Dissertations / Theses on the topic 'Digital signal transmission'
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Moore, Philip John. "Adaptive digital distance protection." Thesis, City University London, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.328244.
Dogheche, El Hadj. "Transmission optique d'un signal analogique hyperfréquence et digital bas débit." Lille 1, 1993. http://www.theses.fr/1993LIL10056.
Sant'Ana, Roberto Garcia Rosa. "Investigation of new digital protection for multi-terminal power lines." Thesis, University of Manchester, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.334628.
Shahri, Javad Yazdani Kohneh. "High frequency digital power line transmission for terrestrial and marine networks." Thesis, Lancaster University, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.288950.
Usta, Ö. "A power based digital algorithm for the protection of embedded generators." Thesis, University of Bath, 1992. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.251234.
Lundbäck, Jonas. "On signal processing and electromagnetic modelling : applications in antennas and transmission lines /." Karlskrona : Department of Signal Processing, School of Engineering, Blekinge Institute of Technology, 2007. http://www.bth.se/fou/Forskinfo.nsf/allfirst2/62a51cd9a6f3d716c12572c1003f0063?OpenDocument.
Wong, K.-H. H. "Transmission of channel coded speech and data over mobile radio channels." Thesis, University of Southampton, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.235340.
Irizar, JoseÌ MariÌa Zabalegui. "Combined equalisation and decoding for OFDM over wireless fading channels." Thesis, Staffordshire University, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.272580.
Loasby, J. M. "Real time transmission line modelling of the vocal tract using multiple digital signal processors." Thesis, University of Nottingham, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.339551.
Prodaniuc, Cristian. "Advanced Signal Processing for Pulse-Amplitude Modulation Optical Transmission Systems." Doctoral thesis, Universitat Politècnica de València, 2019. http://hdl.handle.net/10251/117315.
[CAT] Actualment, s'utilitzen sistemes òptics no coherents en xarxes òptiques de curt abast ( < 80 km), com són les xarxes d'àmbit metropolità. La implementació més comuna que podem trobar en l'estat de l'art es correspon amb sistemes emplenant multiplexació per divisió en longitud d'ona (WDM, wavelength division multiplexing) de quatre longituds d'ona (¿) proporcionant un règim binari de 100 Gbps (4¿×25 Gbps). En els últims anys, els sistemes de transmissió òptica no-coherents han evolucionat des de 100 Gbps cap a 400 Gbps (100 Gbps/¿). Atès que el mercat de sistemes de curt abast compren un gran volum de dispositius òptics instal·lats, el cost unitari és molt important i ha de ser el més baix possible. L'objectiu d'aquesta tesi és analitzar aspectes del processament de senyal en general i, específicament, investigar noves tècniques de processament digital de senyal (DSP, digital signal processing) que puguen ser utilitzades en sistemes de transmissió òptica no-coherent que utilitzen la modulació per amplitud d'impulsos (PAM, pulse-amplitude modulation). Per tal que una tècnica DSP es considere interessant per a una xarxa òptica WDM no-coherent, aquesta ha de mitigar efectivament almenys una de les tres principals limitacions que afecten aquests sistemes: limitacions d'ample de banda, limitacions per dispersió cromàtica (CD), i el soroll. En aquesta tesi s'examinen una sèrie d'algoritmes, el seu rendiment s'analitza per simulació i experimentalment en laboratori: - Feed-forward equalizer (FFE): aquest és l'esquema d'equalització més comú i s'utilitza bàsicament en les transmissions òptiques no coherents d'alt règim binari. Pot compensar grans quantitats de limitacions d'ample de banda. - Estimació de la seqüència de probabilitat màxima (MLSE): el MLSE és un detector òptim i, per tant, proporciona el millor rendiment quan es tracta de limitacions d'ample de banda i de CD. - Conformació geomètrica de la constel·lació: en esquemes de modulació òptica d'intensitat multinivell es pot ajustar la distància entre els nivells d'amplitud (de manera que ja no són equidistants) per augmentar la tolerància del senyal al soroll. - Conformació probabilística: una tècnica dissenyada específicament per als esquemes de modulació multinivell; ajusta la probabilitat de cada nivell d'amplitud de manera que augmenta la tolerància al soroll òptic. - Senyalització de resposta parcial (PRS, partial signaling response): és un enfocament basat en DSP on la interferència entre símbols (ISI, inter-symbol interference) controlada s'introdueix intencionalment de manera que el senyal resultant requereix menys ample de banda. La tècnica PRS es pot adaptar per combatre els efectes del CD. - Pre-èmfasi digital (DPE, digital pre-emphasis): aquesta tècnica consisteix a aplicar la inversió de la funció de transferència del sistema a la senyal en el transmissor de manera que es redueix l'impacte de les limitacions d'ample de banda en la senyal en el receptor. - Modulació amb codificació Trellis (TCM, Trellis-coded modulation): esquema de modulació que combina els elements de correcció d'errors avançats (FEC, forward error correction) amb tècniques de partionament de conjunts i modulació multidimensional per generar un senyal més resistent al soroll. - Modulació multidimensional per partició en conjuntes: molt similar a TCM però sense elements FEC. Té guanys menors que TCM en termes de tolerància al soroll, però no és tan sensible a l'ISI. Mitjançant l'ús d'aquestes tècniques, aquesta tesi demostra que és possible aconseguir una transmissió òptica amb un règim binari de 100 Gbps/¿ utilitzant components de baix cost. Esta tesi també demostra règims binaris de més de 200 Gbps, el que indica que la tecnologia no-coherent amb modulació PAM és una solució viable i eficient en cost per a una nova generació de sistemes transceptors òptics WDM funcionant a 800 Gbps (4¿×200 G
[EN] Non-coherent optical transmission systems are currently employed in short-reach optical networks (reach shorter than 80 km), like metro networks. The most common implementation in the state-of-the-art is the four wavelength (¿) 100 Gbps (4¿×25 Gbps) wavelength division multiplexing (WDM) transceiver. In recent years non-coherent optical transmissions are evolving from 100 Gbps to 400 Gbps (4¿×100 Gbps). Since in the short-reach market the volume of optical devices being deployed is very large, the cost-per-unit of the devices is very important, and it should be as low as possible. The goal of this thesis is to investigate some general signal processing aspects and, specifically, digital signal processing (DSP) techniques required in non-coherent pulse-amplitude modulation (PAM) optical transmission, and also to investigate novel algorithms which could be applied to this application scenario. In order for a DSP technique to be considered an interesting solution for non-coherent WDM optical networks it has to effectively mitigate at least one of