The Experts below are selected from a list of 300 Experts worldwide ranked by ideXlab platform
A. Opal - One of the best experts on this subject based on the ideXlab platform.
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Distortion analysis of periodically switched Nonlinear Circuits using time-varying Volterra series
IEEE Transactions on Circuits and Systems I: Fundamental Theory and Applications, 2001Co-Authors: Fei Yuan, A. OpalAbstract:This paper presents a new frequency-domain method for distortion analysis of general periodically switched Nonlinear Circuits. It generalizes Zadeh's time-varying network functions and bifrequency transfer functions from linear time-varying systems to Nonlinear time-varying systems. The periodicity of time-varying network functions of linear and Nonlinear periodically time-varying systems is investigated using time-varying Volterra series. We show that a periodically switched Nonlinear Circuit can be characterized by a set of coupled periodically switched linear Circuits. Distortion of the periodically switched Nonlinear Circuit is obtained by solving these linear Circuits. This result is a generalization of the multi-linear theory known for Nonlinear time-invariant Circuits. We also show that the aliasing effect encountered in noise analysis of switched analog Circuits exists in distortion analysis of periodically switched Nonlinear Circuits. Computation associated with the folding effect can be minimized by using the adjoint network of periodically switched linear Circuits, in particular, the frequency reversal theorem. The method presented in this paper has been implemented in a computer program. Distortion of practical switched Circuits is analyzed and the results are compared with SPICE simulation.
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Distortion Analysis of Periodically Switched Nonlinear Circuits Using Time-Varying
2001Co-Authors: Fei Yuan, A. OpalAbstract:This paper presents a new frequency-domain method for distortion analysis of general periodically switched Nonlinear Circuits. It generalizes Zadeh's time-varying network functions and bifrequency transfer functions from linear time-varying systems to Nonlinear time-varying systems. The periodicity of time-varying network functions of linear and Nonlinear period- ically time-varying systems is investigated using time-varying Volterra series. We show that a periodically switched Nonlinear Circuit can be characterized by a set of coupled periodically switched linear Circuits. Distortion of the periodically switched Nonlinear Circuit is obtained by solving these linear Circuits. This result is a generalization of the multi-linear theory known for Nonlinear time-invariant Circuits. We also show that the aliasing effect encountered in noise analysis of switched analog Circuits exists in distortion analysis of periodically switched Nonlinear Circuits. Computation associated with the folding effect can be minimized by using the adjoint network of periodically switched linear Circuits, in particular, the frequency reversal theorem. The method presented in this paper has been implemented in a computer program. Distortion of practical switched Circuits is analyzed and the results are compared with SPICE simulation.
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ISCAS - Sensitivity analysis of Nonlinear Circuits using Volterra series
2006 IEEE International Symposium on Circuits and Systems, 1Co-Authors: Guoji Zhu, A. OpalAbstract:Volterra series (VS) is frequently used in the analysis of mildly Nonlinear Circuits. In this approach, Nonlinear Circuit analysis is converted into the analysis of a series of linear Circuits. The main benefit of this approach is that linear Circuit analysis is well established and direct frequency domain analysis of a Nonlinear Circuit becomes possible. In this paper, we present for the first time the sensitivity analysis of mildly Nonlinear Circuits in the frequency domain as an extension of the VS approach. Sensitivity analysis is useful in comparing the quality of two different designs and in gradient based optimization methods. One example Circuit is analyzed and the sensitivity of the output to Circuit parameters is given.
