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Circuits and Systems I: Fundamental Theory and Applications, IEEE Transactions on

Issue 2 • Date Feb 2000

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Displaying Results 1 - 19 of 19
  • Improved delay time estimation of RC ladder networks

    Publication Year: 2000 , Page(s): 242 - 246
    Cited by:  Papers (6)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (188 KB)  

    An improved delay time bound estimation is given in this paper for an n-cell RC ladder network with capacitive load. An RC lumped model of the networks is preferred at the design stage, as it gives a faster prediction. We believe that the proposed delay time estimation for the networks will be useful for circuit analysis View full abstract»

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  • On robust stability of time-variant discrete-time nonlinear systems with bounded parameter perturbations

    Publication Year: 2000 , Page(s): 185 - 188
    Cited by:  Papers (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (96 KB)  

    The upper and lower bounds for asymptotic stability (AS) of a time-variant discrete-time nonlinear system with bounded parameter perturbations are provided. The analysis is undertaken for a class of nonlinear relaxation systems with the saturation nonlinearity of sigmoid type. Based upon the theory of convex polytopes and underlying linear relaxation equation, the bounds of the stability region for such a nonlinear system are derived for every time instant View full abstract»

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  • A general analytical theory of frequency conversion

    Publication Year: 2000 , Page(s): 189 - 199
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (228 KB)  

    Three theorems are announced as the groundwork of a new methodology for rigorous analysis of frequency conversion. One of several advantages of this methodology is that it obviates numerical integrations for Fourier coefficients. Casting the Taylor series in the formalism of differential operators leads to the introduction of a new entity called Mixer Functional which is composed of modified Bessel functions. Harmonic generation, frequency mixing, frequency modulation, and heterodyne detection are consolidated under one common approach. The Mixer Functional of first order yields Fourier coefficients of nonlinear functions of cos ωt (Theorem 1). The second- and higher order functionals give amplitudes of mixed harmonics of two or more primary frequencies (Theorem 2). A definition of the basic passive nonlinear elements is proposed and used, and then the methodology is illustrated by application to typical semiconductor devices. Nonlinear perturbation theory is developed for analyzing feedback when a linear load is in series with a nonlinear device and a voltage source. Theorem 3 addresses augmented conversion when the linear load is a resistor. This theorem also yields an analytical solution for the quiescent operating point in electronic circuits, thus complementing the traditional graphical load line approach View full abstract»

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  • Unity input displacement factor correction principle for direct AC to AC matrix converters based on modulation strategy

    Publication Year: 2000 , Page(s): 221 - 230
    Cited by:  Papers (22)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (372 KB)  

    Modulation strategies for a matrix structured direct AC to AC converter are developed. In principle, for a given set of input three-phase voltages, any desired set of output voltages can be synthesized by suitable toggling matrix switches. Mathematical proof that the direct AC to AC matrix converter can operate with unity displacement factor is provided by analyses based on the switching matrix approach. A symmetric and antisymmetric switching strategy is developed for synthesizing an output voltage vector from the appropriate combination of input voltage vectors. Unity displacement factor operation is achieved by using the combined symmetric and antisymmetric modulation strategy. This combined algorithm enables unity displacement factor operation without current sensing and current control View full abstract»

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  • Operating points in n-dimensional nonlinear nonuniform infinite and finite grounded grids

    Publication Year: 2000 , Page(s): 144 - 149
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (164 KB)  

    An existence and uniqueness theorem for the operating point of a resistive, infinite, n-dimensional nonlinear nonuniform grounded grid is established. A similar result is established for finite grids of arbitrary size. The grid may be triangular (also called hexagonal), rectangular, or more generally automorphic under every shift mapping of the nodes, but it is locally finite. The analysis is accomplished under conditions restricting the nonlinearity and nonuniformity sufficiently to allow the operator arising from a nodal analysis to be decomposed into the sum of a Laurent operator and a nonlinear operator, which in turn can be rearranged into a contraction mapping. A similar analysis, wherein the Laurent operator is replaced by a circulant matrix, works for a finite grid. The grounding elements must have monotone characteristics, while the floating elements can be nonmonotone as well as active View full abstract»

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  • A discrete-time approach to the steady-state and stability analysis of distributed nonlinear autonomous circuits

    Publication Year: 2000 , Page(s): 231 - 236
    Cited by:  Papers (9)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (220 KB)  

    We present a direct method for the steady-state and stability analysis of autonomous circuits with transmission lines and generic nonlinear elements. With the discretization of the equations that describe the circuit in the time domain, we obtain a nonlinear algebraic formulation where the unknowns to determine are the samples of the variables directly in the steady state, along with the oscillation period, the main unknown in autonomous circuits. An efficient scheme to build the Jacobian matrix with exact partial derivatives with respect to the oscillation period and with respect to the samples of the unknowns is described. Without any modification in the analysis method, the stability of the solution can be computed a posteriori constructing an implicit map, where the last sample is viewed as a function of the previous samples. The application of this technique to the time-delayed Chua's circuit (TDCC) allows us to investigate the stability of the periodic solutions and to locate the period-doubling bifurcations View full abstract»