the three main impairments affecting such systems: bandwidth limitations, chromatic dispersion (CD) and noise (in optical or electrical domain). A series of algorithms are proposed and examined in this thesis, and their performance is analyzed by simulation and also experimentally in the laboratory: - Feed-forward equalization (FFE): this is the most common equalizer and it is basically employed in every high-speed non-coherent optical transmission. It can compensate high bandwidth limitations. - Maximum likelihood sequence estimation (MLSE): the MLSE is the optimum detector and thus provides the best performance when it comes to dealing with CD and bandwidth limitations. - Geometrical constellation shaping: in multilevel optical intensity modulation schemes the distance between amplitude levels can be adjusted (such that they are no longer equidistant) in order to increase the signal's tolerance to noise. - Probabilistic shaping: another technique designed specifically for multilevel modulation schemes; it adjusts the probability of each amplitude level such that the tolerance to optical noise is increased. - Partial response signaling (PRS): this is a DSP-based approach where a controlled inter-symbol interference (ISI) is intentionally introduced in such a way that the resulting signal requires less bandwidth. PRS can be customized to also mitigate CD impairment, effectively increasing transmission distances up to three times. - Digital pre-emphasis (DPE): this technique consists in applying the inverse of the transfer function of the system to the signal at the transmitter side which reduces the impact of bandwidth limitations on the signal at the receiver side. - Trellis-coded modulation (TCM): a modulation scheme that combines forward error correction (FEC) elements with set-partitioning techniques and multidimensional modulation to generate a signal that is more resistant to noise. - Multidimensional set-partitioned modulation: very similar with TCM but without any FEC elements. It has lower gains than TCM in terms of noise tolerance but is not so sensitive to ISI. By using the techniques enumerated above, this thesis demonstrates that is possible to achieve 100 Gbps/¿ optical transmission bitrate employing cost-effective components. Even more, bitrates higher than 200 Gbps are also demonstrated, indicating that non-coherent PAM is a viable cost-effective solution for next-generation 800 Gbps (4¿×200 Gbps) WDM transceivers.
Prodaniuc, C. (2019). Advanced Signal Processing for Pulse-Amplitude Modulation Optical Transmission Systems [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/117315
TESIS
Guiomar, Fernando Pedro Pereira. "Digital nonlinear equalization for optical transmission systems." Doctoral thesis, Universidade de Aveiro, 2015. http://hdl.handle.net/10773/15977.
This thesis focuses on digital equalization of nonlinear fiber impairments for coherent optical transmission systems. Building from well-known physical models of signal propagation in single-mode optical fibers, novel nonlinear equalization techniques are proposed, numerically assessed and experimentally demonstrated. The structure of the proposed algorithms is strongly driven by the optimization of the performance versus complexity tradeoff, envisioning the near-future practical application in commercial real-time transceivers. The work is initially focused on the mitigation of intra-channel nonlinear impairments relying on the concept of digital backpropagation (DBP) associated with Volterra-based filtering. After a comprehensive analysis of the third-order Volterra kernel, a set of critical simplifications are identified, culminating in the development of reduced complexity nonlinear equalization algorithms formulated both in time and frequency domains. The implementation complexity of the proposed techniques is analytically described in terms of computational effort and processing latency, by determining the number of real multiplications per processed sample and the number of serial multiplications, respectively. The equalization performance is numerically and experimentally assessed through bit error rate (BER) measurements. Finally, the problem of inter-channel nonlinear compensation is addressed within the context of 400 Gb/s (400G) superchannels for long-haul and ultra-long-haul transmission. Different superchannel configurations and nonlinear equalization strategies are experimentally assessed, demonstrating that inter-subcarrier nonlinear equalization can provide an enhanced signal reach while requiring only marginal added complexity.
A presente tese foca-se no tema da equalização digital de distorções não lineares da fibra em sistemas coerentes de transmissão ótica. Tirando partido de modelos físicos bem conhecidos para a propagação de sinal em fibras óticas mono-modo, novas técnicas de equalização não linear são propostas, testadas numericamente e validadas por demonstração experimental. A estrutura dos algoritmos propostos é fortemente condicionada pela otimização do compromisso entre complexidade e desempenho, tendo em conta a sua futura implementação prática em transcetores comerciais operando em tempo-real. O trabalho desenvolvido foca-se inicialmente na mitigação das distorções não lineares intra-canal, aplicando o conceito de propagação digital inversa realizado através de filtros de Volterra. Após uma análise sistemática do núcleo de Volterra de terceira ordem, é identificado um conjunto de simplificações críticas, culminando no desenvolvimento de algoritmos de equalização não linear de baixa complexidade, formulados no domínio do tempo e frequência. A complexidade de implementação das técnicas propostas e analiticamente descrita em termos de esforço computacional e latência de processamento, através da determinação do número de multiplicações reais por amostra e do número de multiplicações realizadas em série, respetivamente. O desempenho da equalização e avaliado recorrendo a simulação numérica e validação experimental através da medição da taxa de erros. Por fim, a questão da compensação não linear inter-canal é abordada no contexto da propagação de supercanais 400G para sistemas de transmissão metro e longa distância. Nesse âmbito são experimentalmente testadas diferentes configurações de supercanal e estratégias de equalização não linear, demonstrando assim que a implementação de equalização inter-subportadora permite estender consideravelmente o alcance, requerendo apenas um esforço computacional ligeiramente superior.
Kim, Dukhyun. "Orthogonal frequency division multiplexing for digital broadcasting." Diss., Georgia Institute of Technology, 1998. http://hdl.handle.net/1853/13704.
Frappé, Antoine. "All-digital RF signal generation using delta-sigma modulation for mobile communication terminals." Lille 1, 2007. https://pepite-depot.univ-lille.fr/LIBRE/Th_Num/2007/50376-2007-Frappe.pdf.
Shehata, Mohamed. "Hybrid Analogue and digital techniques applied to massive MIMO systems for 5G transmission at millimeter waves." Thesis, Rennes, INSA, 2019. http://www.theses.fr/2019ISAR0026.