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A unified sampled-data simulation method for Nonlinear Circuits - response, sensitivity, and stochastic behavior
Proceedings of the 44th IEEE 2001 Midwest Symposium on Circuits and Systems. MWSCAS 2001 (Cat. No.01CH37257), 1Co-Authors: Fei Yuan, A. OpalAbstract:This paper presents a new, efficient, and unified time-domain analysis method for mildly Nonlinear Circuits. The method characterizes Nonlinear Circuits using a set of Volterra Circuits. The input of the first-order Volterra Circuit is identical to that of the Nonlinear Circuit, whereas that of higher-order Volterra Circuits is obtained from the response of lower-order Volterra Circuits and interpolating Fourier series. The response, sensitivity, mean, and variance of the Nonlinear Circuit are computed at equally spaced intervals of time. The accuracy and speed of the method are examined by comparing with those of Predictor-Corrector (PC) methods for time-domain response computation, the Brute-Force (BF) methods for sensitivity analysis, and Monte Carlo (MC) simulation for statistical estimation using example Circuits.
Qi-jun Zhang - One of the best experts on this subject based on the ideXlab platform.
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neural network approaches to electromagnetic based modeling of passive components and their applications to high frequency and high speed Nonlinear Circuit optimization
IEEE Transactions on Microwave Theory and Techniques, 2004Co-Authors: Xiaolei Ding, V K Devabhaktuni, B Chattaraj, M C E Yagoub, Jianjun Xu, Qi-jun ZhangAbstract:In this paper, artificial neural-network approaches to electromagnetic (EM)-based modeling in both frequency and time domains and their applications to Nonlinear Circuit optimization are presented. Through accurate and fast EM-based neural models of passive components, we enable consideration of EM effects in high-frequency and high-speed computer-aided design, including component's geometrical/physical parameters as optimization variables. Formulations for standard frequency-domain neural modeling approach, and recent time-domain neural modeling approach based on state-space concept, are described. A new EM-based time-domain neural modeling approach combining existing knowledge in the form of equivalent Circuits (ECs), with state-space equations (SSEs) and neural networks (NNs), called the EC-SSE-NN, is proposed. The EC-SSE-NN models allow EM behaviors of passive components in the Circuit to interact with Nonlinear behaviors of active devices, and facilitate Nonlinear Circuit optimization in the time domain. An automatic mechanism for EM data generation, which can lead to efficient training of neural models for EM components, is presented. Demonstration examples including EM-based frequency-domain optimization of a three-stage amplifier, time-domain Circuit optimization in a multilayer printed Circuit board, including geometrical/physical-oriented neural models of power-plane effects, and EM-based optimization of a high-speed interconnect Circuit with embedded passive terminations and Nonlinear buffers in the time domain are presented.
Harish Parthasarathy - One of the best experts on this subject based on the ideXlab platform.
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Perturbation-Based Stochastic Modeling of Nonlinear Circuits
Circuits Systems and Signal Processing, 2013Co-Authors: Akash Rathee, Harish ParthasarathyAbstract:This paper presents a general model for a Nonlinear Circuit, in which, the Circuit parameters (e.g. resistance and capacitance) are subject to random fluctuations due to noise, which vary with time. The fluctuating amplitudes of these parameters are assumed to be Ornstein–Uhlenbeck (O.U.) processes and not the white noise owing to temporal correlations. The Nonlinear Circuit is represented by a system of Nonlinear differential equations depending upon a set of parameters that fluctuate slowly with time. To model these fluctuations, we use the theory of Ito’s stochastic differential equations (SDEs). Then the driving force of the Circuit dynamics is in accordance with the general perturbation theory decomposed into the sum of a strong linear component and a weak Nonlinear component by the introduction of a small perturbation parameter. The Circuit states are expanded in the powers of this small perturbation parameter and recursive solutions to the various approximates obtained. Finally, the approximate expressions for the output states are obtained as stochastic integrals with respect to Brownian motion processes. The proposed method is applied to a half-wave rectifier Circuit which is built out of a diode, a resistor and a capacitor. The diode is represented by Nonlinear voltage–current equation, and resistance and capacitance are subject to random fluctuations due to noise, which vary slowly with time. The results, obtained using the proposed method, are compared with those obtained via the conventional perturbation-based deterministic differential equations model for a Nonlinear Circuit. Hence, the noise process component, present at the output, is obtained.
