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

Issue 8 • Date Aug 2000

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Displaying Results 1 - 18 of 18
  • Finding ambiguity groups in low testability analog circuits

    Publication Year: 2000 , Page(s): 1125 - 1137
    Cited by:  Papers (19)
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    This paper discusses a numerically efficient approach to identify complex ambiguity groups for the purpose of analog fault diagnosis in low-testability circuits. The approach presented uses a numerically efficient QR factorization technique applied to the testability matrix. Various ambiguity groups are identified. This helps to find unique solution of fault diagnosis equations or identifies which groups of components can be uniquely determined. This work extends results reported earlier in literature, where QR factorization was used in low-testability circuits, significantly increasing efficiency to determine ambiguity groups. A Matlab program that implements this method was integrated with a symbolic analysis program that generates test equations. The method is illustrated on two low-testability electronic circuits. Finally, method efficiency is tested on larger electronic circuits with several hundred tested parameters View full abstract»

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  • Worst case tolerance analysis of linear analog circuits using sensitivity bands

    Publication Year: 2000 , Page(s): 1138 - 1145
    Cited by:  Papers (28)
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    The major difficulty of accurate worst case tolerance analysis is to identify the worst case parameter sets. Traditional vertex analysis presumes the monotonicity between circuit response and circuit parameters, and uses nominal sensitivity information to select the vertices of parameter space as the worst case parameter sets. However, under parameter variations, the sensitivity itself is uncertain within an interval range, furthermore, the worst case parameter sets may not be the vertices of parameter space. In this paper, the relationship among monotonicity, sensitivity, and worst case parameter sets is investigated in the context of parameter variations. An efficient yet accurate approach for linear circuit worst case tolerance analysis is proposed. The underlying idea is that if the circuit response is monotonic with respect to the changes in a specific circuit parameter over the parameter space, then the worst case parameter sets are located at the corners of that parameter. The monotonicity is identified by the sensitivity band computation, and is used to generate uncertainty-reduced simulation problems. Experimental results strongly meet the expectation for accuracy and efficiency View full abstract»

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  • Universal current-mode OTA-C biquad with the minimum components

    Publication Year: 2000 , Page(s): 1235 - 1238
    Cited by:  Papers (33)
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    A universal current mode operational transconductance amplifier-capacitor (OTA-C) biquad with three inputs and four outputs employing the minimum of components: only two OTAs and only two grounded capacitors is presented. The proposed circuit offers the following advantageous features: realization of low-pass, bandpass, high-pass, notch; and all-pass signals from the same simple configuration, employment of two grounded capacitors ideal for integration and low-sensitivity performance View full abstract»

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  • A new BiCMOS increased full-swing converter for low-internal-voltage ULSI systems

    Publication Year: 2000 , Page(s): 1238 - 1242
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    In this work, a new BiCMOS increased full-swing inverter (IFSI) and a new BiCMOS increased full-swing buffer (IFSB) for low voltage/low power ULSI systems are proposed. Based on the SPICE simulations, we demonstrate that these circuits can operate at low internal voltage (V int) and have low input signal swing. With Vint>|Vt| (assuming Vtn=-Vtp ), the circuits work properly. When the capacitor load is larger than 0.6 pf, the propagation delays and the delay power products of the proposed circuits for different internal voltages are better than those of previous circuits under the same circuit design parameters. Moreover, the proposed circuits achieve significant improvement in speed and noise margin. The results given here can avoid the trial and error step in the circuit sizing operation to reduce the power consumption View full abstract»

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  • Absolute exponential stability of neural networks with a general class of activation functions

    Publication Year: 2000 , Page(s): 1258 - 1263
    Cited by:  Papers (30)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (208 KB)  

    The authors investigate the absolute exponential stability (AEST) of neural networks with a general class of partially Lipschitz continuous (defined in Section II) and monotone increasing activation functions. The main obtained result is that if the interconnection matrix T of the network system satisfies that -T is an H-matrix with nonnegative diagonal elements, then the neural network system is absolutely exponentially stable (AEST); i.e., that the network system is globally exponentially stable (GES) for any activation functions in the above class, any constant input vectors and any other network parameters. The obtained AEST result extends the existing ones of absolute stability (ABST) of neural networks with special classes of activation functions in the literature View full abstract»

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  • Minimum fuel neural networks and their applications to overcomplete signal representations

    Publication Year: 2000 , Page(s): 1146 - 1159
    Cited by:  Papers (8)
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    The overcomplete signal representation (OSR) is a recently established adaptive signal representation method. As an adaptive signal representation method, the OSR means that a given signal is decomposed onto a number of optimal basis components, which are found from an overcomplete basis dictionary via some optimization algorithms, such as the matching pursuit (MP), method of frame (MOF) and basis pursuit (BP). Such ideas are actually very close to or exactly the same as solving a minimum fuel (MF) problem. The MF problem is a well-established minimum L1-norm optimization model with linear constraints. The BP-based OSR proposed by Chen and Donoho is exactly the same model as the MF model. The work of Chen and Donoho showed that the MF model could be used as a generalized method for solving an OSR problem and it outperformed the MP and the MOF. In this paper, the neural implementation of the MF model and its applications to the OSR are presented. A new neural network, namely the minimum fuel neural network (MFNN), is constructed and its convergence in solving the MP problem is proven theoretically and validated experimentally. Compared with the implementation of the original BP, the MFNN does not double the scales of the problem and its convergence is independent of initial conditions. It is shown that the MFNN is promising for the application in the OSR's of various kinds of nonstationary signals with a high time-frequency resolution and feasibility of real-time implementation. As an extension, a two-dimensional (2-D) MF model suitable for image data compression is also proposed and its neural implementation is presented View full abstract»

