The Experts below are selected from a list of 161937 Experts worldwide ranked by ideXlab platform
Piet Wambacq - One of the best experts on this subject based on the ideXlab platform.
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compact modeling of Nonlinear distortion in analog communication circuits
2000Co-Authors: Piet Wambacq, Petr Dobrovolny, S Donnay, M Engels, I BolsensAbstract:The design of analog front-ends of digital telecommunication transceivers requires simulations at the architectural level. The Nonlinear nature of the analog front-end blocks is a complication for their modeling at the architectural level, especially when the Nonlinear Behavior is frequency dependent. This paper describes a method to derive a bottom-up model of Nonlinear analog continuous-time circuits used in communication systems. The models take into account frequency dependence of the Nonlinear Behavior, making them suitable for wideband applications. Such model consists of a block diagram that corresponds to the most important contributions to the second- and third-order Volterra kernels of the output quantity (voltage or current) of a circuit. The examples in this paper, a high-level model of a CMOS low-noise amplifier and an active lowpass filter, demonstrate that the generated models can be efficiently evaluated in high-level dataflow-type simulations of mixed-signal front-ends and that they yield insight in the Nonlinear Behavior of the analog front-end blocks.
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Compact Modeling of Nonlinear Disto Rtion in Analog Communication Circuits
2000Co-Authors: Piet Wambacq, S Donnay, M Engels, Petr Dobrovoln, I BolsensAbstract:The design of analog front-ends of digital telecommunication transceivers requires simulations at the architectural level. The Nonlinear nature of the analog front-end blocks is a complication for their modeling at the architectural level, especially when the Nonlinear Behavior is frequency dependent. This paper describes a method to derive a bottom -up model of Nonlinear analog continuous-time circuits used in communication systems. The models take into account frequency dependence of the Nonlinear Behavior, making them suitable for wideband applications. Such model consists of a block diagram that corresponds to the most important contributions to the second- and thirdorder Volterra kernels of the output quantity (voltage or current) of a circuit. The examples in this paper, a highlevel model of a CMOS low-noise amplifier and an active lowpass filter, demonstrate that the generated models can be efficiently evaluated in high-level dataflow-type simulations of mixed-signal front-ends and that they yield insight in the Nonlinear Behavior of the analog front-end blocks
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High-frequency distortion analysis of analog integrated circuits
1999Co-Authors: Piet Wambacq, G.g.e. Gielen, Peter R. Kinget, Willy SansenAbstract:An approach is presented for the analysis of the Nonlinear Behavior of analog integrated circuits. The approach is based on a variant of the Volterra series approach for frequency domain analysis of weakly Nonlinear circuits with one input port, such as amplifiers, and with more than one input port, such as analog mixers and multipliers. By coupling numerical results with symbolic results, both obtained with this method, insight into the Nonlinear operation of analog integrated circuits can be gained. For accurate distortion computations, the accuracy of the transistor models is critical. A MOS transistor model is discussed that allows us to explain the measured fourth-order Nonlinear Behavior of a 1 GHz CMOS upconverter. Further, the method is illustrated with several examples, including the analysis of an operational amplifier up to its gain-bandwidth product. This example has also been verified experimentally.
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distortion analysis of analog integrated circuits
1998Co-Authors: Piet Wambacq, Willy SansenAbstract:From the Publisher: Distortion Analysis of Analog Integrated Circuits provides both qualitative and quantitative insight into the Nonlinear Behavior of analog integrated circuits at low and high frequencies. General techniques to suppress Nonlinear Behavior such as pre-distortion, linear and Nonlinear feedback are explained in detail and illustrated with realistic examples. In this way the book fills the gap between the theory of Nonlinear systems and practical analog integrated circuits. Distortion Analysis of Analog Integrated Circuits is essential reading for practicing analog and mixed-signal design engineers and researchers in the field. It is also suitable as a text for an advanced course on the subject.
Willy Sansen - One of the best experts on this subject based on the ideXlab platform.
