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

Issue 4 • Date April 1999

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Displaying Results 1 - 19 of 19
  • New designs of linear-phase transmitter and receiver filters for digital transmission systems

    Page(s): 428 - 433
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    New solutions to the issue of designing transmitter and receiver filters for data transmission are proposed. In this design issue, good frequency selectivity, matched filter pairs, transmit, and receive filters with a linear phase characteristic and zero intersymhol interference (ISI) are desired. As these properties cannot be-simultaneously achieved, most of the previously known algorithms relax the phase-linearity constraint. We show that relaxing the exact zero-ISI or the matched filter pair provides very efficient transmit and receive linear phase filters with high frequency selectivity. Two design algorithms are described: we propose matched filter pairs with very low ISI and nonmatched filter pairs with exact zero-ISI. View full abstract»

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  • Comments on "Linear circuit fault diagnosis using neuromorphic analyzers"

    Page(s): 483 - 485
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    For the original paper see ibid., vol. 44, no. 3, p. 188-96 (1997). In the aforementioned paper, Spina and Upadhyaya presented a method for the fault diagnosis of analog linear circuits. The method, which is based on a white noise generator and an artificial neural network for response analysis, has been applied to circuits of reasonable dimensions, taking into account the effect of the component tolerances. However, the commenters state that the proposed method does not take into account the testability analysis of the circuit under test. They point out that research on testability analysis of linear circuits has been developed by several authors in the last 20 years, and algorithms and programs for testability evaluation have been presented in several publications. It is their opinion that the testability analysis concept could be useful in the approach proposed by Spina and Upadhyaya to improve the quality of the results even further. Here they discuss this possibility. View full abstract»

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  • Excess loop delay in continuous-time delta-sigma modulators

    Page(s): 376 - 389
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (456 KB)  

    Continuous-time (CT) delta-sigma modulators (ΔΣM's) suffer from a problem not seen in discrete-time (DT) designs, that of excess loop delay: nonzero delay between the quantizer clock edge and the time when a change in output bit is seen at the feedback point in the modulator. This paper analytically shows how such delay affects the equivalence between the CT modulator loop filter and its DT counterpart. The effect of this delay on modulator dynamic range is studied through simulation for the standard double-integration (low pass) CT modulator and its equivalent fourth-order fs/4 band pass circuit. For the first time, the results are extended to higher order low-pass and bandpass designs, as well as multibit designs. Methods for alleviating the performance loss caused by excess loop delay are also discussed View full abstract»

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  • Hermite reduction methods for generation of a complete class of linear-phase perfect reconstruction filter banks-Part I: Theory

    Page(s): 434 - 447
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    Motivated by the possibility of extensions to two-dimensions, we address the problem constructing a linear-phase multiband perfect reconstruction finite impulse response filter bank by constructing the polyphase matrix associated with it. The equivalent problem of construction of linear phase, i.e., symmetric or antisymmetric compactly supported wavelets are, thus, also considered. Our approach rests on the fact that if any proper subset of the set of linear-phase analysis filters is almost arbitrarily specified, then the complete set of linear-phase analysis filters can always be constructed. The solution to this problem is obtained by solving the problem of completing an incompletely specified analysis polyphase matrix having the structure mandated by the linear-phase property. Symmetric versions of matrix reduction algorithms akin to the Hermite reduction algorithm well known in system theory are used in our method of construction. The technique closely follows the proof of (nonsymmetric) Quillen-Suslin theorem for the completion of multivariable polynomial matrices, and, thus, in addition, has the potential for extension to the multidimensional case. Examples are given to demonstrate the procedure View full abstract»

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  • Discrete-time signals arising from simple polynomial sets

    Page(s): 472 - 475
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    The simple polynomial set is introduced as a mathematical tool for representing and generating discrete-time signals. Two benefits result. A signal derived from a simple polynomial set comes with an expression for its z-transform and a recurrence relation for its rapid computation. Two examples are presented. The purpose of these examples is to show that simple sets of polynomials can give rise to signals having more diverse properties than signals with rational z-transforms View full abstract»

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  • The optimal RLS parameter tracking algorithm for a power amplifier feedforward linearizer