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  • Lorenz-based chaotic cryptosystem: a monolithic implementation

    Publication Year: 2000 , Page(s): 1243 - 1247
    Cited by:  Papers (22)
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    A monolithic implementation of a cryptosystem based on the Corron and Hahs (1997) scheme is hereby presented. The baseband chaotic encryption/decryption system has been designed at the transistor level and fabricated using AMI 1.2 μm CMOS technology available through the MOSIS foundry. While the mathematical model of the Lorenz system is straightforward, its silicon implementation is not. Typical circuit design considerations need to be considered such as the system's dynamic range, internal signal processing mode and basic building blocks all with the intent to provide an optimal design. This work addresses in detail: (1) practical design considerations of the cryptosystem and (2) actual measurement results that verify theoretical findings View full abstract»

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  • Fault detection method for the subcircuits of a cascade linear circuit

    Publication Year: 2000 , Page(s): 1254 - 1258
    Cited by:  Papers (1)
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    The fault detection method for the subcircuits of a cascade linear circuit is discussed. While there is any fault (either “hard” or “soft” and either “single” or “multiple”) at one subcircuit of a cascade linear circuit, it can be quickly detected by using the method proposed. While there are faults simultaneously existing at multiple subcircuits, they can generally be detected by the searching approach proposed here. The aforementioned method is the continuation and development of the unified fault detection dictionary method for linear circuits proposed previously by the authors (see ibid., vol. 46, Oct. 1999) View full abstract»

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  • Nonsmooth bifurcations in a piecewise-linear model of the Colpitts oscillator

    Publication Year: 2000 , Page(s): 1160 - 1177
    Cited by:  Papers (27)
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    This paper deals with the implications of considering a first-order approximation of the circuit nonlinearities in circuit simulation and design. The Colpitts oscillator is taken as a case study and the occurrence of discontinuous bifurcations, namely, border-collision bifurcations, in a piecewise-linear model of the oscillator is discussed. In particular, we explain the mechanism responsible for the dramatic changes of dynamical behavior exhibited by this model when one or more of the circuit parameters are varied. Moreover, it is shown how an approximate one-dimensional (1-D) map for the Colpitts oscillator can be exploited for predicting border-collision bifurcations. It turns out that at a border collision bifurcation, a 1-D return map of the Colpitts oscillator exhibits a square-root-like singularity. Finally, through the 1-D map, a two-parameter bifurcation analysis is carried out and the relationships are pointed out between border-collision bifurcations and the conventional bifurcations occurring in smooth systems View full abstract»

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  • On stability analysis of 2-D systems based on 2-D Lyapunov matrix inequalities

    Publication Year: 2000 , Page(s): 1263 - 1265
    Cited by:  Papers (32)
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    A sufficient condition for the stability of two-dimensional (2-D) systems described in the Fornasin-Marchesini model is presented in a succinct form. The condition is expressed as a Lyapunov-like matrix inequality involved with the parallel addition of two positive definite matrices View full abstract»

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  • Simulation of single and coupled transmission lines using time-domain scattering parameters

    Publication Year: 2000 , Page(s): 1224 - 1234
    Cited by:  Papers (14)
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    A new method of transient analysis and simulation of interconnects is introduced. The presented approach permits calculation of scattering parameters of lossy nonuniform transmission lines and n-wire lossy coupled uniform lines directly in the time domain. In both cases, the procedure is the same. First, the partial differential equations are converted to integral telegrapher's equations, using the method of characteristics. Next, these integral equations are solved by the method of successive approximations, and infinite series expansions of scattering parameters in the time domain are obtained. The terms of the series expansions are expressed by elementary functions. The infinite series obtained are generally fast convergent and can be truncated after a few first terms, with the small relative truncation error previously defined. The number of terms in the truncated series can be determined on the basis of transmission line parameter values and the assumed relative truncation error. Finally, test examples for single and n-wire coupled line are presented. Simulation time and memory occupation are very small View full abstract»

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  • Novel CMOS wide-linear-range transconductance amplifier

    Publication Year: 2000 , Page(s): 1248 - 1253
    Cited by:  Papers (10)
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    A novel technique for linearizing long tail differential pairs is proposed. It is shown that the proposed linearized transconductor offers excellent linearity and exceptionally wide operating range, which makes it suitable for operating in analog signal processing applications. PSpice simulation results are given View full abstract»

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  • Characterization and modeling of multiple coupled lines in an inhomogeneous medium from time-domain reflection measurements

    Publication Year: 2000 , Page(s): 1191 - 1201
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (328 KB)  

