a determining factor when accessing the reliability of the design. The conducted RN level across the terminals of a PLC receiver, used in the teleprotection system of the line, is of particular concern. In this dissertation, existing empirical and semi-analytical RN prediction methods are evaluated by comparing the conducted RN levels of four South African lines to the predicted levels. Existing RN measurement protocols are consolidated and a new RN measurement protocol is proposed for the comparison. A prediction methodology, based on the EdF, EPRI and IREQ semi-analytical methods, is formulated. The semi-analytical methods are not able to accurately predict the variation of the conducted RN with frequency in the PLC band, nor are they able to predict the RN performance of short lines. A wideband excitation function, which considers the statistical characteristics of the measured RN pulse train, is therefore proposed in this dissertation. Having investigated the extraction of this excitation function from ESKOM’s Megawatt Park corona cage, it is concluded that a small corona cage is required. The design of a small cage is presented and the extraction of the excitation function is described. Attention is given to assessing the effect of changes in space charge distributions. The effect of space charge collision with an insulated cage on the extracted pulse parameters is linear, provided space charge diffusion is negligible. The onset streamer, positive streamer and negative streamer corona modes were identified as the only modes with measurable RN in the frequency regime 150 kHz to 30 MHz. Formulas are derived for the prediction of the inception gradients for these modes. The RN performance of an ACSR Hare conductor is extracted from the small cage. The RN performance of the Acacia-Koeberg line is also approximated in the PLC band. The dissertation concludes that the proposed wideband excitation function method is capable of accurately predicting the variation of RN levels with frequency. It can also be used to predict the RN performance of short line sections, as well as the relationship between RMS, QP and average RN levels from a transmission line.
AFRIKAANSE OPSOMMING: Die korona-werkverrigting van ‘n WS hoogspanningstransmissielyn het belangrike gevolge vir die betroubaarheid van die ontwerp van die lyn. Die geleide radioruis (RR) vlak op die kraglyndragolf kommunikasie sisteem, wat vir tele-beveiliging gebruik word, is veral van belang. In hierdie werkstuk word bestaande metodes gebruik om die korona-werkverrigting te bepaal en dan met gemete waardes van vier Suid Afrikaanse lyne te vergelyk. Bestaande RR meetmetodes word saamgevat en ‘n nuwe metingsprotokol word voorgestel om resultate te vergelyk. Na aanleiding van hierdie vergelykings word ‘n tegniek ontwikkel om die RR van ‘n lyn te voorspel. Hierdie tegniek gebruik die EdF, EPRI en IREQ metodes. Die voorgestelde tegniek kan nie die verandering van die RR met frekwensie bepaal nie. Dit kan ook nie die RR van kort lyne bepaal nie. ‘n Wyeband RR bron word dus voorgestel. Nadat ESKOM se Megawatt Park korona-kou ondersoek is, is die gevolgtrekking gemaak dat ‘n klein koronakou die nodige wyeband RR bron sal voorsien. Ruimtelading bots met die klein korona-kou. Die effek van hierdie botsings op die pulsparameters is lineer indien ladingsdiffusie nie plaasvind nie. Die aanvangs, positiewe en negatiewe kanaalontladings (“streamers”) is identifiseer as die enigste koronamodusse wat RR veroorsaak tussen 150 kHz en 30 MHz. Die spanning waarby hierdie modusse voorkom, is bepaal. Die korona-werkverrigting van ‘n “ACSR Hare” geleier is bepaal. Die korona-werkverrigting van die Acacia-Koeberg transmissie lyn is ook gekwantifiseer by die kraglyn-dragolf kommunikasie frekwensies. Die wyebandbron metode kan die verandering in RR met frekwensie goed voorspel. Die nuwe metode kan ook gebruik word om die RR van kort lyne te bepaal, asook die verband tussen RMS, QP en gemiddelde RR vlakke.
Seo, Youngmin, and Youngmin Seo. "The L1495-B218 Filaments in Taurus Seen in NH₃ & CCS and Dynamical Stability of Filaments and Dense Cores." Diss., The University of Arizona, 2016. http://hdl.handle.net/10150/621572.
Full textWatson, Linda Ceva. "Properties of Bulgeless Disk Galaxies: Atomic Gas and Star Formation." The Ohio State University, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=osu1313525138.