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  • Reduced-order H optimal filtering for systems with slow and fast modes

    Publication Year: 2000 , Page(s): 250 - 254
    Cited by:  Papers (12)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (164 KB)  

    In this paper we present a method that allows complete time scale separation and parallelism of the H optimal filtering problem for linear systems with slow and fast modes (singularly perturbed linear systems). The algebraic Riccati equation of singularly perturbed H filtering problem Is decoupled into two completely independent reduced-order pure-slow and pure-fast H algebraic Riccati equations. The corresponding H filter is decoupled into independent reduced-order, well-defined pure-slow and pure-fast filters driven by system measurements. The proposed exact closed-loop decomposition technique produces many savings in both on-line and off-line computations and allows parallel processing of information with different sampling rates for slow and fast signals View full abstract»

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  • Electronically tunable dual-OTA second-order sinusoidal oscillators/filters with non-interacting controls: a systematic synthesis approach

    Publication Year: 2000 , Page(s): 117 - 129
    Cited by:  Papers (23)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (268 KB)  

    In this paper a novel method of generating canonic sinusoidal oscillators with two operational transconductance amplifiers (OTAs), two grounded capacitors (GCs), and a small number of resistors is introduced. Noninteracting control of the frequency of oscillation (FO) and the condition of oscillation (CO) are realized with the transconductance parameters of the two OTAs respectively. Bandpass (BP) and lowpass (LP) filter functions can also be realized with the same topologies. The independent tuning of the natural frequency ωo and ωo/Q of most filters can be realized without changing the topologies View full abstract»

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  • Output voltage analysis for the MOS Colpitts oscillator

    Publication Year: 2000 , Page(s): 260 - 263
    Cited by:  Papers (15)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (160 KB)  

    An analysis of the MOS Colpitts oscillator is presented that includes MOSFET operation in the cutoff linear, and saturation regions of operation. The steady-state output voltages calculated from this analysis are in excellent agreement with SPICE3 simulations for a wide range of circuit parameters. An application of this analysis to the synthesis of a Colpitts oscillator design is also provided View full abstract»

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  • A low-voltage single input class AB transconductor with rail-to-rail input range

    Publication Year: 2000 , Page(s): 236 - 242
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (176 KB)  

    A new CMOS programmable rail-to rail transconductor is presented. A linear V-I characteristic is obtained by using the principle of nonlinearity cancellation of matched MOS transistors operating in the ohmic region. Rail-to-rail operation is achieved by using two complementary blocks. The circuit is suitable for low voltage as it can operate from supply voltages down to ±1.5 V. PSpice simulations show that the transconductance gain can be electronically tuned from 13 to 90 μ A/V with bandwidth of about 40 MHz View full abstract»

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  • Discrete-time maps for the analysis of bifurcations and chaos in DC/DC converters

    Publication Year: 2000 , Page(s): 130 - 143
    Cited by:  Papers (115)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (280 KB)  

    The main aim of this paper is to present a systematic classification of discrete-time models proposed in the literature for the analysis of nonlinear phenomena in power electronic DC/DC converters. It is shown how these models can be applied to different operating conditions and used to analyze the converter dynamics under both voltage-mode and current-mode control. The derivation of simplified maps is discussed together with the Jacobian matrices of the maps that are used for the analysis of several bifurcations and chaotic behaviors. The three most common converter topologies, i.e., boost, buck and buck-boost, operating in continuous conduction mode, are considered. An extensive literature review is also reported View full abstract»

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  • Bifurcations and chaos in the tolerance band PWM technique

    Publication Year: 2000 , Page(s): 254 - 259
    Cited by:  Papers (8)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (284 KB)  

    In this paper we study the dynamical behavior of the tolerance band PWM technique, which is used in controlling power electronic ac inverters and dc-dc converters. We demonstrate numerically as well as experimentally the existence of three basic modes: quasiperiodic, chaotic, and square wave mode. We also observe saddle node bifurcation as the cause of boundary crises with transient chaos, merging crisis following symmetry breaking bifurcations and interior crisis. The critical value of the amplitude of external reference for saddle node bifurcation is evaluated analytically by the Tsypkin method View full abstract»

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  • Improved behavioral and design model of an Nth-order charge pump

    Publication Year: 2000 , Page(s): 264 - 268
    Cited by:  Papers (10)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (132 KB)  

