IEICE Electronics Express
Online ISSN : 1349-2543
ISSN-L : 1349-2543
Volume 7 , Issue 3
Showing 1-18 articles out of 18 articles from the selected issue
LETTER
  • Tae-Wuk Bae, Young-Choon Kim, Sang-Ho Ahn, Kyu-Ik Sohng
    2010 Volume 7 Issue 3 Pages 112-117
    Published: 2010
    Released: February 10, 2010
    JOURNALS FREE ACCESS
    In this paper, we propose a novel TDLMS filter using a sub-sampling mask and step-size index for small target detection in infra-red (IR) imagery. The concept of the proposed TDLMS is to utilize the sub-sampling mask of the weight-matrix having the structure reducing effects of the target pixels in order to predict the background exactly. And the nonlinear step size using the luminance rate (LR) and contrast rate (CR) is used and then background is predicted finally by using the two-dimensional Gaussian distance (TDGD). Experimental results show that the proposed method exhibits higher detection rates in comparison to the conventional TDLMS filter.
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  • Mohammad Esmaeildoust, Keivan Navi, MohammadReza Taheri
    2010 Volume 7 Issue 3 Pages 118-125
    Published: 2010
    Released: February 10, 2010
    JOURNALS FREE ACCESS
    In this paper an efficient reverse converter for the new five moduli set {2n, 22n+1-1, 2n/2-1, 2n/2+1, 2n+1} for even n is presented. With a little changes in latest introduced five moduli set {2n, 2n/2-1, 2n/2+1, 2n+1, 22n-1-1} in order to achieve simple multiplicative inverse, this new moduli set is presented. The converter is designed in two levels architecture. The first level is based on CRT and the second one is based on MRC algorithm. The proposed converter achieved significant improvement in terms of speed with less hardware requirement comparing to other five moduli sets.
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  • Qiang Guo, Songnian Yu
    2010 Volume 7 Issue 3 Pages 126-131
    Published: 2010
    Released: February 10, 2010
    JOURNALS FREE ACCESS
    A new method based on the curvelet transform is proposed for image denoising. This method exploits a multivariate generalized spherically contoured exponential (GSCE) probability density function to model neighboring curvelet coefficients. Based on the multivariate probability model, which takes account of the dependency between the estimated curvelet coefficients and their neighbors, a multivariate shrinkage function for image denoising is derived by maximum a posteriori (MAP) estimator. Experimental results show that the proposed method obtains better performance than the existing curvelet-based image denoising method.
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  • Zeyad Assi Obaid, Nasri Sulaiman, M. H. Marhaban, M. N. Hamidon
    2010 Volume 7 Issue 3 Pages 132-137
    Published: 2010
    Released: February 10, 2010
    JOURNALS FREE ACCESS
    This paper presents an implementation of Multistructure PIDFLC. Modification has been made to structure of the proposed PIDFLC in order to make it acts as PDFLC, PIFLC or PIDFLC depending on two external signals. Two versions of this controller have been designed using VHDL language for FPGA implementation. A new package has been designed in VHDL code to implement trigonometric functions and fourth-order Runge-Kutta method to test the proposed design with nonlinear systems. The controller was able to produce an output in 0.3µsec for linear plants and 0.7µsec for nonlinear plant. Therefore, the proposed controller will be able to control many systems with high sampling rate.
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  • M. H. Madani, A. Abdipour, A. Mohammadi
    2010 Volume 7 Issue 3 Pages 138-145
    Published: 2010
    Released: February 10, 2010
    JOURNALS FREE ACCESS
    This paper presents a new and exact theoretical analysis of performance degradation of OFDM systems due to circuit nonlinearity effects. This nonlinearity is modeled as a fifth order memoryless nonlinear polynomial model. Theoretical analysis shows that the detected data symbol at the receiver consists of attenuated version of the original transmitted data symbol, third and fifth order intermodulation components. Analytical expressions for inter- modulation noise term are derived using combinatorial methods. By use of the derived expressions, a closed form output signal to noise ratio and degradation factor can be evaluated theoretically. The analytical results are compared with simulations outcomes.
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  • Young-Chan Jang
    2010 Volume 7 Issue 3 Pages 146-152
    Published: 2010
    Released: February 10, 2010
    JOURNALS FREE ACCESS
    A digital phase corrector is proposed to reduce the time jitter noise in a high speed parallel chip-to-chip interface system with a quad data rate (QDR) input/output (I/O) scheme. The proposed digital phase corrector for the 4-phase clock utilizes only one duty cycle detector by using a digitally controlled phase correction method and multiplexing function of transmitter for a QDR I/O scheme. Also, it reduces the static phase error generated in the transmitter, because of the inclusion of a replica of the transmitter in the feedback loop. To verify the proposed digital phase correction scheme, a digital phase corrector for the QDR I/O scheme with a 1.25GHz 4-phase clock was designed by using a 70nm 3-metal CMOS process with a 1.35V supply. The current consumption and phase correction range were 2.73mA and ±8%, respectively.
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  • Fattah Talaei, Mohammad N. Azarmanesh, Gholamreza Askari, Hamid Mirmoh ...
    2010 Volume 7 Issue 3 Pages 153-158
    Published: 2010
    Released: February 10, 2010
    JOURNALS FREE ACCESS
    A quasi fractal structure is introduced to build up a nondegenerate dual mode dual band bandpass filter. In the proposed filter a Koch fractal structure is applied to a microstrip patch resonator for miniaturization and dual band operation. The first band is specified by the first iteration of the fractal patch while the second band is determined with the second iteration. The most important feature is that the second band is independent of the first band and is simply tuned which is a challenge in dual band filters. A precise analysis of operation of the filter is presented. The measured results of the filter have good agreement with the full-wave simulated results.
