Radio Noise
Mostrando 1-12 de 25 artigos, teses e dissertações.
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1. Passively Q-Switched Pulses Generation from Erbium-Doped Fiber Laser Using Lutetium Oxide as Saturable Absorber
Abstract In this paper, a configuration of a passive Q-switched Erbium-doped fiber laser (EDFL) using a Lutetium Oxide (Lu2O3) thin film as a saturable absorber (SA) is experimentally implemented to generate high pulse energy with a high signal to noise ratio. A stable Q-switched pulse train is initiated at the input pump power of 30.442mW, and a maximum pul
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 2021-03
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2. Two-Level Allocation for H-CRAN Architecture Based in Offloading
Abstract The accelerated data and apps growth represents significant challenges to the next generation of mobile networks. Amongst them, it is highlighted the necessity for a co-existence of new and old patterns during the transition of architectures. Thus, this paper has investigated solutions for offloading into a hybrid architecture, also known as H-CRAN
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 19/06/2019
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3. Savitzky-Golay Filter for Denoising Lung Sound
ABSTRACT For computerized analysis of respiratory sounds to be effective, the acquired signal must be free from all the interfering elements. Different forms of noise which can degrade the quality of lung sounds are recording artifacts, power line/Radio Frequency (RF) interferences, ambient acoustic interferences, heart sound interference etc. Such interfere
Braz. arch. biol. technol.. Publicado em: 29/11/2018
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4. Volumetric T1 and T2 magnetic resonance brain toolkit for relaxometry mapping simulation
Abstract Introduction Relaxometry images are an important magnetic resonance imaging (MRI) technique in the clinical routine. Many diagnoses are based on the relaxometry maps to infer abnormal state in the tissue characteristic relaxation constant. In order to study the performance of these image processing approaches, a controlled simulated environment is
Res. Biomed. Eng.. Publicado em: 10/10/2016
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5. Phase Noise Effects on Wideband Mobile Radio Channel Sounding
Abstract In this work three wideband mobile radio channel sounding methods are simulated and compared using computational tools. The considered sounders include the traditional STDCC and two other proposed sounding methods that are based on OFDM digital transmission and detection procedures and on matched filtering. The impact of the phase noise introduced b
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 2015-12
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6. Simulador para avaliação da eficiência espectral média de redes celulares na presença de interferência de co-canal / Simulator for the evaluation of the mean spectral efficiency of cellular networks in the presence of co-channel interference
Na próxima geração de redes celulares, a ICC (Interferência de Co-Canal ) constitui a causa principal para a degradação do desempenho, especialmente para os usuários na borda da célula, o que é um grande obstáculo para alcançar amplas áreas de cobertura e alta eficiência espectral. Neste trabalho, o desempenho do enlace reverso de uma rede celul
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 22/11/2011
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7. Automação e otimização do projeto de um oscilador controlável por tensão para aplicações em rádio frequência. / Automation and optimization of a voltage controlled oscillator for radio frequency applications.
Nesta dissertação os conceitos e técnicas relacionadas com a automação e otimização do projeto de um oscilador controlável por tensão para aplicações de rádio frequência são apresentados. O problema de projeto do oscilador foi formulado como um problema de otimização matemática conhecido como programação geométrica. Uma abordagem à aplic
Publicado em: 2010
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8. Análise experimental da aplicação da tecnologia de rádio sobre fibra em redes IEEE 802.15.4 / Analysis of applying the technology of radio-overfiber networks in IEEE 802.15.4.
This work presents an experimental investigation on the implementation of wireless sensor networks (IEEE 802.15.4) over fiber optics. Such investigation was performed with the utilization of IEEE 802.15.4 transceivers, an optical fiber infrastructure inside a field-trial network, called KyaTera Network, and directly modulated lasers and photodiodes designed
Publicado em: 2009
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9. Contribuições teoricas para o estudo de funções de distribuição correlacionadas em um canal sem fio / Theoretical contributions to the study of correlated distributions funcions of wireless channels
In wireless communications, the multipath fading is modeled by several distributions including Hoyt, Rayleigh, Weibull, Nakagami-m, and Rice. In this thesis, new, exact expressions for the bivariate Hoyt (Nakagami-q) processes with arbitrary correlation in a nonstationary environment are derived. More specifically, the following are obtained: joint probabili
Publicado em: 2009
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10. Frequency synthesizers of 2.4 GHz from CMOS with 0.35 µm for ZigBee applications. / Sintetizador de freqüências de 2,4 GHz em CMOS, 0,35 µm para aplicações em ZigBee.
Frequency Synthesizers are circuits that generate pre-determined frequencies, used in both radio frequency reception and transmission. The Synthesizer circuits are composed by several blocks, such as Voltage-Controlled Oscillator (VCO), Prescaler, PFD (Phase/Frequency Detector), Charge Pump (CP), and Low Pass Filters (LPF). In 2003, an Integer-N architecture
Publicado em: 2008
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11. Circuitos integrados de radio-recepção para a operação de multiplexação espacial de antenas em tempo real / Integrated circuits of radio-reception for spatial multiplexing of antennas in real time
This research aims the conception of new topologies of integrated circuits and its characterizations for operation in radio-receiver systems. The design and fabrication of RF switches, LNAs, mixer, and VCOs are presented. The SMILE - Spatial MultIplexing of Local Elements - technique was adopted due to its advantages and functionality for the intelligent ant
Publicado em: 2008
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12. Development of MEMS switch device technology MEMS - MicroelectromechanicalSystems - for RF - radio frequency - and new topologies of RF CMOS integrated circuits for radio receivers input sub-systems / Desenvolvimento de tecnologia de dispositivos chaves MEMS - MicroelectromechanicalSystems - para RF - Radio Frequencia - e novas topologias para circuitos integrados CMOS de RF em sub-sistemas de entrada de radio receptores
Este trabalho apresenta dois tópicos de pesquisa, o primeiro é referente ao projeto e desenvolvimento da tecnologia de fabricação de Chaves MEMS (Micro Electro Mechanical System) de RF e o segundo é o projeto de circuitos integrados. No que se refere a chaves MEMS, descreve-se o processo e a metodologia para projeto de Chaves MEMS paralela sobre linha d
Publicado em: 2008