    Page(s): 464 - 468
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    Digital signal processing (DSP) techniques have been proposed in recent years to adaptively track the control parameters of a power amplifier (PA) feedforward linearizer. In most of the propositions, gradient-based searching algorithms are applied to the parameter tracking. In this paper, we propose an optimal recursive least square (RLS) parameter tracking algorithm, which significantly accelerates the convergence speed and eliminates the gradient noise. There exist two problems for the RLS algorithm. First, the least square solution is not the optimal solution because of the nonlinearity of the PA. Second, the vector modulator (VM) which introduces the control parameters into the linearizer circuit may not be accurate enough to provide a precise power gain and phase shift calculated by the DSP. We solve both problems, respectively; by rearranging the circuit components and by constraining the VM characteristics. We also present simulation results to verify the performance improvement of the proposed algorithm View full abstract»

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  • The block-optimal realization of separable-in-denominator 2-D digital filters

    Page(s): 457 - 460
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    The optimal synthesis of a single input single output separable-in-denominator 2-D digital filter with fixed-point arithmetic is investigated. In the first phase, a general partial fraction expansion for this class of filter is presented. In sequel, a parallel block-optimal realization is proposed in order to minimize the round-off noise under L2 scaling. A novel criterion for the absence of limit cycle of second order block-optimal structure is also derived. A numerical example is provided to illustrate the effectiveness of the proposed method View full abstract»

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  • Double-index averaging: a novel technique for dynamic element matching in Σ-Δ A/D converters

    Page(s): 353 - 358
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    We report the study of a second-order Σ-Δ modulator for audio applications with a nine-levels quantizer. The feedback digital-to-analog has been implemented with four capacitors and two voltage references, taking the structure typical of fully differential system. We first discuss the performance achievable with the most popular dynamic element-matching techniques, namely the data-weighted averaging and individual-level averaging. We then introduce a new algorithm, the double-index averaging, that performs better than the other algorithms by 10-15 dB over the entire dynamic range of the modulator, and 6 dB at the peak of signal/(quantization noise+total harmonic distortion) View full abstract»

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  • Analyzing television coding techniques using three-dimensional signal analysis

    Page(s): 414 - 427
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    An understanding of the three-dimensional (3-D) nature of a television signal and its spectrum has been commonly used as an aid in visualizing and developing new analog coding techniques. Determining the actual 3-D (spatio-temporal) characteristics of a television system is, however, more difficult. This paper introduces a mathematical representation for the spatio-temporal characteristics of a television system. This representation is extended to include both time-invariant and time-varying coding effects (e.g., aliasing, modulation), and then simplified into six useful functions. A piecewise-Fourier analysis technique is used to obtain the characteristics for several simulated coding techniques. Results are presented for conventional delay-line PAL, I-PAL, and film-mode ColourPlus, in a 5-MHz transmission bandwidth View full abstract»

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  • Sampling and generalized almost periodic extension of functions

    Page(s): 475 - 478
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    The author explores the connections between nonuniform sampling of a certain function and the almost periodic extension of its Fourier transform. It is shown that the Fourier transform of a bandlimited function can be extended (as a weighted sum of translates) as a Stepanoff almost periodic function, to the whole frequency axis. This result leads to a generalized nonuniform sampling theorem which, unlike previous results, does not require the continuity of the Fourier transform of the sampled function, and is valid for finite-energy band-limited functions View full abstract»

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  • New CMOS realization of the CCII-

    Page(s): 460 - 463
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    New second-generation current conveyor negative (CCII-) realization suitable for very large scale implementation is described. The proposed architecture provides a very low impedance level at the N terminal and a wide dynamic voltage range, as well as a high current tracking accuracy. Simulations show that the CCII- current follower bandwidth extends beyond 100 MHz. Two compensation methods are discussed: the first results in voltage-offset cancellation, while the second results in voltage-offset compensation as well as Rx reduction View full abstract»

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  • Synchronizing hyperchaotic systems by observer design

    Page(s): 478 - 483
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    In this work, a technique for synchronizing hyperchaotic systems is presented. The basic idea is to make the driven system a linear observer for the state of the drive system. By developing this approach, a linear time-invariant synchronization error system is obtained, for which a necessary and sufficient condition is given in order to asymptotically stabilize its dynamics at the origin. The suggested tool proves to be effective and systematic in achieving global synchronization. It does not require either the computation of the Lyapunov exponents, or the initial conditions belonging to the same basin of attraction. Moreover, it guarantees synchronization of a wide class of hyperchaotic systems via a scalar signal. Finally, the proposed tool is utilized to design a secure communications scheme, which combines conventional cryptographic methods and synchronization of hyperchaotic systems. The utilization of both cryptography and hyperchaos seems to make a contribution to the development of communication systems with higher security View full abstract»

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  • The Cramer-Rao bound for position and amplitude estimation of multiple pulses in Gaussian noise