Full textYao, Wenhao [Verfasser]. "Disulfiram (Antabuse) acts as a potent chemo-radio sensitizer and abolishes stem cells in HNSCC cell lines in vitro / Wenhao Yao." Berlin : Medizinische Fakultät Charité - Universitätsmedizin Berlin, 2020. http://d-nb.info/1212435710/34.
Full textMustafa, Incebacak. "Design Of Series-fed Printed Slot Antenna Arrays Excited By Microstrip Lines." Master's thesis, METU, 2010. http://etd.lib.metu.edu.tr/upload/12612447/index.pdf.
Full textt require high power levels with having advantage of easy integration with microwave front-end circuitry. In this thesis, design and analysis of microstrip line fed slot antenna arrays are investigated. First an equivalent circuit model that ignores mutual coupling effects between slots is studied. A 6-element array is designed by using this equivalent circuit model. From the measurement and electromagnetic simulation results of this array, it is concluded that mutual coupling effects should be considered in order to achieve a successful design that meets the design specifications related to the main beam direction and sidelobe levels of the antenna. Next, an improved equivalent circuit model proposed for stripline fed slot antenna arrays is studied. It is observed that, the mutual coupling effects are incorporated into the equivalent model through the utilization of active impedance concept. Finally, the design equations proposed in the improved equivalent circuit model are derived for the microstrip line fed slot antenna array structure. To demonstrate the validity and the accuracy of the derived design equations, results obtained by the proposed analysis method are compared with simulation and measurement results. It is concluded that the proposed method successfully predicts the radiation pattern of the array by including the mutual coupling effects.
Jiang, Bing. "Ubiquitous monitoring of distributed infrastructures /." Thesis, Connect to this title online; UW restricted, 2006. http://hdl.handle.net/1773/6118.
Full textRoberts-Borsani, G. W., M. J. Jiménez-Donaire, M. Daprà, K. Alatalo, I. Aretxaga, J. Álvarez-Márquez, A. J. Baker, et al. "Multiwavelength Characterization of an ACT-selected, Lensed Dusty Star-forming Galaxy at z = 2.64." IOP PUBLISHING LTD, 2017. http://hdl.handle.net/10150/625330.
Full textRho, J., J. W. Hewitt, J. Bieging, W. T. Reach, M. Andersen, and R. Güsten. "DISCOVERY OF BROAD MOLECULAR LINES AND OF SHOCKED MOLECULAR HYDROGEN FROM THE SUPERNOVA REMNANT G357.7+0.3: HHSMT, APEX, SPITZER , AND SOFIA OBSERVATIONS." IOP PUBLISHING LTD, 2016. http://hdl.handle.net/10150/622645.
Full textCui, Xian. "Efficient radio frequency power amplifiers for wireless communications." Columbus, Ohio : Ohio State University, 2007. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1195652135.
Full textLi, Shanghuo, Junzhi Wang, Zhi-Yu Zhang, Min Fang, Juan Li, Jiangshui Zhang, Junhui Fan, Qingfeng Zhu, and Fei Li. "Millimetre spectral line mapping observations towards four massive star-forming H ii regions." OXFORD UNIV PRESS, 2017. http://hdl.handle.net/10150/623847.
Full textShao, Yali, Ran Wang, Gareth C. Jones, Chris L. Carilli, Fabian Walter, Xiaohui Fan, Dominik A. Riechers, et al. "Gas Dynamics of a Luminous z = 6.13 Quasar ULAS J1319+0950 Revealed by ALMA High-resolution Observations." IOP PUBLISHING LTD, 2017. http://hdl.handle.net/10150/625774.
Full textChippendale, Aaron Paul. "Detecting cosmological reionization on large scales through the 21 cm HI line." Thesis, The University of Sydney, 2009. http://hdl.handle.net/2123/6256.
Full textChippendale, Aaron Paul. "Detecting cosmological reionization on large scales through the 21 cm HI line." University of Sydney, 2009. http://hdl.handle.net/2123/6256.