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High-frequency distortion analysis of analog integrated circuits
1999Co-Authors: Piet Wambacq, G.g.e. Gielen, Peter R. Kinget, Willy SansenAbstract:An approach is presented for the analysis of the Nonlinear Behavior of analog integrated circuits. The approach is based on a variant of the Volterra series approach for frequency domain analysis of weakly Nonlinear circuits with one input port, such as amplifiers, and with more than one input port, such as analog mixers and multipliers. By coupling numerical results with symbolic results, both obtained with this method, insight into the Nonlinear operation of analog integrated circuits can be gained. For accurate distortion computations, the accuracy of the transistor models is critical. A MOS transistor model is discussed that allows us to explain the measured fourth-order Nonlinear Behavior of a 1 GHz CMOS upconverter. Further, the method is illustrated with several examples, including the analysis of an operational amplifier up to its gain-bandwidth product. This example has also been verified experimentally.
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distortion analysis of analog integrated circuits
1998Co-Authors: Piet Wambacq, Willy SansenAbstract:From the Publisher: Distortion Analysis of Analog Integrated Circuits provides both qualitative and quantitative insight into the Nonlinear Behavior of analog integrated circuits at low and high frequencies. General techniques to suppress Nonlinear Behavior such as pre-distortion, linear and Nonlinear feedback are explained in detail and illustrated with realistic examples. In this way the book fills the gap between the theory of Nonlinear systems and practical analog integrated circuits. Distortion Analysis of Analog Integrated Circuits is essential reading for practicing analog and mixed-signal design engineers and researchers in the field. It is also suitable as a text for an advanced course on the subject.
F S K Bijlaard - One of the best experts on this subject based on the ideXlab platform.
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finite element modeling of the Nonlinear Behavior of bolted t stub connections
2006Co-Authors: Ana Girao M Coelho, Luis Simoes Da Silva, F S K BijlaardAbstract:This paper describes a finite element model for the characterization of the Nonlinear Behavior of bolted T-stub connections that idealize the tension zone of bolted joints. Two different types of T-stub elements are considered: rolled profiles that are cut along the web, and two plates, flange and web, that are welded in a T shape by means of a continuous fillet weld. The results of existing experimental work are used to calibrate the models. It is found that the numerical approach allows the quantitative actual response to be accurately reproduced. In the case of welded T-stubs, the differences between the numerical model and the experiments are greater due to the effects of residual stresses and modified mechanical properties close to the weld toe, which are not easy to quantify. A parametric study is also undertaken to provide insight into the overall Behavior, failure modes, and deformation capacity of the various specimens. A proposal for prediction of failure criteria of these simple connections is also presented and discussed.
Decheng Feng - One of the best experts on this subject based on the ideXlab platform.
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stochastic Nonlinear Behavior of reinforced concrete frames ii numerical simulation
2016Co-Authors: Decheng FengAbstract:AbstractExperimental investigations on the stochastic Nonlinear Behavior of eight half-scale reinforced concrete (RC) frames with the same conditions in the companion paper indicates that the coupling effect between randomness and Nonlinearity of concrete will cause a remarkable fluctuation in structural Nonlinear responses. In the current paper, a validation program is presented through numerical simulation. Deterministic Nonlinear analysis of test specimens is performed on the basis of a force-based beam–column element model. Probability density evolution method (PDEM) is introduced to analyze the stochastic response analysis of structures. Probability density functions of the stochastic structural responses of the specimens are provided at both the load–displacement level and internal-force level. Comparative studies between numerical and experimental results reveal that the numerical method in conjunction with PDEM can not only qualify the fundamental trend of stochastic Nonlinear responses of structu...
Aijun Zhu - One of the best experts on this subject based on the ideXlab platform.
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reinforcement mechanism of nanofilled polymer melts as elucidated by Nonlinear viscoelastic Behavior
2002Co-Authors: S S Sternstein, Aijun ZhuAbstract:Nonlinear viscoelastic properties are reported for composites of fumed silica with various surface treatments and matrices of poly(vinyl acetate) of different molecular weights as well as a copolymer matrix of vinyl acetate and vinyl alcohol. Data above the glass transition temperature are reported here. The increase in the composite storage and loss moduli measured at low strains, and their relative rates of decrease with strain, are found to depend on filler surface treatment. The Nonlinear Behavior of the loss factor with strain is dramatically altered by filler treatment and quite revealing as to the likely mechanism causing the Nonlinearity. In addition, the relative reinforcement and the degree of Nonlinearity are found to be the highest for the lowest molecular weight matrices. The effect of copolymer substitution for the homopolymer matrix is equivalent to an increase in molecular weight. The primary underlying mechanism for reinforcement and Nonlinear Behavior appears to be the filler−matrix inte...
