Digital Modulation
Mostrando 13-24 de 75 artigos, teses e dissertações.
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13. Enfermidades Cutâneas Digitais Bovina: Aspectos Genéticos E Terapêuticos / Digital dermatitis disease bovine: genetic and therapeutic aspects
This study has aimed do evaluate a risk factor for bovine digital dermatitis and the efficacy of 5% aqueous barbatimão extract solution as ancillary in interdigital skin incisional wound repair. One hundred bovine females, 50 Holstein and 50 Girolando, from two different farms were used for the risk factor study. Experimental units were divided into four gr
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 18/03/2011
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14. Sistema e processo para geração, sincronização remota e comparação de sinais temporais precisos / System and process for the generation, remote synchronization and comparison of precise time signals
This thesis present new proposals for time dissemination systems, which were analyzed and implemented as complete solutions providing high resolution in radio links focusing in the requirements of the new geolocation system known as GEOLOCAL. The solutions found are useful for other applications equiring time synchronization. The work has been developed in d
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 05/07/2010
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15. Reproducibility of heart rate variability parameters measured in healthy subjects at rest and after a postural change maneuver
Heart rate variability (HRV) provides important information about cardiac autonomic modulation. Since it is a noninvasive and inexpensive method, HRV has been used to evaluate several parameters of cardiovascular health. However, the internal reproducibility of this method has been challenged in some studies. Our aim was to determine the intra-individual rep
Brazilian Journal of Medical and Biological Research. Publicado em: 2010-10
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16. Experimental and theoretical study of a telemetric dynamic torque meter
This paper presents the development of a dynamic torque meter to be applied to rotating shafts using electronic transduction, strain gage, telemetry and LabView Graphic programming. A mathematical model was developed. The electronic transduction signal is transmitted by digital modulation from a remote transduction unit fixed to a shaft to a base station, se
Journal of the Brazilian Society of Mechanical Sciences and Engineering. Publicado em: 2010-09
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17. A comparative study between the OFDM and SCCP systems. / Um estudo comparativo entre os sistemas OFDM e SCCP.
Este trabalho trata da comparação entre os sistemas OFDM (orthogonal frequency division multiplexing) e SCCP (single carrier with cyclic prefix). Tais sistemas são analisados em função da ordem da modulação, da sensibilidade em relação à taxa de codificação de canal e do tipo de entrelaçamento utilizado. A comparação é efetuada através da ad
Publicado em: 2010
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18. DESENVOLVIMENTO DE UMA FONTE DE POTÊNCIA CA PARA GERAÇÃO DE FORMAS DE ONDA DE ATÉ 2kHz / DEVELOPMENT OF AN AC POWER SOURCE FOR GENERATION OF WAVEFORMS UP TO 2kHz
Este trabalho apresenta o desenvolvimento de uma fonte de potência de corrente alternada com um inversor de tensão em ponte completa monofásico, composto por interruptores eletrônicos. Esta fonte é concebida para o acionamento de plantas elétricas e eletromecânicas. O protótipo projetado tem uma potência nominal de 1kVA e é capaz de gerar formas de
Publicado em: 2010
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19. Caracterização espectral e avaliação de desempenho para formatos avançados de modulação digital optica em 40 Gb/s / Spectral characterization and performance evaluation for advanced digital optical modulation formats at 40 Gb/s
This work compares the performance of four feedforward carrier recovery architectures in coherent QPSK and 8-PSK receivers, with polarization multiplexing and differential decoding. We focused on the scenarios showing an SNR imbalance between orthogonal polarizations, as in PDL impaired systems. Using Monte Carlo simulations, we observed that the proposed jo
Publicado em: 2009
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20. Study of special modulation formats for optical communication / Estudo de formatos especiais na modulação digital para comunicações ópticas
This MSc thesis investigates optical modulation formats as an alternative to the use of the traditional intensity binary format NRZ (Non-return-to-zero). Those formats, classified as advanced, represent one of the key technologies aimed to enable the high data volume and broadband, demanded by the present telecommunication market, with cost reduction of tran
Publicado em: 2009
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21. Geradores de seqüências pseudoaleatórias usando caos em sistemas de espalhamento espectral
Spread sprectrum is a modulation technique that uses a binary sequence to spread an information signal in frequency domain. Conventionally, the process of spreading uses pseudo-random sequences created by shift-registers. However, sequences created using chaotic signals can also be employed because they have compatible spectral and autocorrelation properties
Publicado em: 2009
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22. Estimativa do número de estações de rádio base para a implantação do WIMAX no Distrito Federal
During the past years, the video, voice and data services available in the fixed communications networks have been requested by users in mobility. This fact has motivated the development of technologies that allow traffic of a lot of information in cellular telephone networks. WiMAX e UMTS are technologies that can help the traffic flow. The WiMAX, known as
Publicado em: 2009
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23. Intercalamento temporal por transformada de Fourier: um novo método robusto para transmissão de sinais de TV Digital. / Fourier transform based time interleaving.
This work introduces a new transform-based time interleaving algorithm: FTI-OFDM (Fourier Transform Interleaved OFDM), in which binary information is spread over several symbols, both in time and frequency domains. This process, designed to be included in digital modulation systems, is computationally efficient when used in conjunction with OFDM modulation.
Publicado em: 2008
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24. Front-end of the Brazilian Digital TV system. / Sintonizador-demodulador para o sistema brasileiro de TV digital.
O sintonizador-demodulador de RF, também chamado de Front End, é definido de uma forma geral como sendo o conjunto ou módulo que está entre a antena e o sistema digital. Para um receptor isto inclui todos os filtros, amplificadores de baixo ruído, misturadores e demoduladores, necessários para processar o sinal modulado recebido na antena, demodulá-lo
Publicado em: 2008