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Parameter estimation for time varying Nonlinear Circuit from state analysis and simulation
Communications in Nonlinear Science and Numerical Simulation, 2008Co-Authors: Vipin B. Vats, Harish ParthasarathyAbstract:Abstract This paper develops a parameter estimation technique for a Nonlinear Circuit. The Nonlinear Circuit is represented by a state space model and perturbation theory is applied to obtain the approximate analytical solution for the state vector. The state model is assumed to be slowly time varying so that the parameter vector is constant over different time slots. The expressions obtained for the state vector are matched with the noisy data using the gradient algorithm and hence the parameter vector is estimated. Simulations are based on discretization of the state space model using MATLAB.
Philippe Eudeline - One of the best experts on this subject based on the ideXlab platform.
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Measured and Simulated Impact of Irregular Radar Pulse Trains on the Pulse-to-Pulse Stability of Microwave Power Amplifiers
IEEE Transactions on Microwave Theory and Techniques, 2014Co-Authors: Julien Delprato, Denis Barataud, Michel Campovecchio, Guillaume Neveux, Clément Tolant, Philippe EudelineAbstract:This paper investigates the impact of irregular pulsed RF signals on the pulse-to-pulse (P2P) stability of a microwave power GaN HEMT amplifier. This study is based on both the time-domain envelope measurements and Nonlinear Circuit envelope simulations of P2P stabilities. Measurements and simulations are performed with an irregular pulse train that integrates a long silence (i.e., off-time) between each periodic burst of RF pulses because of its influence on temperature and trap behaviors of GaN HEMTs. The first aim is to experimentally characterize the impact of silence durations and output mismatching on the amplitude and phase P2P stabilities of a 10-W S-band GaN HEMT amplifier. The second objective is to assess the ability of Nonlinear HEMT models to fit the time-domain measurements of pulse-to-pulse stabilities. This final part of the paper is focused on the relative impact of electro-thermal and drain-lag models on the Nonlinear Circuit envelope simulations of pulse-to-pulse stabilities. It is demonstrated that both the thermal and trapping effects have to be considered to fit the complex behavior of measured pulse-to-pulse stabilities for microwave GaN HEMT power amplifiers.
Hideki Asai - One of the best experts on this subject based on the ideXlab platform.
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Relaxation‐based spectrum analysis for Nonlinear Circuits
Electronics and Communications in Japan (Part III: Fundamental Electronic Science), 1991Co-Authors: Takahiro Kawashima, Takeshi Higashiyama, Hideki AsaiAbstract:In the spectrum analysis of a Nonlinear Circuit by the conventional harmonic balance method, a problem occurs when a large number of harmonic components is assumed, that is, the Jacobian matrix of Newton's method for the solution of the determining equation has a large dimension which requires a long computation time and a large memory capacity. From such a viewpoint, this paper proposes an algorithm for the spectrum analysis in the harmonic balance method, where the Nonlinear relaxation is applied to the solution of the determining equation. A continuous method is introduced to cope with the convergence problem of the harmonic relaxation method in the strongly Nonlinear Circuit. Then, to handle the multinode Circuit, an iterated spectrum analysis is proposed in which the harmonic balance is applied to each node individually. It is shown that the computation speed in the analysis is improved greatly, while drastically saving the memory capacity in the proposed method, compared to the conventional method based on Newton's method.
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Under relaxation techniques for stable convergence in Nonlinear Circuit simulation
IEEE International Symposium on Circuits and Systems, 1Co-Authors: Hideki Asai, T. KokadoAbstract:A description is given of under relaxation techniques for obtaining stable convergence in network simulation. The virtual state relaxation (VSR) technique is presented, and under relaxation techniques developed from the VSR method are then considered. These techniques are utilized in the simulation program DESIRE. The authors apply the modified under relaxation to the simulation of Nonlinear resistive networks, including bipolar transistor Circuits, and verify stable convergence. >