The main aim of this work is to analytically analyze the performance of Hybrid Beamforming (HBF) in Millimeter Wave (mmWave) massive Multiple Input Multiple Output (MIMO) systems, to develop low complexity HBF algorithms to adapt with such systems and finally to verify the practical validity of these algorithms. The massive MIMO antenna array provides high transmit gain overcoming the severe path-loss limitation of the mm Wave systems. On the other had applying HBF in sparse channels achieves close Spectral Efficiency (SE) perfonnance compared to the full digital beamforming, however with lower hardware cost and power consumption. In this thesis we start by defining the conditions for which bath the HBF and full digital beamfonning can achieve exactly similar SE performance. Then, we analyze the SE perfonnance gap that arise between them in sparse mmWave MIMO channels. Moreover, we provide closed form SE models for basic analog and HBF techniques in typical mmWave MIMO channels. Later we consider a Multi User (MU) massive MIMO HBF framework that considers multiple spatial signal processing techniques for the analog domain processing, digital domain processing, power allocation and users scheduling. We develop low complexity algorithms for such framework in order to provide a low complexity practical HBF framework for future wireless communication networks that can cope with the challenges of mm Wave channels
Shibahara, Kohki. "Advanced Signal Processing for Fiber-Optic Communication Systems Scaling Capacity Beyond 100 Tb/s." Kyoto University, 2017. http://hdl.handle.net/2433/227663.
Xu, Tianhua. "Digital Dispersion Equalization and Carrier Phase Estimation in 112-Gbit/s Coherent Optical Fiber Transmission System." Licentiate thesis, KTH, Optik, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-34034.
QC 20110629
Bai, Neng. "Mode-Division Multiplexed Transmission in Few-mode Fibers." Doctoral diss., University of Central Florida, 2013. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/5761.
Ph.D.
Doctorate
Optics and Photonics
Optics and Photonics
Optics
Abayaje, Furat. "Transmission numérique sans fil en bande de base pour la communication à courte distance avec des circuits cryogéniques." Thesis, Université Grenoble Alpes (ComUE), 2017. http://www.theses.fr/2017GREAT017/document.
Rapid Single-Flux-Quantum (RSFQ) logic circuits based on superconducting Josephson junctions are using to generate, process and transmit very short quantized pulses whose area is the quantum of magnetic flux h/2e and corresponds to 2.07 mV.ps. Such circuits are used to process signals at very high speed with clock frequencies in the 10-120 GHz range and a power consumption about 100 to 1000 times lower that their best available semiconductor counterparts (including the cost of cooling down to 4,2K). RSFQ logic is an interesting alternative for supercomputers and offers unsurpassed performances for processing microwave signals on the fly. Once digital signals are processed at cryogenic temperature the key challenge is to transfer at room temperature the low-voltage output digital signals (about 200-1000µV) at high rates of about 1-10Gbps per channel, by limiting the thermal burden on the cryogenic system, in order to build high performance high throughput systems.A solution is to transmit the signals with a wireless emitting-receiving antenna set with a suitable bandwidth. This work examines several wireless baseband transmission systems in a short distance configuration, associated to the distance between the cryogenic and room temperature stages, for data rates in the range of a few Gbps. It elaborates on four crucial issues :• the choice and study of the proper line codes to be used for baseband transmission of digital signals without the need for analogue modulations, such as Polar Return-to-Zero and Manchester encodings ;• the study and selection of ultra-wide bandwidth antennas with a focus on small size Antipodal Vivaldi Antennas and monopole antennas to meet cryogenic constraints ;• the study of the Bit Error Rate (BER) of the transmitting system. Two methods were developed to recover the digital output signals and minimize the BER.• the comparison between simulations and measurements to assess the performance of the overall system
Le, Bidan Raphaël. "Turbo-equalization for bandwidth-efficient digital communications over frequency-selective channels." Rennes, INSA, 2003. http://www.theses.fr/2003ISAR0012.
Bailey, Brian Douglas. "Design of a video measurement system." Thesis, Virginia Polytechnic Institute and State University, 1988. http://hdl.handle.net/10919/80071.
Fernandez, de Jauregui Ruiz Ivan. "Advanced modulation formats and nonlinear mitigation for spectral efficient optical transmission systems." Thesis, Evry, Institut national des télécommunications, 2018. http://www.theses.fr/2018TELE0009/document.
Global data traffic is expected to reach up to 4.3 ZB per year by 2020. With the majority of the global communications being transported on submarine point-to-point fiber-optic systems, different cutting-edge technologies have been under research to cope with this unprecedented traffic growth. Continuous advances in high-speed integrated circuits have allowed the use of advanced modulation formats and digital signal processing (DSP) techniques to maximize the transmission spectral efficiency. With mitigation of fiber linear effects efficiently carried out by DSP with relative low-complexity, the capacity of modern fiber optic systems rests limited by fiber nonlinearities. To this extent, in the first part of this work, the performance and achievable benefits of low-complexity DSP techniques aiming to mitigate fiber Kerr nonlinear effects are investigated. Besides nonlinear compensation techniques, the use of multi-level modulation formats beyond 16QAM and high symbol rate channels have gained momentum to increase the system spectral efficiency. One of the major breakthroughs in the recent years, has been the introduction of QAM-based probabilistic constellation shaping (PCS-QAM), which has proven to outperform regular QAM formats. In this sense, in the second part of this work, the practical achievable rate increase brought by PCS-QAM for transoceanic distances is investigated. A theoretical and experimental comparison with other high-capacity formats is performed, and the design of a PCS-QAM for trans-Pacific distances is addressed. Finally, in the last section, several transmission records using the two above techniques are reported
Lange, Werner R., and Martin Ravensbergen. "TIME REFERENCE SYSTEM OF THE ESO VERY LARGE TELESCOPE." International Foundation for Telemetering, 1995. http://hdl.handle.net/10150/608540.
The necessity of supplying precise time information in large telemetry ground stations and astronomical observatories is very similar. Therefore the way of solving this problem as it is done in the Very Large Telescope of the European Southern Observatory can be easily adopted to telemetry stations and ranges, especially when fiber optics are used. The European Southern Observatory (ESO) is building a new observatory in Chile for the Very Large Telescope (VLT). This VLT consists of 4 telescopes, each of them has a primary mirror diameter of 8 meters. the control architecture is based on workstations and VMEbus computers. The VMEbus computers are distributed over the whole building and are using real time operating system. Since the availability of the Global Positioning System (GPS) the generation of highly accurate timing signals on remote locations without the use of expensive Cesium standards does not create problems any more. However, distribution of a timing signal to many computer with high accuracy is an issue. The accuracy of the commonly used IRIG B-code is not adequate if the requirements are in the 10 microseconds range. This paper presents the design of a timing system that is adopted to the VLT. An overview of the requirements of the Time Reference System (TRS) is given. These requirements have been defined on the basis of experiences with the timing system of the ESO NTT telescope. The hardware units are described. These are a Central Time Standard, a Time Distribution System and a VME Time Interface Module. The distribution is based on fiber optic transmission, using a simple digital modulation that outperforms the analog IRIG B modulation. The Time Interface Module in the computer does not only perform the timing signal decoding but contains also user-programmable timers that are synchronously clocked from the time source. Presently all units of the TRS have been tested and the series production of the distribution and the Time Interface Modules are in progress.