Full textThis thesis presents the development of new techniques for measuring the mean redshifted 21 cm line of neutral hydrogen during reionization. This is called the 21 cm cosmological reionization monopole. Successful observations could identify the nature of the first stars and test theories of galaxy and large-scale structure formation. The goal was to specify, construct and calibrate a portable radio telescope to measure the 21 cm monopole in the frequency range 114 MHz to 228 MHz, which corresponds to the redshift range 11.5 > z > 5.2. The chosen approach combined a frequency independent antenna with a digital correlation spectrometer to form a correlation radiometer. The system was calibrated against injected noise and against a modelled galactic foreground. Components were specified for calibration of the sky spectrum to 1 mK/MHz relative accuracy. Comparing simulated and measured spectra showed that bandpass calibration is limited to 11 K, that is 1% of the foreground emission, due to larger than expected frequency dependence of the antenna pattern. Overall calibration, including additive contributions from the system and the radio foreground, is limited to 60 K. This is 160 times larger than the maximum possible monopole amplitude at redshift eight. Future work will refine and extend the system known as the Cosmological Reionization Experiment Mark I (CoRE Mk I).
Herrera, Contreras Cinthya Natalia. "How do the large-scale dynamics of galaxy interactions trigger star formation in the Antennae galaxy merger?" Phd thesis, Université Paris Sud - Paris XI, 2012. http://tel.archives-ouvertes.fr/tel-00800077.
Full textRice, Johnathan Scott. "The Transition From Diffuse to Dense Molecular Clouds." University of Toledo / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1534945134382193.
Full textSalmon, Brian P. "Optimizing LDPC codes for a mobile WiMAX system with a saturated transmission amplifier." Pretoria : [s.n.], 2008. http://upetd.up.ac.za/thesis/available/etd-01262009-160431/.
Full textHariharan, S. "Channel estimators for HF radio links." Thesis, Loughborough University, 1988. https://dspace.lboro.ac.uk/2134/6733.
Full textFavre, Cécile. "Étude interférométrique du formiate de méthyle et d’autres molécules complexes dans la nébuleuse d’Orion Kleinmann-Low." Thesis, Bordeaux 1, 2010. http://www.theses.fr/2010BOR14146/document.
Full textOver 150 different molecular species have been detected in the interstellar and circumstellar media. Among these, approximatively 60 are complex molecules and contain 6 or more atoms. The interstellar chemical processes that form more or less complex molecules, either on the surface of dust grains or in gas phase, are different from the processes we know on Earth. The only way to constrain chemical models relies on the observation and the analysis of the emission coming from various molecular species.The main goal of my PhD is to look for complex molecules in the nearest star forming region with both high and low mass stars, the Orion Kleinmann-Low nebula. I specially studied the emission of the methyl formate molecule (HCOOCH3) which appeared to be an abundant molecule and a good probe of the temperature and structure of Orion K-L.Using high spectral and spatial resolution millimetre observations (from 7’’ to 2’’ and from 2.3 km/s to 0.4 km/s, respectively) from the IRAM Plateau de Bure Interferometer, I carried out a detailed study of the emission of this O-bearing molecule towards the Compact Ridge component. Our study shows that this region seems to be heated by external mechanisms (e.g. shocks).Moreover, our observations toward the Compact Ridge region and its surroundings tend to confirm that methyl formate or a precursor seems to be formed on grain surfaces and is subsequently desorbed due to shocks.I also looked for the two isomers of methyl formate [C2H4O2] : glycolaldehyde and acetic acid. Owing to strong spectral confusion in the region, it is very difficult to detect low abundance molecules such as these two isomers. In order to lower the confusion level, higher spatial as well as spectral resolutions must be achieved which ALMA will soon allow.We derived upper limits for the column density of glycolaldehyde, a precursor of sugar (CH2OHCHO that has been detected towards SgrB2), these limits provide strong constraints for chemical models
Abbood, Abdul Nasser Abdul Jabbar. "Optimised radio over fibre links for next generation radio access networks." Thesis, Brunel University, 2018. http://bura.brunel.ac.uk/handle/2438/17019.
Full textWalkenhorst, Brett T. "Achieving near-optimal MIMO capacity in a rank-deficient LOS environment." Diss., Atlanta, Ga. : Georgia Institute of Technology, 2009. http://hdl.handle.net/1853/29672.