    A synthesis technique of an equivalent lossless (nondispersive) uniform multiconductor n-coupled lines (UMCLs) 2n-port system from the measured discrete time-domain reflection response is presented. This procedure is based on the decomposition of characteristic immittance matrix of UMCL in terms of partial mode immittance matrices. The decomposition scheme leads to the discrete transition matrix function of a UMCL an-port system. This, in turn, establishes a relationship between the normal-mode parameters of the UMCL and the measured impulse reflection and transmission response. Equivalence between the synthesis procedure presented in this paper and the solution of a special form of algebraic Riccati matrix equation whose solution can lead to the normal-mode parameters and including real termination network is illustrated. In order to exemplify the procedure, a typical microstrip structure with three lines is synthesized from the time-domain reflection (TDR) data View full abstract»

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  • Transient numerical solutions of nonuniform MTL equations with nonlinear loads by wavelet expansion in time or space domain

    Publication Year: 2000 , Page(s): 1178 - 1190
    Cited by:  Papers (24)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (312 KB)  

    This paper deals with the numerical solution of nonuniform transmission lines (TLs) with nonlinear loads. The method presented here is based on the wavelet expansion; a weak formulation of the TL equations is obtained by expanding voltages, currents, and operators by means of wavelet functions. The TL equations are transformed into algebraic equations where the differential operator is represented by a matrix and the unknowns are the coefficients of the wavelet expansion of voltages and currents. The numerical efficiency of the method is tested analyzing uniform, nonuniform lines and nonlinear loads. The results are compared with results obtained by means of different methods View full abstract»

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  • Topological considerations on the symmetrical components transformation

    Publication Year: 2000 , Page(s): 1202 - 1211
    Cited by:  Papers (10)
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    This paper presents the well-known symmetrical components transformation (SCT) by means of a different approach from the traditional matrix analysis: a topological lecture provides, in fact, the results obtained by the existing analysis in a more suitable form for network applications. This approach leaves more space to the intuitive analysis, simplifying the application of such a method for teaching purposes, and completing the traditional mathematical view. Moreover, the use of graph concept allows the unified analysis of unbalanced faults leading the matter to the general theory of balanced three-phase systems. Typical for the physical balanced networks, the real convenience of SCT is also confirmed from the topological point of view, even for the fault analysis View full abstract»

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  • Signal processing with near-neighbor-coupled time-varying quantum-dot arrays

    Publication Year: 2000 , Page(s): 1212 - 1223
    Cited by:  Papers (13)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (248 KB)  

    The Nano-Devices Group at the University of Notre Dame proposed a new device that encodes information in the geometrical charge distribution of artificial (or natural) molecules. Functional units are composed by electrostatic coupling. In these units, processing takes place by reshaping the electron density of the molecules, and not by switching currents. Signal processing potential of next-neighbor-coupled cellular nonlinear networks (CNNs) has been recently explored with the conclusion that local-activity of the cells is necessary to exhibit complexity. It will be shown that Coulomb-coupled time-invariant artificial molecules behave like nonlinear locally passive devices, thus signal-power-gain or multiple equilibria cannot be achieved by integrating them. However, the signal input-output relation of strongly nonlinear molecules can be varied in time by adiabatic pumping, called clock control. It will be shown that strongly nonlinear time-varying molecules can transform the necessary amount of clock energy into the signal flow, thereby enabling the network of molecules to perform signal processing View full abstract»

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  • Analysis of practical expectation of the capacity of PBHC with fault tolerance

    Publication Year: 2000 , Page(s): 1271 - 1275
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    This investigation presents a novel method of practical expectation of the capacity of polynomial bidirectional heterocorrelator (PBHC). This has a higher capacity for pattern pair storage than that of the conventional bidirectional associative memories and fuzzy memories. In this work, the practical capacity of the data processing using PBHC considering fault tolerance in the average case is estimated and simulation results are presented to verify the derived theory View full abstract»

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  • Cooperative phenomena observed in a globally coupled phase-locked loop system

    Publication Year: 2000 , Page(s): 1265 - 1271
    Cited by:  Papers (5)
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    The authors describe cooperative phenomena observed in a globally coupled 8-phase-locked loop (PLL) system in both experiments and simulations by using SPICE. In the present system, each PLL is connected through the coupler that averages the all PLLs' output signals. When the frequency modulated external force is applied, three phases are observed such as (1) the coherent phase in which all subsystems are synchronized, (2) the turbulent phase in which all subsystems oscillate independently, and (3) the partially synchronized phase in which creation of clusters and chaotic itineracy due to the reconstruction of clusters occur. In the partially synchronized phase, the time series of voltage difference between arbitrary two subsystems shows an intermittency. From the statistical analysis for this intermittency it is found that the distribution functions of burst amplitude and laminar duration time show the -1 power law and -1.5 power law, respectively. These properties agree with those of the on-off intermittency. We also investigate the variation of number of cluster in the partially synchronized phase. The distribution function of the duration time of one-cluster state, namely the residence time in the state in which all subsystems are synchronized with each other, is also expressed as the -1.5 power law View full abstract»

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