YE, Zi. "Traitement statistique de l'information et du signal pour l'internet des objets sous-marins." Thesis, Institut polytechnique de Paris, 2021. https://tel.archives-ouvertes.fr/tel-03179373.
There has been recently a large development of human activities associated to the ocean world, where no standard has emerged for the Internet of Things (IoT) linked to marine autonomous objects. Though it has a limited bandwidth, the acoustic wave is the only way to communicate over average to large distances and it is thus used by many underwater systems to communicate, navigate, or infer information about the environment. This led to a high demand for wireless networks that require both spectral efficiency and energy efficiency with the associated low-complexity algorithms. Therefore, in this Ph.D. thesis, we proposed several original solutions to face this challenge.Indeed, due to the inherent Signal Space Diversity (SSD), rotated constellations allow better theoretical performance than conventional constellations with no spectral spoilage. We review the structural properties of uniformly projected rotated M-QAM constellations, so as to propose a low complexity soft demapping technique for fading channels. Then, we present an original blind technique for the reduction of the PAPR for OFDM systems using the rotated constellations with SSD. In order to reduce the complexity of blind decoding for this technique, we again rely on the properties of uniformly projected M-QAM rotated constellations to design a low-complexity estimator. Moreover, to face the selectivity of the acoustic channel, we suggest a sparse adaptive turbo detector with only a few taps to be updated in order to lower down the complexity burden. Finally, we have proposed an original self-optimized algorithm for which the step-sizes of both the equalizer and the phase estimator are updated adaptively and assisted by soft-information in an iterative manner, so as to meet the requirement of fast convergence and low MSE over time-varying channels
Stanton, Kevin Blythe. "Jitter and Wander Reduction for a SONET DS3 Desynchronizer Using Predictive Fuzzy Control." PDXScholar, 1996. https://pdxscholar.library.pdx.edu/open_access_etds/1164.
Bustamante, Danilo. "High-Precision, Mixed-Signal Mismatch Measurement of Metal-Oxide-Metal Capacitors and a 13-GHz 5-bit 360-Degree Phase Shifter." BYU ScholarsArchive, 2020. https://scholarsarchive.byu.edu/etd/9240.
ALENCAR, Raphael Tavares de. "Diversidade de modulação aplicada a canais com múltiplos percursos." Universidade Federal de Campina Grande, 2014. http://dspace.sti.ufcg.edu.br:8080/jspui/handle/riufcg/443.
Made available in DSpace on 2018-04-20T22:42:49Z (GMT). No. of bitstreams: 1 RAPHAEL TAVARES DE ALENCAR - DISSERTAÇÃO PPGEE 2014..pdf: 1279047 bytes, checksum: 21e02690d9f7fa6020cc8bc9de97b124 (MD5) Previous issue date: 2014-08
O canal sem fio tem características de desvanecimento devido ao multipercurso, visto que há reflexões e espalhamentos ao longo do caminho percorrido pelo sinal. O desvanecimento é considerado uma das principais causas de degradação do desempenho em um sistema de comunicações móveis, visto que depende fortemente do canal em que se propaga o sinal transmitido. A diversidade de modulação é uma técnica eficiente em termos de utilização de banda de frequência, que consiste na rotação da constelação do sinal digital transmitido associado ao entrelaçamento das componentes de modulação em fase e em quadratura da constelação do sinal. O objetivo da diversidade em modulação é mitigar os efeitos do desvanecimento em comunicações sem fio. Esta dissertação aborda o estudo da diversidade de modulação no cenário de múltiplos raios de propagação Osresultadosapresentamsimulaçõesdecenárioscom múltiplos raios, isto é, o sinal é transmitido por múltiplos percursos, cada um associado a um fator de desvanecimento e um atraso aleatórios. São feitas comparações entre as taxas de erros para oito cenários com e sem interferência intersimbólica, de um a seis raios, com e sem linha de visada, para os esquemas de modulação digital 4-PSK e 8-PSK. São apresentadas as comparações entre os resultados de taxas de erros com e sem o uso da técnica de diversidade de modulação, com a intenção de avaliar o ganho desta técnica nestes cenários. Também é feita uma análise para obter o ângulo de rotação ótimo para as constelações mencionadas, considerando diferentes cenários de multipercurso. Para tanto, são empregados os conceitos de esquemas de modulação digital, múltiplos percursos, distribuições de probabilidade, canais de comunicação e técnicas de diversidade.
The wireless channel has characteristics of multipath fading,due to reflections and scattering that the signal suffers over the propagation path. Fading is considered one of the main causes of performance degradation of a mobile communications system, as it strongly depends on the channel through which the signal is transmitted. Modulation diversity is a bandwidth-efficient technique that consist on the rotation of the digital signal constellation. assiciated with the interleaving of the in-phase and quadrature modulation components. The objective of the modulation diversity technique is to mitigate the effects of fading in wireless communications The results present simulations of multipath scenarios, that is, the signal is transmitted through multiple channels, each one associated with a stochastic fading factor and random delay Biterrorratesareevaluatedandcomparedforforeightdifferentscenarioswithandwithout intersymbolicinterference,fromonetosixpaths,withandwithoutlineofsight,for4-PSKand 8-PSKdigitalmodulationschemes. Transmissionbiterrorratevalues,withandwithouttheuse ofmodulationdiversityarecompared,astoevaluatethegainofthisdiversitytechniqueforsuch scenarios. Also, an analysis is performed to obtain the optimum rotation angle for the mentioned constellations, considering the different multipath scenarios. In this regard, concepts of digital modulation schemes, multiple paths, probability distributions, communication channels and diversity techniques are used.
Jiang, Jeng-Shiann. "Measurement, Modeling, and Performance, of Indoor MIMO Channels." Diss., Georgia Institute of Technology, 2004. http://hdl.handle.net/1853/5035.
Gareus, Robin. "The Ardour DAW – Latency Compensation and Anywhere-to-Anywhere Signal Routing Systems." Thesis, Paris 8, 2017. http://www.theses.fr/2017PA080116/document.
