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Circuits and Systems II: Analog and Digital Signal Processing, IEEE Transactions on

Issue 6 • Date Jun 1994

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Displaying Results 1 - 12 of 12
  • Symbolic dynamics of piecewise-linear maps

    Page(s): 420 - 424
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    In this paper we develop the theory of symbolic dynamics on piecewise-linear maps. We prove several results concerning periodic points and admissible periodic sequences and show how this theory is used on maps which are composed of signum functions by means of two examples in signal processing, namely digital filters with overflow nonlinearity and sigma-delta modulators. For example, we show that in the double-loop sigma-delta modulator with a two-bit quantizer, the set of initial conditions which generate periodic output has zero measure for any constant input, in contrast to the single-loop sigma-delta modulator View full abstract»

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  • Multistage bandpass delta sigma modulators

    Page(s): 402 - 405
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    A new architecture for oversampled delta sigma A/D conversion of high-frequency narrow band signals using cascaded low-order stages to obtain high overall order of noise shaping is described. The architecture involves using resonators in individual stages to suppress quantization noise at the resonant frequency. Many of the problems of previous single stage high-order architectures including poor stability, large component spread and design complexity are overcome by this new approach. Switched capacitor resonator circuit implementations and simulation results for a sixth-order modulator example are included. Estimates of the potential for 16-bit A/D conversion of 2.5 MHz signals exceed the 80 KHz capability of existing monolithic oversampled CMOS A/Ds View full abstract»

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  • Bounds for floating-point roundoff noise

    Page(s): 424 - 426
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    The dummy multiplier model and the conventional estimates for roundoff noise variance in floating-point implementations are compared. Common upper and lower bounds for the noise estimates are derived and experimental results are presented. Although the two noise estimates have common finite bounds, it is shown that they may differ by more than 10 dB for narrowband lowpass filters View full abstract»

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  • Design of bounded-degree circuits for parallel processing

    Page(s): 428 - 431
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    The design of large circuits to interconnect many processors with low number of I/O ports and short diameter has been one of the major goals of researchers. Unfortunately, the underlying topologies of most of the popular circuits have a degree of the node which is a function of the network size. From the implementation viewpoint, networks with unbounded degree of the node pose two problems. First, there is a limit on the number of I/O channels allocated to a processor. Second, the I/O unit of the processor modules may need to be modified as the result of network expansion. In this paper, the design of high performance networks with constant degree of the node is addressed. A transformation applied to a circuit with a varying degree is essentially the replacement of each node with a topology with constant degree. The resulting hybrid circuit usually yields an efficient realization while preserving the advantageous features of designs with unbounded degree. New circuits such as: star-connected cycles, pancake-connected cycles, and bubble-sort connected cycles are introduced as examples of large circuits with constant degree of the node. The proposed networks lend themselves to an efficient VLSI implementation without compromising their efficiency in performing certain parallel algorithms View full abstract»

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  • Properties and ways of calculation of multi-polarity generalized Walsh transforms

    Page(s): 380 - 391
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    A new formulation of the multi-polarity generalized Walsh transform has been introduced. The formulation allows a uniform representation of Boolean functions by a set of orthogonal and generalized Walsh spectral coefficients. Forward and inverse transformation kernels and the method of recursive generation of transform matrices by using Kronecker products of elementary matrices have been given. Mutual relations among transform matrices and spectra for arbitrary polarities have been investigated. Fast forward and inverse generalized Walsh transforms have been developed. An algorithm to calculate the generalized Walsh transform from a cube array specification of incompletely specified Boolean functions has been shown. The transform algorithm makes use of the properties of an array of disjoint cubes and allows the determination of the spectral coefficients in an independent way. The computer implementation drastically reduces the required time of computation by allowing calculation of only chosen coefficients in specified polarity. The entire spectrum-if required-can be computed incrementally for groups of coefficients View full abstract»

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  • Wide-area adaptive active noise cancellation

    Page(s): 405 - 409
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    This paper describes an adaptive active noise cancellation (ANC) system that is based on an output-whitening approach and is an extension of the work of Graupe and Efron on single point adaptive ANC. The controller works by continually estimating the time-series parameters of the noise to be cancelled and by forcing the cancellation network to follow the identified parameters, so that the output is whitened. To address the problem of wide-area cancellation, a system that consists of a weighted array of single point output-whitening cancellation systems is proposed. Each controller is chosen to cancel the local temporal effects of the noise, and the array weights are chosen to match the wavefront shape. A comparison of cancellations based on single-point and wide-area systems demonstrates the superiority of the wide-area system View full abstract»

