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Circuits and Systems II: Express Briefs, IEEE Transactions on

Issue 3 • Date March 2005

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Displaying Results 1 - 19 of 19
  • Table of contents

    Publication Year: 2005 , Page(s): c1
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  • IEEE Transactions on Circuits and Systems—II: Express Briefs publication information

    Publication Year: 2005 , Page(s): c2
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  • Statistical analysis of second-order intermodulation distortion in WCDMA direct conversion receivers

    Publication Year: 2005 , Page(s): 117 - 121
    Cited by:  Papers (6)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (232 KB) |  | HTML iconHTML  

    Nonlinear spectral analysis is exploited in this brief to investigate the second-order intermodulation distortion in direct conversion receivers (DCRs) for wideband code division multiple access systems. The emphasis is on the accurate modeling of the interferer, and on the derivation of the second-order intermodulation distortion spectra. Depending on the number of code multiplexed channels, the second-order intermodulation distortion power produced in the receiver can be significantly different. It varies by 6.5 dB between two boundary cases: multichannel versus single-channel signal. The developed analysis is verified by means of experiments carried out on a 0.18-μm CMOS DCR realized for the universal mobile telecommunications system standard. View full abstract»

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  • Novel allpass filter configuration employing single OTRA

    Publication Year: 2005 , Page(s): 122 - 125
    Cited by:  Papers (35)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (176 KB) |  | HTML iconHTML  

    A new circuit configuration uses a single operational transresistance amplifier (OTRA) and four passive elements to realize both first- and second-order allpass filters. Owing to internal grounding of the OTRA input terminals, effects of input parasitics are significantly reduced. Applications of the circuit include the realization of the phase equalizer, the quadrature oscillator, and the high-Q bandpass filter for analog signal processing. The performance of the allpass filter is illustrated by circuit-level simulation of a quadrature oscillator with CMOS realization of the OTRA. View full abstract»

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  • Global stability of a class of neural networks with time-varying delay

    Publication Year: 2005 , Page(s): 126 - 130
    Cited by:  Papers (28)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (160 KB) |  | HTML iconHTML  

    This paper presents a new sufficient condition for the uniqueness and global asymptotic stability of the equilibrium point for a class of neural networks with time-varying delays. The result is obtained by the use of a more general type of Lyapunov-Krasovskii functional, establishing a relation between the network parameters of the neural system and time-varying delay parameter. The result is also shown to be a generalization of a previously published result. View full abstract»

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  • High-speed and high-precision current winner-take-all circuit

    Publication Year: 2005 , Page(s): 131 - 135
    Cited by:  Papers (12)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (232 KB) |  | HTML iconHTML  

    A CMOS high-performance current-mode winner-take-all circuit is presented. The circuit employs a novel technique for inhibitory and excitatory feedbacks based on input currents average computation, achieving both high speed and high precision. The circuit is designed for operation with a wide range of input current values, allowing its integration with circuits operating both in subthreshold and in strong inversion regions. Two circuits, each for a different range of input currents, have been implemented in a standard 0.35-μm CMOS process available through MOSIS and are operated via a 3.3-V supply. Their operation is discussed, simulation results are reported and preliminary measurements from a test chip are presented. View full abstract»

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  • Improving the bandwidth gain-independence and accuracy of the current feedback amplifier

    Publication Year: 2005 , Page(s): 136 - 139
    Cited by:  Papers (9)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (232 KB) |  | HTML iconHTML  

    A high-performance current feedback amplifier circuit referred to as an operational current feedback amplifier is described in this paper. The technique employed involves the incorporation of the input circuit of the current feedback amplifier in the feedback loop of an operational amplifier to reduce the input impedance at the inverting terminal of the current feedback amplifier. The new circuit possesses the gain accuracy and bandwidth of the current feedback amplifier but realizes significant improvement in bandwidth accuracy and bandwidth gain-independence. Experimentally, using AD844s, an order of magnitude reduction in bandwidth variation with changing gain was achieved in the noninverting configuration and almost complete bandwidth invariance was realized in the inverting configuration. View full abstract»

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  • A 2.5-GHz eight-phase VCO in SiGe BiCMOS technology

    Publication Year: 2005 , Page(s): 140 - 144
    Cited by:  Papers (11)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (224 KB) |  | HTML iconHTML  

    We present a 2.5-GHz voltage-controlled oscillator (VCO) with eight equally distributed phases derived from a 10-GHz LC VCO. Stochastic and static phase errors were obtained by spectrum analyzer measurements in conjunction with an on-chip single-sideband mixer. From the measured phase noise spectrum, we predict an absolute rms jitter contribution of 130 fs in a 2-MHz bandwidth phase-locked loop. A static phase error of less than 0.7° was deduced from the sideband suppression. The eight-phase VCO is tunable from 2.35 to 2.85 GHz and draws 16 mA from a 2.0-V supply. Possible applications include clock and data recovery of a 10-Gb/s signal in a fiber-optic receiver as well as high-precision image rejection receivers and I/Q direct up-converters for radio-frequency applications. View full abstract»

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  • CMOS current-mode divider and its applications

    Publication Year: 2005 , Page(s): 145 - 148
    Cited by:  Papers (7)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (336 KB) |  | HTML iconHTML  

    Compact, accurate and low-power analog CMOS circuits for current-mode division and pseudo-exponential function generation are presented, based on a new variable transresistance amplifier. Experimental results of the circuits fabricated in a 0.5-μm 2P2M n-well CMOS process show better than 0.3% total harmonic distortion. Measured power is less than 0.22 mW at 100-MHz bandwidth and ±1.5-V supply voltages. View full abstract»