In inherently latent digital systems it is not trivial to compensate for latency, particularlyin situations of complex signal routing graphs as is the case in a Digital AudioWorkstation.While the general problem is of mathematical nature, design complexities arisein real-time audio systems due to constraints by hardware, system-architecture andengineering.To construct a system providing for full-graph latency compensation with anywhereto-anywhere routing capabilities, it is insufficient to merely describe mechanisms.The complete system has to be designed as one and prototyped to take real-worldlimitations into account.This research was carried out using Ardour, a digital audio workstation, whichis freely available under the GPL free-software licence. This thesis is as much adesign-report as it is research documentation.A complete breakdown of building-blocks and interaction is presented, most of whichhas also been implemented beyond a proof-of-concept with the goal to bridge the gapbetween professional audio production systems and freely accessible documentationfor research and development.While ostensibly focusing on Ardour, this thesis describes generic concepts of AudioWorkstations like Ports, Tracks, Busses, and DSP Processors, as well as operationalinteraction between them.Basic concepts common to all digital I/O processes an,d sources of latency areexplained, and process- and latency graphs are illustrated to provide a completepicture. General issues related to time-alignment, both local, and global, as wellas more DAW specific cases like parameter-automation and parallel-execution arediscussed. Algorithms are modelled with pseudocode where appropriate and applicationprogramming interfaces are presented as examples to concepts throughout the text
Muñoz, Limay Katherine, and Rentería David Alonso Barrios. "Mejoramiento de calidad de servicio de señal abierta en una empresa televisiva de la Región de Ica." Bachelor's thesis, Universidad Ricardo Palma, 2015. http://cybertesis.urp.edu.pe/handle/urp/1289.
Axelberg, Peter. "On Tracing Flicker Sources and Classification of Voltage Disturbances." Doctoral thesis, Högskolan i Borås, Institutionen Ingenjörshögskolan, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:hb:diva-3416.
Teichmann, Jürgen. "Untersuchung allgemeiner Eigenschaften, Optimierung und integrierte Realisierung logischer Schaltungen mit hystereseförmiger Übertragungskennlinie." Doctoral thesis, Universitätsbibliothek Chemnitz, 2014. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-qucosa-132705.
To enhance the noise immunity of digital signal transmission, a hysteresis is introduced to the transfer characteristic of integrated digital circuit. The influence of height of the two threshold values to the number of occurring errors is examined by a computer program. A random number generator generates signals of different heights and widths, which are superimposed on the undisturbed signals. There is an implementation of an integrated circuit on a TTL master. The DC performane is calculated by means of a specially developed circuit analysis program. Measurement results are presented
Amari, Abdelkerim. "Compensation des effets nonlinéaires pour les transmissions WDM longue distance à 400Gbps et au-delà." Thesis, Paris, ENST, 2016. http://www.theses.fr/2016ENST0031/document.
Optical communication systems have evolved since their deployment to meet the growing demand for high-speed communications. Over the past decades, the global demand for communication capacity has increased exponentially and the most of the growth has occurred in the last few years when data started dominating network traffic. In order to meet the increase of traffic demands fueled by the growth of internet services, an increase of access network capacity and consequently metro and long-haul network capacities is required. Next generation of long-haul WDM transmission systems is expected to operate at 400Gbps or 1Tbps bit rate. Superchannel approaches, such as Nyquist WDM and multi-band OFDM, allow both high spectral efficiency and small guardband which makes them promising candidates to generate these high bit rates in combination with multi-level modulations formats. Such transmission systems are strongly disturbed by fiber nonlinear effects which increase with the data rate and the small guard band. Therefore, fiber nonlinearities compensation is required to get the desired performance in terms of transmission reach. DSP based approaches such as digital back propagation and third-order Volterra based nonlinear equalizer have been already proposed to deal with intra-channel or intra-band nonlinear effects. In the context of superchannel systems, we have proposed two new compensation techniques to deal with fiber nonlinear effects. The first one, called fifth-order inverse Volterra based nonlinear equalizer, compensate for intra-band nonlinear effects. The second approach, which is the interband/ subcarrier nonlinear interference canceler, is proposed to combat the nonlinear interference insuperchannel systems
Le, Son Thai. "Advanced digital signal processing for coherent optical OFDM transmissions." Thesis, Aston University, 2016. http://publications.aston.ac.uk/28889/.
Mavares, Terán Dimas. "Estimación de canal y selección adaptativa de código espacio-tiempo en sistemas de diversidad en transmisión." Doctoral thesis, Universidad de Cantabria, 2006. http://hdl.handle.net/10803/10662.
Channel estimation and adaptive transmission techniques are areas of increasing interest these days when considering transmit diversity systems for the 3G and 4G wireless communication systems. In this thesis an analysis of the channel estimation and channel correlation impact on transmit diversity OFDM systems based on space-time block coding (STBC) is presented, two channel estimation techniques are outlined and an adaptive space-time code selection technique is proposed. First, a simple frequency domain least square technique allows channel estimation for two transmitter systems with complex constellation, and three or four transmitter systems with real or complex constellation, using orthogonal STBCs as training blocks. Second, an 'overcomplete' representation allows a di.erential channel estimation for three transmitter systems through the instantaneous selection from a bank of estimators, based on the redundacy provided by the non-square transmission matrix of the sporadic 3/4-rate STBC for three transmitters.In the context of transmit adaptive systems, the proposed adaptive space-time code selection technique is based on both the instantaneous channel vector state and a set of predetermined threshold levels found o.-line as a function of the feedback period. Analytical and simulation results show that the proposed technique has a good performance in the presence of correlated and uncorrelated channels. Its application to OFDM systems has been considered, outperforming classical antenna selection techniques and other closed-loop adaptive transmission techniques.
Malkoc, Veysi. "Sequential alignment and position verification system for functional proton radiosurgery." CSUSB ScholarWorks, 2004. https://scholarworks.lib.csusb.edu/etd-project/2535.
Ribeiro, Moises Vidal. "Tecnicas de processamento de sinais aplicadas a transmissão de dados via rede eletrica e ao monitoramento da qualidade de energia." [s.n.], 2005. http://repositorio.unicamp.br/jspui/handle/REPOSIP/261263.
