Encontrados 11 documentos, a visualizar página 1 de 2
Análise do regime transitório de circuitos com linhas de transmissão
Filipa Borrego; José Carlos PedroThis work has the pedagogical objective of showing the value of some signal processing techniques for the determination of the transient regime of circuits composed by transmission lines. The analysis method begins with the sinusoidal steady-state response determination, an approach usually followed in any undergraduate guided wave propagation course. Then, the general time domain transient regime is derived by...
Microwave Power Amplifier Linearization Techniques
José Carlos Pedro; Jorge Perez Martinez; José Rocha PedreiraIn this work, a possible solution to the problem of integrating a microwave power amplifier and its linearizer, is presented.The most common techniques of power amplifier linearization are reviewed, and its major drawbacks identified. (...)keywords: power amplifiers; intermodulation distortion; nonlinear models; Volterra seriesPh.D., 1993more info: http://opac.ua.pt/F/?func=find-b&find_code=SYS&am...
Highly Efficient Power Amplifier
Luís Miguel Ramos Gomes; José Carlos PedroThe following work presents the development of a power amplifier with high efficiency. The process used to get the best results is presented as well as the study of the main conditionings in this kind of project. A description of the simulations made, which were part of the study, is also presented. (...)Keywords: RF power amplifier; GaAs MMIC; Class- FM.S., 1997more info. http://opac.ua.pt/F/?func=fi...
Repetidor para o Sub-Sistema Rádio da Rede UMTS
Daniel Pedro Ferreira; Pedro Miguel Cabral; José Carlos Pedro; Nuno Borges CarvalhoThis paper describes the design, implementation and test of a Repeater for the Radio Sub-System of UMTS Networks.First of all, the integration of a Repeater in the UMTS System is presented, defining the goals in view (Section I).Then, the general Repeater specifications and architectureare addressed (Section II), which then led to its implementation (Section III). Section III also details th...
State-of-Art Nonlinear Electronic Design Automation Tools for Microwave/RF Circ...
José Carlos PedroThis paper presents an overview of state-of-theart techniques for the analysis and simulation of microwave and RF nonlinear circuits. It is the result of the work done for preparation of “Provas de Agregação” (the habilitation degree for full professorship in Portuguese Universities) of its author, and the various seminars given on this subject.Using a pedagogi...
Alternativa ao SPICE para Simulação do Estado Estacionário de Circuitos Não Lin...
Nuno Borges de Carvalho; José Carlos PedroThe objective of this paper is to explain a new technique to simulate non-linear steady-state circuits that does not use time domain, like SPICE[12], but spectral domain to do the simulations.In this paper we develop a new frequency mapping technique to use in the discretization of continuous spectrum and a new tool to do convolution and deconvolution. Finally we prove the validity of this technique. ; Pr...
Estudo das Características de Distorção Não Linear de Intermodulação de Desmodu...
Nuno Borges Carvalho; Raquel Castro Madureira; José Carlos PedroThe nonlinear distortion of a PLL frequency discriminator is addressed using the Volterra Series approach. The analysis, made entirely in the frequency domain, allows distortion calculations for periodic and nonperiodic sets of discrete excitation frequencies (harmonic and intermodulation distortion up to 3rd order) and random inputs. It also includes, simultaneously, the two major...
Practical Issues on RF Modelling of Multi-rate Nonlinear Systems
Telmo Reis Cunha; José Carlos PedroThis paper presents an analysis on practical issues regarding the use of RF modelling of multi-rate nonlinear systems. Multi-rate systems are characterizcd by a frequency spectrum concentrated on distinct and separated frequency bands. This characteristic makes impossible the use of baseband models (that consider frequency shifting of the system spectrum), and so, RF modelling is n...
Linearization of Power Amplifiers for Active Feedback
José Carlos Pedro; Jorge Perez; José Rocha PereiraThis paper describes the work developed under thePh.D. course of its author [I]. It is devided in four main partswhich refer to the motivation, theoretical background ofamplifier linearization circuits design, GaAs MESFETmodeling, and finally, experimental validation. That wasacheived by the design and test of a MMIC power amplifier,linearized by means of active feedback. ; O trabalho que neste artigo se descr...
A low cost and high linearity receiver's for Cable TV Systems to the Home (FTTH)
Paulo Grilo Domingues; José Carlos PedroA receiver circuit for use in Fiber to the Home (FTTH) Cable TV Systems is presented. The design is based on low cost small signal GaAs FET devices and proposes a new scheme for the reduction of the 2nd order non-linear distortion generated by the active devices. ; É apresentado um circuito para utilização em receptores de Televisão por Cabo Óptico at...
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