Modulation Transfer Function
Mostrando 1-12 de 63 artigos, teses e dissertações.
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1. Determining attributed factors of hearing handicap in individuals with auditory sensory and neural pathology
Abstract Introduction: There is a modest relationship between speech perception skills and perceived hearing handicap in individuals with hearing loss. In this study, an attempt is made at linking psychoacoustic results and speech perception skills to understand the subjective handicap and quality of life. Objective: To investigate how speech perception in
Brazilian Journal of Otorhinolaryngology. Publicado em: 2022
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2. Evaluation of OFDM Channel Sounding Techniques with Three Modulation Sequences
Abstract This paper presents an evaluation of multicarrier channel sounding techniques using different random and pseudo-random sequences to modulate the OFDM sounding signal. The Random (Rand), Pseudo-Noise (PN) and Zadoff-Chu (ZC) were tested, both in laboratory simulations and in field measurements. For the laboratory simulations Matlab routines were used
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 11/11/2019
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3. Objective evaluation of vision quality in pseudophakic patients with posterior capsular opacification using double-pass retinal imaging
RESUMO Objetivo: Avaliar objetivamente a qualidade da visão óptica antes e depois da capsulotomia com Nd: YAG, obtida por imagem pelo metodo de dupla passagem de luz em pacientes com opacificação capsular posterior. Método: Análise retrospectiva de 26 olhos pseudofácicos com opacificação capsular posterior visualmente significativa, que foram subm
Arq. Bras. Oftalmol.. Publicado em: 25/02/2019
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4. An Analytical Solution for Fiber Optic Links with Photonic-Assisted Millimeter Wave Upconversion Due to MZM Nonlinearities
Abstract Photonic-assisted technique employed in the generation of stable and high-purity signals in the millimeter wave band has been investigated using dual-parallel Mach-Zehnder modulator. Indeed, this type of generation performs a high order RF multiplier, whose operation principle steams out from the nonlinear characteristic of the external modulators.
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 2017-03
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5. Análise óptica de sistemas eletro-ópticos por meio do cálculo da função de transferência de modulação / Optical analyze of electro-optical systems by modulation transfer function calculus
Um grande número de equipamentos utilizam sistemas ópticos ou eletro-ópticos em suas estruturas, dentre esses equipamentos tem-se os microscópios, telescópios, equipamentos médicos, câmeras de satélites, entre outros. Com isso a necessidade de métodos e ferramentas que auxiliem na determinação do desempenho e da qualidade dos sistemas ópticos é
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 13/04/2012
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6. Enumeração de espectro de distâncias de esquemas de modulação codificada em treliça empregando codificação turbo
In this work, a performance analysis of transmission schemes employing turbo trellis coded modulation. In general, the performance analysis of such schemes is guided by evaluating the error probability of these schemes. The exact evaluation of this probability is very complex and inefficient from the computational point of view, a widely used alternative is
Publicado em: 2010
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7. Estudo comparativo entre a ceratectomia fotorrefrativa e a ceratomileusis in situ a laser guiadas pela análise de frente de onda / Comparative study between wavefront-guided photorefractive keratectomy (PRK) and laser in situ keratomileusis (LASIK)
PURPOSE: To compare clinical results of two wavefront-guided treatments, photorefractive keratectomy (PRK) and laser in situ keratomileusis (LASIK), for low to moderate myopia correction, with or without astigmatism. SETTING: Refractive Surgery Service, General Hospital, University Of São Paulo, São Paulo, Brazil. METHODS: Prospective randomized study of 7
Publicado em: 2010
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8. A contralateral eye study comparing apodized diffrative and full diffrative lenses: wavefront analysis and distance and near uncorrected visual acuity
PURPOSE: To evaluate intraindividual visual acuity, wavefront errors and modulation transfer functions in patients implanted with two diffractive multifocal intraocular lenses. METHODS: This prospective study examined 40 eyes of 20 cataract patients who underwent phacoemulsification and implantation of a spherical multifocal ReSTOR intraocular lens in one ey
Clinics. Publicado em: 2009
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9. Computational scheme for automatic evaluation of mammography equipments quality parameters / Esquema computacional para avaliação automática de parâmetros de qualidade de equipamentos mamográficos
Este trabalho tem como objetivo o desenvolvimento de um conjunto de procedimentos de avaliação da qualidade de equipamentos mamográficos a partir do processamento de imagens digitais obtidas com a exposição radiográfica de objetos de testes (phantoms) padronizados. O sistema desenvolvido permite a avaliação de diversos parâmetros físicos de qualida
Publicado em: 2009
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10. Simulation of optical and physiological phenomena of the human vision / Simulação de fenômenos óticos e fisiológicos do sistema de visão humana
The increase in performance of the modern computers has driven scientific work in the areas of computer simulation. Many authors use in their research commercial tools that use embedding algorithms, which sources are not provided, and it makes harder and sometimes impossible, the development of novel theories or experiments. This work explores this gap left
Publicado em: 2008
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11. Different schematic eyes and their accuracy to the in vivo eye: a quantitative comparison study
Current ophthalmic technology allows the manipulation of eye components, such as anterior cornea and lens, of the human eye with a considerable precision and customization. This technology opens up the possibility of exploiting some characteristics of the eye in order to improve the methods of correcting optical aberrations. Moreover, product development and
Brazilian Journal of Physics. Publicado em: 2007-06
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12. Frequency domain concurrent channel equalization for multicarrier systems
Receivers for wireless Orthogonal Frequency Division Multiplexing (OFDM) systems usually perform the channel estimation based on pilot carriers in known positions of the channel spectrum. Interpolation between pilot carriers is applied to determine the channel transfer function in all carrier frequencies. Channel variations along time are compensated by mean
Journal of the Brazilian Computer Society. Publicado em: 2007-03