Tese (doutorado) - Universidade Estadual de Campinas. Faculdade de Engenharia Eletrica e de Computação
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Resumo: A presente tese tem por objetivo propor e discutir o uso de algumas técnicas de processamento de sinais e de inteligência computacional para a melhoria da transmissão digital de dados via redes elétricas e da análise da qualidade da energia elétrica em sistemas de potência. No que tange à transmissão de dados via rede elétrica, novas técnicas são introduzidas para solucionar os problemas de cancelamento de ruídos impulsivos e equalização de canais de comunicação. Para a melhoria do monitoramento da qualidade da energia elétrica, propõem-se novas técnicas para a análise espectral das componentes fundamental e harmônicas, e para a detecção, a classificação e a compressão de distúrbios. As várias técnicas apresentadas no presente trabalho são fundamentadas no princípio de dividir e conquistar, largamente utilizado em diversas áreas do conhecimento. A aplicação adequada desse princípio através de técnicas de processamento de sinais e de inteligência computacional nos permitiram fornecer análises mais precisas dos problemas estudados e propor novas soluções para os mesmos. Os resultados numéricos obtidos nas simulações computacionais confirmam a relevância das técnicas propostas
Abstract: This thesis is aimed at proposing and discussing the use of signal processing and computational intelligence techniques to improve digital communications through power line channels and a more precise power quality analysis of power systems. Regarding power line communication applications, advanced techniques for impulse noise mitigation and channel equalization are introduced. For power quality monitoring applications, novel techniques are proposed for spectral analysis of power line signals and for detection, classification and compression of disturbance events. The techniques proposed are developed on the light of the divider and conquer principle. The appropriate application of such principle, by means of signal processing and computational intelligence techniques, enable us to offering a more precise analysis of the problems investigated and novel solutions for them. By introducing a set of signal processing techniques along with some computational intelligence ones, this contribution succeeds in offering improvements for all the problems investigated. Numerical results obtained by computational simulations verify such improvement and confirm the relevance of the techniques proposed.
Doutorado
Telecomunicações
Doutor em Engenharia Elétrica
Simão, Daniel Hayashida. "Análise do consumo energético em redes subaquáticas utilizando códigos fontanais." Universidade Tecnológica Federal do Paraná, 2017. http://repositorio.utfpr.edu.br/jspui/handle/1/2774.
The present work employs fountain codes in an underwater network, in which data is transmitted using acoustic signals and has many applications. However, underwater networks are usually characterized by low propagation speed and smaller bandwidth than networks that use radio frequency signals, resulting in larger transmission delays. Then, aiming at minimizing the delays and increasing the energy efficiency of underwater networks, the present work employs fountain error-correcting codes at the transmitter. To that end, it was first necessary to model the energy consumption of a success data packet transmission in an underwater network using fountain codes. Our results show that the use of fountain codes is able to reduce up to 30% of energy consumption when the transmission distance is of 20 km for the case with a target frame error rate (FER) of Po = 10^−5 , and 25% for the same distance with a target FER of Po = 10^−3.
Schmidt, Gunnar. "A compatible modulation strategy for embedded digital data streams within high quality video signal transmissions." Thesis, University of South Wales, 1999. https://pure.southwales.ac.uk/en/studentthesis/a-compatible-modulation-strategy-for-embedded-digital-data-streams-within-high-quality-video-signal-transmissions(b5ada1e2-8055-4c94-aa9b-d1dee4f41359).html.
Dangl, Markus A. "Iterative estimation and detection for single carrier block transmission." Tönning Lübeck Marburg Der Andere Verl, 2007. http://d-nb.info/986923419/04.
Maurandi, Victor. "Algorithmes pour la diagonalisation conjointe de tenseurs sans contrainte unitaire. Application à la séparation MIMO de sources de télécommunications numériques." Thesis, Toulon, 2015. http://www.theses.fr/2015TOUL0009/document.
This thesis develops joint diagonalization of matrices and third-order tensors methods for MIMO source separation in the field of digital telecommunications. After a state of the art, the motivations and the objectives are presented. Then the joint diagonalisation and the blind source separation issues are defined and a link between both fields is established. Thereafter, five Jacobi-like iterative algorithms based on an LU parameterization are developed. For each of them, we propose to derive the diagonalization matrix by optimizing an inverse criterion. Two ways are investigated : minimizing the criterion in a direct way or assuming that the elements from the considered set are almost diagonal. Regarding the parameters derivation, two strategies are implemented : one consists in estimating each parameter independently, the other consists in the independent derivation of couple of well-chosen parameters. Hence, we propose three algorithms for the joint diagonalization of symmetric complex matrices or hermitian ones. The first one relies on searching for the roots of the criterion derivative, the second one relies on a minor eigenvector research and the last one relies on a gradient descent method enhanced by computation of the optimal adaptation step. In the framework of joint diagonalization of symmetric, INDSCAL or non symmetric third-order tensors, we have developed two algorithms. For each of them, the parameters derivation is done by computing the roots of the considered criterion derivative. We also show the link between the joint diagonalization of a third-order tensor set and the canonical polyadic decomposition of a fourth-order tensor. We confront both methods through numerical simulations. The good behavior of the proposed algorithms is illustrated by means of computing simulations. Finally, they are applied to the source separation of digital telecommunication signals
Hatae, Daniel Lopes. "Comparação entre esquemas de transmissão e recepção com única e múltiplas portadoras." Universidade Presbiteriana Mackenzie, 2007. http://tede.mackenzie.br/jspui/handle/tede/1448.
Fundo Mackenzie de Pesquisa
transmissão
Farhat, Jamil de Araujo. "Eficiência energética e throughput seguros em decode-and-forward seletivo com alocação de potência distribuída." Universidade Tecnológica Federal do Paraná, 2015. http://repositorio.utfpr.edu.br/jspui/handle/1/1368.
We investigate the secure energy efficiency and throughput in cooperative wireless communications systems, in which a pair of legitimate users (Alice and Bob) are assisted by a relay node and the communication occurs in the presence of a passive eavesdropper (Eve). Several cooperative protocols are compared with respect to these measures and we use of an iterative and distributed algorithm, based on Dinkelbach algorithm, to allocate power between Alice and the relay. The power allocation is performed in order to increase the secure energy efficiency, measured in secure bits/J/Hz, or secure throughput, measured in secure bits/s/Hz. About the protocols, we consider the case where Alice has perfect knowledge only about the instantaneous channel state of the legitimate channel. So, we employ a Selective Decode-and-Forward (SDF) protocol, which chooses the best type of communication between Alice and Bob (direct or cooperative communication) in order to improve security. For comparison, we consider other classical cooperative schemes such as the Amplify-and-Forward (AF), the Fixed Decode-and-Forward (DF) and the Cooperative Jamming (CJ). Our results show that SDF outperforms AF, DF and CJ in most situations. However, when the transmit rate increases or when Eve is close to the legitimate nodes, CJ has a better performance.
Dghais, Wael. "Behavioral modeling optimization and enhancement for high-speed analog mixed-signal I/O interfaces." Doctoral thesis, Universidade de Aveiro, 2013. http://hdl.handle.net/10773/12094.