Full textCommittee Chair: Ingram, Mary Ann; Committee Member: Durgin, Greg; Committee Member: Kenney, Steve; Committee Member: Landgren, Jack; Committee Member: Li, Ye. Part of the SMARTech Electronic Thesis and Dissertation Collection.
Codreanu, M. (Marian). "Multidimensional adaptive radio links for broadband communications." Doctoral thesis, University of Oulu, 2007. http://urn.fi/urn:isbn:9789514286223.
Full textKo, Yiu Fai. "Digital cellular mobile radio links and networks." Thesis, University of Southampton, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.280911.
Full textCOSTA, VALÉRIA MILHENA BARBEITO NUNES DA. "PROPAGATION MEASUREMENTS FOR TERRESTRIAL DIGITAL RADIO LINKS." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 1996. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=14227@1.
Full textEMPRESA BRASILEIRA DE TELECOMUNICAÇÕES
TELECOMUNICAÇÕES BRASILEIRAS S/A
Este trabalho teve como objetivo o levantamento de parâmetros para o auxílio no cálculo de desempenho e dimensionamento de sistemas digitais terrestres. Estes parâmetros forma obtidos através de medidas em enlaces analógicos pertencentes a Empresa Brasileira de telecomunicações e a Telesc, espalhados por todo o Brasil. Toda estrutura necessária para obtenção destes dados foi desenvolvida no CETUC. As principais características dos sistemas experimentais de medidas, programas para análise de dados, bem como uma descrição detalhada dos experimentos são apresentadas neste trabalho. Os resultados principais apresentados são as análises estatísticas de parâmetros de propagação em condições de céu claro. Nestes resultados estão incluídos as distribuições anuais, pior mês, desvanecimentos máximos e retardo. Os resultados obtidos foram também usados para avaliação de performance de alguns enlaces digitais.
The aim this work was to obtain design parameters for terrestrial digital systems, and to Access their reliability and quality. These design parameters were obtained from measurements made in analogic links operated by the Brazilian telecommunication company Telebrás and Telesc, localised throughout Brazil.The techniques necessary to obtain the data were developed at CETUC. The main characteristcs of experimental links used in this work are presented, as well as the software used for the analyses. A complete description of the experimental set-up is also presented. The main results are the statistical analyses of the propagation parameters for cleae sky. Thes eresults include the annual attenuation, worst month attenuation, relative delay and maximum fading distributions. The results obtained were also used for performance evaluation of some digital links.
Lam, Doan Duc. "The circumstellar envelope of the S-type AGB star π1 Gruis." Licentiate thesis, Uppsala universitet, Teoretisk astrofysik, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-327397.
Full textJemtelius, Filip, and André Färnsveden. "Vad vet Sveriges Radio om Black lives matter? : En studie om Sveriges Radios rapportering kring Black livesmatter 2020." Thesis, Mittuniversitetet, Institutionen för medie- och kommunikationsvetenskap, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:miun:diva-40964.
Full textFreudinger, Lawrence C., Filiberto Macias, and Harold Cornelius. "Frequency Agile Transceiver for Advanced Vehicle Data Links." International Foundation for Telemetering, 2009. http://hdl.handle.net/10150/605968.
Full textEmerging and next-generation test instrumentation increasingly relies on network communication to manage complex and dynamic test scenarios, particularly for uninhabited autonomous systems. Adapting wireless communication infrastructure to accommodate challenging testing needs can benefit from reconfigurable radio technology. Frequency agility is one characteristic of reconfigurable radios that to date has seen only limited progress toward programmability. This paper overviews an ongoing project to validate a promising chipset that performs conversion of RF signals directly into digital data for the wireless receiver and, for the transmitter, converts digital data into RF signals. The Software Configurable Multichannel Transceiver (SCMT) enables four transmitters and four receivers in a single unit, programmable for any frequency band between 1 MHz and 6 GHz.
Nader, Joe. "Modeling and performance of microwave radio links in rain." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape8/PQDD_0022/MQ50644.pdf.
Full textNader, Joe. "Modeling and performance of microwave radio links in rain." Thesis, McGill University, 1998. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=21315.
Full textThe theoretical model is simulated and compared to the ITU and Crane prediction methods. Both moderate and tropical climates are considered. A simple line-of-sight radio system is then simulated and evaluated by incorporating the rain attenuation in the channel. Finally, three basic network blocks are discussed and analyzed for links affected by rain.