    Page(s): 448 - 456
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    Estimating the position or amplitude of a pulse is a common problem in radar and seismic signal processing. In this paper an approximation to the Cramer-Rao bound for estimation of positions and amplitudes of multiple pulses is derived. It is shown that a vector can be associated with each parameter and the effect of a parameter on the estimation of another parameter is expressed as the normalized cross correlation of the vectors associated with these two parameters. We give examples to show that this approximation is good. These results provide a simple, geometric explanation for the effect of one pulse on the estimation of another View full abstract»

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  • A current-mode testable design of operational transconductance amplifier-capacitor filters

    Page(s): 401 - 413
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    Analog filters are important building blocks of many communication and instrumentation systems. However, similar to other analog circuits, testing an analog filter is a difficult problem. In recent years, this problem has become even more difficult because of the increase of circuit complexity. Operational transconductance amplifier-capacitor (OTA-C) filters are especially useful in video applications such as HDTV. In this paper, we first present the design of an OTA-C low-pass filter with a passband from 0 to 4.5 MHz. We then propose a current-mode method for the error detection of this filter. By comparing the current consumed by the circuit under test (CUT) and the current converted from the voltage levels of the CUT, abnormal function of circuit components can be concurrently detected. This technique has been applied to the OTA-C filter and a testable design is obtained. Experimental results show that our design has the following advantages: (1) easy to design and implement; (2) high accuracy in error detection; (3) little impact on the circuit performance of the filter; and (4) high error-detection speed. From an actual layout, we find that the area overhead is about 25% and only one extra pin is needed View full abstract»

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  • Low-voltage high-speed current-mode continuous-time IC filters with orthogonal ω0-Q tuning

    Page(s): 390 - 400
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    The design of fully differential high-frequency continuous-time current-mode filters is presented. A universal biquad is constructed from two basic building blocks, lossless and lossy differential current-mode integrators, Pole frequency ω0 and quality factor Q are tuned orthogonally by means of a translinear circuit. The design is illustrated on a 200-MHz fifth-order cascade low-pass filter. The tuning scheme is used to switch the transfer function electronically from a Butterworth to a Bessel characteristic. The proposed circuits use a single-ended supply that can be as low as 1.5 V with no special technology required. The design was implemented in an 8-GHz bipolar process View full abstract»

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  • SPICE macro model for MAGFET and its applications

    Page(s): 370 - 375
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    SPICE macro models for magnetic MOSFET (MAGFET) devices in the saturation region are presented. By using the proposed models, the performance of several readout circuits using MAGFET devices could be predictable. In this paper, the magnetic field-to-voltage converter, the magnetically controlled operational-transconductance amplifier, and the magnetically controlled filter and magnetic-operational amplifier using MAGFET devices have been designed, simulated, and tested. The proposed readout circuits using two different CMOS processes have been fabricated. Both simulation and measurement results verify the correctness and flexibility of the proposed SPICE macro models View full abstract»

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  • Efficient block-adaptive parallel-cascade quadratic filters

    Page(s): 468 - 472
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    This brief presents computationally efficient block-adaptive algorithms for quadratic filters employing parallel-cascade realizations of the system model. Parallel-cascade realizations implement higher order Volterra systems using a parallel connection of multiplicative combinations of lower order systems. Such realizations are modular and therefore well-suited for very large scale integrate circuit implementation. They also permit efficient approximations of truncated Volterra systems. Mixed frequency- and time-domain realizations of the least-mean-square (LMS) adaptive filter, as well as that of a normalized LMS adaptive filter, are presented in this brief. The adaptive normalized LMS parallel-cascade quadratic filter has the advantages of computational simplicity and superior performance over its direct form, and unnormalized adaptive parallel-cascade counterparts View full abstract»

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  • Power analysis and optimal design of op amps for oversampled converters

    Page(s): 359 - 369
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    In this paper, we address three issues related to the design of op amps for oversampled converters: the theoretical minimum-power bound for an ideal op amp, the best op amp choice in terms of power dissipation, and the best design strategy to reduce power dissipation. To be able to do so, we develop a model that captures the dynamics of the integrator inside the modulator. Based on this model, power dissipation for various op amp topologies is computed and compared with each other. We show that class-A op amps can consume one to six times the current consumed by an idealized class-AB op amp, though the savings for practical class-AB op amps is likely to be lower. For high-resolution applications, class-A topologies are most optimal, while for lower resolution lower power applications, class-AB op amps may be more suitable. We further demonstrate a design strategy with the help of an example that can be used to minimize the power dissipation for class-A op amps 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