A integridade do sinal em sistemas digitais interligados de alta velocidade, e avaliada através da simulação de modelos físicos (de nível de transístor) é custosa de ponto vista computacional (por exemplo, em tempo de execução de CPU e armazenamento de memória), e exige a disponibilização de detalhes físicos da estrutura interna do dispositivo. Esse cenário aumenta o interesse pela alternativa de modelação comportamental que descreve as características de operação do equipamento a partir da observação dos sinais eléctrico de entrada/saída (E/S). Os interfaces de E/S em chips de memória, que mais contribuem em carga computacional, desempenham funções complexas e incluem, por isso, um elevado número de pinos. Particularmente, os buffers de saída são obrigados a distorcer os sinais devido à sua dinâmica e não linearidade. Portanto, constituem o ponto crítico nos de circuitos integrados (CI) para a garantia da transmissão confiável em comunicações digitais de alta velocidade. Neste trabalho de doutoramento, os efeitos dinâmicos não-lineares anteriormente negligenciados do buffer de saída são estudados e modulados de forma eficiente para reduzir a complexidade da modelação do tipo caixa-negra paramétrica, melhorando assim o modelo standard IBIS. Isto é conseguido seguindo a abordagem semi-física que combina as características de formulação do modelo caixa-negra, a análise dos sinais eléctricos observados na E/S e propriedades na estrutura física do buffer em condições de operação práticas. Esta abordagem leva a um processo de construção do modelo comportamental fisicamente inspirado que supera os problemas das abordagens anteriores, optimizando os recursos utilizados em diferentes etapas de geração do modelo (ou seja, caracterização, formulação, extracção e implementação) para simular o comportamento dinâmico não-linear do buffer. Em consequência, contributo mais significativo desta tese é o desenvolvimento de um novo modelo comportamental analógico de duas portas adequado à simulação em overclocking que reveste de um particular interesse nas mais recentes usos de interfaces de E/S para memória de elevadas taxas de transmissão. A eficácia e a precisão dos modelos comportamentais desenvolvidos e implementados são qualitativa e quantitativamente avaliados comparando os resultados numéricos de extracção das suas funções e de simulação transitória com o correspondente modelo de referência do estado-da-arte, IBIS.
Signal integrity (SI) simulation of high-speed digital interconnected system via transistor level models is computational expensive (e.g. CPU time and memory storage), and requires the availability of physical details information of device’s internal structure. This scenario raises the interest for a behavioral modeling alternative which describes the device’s operation characteristics based on the observed input/output (I/O) electrical signal. I/O buffers that interface memory’s interconnects have major share in the computational load containing a very active complex functional part and high numbers of pins. Particularly, output buffers/drivers are forced to distort the I/O signals due to their nonlinear dynamics. In this concern, they constitute the integrated circuit (IC) bottleneck of ensuring reliable data transmission in the high-speed digital communication link. In this PhD work, the previously neglected driver’s nonlinear dynamic effects are efficiently captured to significantly reduce the state of the art black-box parametric modeling complexities and enhance the input/output buffers information specifications (IBIS). This is achieved by following the gray-box approach that merges the features of the black-box model’s formulation, the analysis of the observed I/O electrical signals and the buffer’s physical structure properties under practical operation conditions. This approach leads to physically inspired behavioral model’s construction procedure that overcomes the issues of the previous modeling approaches by optimizing the resources used at different model’s generation steps (i.e. characterization, formulation, extraction, and implementation) to mimic the driver’s nonlinear dynamic behavior. Moreover, the most important achievement is the development of a new two-port analog behavioral model for overclocking simulation that copes with the recent trends in I/O memory interfaces characterized by higher data rate transmission. The effectiveness and the accuracy of the developed and implemented behavioral models are qualitatively and quantitatively assessed by comparing the numerical results of their functions extraction and transient simulation to the ones simulated and extracted with transistor level models and the state of the art IBIS in order to validate their predictive and the generalization capabilities.
Almehmadi, Fares Saleh S. "Secure Chaotic Transmission of Digital and Analog Signals Under Profiled Beam Propagation in Acousto-Optic Bragg Cells with Feedback." University of Dayton / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1426781250.
Qian, Hua. "Power Efficiency Improvements for Wireless Transmissions." Diss., Georgia Institute of Technology, 2005. http://hdl.handle.net/1853/11649.
Glock, Henry Saute. "Metodologia para implantação de redes de frequência única Single Frequency Network – SFN em televisão digital." Programa de Pós-graduação em Sistemas de Comunicação e Automação, 2016. http://bdtd.ufersa.edu.br:80/tede/handle/tede/742.
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This paper presents a methodology that includes the structure and the care needed to design and implement a Single Frequency Network (SFN), with the benefits of energy conservation, transmitted power, and optimization of coverage area. It shows the network synchronization options and how to adjust the converged signal coverage areas within a region, showing clearly that this technology is a good and safe technological investment option. It also contains a history of one of the greatest technological developments that has occurred, indicating their form and difficulty in analog times. In the theoretical review are evidenced the technical limitations and the actions towards building a new, modern and robust digital transmission technology
Neste trabalho é apresentada uma metodologia que contempla a estrutura e cuidados necessários para projetar e implantar uma Single Frequency Network (SFN), apresentando os benefícios da racionalização de energia, potência transmitida, e otimização das áreas de cobertura. Apresenta as opções de sincronismo de rede bem como ajustar as regiões de cobertura de sinais convergentes a uma mesma região, mostrando com clareza que a tecnologia é uma boa e segura opção de investimento tecnológico. Também contém um histórico de um dos maiores desenvolvimentos tecnológicos já ocorridos, indicando sua forma e dificuldades em épocas analógicas. Na revisão teórica são é evidenciado o porquê das limitações técnicas até então existentes bem como as ações rumo a construção de uma nova, moderna e robusta tecnologia de transmissão digital
2017-06-27
Martins, Vinicius Antonio de Oliveira. "Verificação funcional para circuitos de transmissão e recepção de sinais mistos." Universidade de São Paulo, 2017. http://www.teses.usp.br/teses/disponiveis/3/3140/tde-12072017-081700/.
This work proposes the development of a verification methodology, used during the verification process of a mixed signal integrated circuit, which represents a communication system operating in simplex mode. In order to optimize the verification process, reverse reception and transmission will be used. With the intention of developing our verification methodology, a study on other methodologies used for the verification of mixed signals integrated circuits and the evolution of such methodologies was carried out. The proposed methodology has been applied in an advanced circuit used to establish data transmission by satellite (Transponder for Satellite). The targeted data transmission system is composed by analog receptor and transmitter, analog to digital converters and a digital signal-processing unit, all developed in hardware. The verification methodology consists of two steps: first, the development of a verification structure that are able to stimulate digital and analog blocks in order to guarantee the functionality of each system component. In a following step, the developed verification environment provides the stimulation for all the Transponder IP (digital and analog blocks), and for transmission and reception blocks as well. The verification process development was performed in high level, meaning all the characteristics and properties has been observed using only simulators with the purpose of guarantee the functionality of the mixed signal integrated circuit that composes the satellite Transponder IP.