    An equivalent RC to model the dynamic behavior of a charge pump which takes into account the parasitic capacitances is presented. From the model, simple design equations to allow a pencil and paper design equation are developed. The model proposed was validated by means of Spice simulation and typically shows errors lower than 15% View full abstract»

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  • State analysis and parameter estimation of bilinear systems via Haar wavelets

    Publication Year: 2000 , Page(s): 246 - 250
    Cited by:  Papers (21)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (192 KB)  

    This paper studies the state analysis and parameter estimation of bilinear systems via Haar wavelets. Some intrinsic properties of Haar wavelets are exploited and a Haar product matrix and a coefficient matrix are also derived. With the aid of the above tools, the state analysis and parameter estimation of bilinear systems can be solved easily. The local property of Haar wavelets is fully applied to shorten the calculation process in the task View full abstract»

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  • On the robustness of R-2R ladder DACs

    Publication Year: 2000 , Page(s): 109 - 116
    Cited by:  Papers (17)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (240 KB)  

    A model of the linear R-2R ladder digital-to-analog converter (DAC) is developed in terms of the ratios of the effective resistances at the nodes of the ladder. This formulation demonstrates clearly why an infinite number of different sets of resistors can produce the same linearity error and shows how this error can be reduced by trimming. The relationship between the weights of the bits and the resistor ratios suggests appropriate trimming, design, and test strategies View full abstract»

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  • A mathematical solution to a network construction problem

    Publication Year: 2000 , Page(s): 166 - 184
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (580 KB)  

    One of the major open issues in neural networks includes a network construction problem (NCP) to find a procedure, polynomial time if possible, that produces a minimal structure (minimum size, threshold and weight) of a multilayer threshold feed-forward network where its output must not exceed any given admissible distortion from a sample, The NCP includes a subproblem, a network training problem (NTP), where the size is prespecified. Approximate versions of the NCP/NTP have been solved with iterative algorithms for the network construction/training. This paper provides a mathematically rigorous solution to the NCP using rate distortion theory from information theory and linear algebra. This solution is used to develop a mathematical procedure that specifically constructs a minimal structure from the sample. The procedure attains the exact minimum though its computational time is, at worst, nonpolynomial. The paper also constructs a polynomial-time shortcut for approximate minimum sizes, which is a promising alternative to current algorithms View full abstract»

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  • Nonlinear system identification using additive dynamic neural networks-two on-line approaches

    Publication Year: 2000 , Page(s): 150 - 165
    Cited by:  Papers (6)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (384 KB)  

    This paper proposes a class of additive dynamic connectionist (ADC) models for identification of unknown dynamic systems. These models work in continuous time and are linear in their parameters. Also, for this kind of model two on-line learning or parameter adaptation algorithms are developed: one based on gradient techniques and sensitivity analysis of the model output trajectories versus the model parameters and the other based on variational calculus, that lead to an off-line solution and an invariant imbedding technique that converts the off-line solution to an on-line one. These learning methods are developed using matrix calculus techniques in order to implement them in an automatic manner with the help of a symbolic manipulation package. The good behavior of the class of identification models and the two learning methods is tested on two simulated plants and a data set from a real plant and compared, in this case, with a feedforward static (FFS) identifier View full abstract»

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  • Uncertainty models for switch-mode DC-DC converters

    Publication Year: 2000 , Page(s): 200 - 203
    Cited by:  Papers (7)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (100 KB)  

    Uncertainty models for the three basic switch-mode converters, buck, boost, and buck-boost, are given in this paper. The resulting models are represented by linear fractional transformations (LFTs) with structured dynamic uncertainties. Uncertainties are assumed for the load resistance R=Ro(1+δR), inductance L=Lo (1+δL), and capacitance C=Co(1+δ C), The interest in these models is clearly motivated by the need to have models for switch-mode DC-DC converters that are compatible with robust control design, which require a model structure consisting of a nominal model, and a norm-bounded modeling uncertainty. Therefore, a robust controller design under parameter uncertainties can be obtained instead of the deterministic approach widely used View full abstract»

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  • Trajectory sensitivity analysis of hybrid systems

    Publication Year: 2000 , Page(s): 204 - 220
    Cited by:  Papers (152)  |  Patents (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (360 KB)  

    The development of trajectory sensitivity analysis for hybrid systems, such as power systems, is presented in the paper. A hybrid system model which has a differential-algebraic-discrete (DAD) structure is proposed. This model forms the basis for the subsequent sensitivity analysis. Crucial to the analysis is the development of jump conditions describing the behavior of sensitivities at discrete events, such as switching and state resetting. The efficient computation of sensitivities is discussed. A number of examples are presented to illustrate various aspects of the theory. It is shown that trajectory sensitivities provide insights into system behavior which cannot be obtained from traditional simulation View full abstract»

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