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

Issue 2 • Date Feb 1997

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Displaying Results 1 - 16 of 16
  • On a new kth-order quadratic learning algorithm

    Page(s): 186 - 190
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    The authors develop a new kth-order quadratic learning algorithm, and compare it with the conventional least squares algorithm. It appears that when the order k is appropriately chosen, the algorithm can improve the learning efficiency View full abstract»

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  • An extension of the Levy-Desplanque theorem and some stability conditions for matrices with uncertain entries

    Page(s): 167 - 170
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    Sufficient conditions for Hurwitz stability and for the “degree of stability” of a family of complex matrices with uncertain entries in bounded sets in the complex plane, are derived. The Levy-Desplanque theorem is extended in two directions: the requirement for strict diagonal dominance is alleviated and the (alleviated) theorem is made applicable to families of matrices with uncertain entries. Also, sufficient conditions for Schur stability and for Schur “degree of stability” of a family of real interval matrices are derived. All the above sufficient conditions, as well as the Levy-Desplanque theorem extension, are remarkable in their simplicity to carry out and in the rich variety of possibilities of using them View full abstract»

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  • EMI effects and timing design for increased reliability in digital systems

    Page(s): 130 - 142
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (608 KB)  

    The failure modes of digital circuits subjected to low levels of electromagnetic interference (EMI) are examined. While low-level EMI will not cause static failures (false switching), it may cause dynamic failures by changing the propagation delays of critical signals. A parameter called delay margin is introduced to define the maximum allowable changes in propagation delay under which the circuit will continue to operate reliably. Experimental results are reported in which circuit immunity to EMI is shown to increase significantly when the delay margin is maximized. It is also shown that delay-insensitive circuits have infinite delay margins and are therefore immune to low-level EMI. It was observed experimentally that an oscillating loop subjected to EMI can become phase locked to the frequency of the interference. The second part of the paper describes a synchronization scheme that takes advantage of this phenomenon. The proposed scheme can be used to reduce errors due to synchronizer metastability on communication links between synchronous and asynchronous systems. A reference signal derived from the clock of the synchronous system is injected into a handshake loop, causing the data transfer rate to be locked to a subharmonic of the clock frequency. Both simulation and experimental results are given, showing that stable operation can be achieved over a wide range of parameters View full abstract»

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  • Properties and performance of the block shift network

    Page(s): 93 - 102
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (284 KB)  

    As an interconnection network, hypercube topology offers certain advantages such as high data bandwidth and low message latency to achieve computational efficiency. However, a significant drawback of this topology is that the number of ports per node increases with the number of nodes. In addition, in many applications not all the links are used equally frequently, and links on certain dimensions may be idle most of the time during a computation. This suggests that we can provide connections over certain dimensions only to reduce the number of links and can still attain comparable performance. In this paper, we propose a new network, called the Block Shift Network (BSN), for constructing very large multicomputer systems for efficient parallel processing. The network is defined through a pair of parameters and cost and performance of a BSN can be controlled by carefully selecting appropriate parameters defining the network. Actually, many popular networks such as the hypercube, the shuffle-exchange, and the complete networks are instances of the BSN. The topological properties of the BSN with different parameters are analyzed and compared with those of existing popular networks. Basic data movement operations on the BSN are also designed and analyzed. The results show that the BSN with certain parameters can surpasses the hypercube in several respects while retaining most of its advantages, especially when the traffic has the locality property View full abstract»

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  • A low-power CMOS implementation of programmable CNN's with embedded photosensors

    Page(s): 149 - 153
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    In this brief, an analog CMOS implementation of a Cellular Neural Network (CNN) is presented, which is based on a combination of MOS transistors operating in different modes: weak and strong-inversion and MOS transistors operated in the lateral bipolar mode. This combination has enabled a VLSI implementation of a simplified version of the original CNN model with the main characteristics of low-power consumption, programmability, and embedded photosensors to process images directly projected on the chip. An 8×8-cell CNN chip prototype is reported with experimental results for different image processing tasks. A density of 10.7 cells/mm2 in a 1.2-μm CMOS technology and a power consumption of tens of microwatts per cell are obtained View full abstract»

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  • The integral equation method of simulating electrical solitons for research into reliable hard-wired long distance digital communications with picosecond transitions

    Page(s): 158 - 161
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    An integral equation relates electric charge and magnetic flux in a delay line with nonlinear and frequency-dependent elements. Iteration can approximate a transmission line that is continuously loaded with ferrite beads, revealing subnanosecond solitons, that is, pulses that resist the effects of dispersion. Electrical solitons are a new phenomenon for picosecond communications where the goal is speed, reliability, and hard-wired security View full abstract»

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  • A digital scattering model of the cochlea

    Page(s): 174 - 180
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    A cascade digital scattering linear model of the cochlea, suitable for Kemp echo cochlea characterization, is developed. This model stems from a unidimensional transmission line model in which nonuniform and loss properties are included. Its lattice structure is obtained by rephrasing the model equations in terms of incident and reflected scattering waves. A characterization of the cochlea, through the estimation of the width, the stiffness, and the damping of the basilar membrane, is made with the model and the results compared to data available in the literature View full abstract»

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  • Feedforward control of DC-DC PWM boost converter