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  • An analytical formulation of phase noise of signals with Gaussian-distributed jitter

    Publication Year: 2005 , Page(s): 149 - 153
    Cited by:  Papers (8)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (216 KB) |  | HTML iconHTML  

    The output of many oscillatory systems can be approximated by a stochastic square-wave signal with noise-free amplitude and Gaussian-distributed jitter. We present an analytical treatment of the phase noise of this signal with white and Lorentzian jitter spectra. With a white jitter spectrum, the phase noise is nearly Lorentzian around each harmonic. With a Lorentzian jitter spectrum, it is a sum of several Lorentzian spectra, a summation that has a 1/f4 shape at far-out frequencies. With a combination of the two, it has 1/f4 and 1/f2 shapes at close-in and far-out frequencies, respectively. In all cases, the phase noise at the center frequency and the total signal power are both finite. These findings will improve our understanding of phase noise and will facilitate the calculation of phase noise using time- domain jitter analysis. View full abstract»

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  • New results for exponential stability of delayed cellular neural networks

    Publication Year: 2005 , Page(s): 154 - 158
    Cited by:  Papers (7)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (168 KB) |  | HTML iconHTML  

    This brief presents new sufficient conditions for the global exponential stability of the equilibrium point for delayed cellular neural networks (DCNNs). It is shown that the use of a more general type of Lyapunov-Krasovskii functional enables us to derive new results for exponential stability of the equilibrium point for DCNNs. The results establish a relation between the delay time and the parameters of the network. The results are also compared with one of the most recent results derived in the literature. View full abstract»

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  • Phase-domain all-digital phase-locked loop

    Publication Year: 2005 , Page(s): 159 - 163
    Cited by:  Papers (77)  |  Patents (9)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (224 KB) |  | HTML iconHTML  

    A fully digital frequency synthesizer for RF wireless applications has recently been proposed. At its foundation lies a digitally controlled oscillator that deliberately avoids any analog tuning controls. When implemented in a digital deep-submicrometer CMOS process, the proposed architecture appears more advantageous over conventional charge-pump-based phase-locked loops (PLLs), since it exploits signal processing capabilities of digital circuits and avoids relying on the fine voltage resolution of analog circuits. An actual implementation of an all-digital PLL (ADPLL)-based local oscillator and transmitter used in a commercial 0.13-μm CMOS single-chip Bluetooth radio has recently been disclosed. The conventional phase/frequency detector, charge pump and RC loop filter are replaced by a time-to-digital converter and a simple digital loop filter. Due to the lack of the correlational phase detection mechanism, the loop does not contribute to the reference spurs. The measured close-in phase noise of -86 dBc/Hz is adequate even for Global System for Mobile communications (GSM) applications. In this paper, we present the mathematical description and operational details of the phase-domain ADPLL. View full abstract»

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  • An accurate analysis of slew rate for two-stage CMOS opamps

    Publication Year: 2005 , Page(s): 164 - 167
    Cited by:  Papers (9)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (616 KB) |  | HTML iconHTML  

    This brief presents a time-domain model for the slew rate of CMOS two-stage Miller compensated operational transconductance amplifiers. The effects of both the first- and second-stage currents are considered in this model and a simple analytical expression is given in terms of the compensation and load capacitors, output voltage change, and device sizes. HSPICE simulation results are provided to show the validity of the proposed model using a 0.25-μm CMOS technology. View full abstract»

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  • Global asymptotic stability and global exponential stability of neural networks with unbounded time-varying delays

    Publication Year: 2005 , Page(s): 168 - 173
    Cited by:  Papers (35)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (216 KB) |  | HTML iconHTML  

    This brief studies the global asymptotic stability and the global exponential stability of neural networks with unbounded time-varying delays and with bounded and Lipschitz continuous activation functions. Several sufficient conditions for the global exponential stability and global asymptotic stability of such neural networks are derived. The new results given in the brief extend the existing relevant stability results in the literature to cover more general neural networks. View full abstract»

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  • The Fourth International Workshop on Multidimensional (nD) Systems NDS 2005

    Publication Year: 2005 , Page(s): 174
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  • Call for participation for 2005 IEEE International Symposium on Circuits and Systems (ISCAS2005)

    Publication Year: 2005 , Page(s): 175
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  • IEEE order form for reprints

    Publication Year: 2005 , Page(s): 176
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  • IEEE Circuits and Systems Society Information

    Publication Year: 2005 , Page(s): c3
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  • IEEE Transactions on Circuits and Systems—II: Express Briefs Information for authors

    Publication Year: 2005 , Page(s): c4
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Aims & Scope

TCAS II publishes brief papers in the field specified by the theory, analysis, design, and practical implementations of circuits, and the application of circuit techniques to systems and to signal processing. Included is the whole spectrum from basic scientific theory to industrial applications. The field of interest covered includes:

  • Circuits: Analog, Digital and Mixed Signal Circuits and Systems  
  • Nonlinear Circuits and Systems, Integrated Sensors, MEMS and Systems on Chip, Nanoscale Circuits and Systems, Optoelectronic
  • Circuits and Systems, Power Electronics and Systems
  • Software for Analog-and-Logic Circuits and Systems
  • Control aspects of Circuits and Systems. 

Full Aims & Scope