Donzelli, Valderez de Almeida. "Polarização elíptica: influência no desempenho de cobertura da TV digital." Universidade Presbiteriana Mackenzie, 2011. http://tede.mackenzie.br/jspui/handle/tede/2748.
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
The technology environment in the broadcast area using analog technology was defined and did not offer a great research interest, in specific topics related to development of the transmitting antenna for broadcast television. With the implementation of the transmission system employing digital technology, which adds as main news the possibility of mobility and portability of the receiving system, the interest in studies and researches returned, showing one of the main themes to be developed using circular polarization or elliptical compared with horizontal polarization, that was most used by broadcasters. Given this new scenario and the need for evaluation by a scientific methodology of the radiating system in the transmission station performance, goals were established that define the scope for this research: to analyze the influence of the radiating system depending on the desired coverage area and the reception possibilities internal fixed , external fixed, portable and mobile, considering the diversity specific propagation environment of the region studied due to topographical and environmental condition. The criteria to be used will be the theoretical propagation prediction and field survey of the signals received which will provide data for the analysis of variables that influence the behavior of the transmission system, considering the location and technical characteristics of the main transmission station installation and different polarization of the radiating system configurations in horizontal, vertical and elliptical.
O cenário tecnológico na área de transmissão empregando tecnologia analógica estava bem segmentado e não oferecia um ambiente de grande interesse em pesquisas específicas para desenvolvimentos de temas relacionados a antena de transmissão para televisão aberta. Com a implantação do sistema de transmissão empregando a tecnologia digital, que agrega como principal novidade a possibilidade de mobilidade e portabilidade do sistema de recepção , o interesse nos estudos e pesquisas retomou, apresentando como um dos principais temas a serem desenvolvidos a utilização de polarização circular ou elíptica comparada com a polarização horizontal, que era a mais utilizada pela emissoras. Tendo em vista este novo cenário e a necessidade de avaliação por meio de uma metodologia científica do comportamento do sistema irradiante de transmissão no resultado no desempenho da estação transmissora, foram estabelecidas as metas que definem o escopo para este trabalho: analisar a influência do tipo de sistema irradiante em função da área de cobertura desejada e das possibilidades de recepção fixa interna, fixa externa, portátil e móvel, frente às diversidades específicas do ambiente de propagação da região estudada devido às condições topográficas e ambientais. Os critérios a serem empregados serão os teóricos de predição de propagação e prático de levantamento de campo dos sinais recebidos os quais irão fornecer dados para a análise das variáveis que influenciam no comportamento do sistema de transmissão, considerando o local e as características técnicas de instalação da estação de transmissão principal e variando a polarização do sistema irradiante nas configurações horizontal, vertical e elíptica.
Nguyen, Trung-Hiên. "Theoretical and experimental study of optical solutions for analog-to-digital conversion of high bit-rate signals." Thesis, Rennes 1, 2015. http://www.theses.fr/2015REN1S110/document.
Bi-dimensional modulation formats based on amplitude and phase signal modulation, are now commonly used in optical communications thanks to breakthroughs in the field of electronic and digital signal processing (DSP) required in coherent optical receivers. Photonic solutions could compensate for nowadays limitations of electrical circuits bandwidth by facilitating the signal processing parallelization. Photonic is particularly interesting for signal sampling thanks to available stable optical clocks. The heart of the present work concerns analog-to-digital conversion (ADC) as a key element in coherent detection. A prototype of linear optical sampling using an original solution for the optical sampling source, is built and validated with the successful equivalent time reconstruction of NRZ, QPSK and 16-QAM signals. Some optical and electrical limitations of the system are experimentally and numerically analyzed, notably the extinction ratio of the optical source or the ADC parameters (bandwidth, integration time, effective number of bits ENOB). Moreover, some new DSPs tools are developed for optical transmission using bi-dimensional modulation formats (amplitude and phase). Two solutions are proposed for IQ quadrature imbalance compensation in single carrier optical coherent transmission: an original method of maximum signal-to-noise ratio estimation (MSEM) and a new structure for joint compensation and equalization; these methods are experimentally and numerically validated with 16-QAM signals. Moreover, an improved solution for carrier recovery (frequency offset and phase estimation) based on a circular harmonic expansion of a maximum loglikelihood function is studied for the first time in the context of optical telecommunications. This solution which can operate with any kind of bi-dimensional modulation format signal is numerically validated up to 128-QAM. All the DSP tools developed in this work are finally used in a demonstration of a 10 Gbaud QPSK 100 km transmission experiment, featuring a strong non-linear phase noise limitation and regenerated using a phase preserving and power limiting function based on a photonic crystal nanocavity
Lecointre, Aubin. "Interface radio IR-UWB reconfigurable pour les réseaux de microsystèmes communicants." Thesis, Toulouse, INSA, 2010. http://www.theses.fr/2010ISAT0026/document.
The research work presented in this thesis is situated in the framework of wireless sensor networks (WSNs). The issue addressed is the design of a radio interface answering the specific needs of WSNs: simplicity, low cost, low power, small size, high data rate and reconfigurability. Current wireless technologies like WiFi, Bluetooth, and Zigbee are not able to respond to these requirements. Thus this study focuses on Impulse Radio Ultra-WideBand (IR-UWB) technology. At first, a joint study of the channel capacity and the hardware implementation is carried out to determine the optimal architecture of IR-UWB transceivers. This study proposes an architecture using multi-band IR-UWB (MB-UWB-IR) with a mixed implementation at 60 GHz with directional antennas. This solution is optimized according to the criteria of data rate and power consumption. To support the all the needs of WSN applications and to adapt to the evolution of the WSN’s environment, reconfigurability must be implemented in the proposed IR-UWB transceiver. This thesis presents a new solution: the reconfigurability by parameters. It supports the widest range of multi-property reconfigurability (with respect to data rate, bit error rate, radio range, power consumption, ...) of the state of the art. Finally, to validate these techniques by measurements, FPGA and ASIC implementations are realized by using the reconfigurability and the IR-UWB transceiver architecture proposed. A new method for joint synchronization and demodulation is proposed for a reconfigurable IR-UWB BPSK S-Rake receiver. The measurements show that the proposed technique improves the circuit performance: synchronization, demodulation, efficiency, network throughput, power consumption and complexity of the circuit. The proposed IR-UWB reconfigurable transceiver achieves a data rate and a wider range of reconfigurability compared to the state of the art