    Page(s): 143 - 148
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    A new feedforward control circuit suitable for applications in the dc-dc pulsewidth modulated (PWM) boost converter operated in the continuous conduction mode (CCM) is proposed. Its principle of operation is described, analyzed for steady state, and experimentally verified. The peak value of the sawtooth voltage at the noninverting input of a PWM modulator is held constant and the voltage at the inverting input of the PWM modulator varies in proportion to the converter dc input voltage. As a result, the complement of the on-duty cycle (1-D) is proportional to the dc converter input voltage, yielding the converter output voltage theoretically independent of the converter input voltage. The circuit is very simple and significantly improves line regulation of the output voltage. The measured open-loop line regulation at fixed loads was less than 5% for the converter dc input voltage change by 400%. The load regulation was also good even without a negative feedback loop View full abstract»

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  • Associative memory design using discrete-time second-order neural networks with local interconnections

    Page(s): 153 - 158
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    In this brief a design method for associative memories using a new model of discrete-time high-order neural networks which includes local interconnections among neurons is illustrated. The synthesis approach, which exploits the properties of pseudoinverse matrices, is flexible as it enables one to choose the complexity of the associative memory to be designed; that is, it can generate networks for associative memories with first-order and/or higher order interactions among neurons. The suggested technique preserves local interconnections among neurons, making feasible an implementation of such networks. Simulation results and comparisons among different neural architectures are reported to show the applicability of the proposed method View full abstract»

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  • Intermodulation noise related to THD in wide-band amplifiers

    Page(s): 180 - 183
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (148 KB)  

    It is shown that the power of the intermodulation noise of a wide-band amplifier with a Gaussian input signal, can be estimated by the total harmonic distortion (THD) with a sinusoid input signal of appropriate amplitude. The THD is, as opposed to the intermodulation noise, easy to measure and use as a design parameter. A novel method based on probability density functions is used. The method is demonstrated by a practical example, and a mathematical experiment is carried out to validate it View full abstract»

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  • Robust functional testing for VLSI cellular neural network implementations

    Page(s): 161 - 166
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (416 KB)  

    A robust testing method for detecting circuit faults within two-dimensional Cellular Neural Network (CNN) arrays is presented. The functional tests consist of a sequence of input vectors that toggle all internal nodes of the conceptual CNN model and propagate the result to the output pins. The resultant output vectors reveal nodes that exhibit opened, shorted, or stuck-at faults. The generated test vectors are universal, detect faults independent of the size or topology of the CNN array, and can be applied to any particular CNN implementation with little effort View full abstract»

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  • New algorithms for the derivation of the transfer-function matrices of 2-D state-space discrete systems

    Page(s): 112 - 119
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (464 KB)  

    New algorithms for the derivation of the transfer-function matrices of two-dimensional (2-D) discrete systems from the Roesser and Fornasini-Marchesini state-space models are presented. Two key steps in developing the algorithms are as follows. First, the transfer-function matrix is reformulated in terms of the characteristic polynomials of the matrices involved. Second, an efficient algorithm for the determination of 1-D polynomial coefficients is developed and is, in turn, used to determine the coefficient matrices of the 2-D transfer-function matrix. The proposed algorithms are computationally efficient and reliable. The efficiency of the algorithms is illustrated by comparing the proposed method with two existing methods through examples View full abstract»

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  • A converse of Tellegen's theorem

    Page(s): 184 - 186
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    Let N and N˜ be directed networks having the same number of branches labeled correspondingly. The main result is that if uT i˜=iTu˜ for all vectors of corresponding branch voltages u, u˜ and currents i,i˜ satisfying Kirchhoff's voltage and current laws in every loop and cutset of N and N, then under imposed correspondence of branches the networks are 2-isomorphic. This establishes the converse to Tellegen's famous theorem View full abstract»

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  • Elementary operation approach to state-space realizations of 2-D systems

    Page(s): 120 - 129
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (436 KB)  

    In this paper, the method for obtaining various state-space realizations of the Roesser type for an assigned two-variable transfer function is developed. Two-variable elementary polynomial operations are employed. A new version of the general, state-space model is constructed. One also throws some new light on the problem of the mutual connections among the different 2-D state-space models such as the Roesser, the Fornasini-Marchesini, and the general one. Singular as well as standard (nonsingular) models are considered View full abstract»

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  • Design of complex FIR filters with arbitrary complex frequency responses by two real Chebyshev approximations

    Page(s): 170 - 174
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    The well-known Parks-McClellan program can only design linear phase real FIR filters, and the Remez exchange algorithm is not readily applied for general complex FIR filter design. Here the problem of designing complex FIR filters is solved by dividing the original complex approximation into two real ones such that the Remez exchange algorithm can be applied by slightly modifying the Parks-McClellan-McCalling program. Arbitrary frequency response complex FIR filters and complex all-pass filters can be easily designed by this efficient technique. This approach has several practical advantages such as fast design time and easy implementation with satisfactory performance View full abstract»

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  • One-dimensional analytical modeling of the VDMOS transistor taking into account the thermoelectrical interactions

    Page(s): 103 - 111
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    An analytical one-dimensional thermoelectrical model for the power MOSFET transistor (VDMOS transistor) has been developed and implemented in the Saber circuit simulator. The device temperature becomes an interactive variable during the simulation. The model results in the combination of the electrical model of the device with a thermal network which models the different material layers crossed by the heat flow from the silicon chip to the heatsink (conduction phenomenon), and also takes into account the radiation and convection phenomena. The accuracy of the model is evaluated with electrical and thermal characterizations, and with a validation circuit View full abstract»

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