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  • A preprocessing architecture for resolution enhancement in high-speed analog-to-digital converters

    Page(s): 373 - 379
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    High performance analog-to-digital converters (ADC's) employ a parallel configuration of analog folding circuits to symmetrically fold the input signal prior to quantization by high speed comparators (analog preprocessing). This paper identifies a new preprocessing approach that can be easily incorporated into the established techniques to provide an enhanced resolution capability with fewer number of comparators loaded in parallel. The approach is based on preprocessing the analog signal with a symmetrical number system (SNS). The SNS preprocessing is used to decompose the analog amplitude analyzer operation into a number of sub-operations (moduli) which are of smaller computational complexity. Each sub-operation symmetrically folds the analog signal with folding period equal to the moduli. Thus, each sub-operation only requires a precision in accordance with that modulus. A much higher resolution is achieved after the N different SNS moduli are used and the results of these low precision sub-operations are recombined. By incorporating the SNS folding concept, the dynamic range of a specific configuration of folding periods and comparator arrangements can be analyzed exactly View full abstract»

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  • Application of multitransforms for lossy image representation

    Page(s): 431 - 434
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    The multitransform technique is applied for lossy image representation. The image is first divided into smaller non-overlapping subimages. Each subimage is resolved into two dimensional (2-D) subsignals, which are then compactly represented in a particular transform domain. This leads to an efficient representation of the subimage by superimposing the dominant coefficients corresponding to each subsignal. An adaptive algorithm in conjunction with an optimization strategy are developed to minimize the difference between the original and the reconstructed subimage. Extensive simulations verify that, for a given number of retained coefficients, the combination of the DCT and Haar transforms yields a more compact representation than using DCT or Haar alone View full abstract»

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  • Analysis of adaptive FIR filters in cascade form

    Page(s): 392 - 401
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    This paper deals with the behavior of adaptive FIR filters in cascade form. The cascade filters are investigated with simulations and analysis. The results and methods for the cascade filters are compared with the corresponding cases for the transversal filter and, especially, the well-known LMS algorithm. In the analysis, we treat a cascade filter updated with a gradient algorithm. The analysis, which uses a “slow“ adaptation assumption, gives a recursive expression for the expected value of the error in the coefficient vector. A steady-state solution for the covariance matrix of the coefficients is derived and analytical learning curves are computed. Using an assumption of accurate power measures, these results are then applied to a filter updated with a normalized gradient View full abstract»

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  • Calculation of minimum number of registers in arbitrary life time chart

    Page(s): 434 - 436
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    This paper presents a general approach to calculate the minimum number of registers in any digital signal processing (DSP) circuit for any arbitrarily specified life time chart and periodicity of computation. DSP operations are repetitive and periodic in nature. The life time chart specifies the life period of all variables in a single frame and the subsequent frames are computed in a periodic manner. We present the techniques for the calculation of minimum number of registers by using the life time chart and the circular life time graph View full abstract»

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  • A new nonparametric method for linear system phase recovery from bispectrum

    Page(s): 415 - 419
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    For input signals with nonzero third order moment, the phase of a linear system transfer function can be identified from the bispectrum of its output signal. Instead of using partial bispectrum phase information which is more sensitive to noises and measurement errors, a new nonparametric method is proposed to utilize all the available bispectrum phase information. The proposed new method is computationally simple. It does not require finding the pseudo-inverse of a gigantic matrix as some existing methods do. Its effectiveness is demonstrated through computer simulations View full abstract»

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  • Design and characterization of a standard cell set for delay insensitive VLSI design

    Page(s): 410 - 415
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    A working synthesis system for delay insensitive (DI) VLSI design is used as a case study to investigate the correspondence between theoretical formalization and electric circuit operation. Most of the previous research has treated DI VLSI design from a formal point of view. We illustrate the new features involved in the electrical design and characterization of DI cells, reporting circuit schematic and standard cell characterization results. Some integrated circuits built with the cells have been fabricated View full abstract»

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Aims & Scope

This title ceased production in 2003. The current updated title is IEEE Transactions on Circuits and Systems II: Express Briefs.

Full Aims & Scope