Non Linear Channel
Mostrando 1-12 de 64 artigos, teses e dissertações.
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1. A Finite-Difference Time-Domain Formulation for Modeling Air Ionization Breakdown Streamers
Abstract A numerical model based on the finite-difference time-domain (FDTD) method is developed for calculating discharge currents and fields produced due air ionization between two electrodes. Electric conductivity σ of the ionized channel between two electrodes is calculated using non-linear equations, i.e., σ is obtained using functions of time. The fu
Journal of Microwaves, Optoelectronics and Electromagnetic Applications. Publicado em: 2022
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2. Link Optimization and Performance Analysis of a 40 Gbps DQPSK Modulated Ultra DWDM System with 32 Orthogonally Polarized channels
Abstract The demand for higher speed at a lesser transmission cost per bit resulted in growth of optical networks with improved spectral efficiency even at narrower channel spacing. Incorporation of multilevel modulation formats in DWDM system led to the exploration of the 25 GHz channel grid, popularly known as Ultra Dense Wavelength Division Multiplexed (U
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 2016-12
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3. The Control of Asymmetric Rolling Missiles Based on Improved Trajectory Linearization Control Method
ABSTRACT According to motion characteristic of an asymmetric rolling missile with damage fin, a three-channel controlled model is established. The controller which is used to realize non-linear tracking and decoupling control of the roll and angle motion is introduced based on an improved trajectory linearization control method. The improved method is compos
J. Aerosp. Technol. Manag.. Publicado em: 2016-09
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4. On the evaluation of linear and non-linear models using DNS data of turbulent channel flows
In this paper, a priori and a posteriori analyses of algebraic linear and non-linear models are carried out in order to compare their ability to predict near wall turbulent flows. Tests were done using data from a direct numerical simulation (DNS) of a plane channel flow for three Reynolds numbers, based on the friction velocity, Reτ = 180, Reτ = 395 and R
J. Braz. Soc. Mech. Sci. & Eng.. Publicado em: 2012-12
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5. Operação analógica de transistores de múltiplas portas em função da temperatura. / Analog operation of multiple gate transistors as a function of the temperature.
In this work it is presented an analysis of the analog operation of multiple gate transistors, evaluating the Early Voltage, the open-loop voltage gain, the transconductance over the drain current ratio (gm/IDS), the drain conductance and, especially, the harmonic distortion exhibited by these devices. Along the work, FinFETs, Gate-All-Around (GAA) devices w
Publicado em: 2010
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6. EQUALIZAÇÃO DE CANAL EM SISTEMAS COM TRANSMISSÃO EM BLOCOS / CHANNEL EQUALIZATION IN BLOCK TRANSMISSION SYSTEMS
The demand for high rate transmission systems, for example in HDTV, third and fourth generation cellular telephony, DSL and so on, causes the rise of a problem: The multipath communications channel (specially in wireless communications), which leads to intersymbol interference phenomenon (ISI). The present work investigates the performance of single-carrier
Publicado em: 2007
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7. DISTORÇÃO ESPECTRAL DE SINAIS OFDM DEVIDA À NÃO-LINEARIDADE DO CANAL DE TRANSMISSÃO / SPECTRAL DISTORTION OF OFDM SIGNALS DUE TO CHANNEL NON-LINEARITY
This MSc dissertation presents a theoretical analysis that evaluates the distortion experienced by the power spectrum density of OFDM signals when they are transmitted through a non-linear channel. The complex envelope of the OFDM signals are modeled as a complex proper gaussian random process and the channel non-linearity is characterized through a power se
Publicado em: 2006
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8. Sistema multicanal de geração e recepção de ondas ultra-sonicas para transdutor matricial linear / Multichannel system for generation and detection of ultrasonic waves with a linear array transducer
Ultrasound in medicine has gone through great evolution in the last few decades and has occupied important position as a tool for therapy and diagnosis. This is due to the ultrasound equipment be of relatively low-cost, ultrasound is a non-ionizing radiation, is a non-invasive imaging method, and the images are created and seen in real time. It is common the
Publicado em: 2006
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9. Estudo de amplificadores parametricos para sistemas de comunicações opticas de altas taxas de transmissão / Study of parametric amplifiers for high bit rate optical communication systems
This thesis presents a theoretical and experimental study on fiber optics parametric amplifiers. For the double-pumped case, we show the performance of the amplifier in terms of spectral bandwidth and gain uniformity, both fundamental properties for WDM applications. By using short dispersion shifted fibers and highly non-linear fibers, we made parametric am
Publicado em: 2006
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10. Solução numérica do modelo PTT para escoamentos viscoelásticos com superfícies livres / Numerical solution of the PTT model for viscoelastic surface flows
The aim of this work is to develop a numerical method capable of simulating viscoelastic free surface flows governed by the non-linear constitutive equation PTT (Phan-Thien-Tanner). In this work three numerical methods to simulate vicoelastic Flows of fluids modelled by the PTT equation are presented. Two of these methods were developed to simulate two-dimen
Publicado em: 2006
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11. Estudo da dinâmica populacional do caranguejo-uçá, Ucides cordatus cordatus (LINNAEUS, 1763) (CRUSTACEA-DECAPODA-BRACHYURA), e dos efeitos de uma mortalidade em massa desta espécie em manguezais do Sul da Bahia / Study of the population dynamic of the mangrove crab, Ucides cordatus (LINNAEUS, 1753) (CRUSTACEA-DECAPODA-BRACHYURA_, and the effects of a mass mortality of this specie in Southern Bahia mangroves
The mangrove crab (Ucides cordatus cordatus) is an important fishing resource for the low income communities in Brazil and also plays a role for the environment in the mangrove ecosystem. Massive mortality events of this specie have been registered in many mangrove areas in the Northeast Region of Brazil. The first step of this work was realized from October
Publicado em: 2006
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12. Análise de desempenho de sistemas multiportadoras utilizando modulações M-QAM não quadradas em canais com ceifamento / Analisys of Multicarrier Systems Performance Using Non-Square M-QAM in Clipping Channel
A técnica OFDM (Orthogonal Frequency Division Multiplexing) tem sido alvo de pesquisas em instituições de todo o mundo. O emprego do OFDM tem sido especialmente considerado em sistemas de transmissão digital susceptíveis aos efeitos causados pelo desvanecimento seletivo em freqüência. Dentre as aplicações desta técnica, pode-se destacar os padrões
Publicado em: 2004