NAVARRO, KEYLA MARIA MORA. "RAIN EFFECTS ON MICROWAVE AND MILLIMETER WAVE RADIO LINKS." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2017. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=33982@1.
Full textCOORDENAÇÃO DE APERFEIÇOAMENTO DO PESSOAL DE ENSINO SUPERIOR
CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO
PROGRAMA DE EXCELENCIA ACADEMICA
A principal meta desta tese é estudar os efeitos da chuva nos enlaces operando na faixa de micro-ondas e comprimentos de ondas milimétricas. Para realizar este estudo, é considerado o modelo de chuva que considera um meio de chuva realista composto por um conjunto de gotas com a relação formato-tamanho proposta por Chuang e Beard, uma distribuição de tamanho das gotas dada por de Wolf, o índice de refração complexo da água para uma frequência e temperatura dada sugerido por Ray e uma distribuição de orientação dos eixos de simetria da partícula. O Extended Boundary Condition Method (EBCM) foi aplicado ao modelo descrito para determinar a atenuação, depolarização e espalhamento devidos à chuva. O desenvolvimento foi validado com sucesso por intermédio de comparações de seus resultados com os correspondentes disponíveis na literatura. O modelo de chuva realista foi utilizado em duas aplicações diferentes. Na primeira, foi estudada a interferência devida à chuva entre enlaces de telecomunicações sem fio operando em frequências de ondas milimétricas em ambientes urbanos. Outra aplicação envolve a determinação da taxa de precipitação por intermédio de radares meteorológicos (em particular, radares banda-X). Considerando que seu custo é relativamente baixo e sua resolução elevada, os radares em banda-X estariam entre as melhores opções para monitorar eventos meteorológicos. Entretanto, são susceptíveis à atenuação devida a gases atmosféricos e chuva ao longo dos enlaces, que impedem que a taxa de precipitação seja estimada diretamente a partir da potência recebida correspondente a uma determinada posição. Desta forma, um modelo de chuva realista foi implementado para calcular a seção reta de retroespalhamento e estimar a atenuação específica por intermédio do EBCM em cada um dos volumes existentes entre o radar e a posição selecionada. Este desenvolvimento permite a correção dos efeitos da atenuação existente no enlace formado entre estas duas posições.
The main goal of this research is to study the rain effects on microwave and millimeter wave radio links. Thus, the rain-induced attenuation, depolarization and scattering are studied. To carry out this study, a realistic rain model is proposed, which consider a realistic rain medium composed by a cluster of raindrops with the shape-size relation proposed by Chuang and Beard, a raindrop size distribution given by de Wolf, index of refraction of water for a given temperature and frequency suggested by Ray and a distribution of the orientation angle of the symmetry axis. The realistic rain model is evaluated with two different applications of systems operating at microwave and millimeter wave frequencies. One of the applications involves wireless telecommunication systems, which are strongly affected by the presence of precipitation. To design an efficient radio communication system, the realistic rain model is applied for the analysis and quantification of rain-induced effects on links operating at millimeterwave frequencies in urban environments. Another application involves weather radars (X-band radars in particular). Considering their relatively low cost and high resolution, X-band radars would be among the best options to monitor meteorological events. However, they are susceptible to attenuation by fog, snow or rain. To solve this problem, a realistic and improved rain model is implemented to compute backscattering cross sections and estimate rain attenuation at each range gate. The proposed method is evaluated using radar data provided by the CASA OTG X-band (lambda equal a 3cm) radar located in Mayaguez, Puerto Rico, and X-band radar METEOR 50DX –Selex located in Belém, Brazil.
Liu, Zhansheng. "Characterization of RSOA modulators in radio over fiber links." Doctoral thesis, Universidade de Aveiro, 2014. http://hdl.handle.net/10773/13985.
