Coherent Detection
Mostrando 1-12 de 21 artigos, teses e dissertações.
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1. Mejora en la calidad de imágenes ultrasónicas aplicando métodos de composición espacial y empleando sistemas de Phased Array
ABSTRACT The Phased Array Ultrasonic Technique (PAUT) has become a widely used imaging tool for the Nondestructive Testing in the industrial field. The PAUT allows making deflections and focusing the ultrasound beam at different depths within the material, through an electronic control of each one of the N elements that make up the array transducer. Thus, se
Matéria (Rio J.). Publicado em: 19/07/2018
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2. A Multilayer Approach for Optical Network Planning
With the increase in demand to Backbone networks, one became fundamental the application of new telecommunication technologies for efficient use of devices and optical links, such as xPSK modulations with dual polarization, dispersion compensating fibers, coherent detection and digital processing signals. Thus, network planning using analytical models have b
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 2016-03
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3. Spectrally-efficient 17.6-Tb/s DWDM optical transmission system over 678 km with pre-filtering analysis
We present and analyze a 17.6-Tb/s DWDM optical transmission composed of 79 channels with 224-Gb/s RZ-DP-16QAM modulation format per-channel and coherent detection. A maximum reach of 678 km is obtained with an optical recirculation loop composed by 226 km of pure-silica core fibers and EDFA amplification only in a 50-GHz grid system with spectral efficiency
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 2013-12
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4. Spectrally-efficient 17.6-Tb/s DWDM optical transmission system over 678 km with pre-filtering analysis
We present and analyze a 17.6-Tb/s DWDM optical transmission composed of 79 channels with 224-Gb/s RZ-DP-16QAM modulation format per-channel and coherent detection. A maximum reach of 678 km is obtained with an optical recirculation loop composed by 226 km of pure-silica core fibers and EDFA amplification only in a 50-GHz grid system with spectral efficiency
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 2013-06
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5. Estudos de sistemas OFDM para comunicações ópticas / Studies OFDM systems for optical communications
The development of digital modulation formats in optical communications systems is considered to be a promising way to increase the spectral efficiency and to combat the effects of signal degradation in optical fiber without changing the infrastructure already deployed. In this context, the technique called OFDM (orthogonal frequency division multiplexing) e
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 03/10/2012
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6. Microlasers de cavidades estadio aplicados a detecção nanovolumetrica / Stadium cavities microlasers applied to the nanovolumetric detection
This work presents the development of resonant cavities based on chaotic billiard geometries built with semiconductor active optical medium for sensing applications. In spite of the classically chaotic behavior of the stadium, the quantum description of the problem in the semi-classical limit shows unexpected accumulations of the density of probability on cl
Publicado em: 2010
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7. Estudo estrutural de nanossistemas semicondudores e semicondutores implantados por difração de raios-X de n-feixes / Structural study of semiconductors nanosystems and implanted semiconductors by means of n-beams X-ray diffraction
In this paper, X-ray multiple diffraction (MD) associated with the advantages of synchrotron radiation appears as a high-resolution microprobe and it is used to obtain relevant contributions to the study of structural properties of semiconductor materials, as they present themselves nanosystems epitaxial or implanted with ions. The study and detection of neg
Publicado em: 2010
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8. TÃcnicas de Interferometria Ãptica aplicada à medicina, odontologia e comunicaÃÃes Ãpticas
In the work described in this thesis, we used two different interferometric techniques, the coherent optical frequency domain reflectometry (COFDR), and the optical coherence tomography (OCT). Both techniques are based on the Michelson interferometer. They were applied to optical communications and to medical and dentistry imaging. We will give a general des
Publicado em: 2006
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9. Uso de métodos analíticos convencionados no estudo da autenticidade do óleo de copaíba
The acidity and ester index are suggested, as simple and cheap methods, adequate to be employed in the study of the authenticity of copaíba oil by small drugstores and export firms. The acidity index permits both the detection and the evaluation of the content of adulteration of copaíba oil. The ester index permits to know if the adulterant either contain
Química Nova. Publicado em: 2002-12
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10. Uma rede de codificação/decodificação para canais não-coerentes
Due to the extraordinary results, widely mentioned in the literature, attained with turbo decoding, new research lines have been suggested and followed, trying to apply these contributions in new decoding sceneries. Among the existing applications, the concept of decoding networks, reception systems using what is known as turbo principIe or iterative process
Publicado em: 2001
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11. SINCRONIZAÇÃO DE PORTADORA EM SISTEMAS COM MODULAÇÃO CODIFICADA EM TRELIÇA / CARRIER DISCOVERY FOR DETECTION OF TRELLIS-CODED MODULATED SIGNAL
This thesis analyses some coherent decoding schemes for TCM signals reception. In addition, a new scheme, which makes use of a per survivor processing, is propoed. In this scheme, each trellis state has an associated phase estimate which is generated by a data-aided PLL-like algorithm, based on the survivor sequence associated to that state. Some useful expr
Publicado em: 1993
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12. ANALYSIS OF DIFFERENTIAL AND COHERENT DETECTION OF BPSK SIGNALS FOR SATELITE MOBILE COMMUNICATIONS / ANÁLISE DAS DETEÇÕES COERENTES E DIFERENCIAL DE PORTADORAS BPSK EM COMUNICAÇÕES MÓVEIS VIA SATÉLITE
No presente trabalho são analisadas diferentes técnicas de transmissão utilizadas em comunicação móveis via satélite. Em particular, é caracterizado o desempenho corresponde à transmissão de portadoras BPSK em um canal com desvanecimento rápido quando se emprega detecção diferencial convencional (malha de Costas) ou detecção diferencial. No ca
Publicado em: 1992