Full textIn this work physical and behavioral models for a bulk Reflective Semiconductor Optical Amplifier (RSOA) modulator in Radio over Fiber (RoF) links are proposed. The transmission performance of the RSOA modulator is predicted under broadband signal drive. At first, the simplified physical model for the RSOA modulator in RoF links is proposed, which is based on the rate equation and traveling-wave equations with several assumptions. The model is implemented with the Symbolically Defined Devices (SDD) in Advanced Design System (ADS) and validated with experimental results. Detailed analysis regarding optical gain, harmonic and intermodulation distortions, and transmission performance is performed. The distribution of the carrier and Amplified Spontaneous Emission (ASE) is also demonstrated. Behavioral modeling of the RSOA modulator is to enable us to investigate the nonlinear distortion of the RSOA modulator from another perspective in system level. The Amplitude-to-Amplitude Conversion (AM-AM) and Amplitude-to-Phase Conversion (AM-PM) distortions of the RSOA modulator are demonstrated based on an Artificial Neural Network (ANN) and a generalized polynomial model. Another behavioral model based on Xparameters was obtained from the physical model. Compensation of the nonlinearity of the RSOA modulator is carried out based on a memory polynomial model. The nonlinear distortion of the RSOA modulator is reduced successfully. The improvement of the 3rd order intermodulation distortion is up to 17 dB. The Error Vector Magnitude (EVM) is improved from 6.1% to 2.0%. In the last part of this work, the performance of Fibre Optic Networks for Distributed and Extendible Heterogeneous Radio Architectures and Service Provisioning (FUTON) systems, which is the four-channel virtual Multiple Input Multiple Output (MIMO), is predicted by using the developed physical model. Based on Subcarrier Multiplexing (SCM) techniques, four-channel signals with 100 MHz bandwidth per channel are generated and used to drive the RSOA modulator. The transmission performance of the RSOA modulator under the broadband multi channels is depicted with the figure of merit, EVM under di erent adrature Amplitude Modulation (QAM) level of 64 and 254 for various number of Orthogonal Frequency Division Multiplexing (OFDM) subcarriers of 64, 512, 1024 and 2048.
Nesta tese são propostos modelos físicos e comportamentais para o amplificador óptico semicondutor reflectivo (RSOA), tendo como objectivo a avaliação do seu desempenho quando utilizado como modulador em ligações de rádio sobre fibra (RoF). Os modelos propostos são capazes de prever o comportamento do dispositivo quando utilizado com sinais de banda larga bem como quando estimulado por sinais de elevada potência. Inicialmente propõe-se um modelo físico simplificado para o RSOA baseado nas equações de taxa e nas equações de propagação electromagnética. A implementação do modelo utiliza o ADS (Advanced Design Systems) e o bloco designado por dispositivo definido simbolicamente (SDD) para descrever as equações de taxa, assim como a propagação de fotões ao longo da cavidade. O modelo permite uma análise detalhada do ganho óptico, distorções harmônicas, intermodulação e seu desempenho de transmissão com portadoras RF modeladas. Foram também considerados modelos comportamentais. Um modelo baseado em rede neural artificial (ANN) e um modelo polinomial generalizado para banda base foram considerados tendo os parâmetros respectivos sido extraídos utilizando, para o efeito, dados obtidos experimentalmente. São demonstradas a característica da distorção resultante da conversão amplitude - amplitude (AM-AM) e conversão da fase - amplitude (AM-PM) no modulador RSOA. Um modelo baseado em parametros X, obtidos a partir do modelo físico, foi também analisado. Compensação da não-linearidade do modulador RSOA é realizada com base num modelo polinomial com memória. Demonstra-se que a distorção não linear do modulador RSOA pode ser compensada com sucesso. Com a compensação obtem-se uma redução de 17 dB da distorção introduzida pelos produtos de intermodulação de terceira ordem. O EVM (Error Vector Magnitude) apresenta uma melhoria de 6,1% para 2,0%. Na última parte deste trabalho considera-se uma configuração que representa a ligação ascendente por fibra de um sistema de antenas remoto a uma estação central de processamento. Com esta configuração pretendese demonstrar a possibilidade de implementação de uma tecnologia MIMO, suportada num sistema RoF. Baseado numa técnica de multiplexação subportadora (SCM), os sinais de quatro canais com largura de banda de 100 MHz por canal são multiplexados e utilizados para modelar o ganho do RSOA. O desempenho deste link óptico é caracterizado para modulações OFDM considerando diferentes números de sub-portadoras por símbolo (64, 512 , 1024 e 2048) assim como o formato QAM imposto sobre cada sub-portadora.