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  • Bobae Kim, Kwangchan Lee, Jongsoo Lee
    2010 Volume 7 Issue 3 Pages 159-164
    Published: 2010
    Released: February 10, 2010
    JOURNALS FREE ACCESS
    This paper presents the effect of different bias circuits configurations on the noise performance of GaAs HBT (heterojunction bipolar transistor) power amplifiers at the receiver band. Various bias circuits have been used for the power amplifier in an WCDMA (wideband code division multiple access) transmitter module including the output duplexer at PCS band (Tx: 1850 ∼ 1910MHz, Rx: 1930 ∼ 1990MHz). A bias circuit with cascode current mirrors for the 1st and the 2nd stages shows less than -180dBm/Hz receiver band noise with -39dBc of ACPR (adjacent channel power ratio) at 25.2dBm antenna output power.
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  • Shoichi Tanifuji, Tuan Thanh Ta, Suguru Kameda, Tadashi Takagi, Kazuo ...
    2010 Volume 7 Issue 3 Pages 165-169
    Published: 2010
    Released: February 10, 2010
    JOURNALS FREE ACCESS
    In this paper, low phase noise 5GHz oscillator is presented. This oscillators designed with 90nm silicon complementary metal oxide semiconductor (Si-CMOS) process. To achieve low phase noise, we used high Q value film bulk acoustic resonator (FBAR) instead of conventional LC resonant circuit. This FBAR oscillator has phase noise of lower than -130dBc/Hz at 1MHz offset.
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  • Yong-Ho Yoo, YoonSang Kim, Sang-Youn Kim
    2010 Volume 7 Issue 3 Pages 170-176
    Published: 2010
    Released: February 10, 2010
    JOURNALS FREE ACCESS
    This paper presents a unified haptic modeling method for physical systems irrespective of their types. Previously, we have proposed an energy-based approach which haptically renders rigid and deformable objects without reference to their material. However, it is not easy to represent the haptic behavior of a fluid or fluid-deformable object with the previously proposed method because there is no method for handling fluid objects and no additional interface between a fluid object and the other objects. Therefore, this paper proposes a modeling framework in which rigid, deformable, and fluid objects are represented by one modeling method.
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  • Chanyong Jeong, Young-Jae Min, Soo-Won Kim
    2010 Volume 7 Issue 3 Pages 177-183
    Published: 2010
    Released: February 10, 2010
    JOURNALS FREE ACCESS
    This letter presents a new two-stage digital I/Q demodulator employing a reconfigurable 16-phase quadrature intermediate frequency (IF) sampling technique for multistandard wireless systems such as mobile TV applications. The proposed two-stage digital I/Q demodulator provides the flexibility for the multiphase scheme such as a quadrature phase shift keying (QPSK) and 16-quadrature amplitude modulation (QAM) at the level of down-mixing, which introduces an efficient architecture for the following decimation filter. In this letter, the prototype chip has been implemented in a 0.18µm standard CMOS technology and occupied with the active chip area of 0.02mm2. The power consumption of the fabricated chip is 0.42mW with a 1.8V supply voltage at the sampling frequency of 26 MHz. The experimental results show that the proposed two-stage digital I/Q demodulator is suitable for multistandard wireless systems which require small silicon area and low power dissipation.
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  • Jun Hasegawa, Tetsuya Yagi
    2010 Volume 7 Issue 3 Pages 184-189
    Published: 2010
    Released: February 10, 2010
    JOURNALS FREE ACCESS
    In this paper, a real-time simulation of neural activities of the retinal circuits during fixational eye movements is presented. The fixational eye movements were emulated using a digital logic circuit implemented on a field-programmable gate array (FPGA) chip and installed on a previously designed retina emulator that consists of 96 × 96 pixels of photodiodes with double-layered resistive networks and a digital computer. The emulated eye movements well reproduced the temporal properties of the drift component of fixational eye movements. The system developed in the present study can emulate retinal responses to natural scenes during fixational eye movements, and it can be used to realistically and effectively analyze the visual functions of the retina.
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  • Anh Tuan Phan, Ronan Farrell
    2010 Volume 7 Issue 3 Pages 190-196
    Published: 2010
    Released: February 10, 2010
    JOURNALS FREE ACCESS
    This paper presents a DC-11GHz CMOS low noise amplifier (LNA) for software-defined radio (SDR). The broadband performance is extended to cover the spectrum from near DC to 11GHz by adopting extra inductors with modified resistive feedback, folded current reuse topology. Bandwidth extension is proposed by inserting pole splitting, interstage and LC ladder inductors. A source follower jointly acts as the buffer stage for broadband output matching and feed-forward path for gain enhancement as well as noise cancellation. Simulation shows power gain of 11 ±4dB and the NF ranging from 1.8 to 3dB in 0.4-11GHz band. The LNA achieves an average IIP3 of -10dBm while consumes only 5.3mW. The proposed broadband LNA is designed in 0.18-µm CMOS process from 1.5V supply.
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  • Takashi Matsuda, Takashi Takeuchi, Takefumi Aonishi, Masumi Ichien, Hi ...
    2010 Volume 7 Issue 3 Pages 197-202
    Published: 2010
    Released: February 10, 2010
    JOURNALS FREE ACCESS
    Network protocols for wireless sensor networks should be evaluated in terms of life time in a whole system. There exists power variation node due to the manufacturing variation. In this paper, we develop a power model, in which we consider threshold-voltage variation. We implement it to QualNet in order to evaluate the impact against a life time. The simulation results show that the conventional model has overestimated the life time longer than our model when nodes are randomly deployed. In addition, the network life time is extended by 19.3% compared with the conventional model by an optimum deployment.
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  • Narges Noori, S. Mohammad Razavizadeh, Alireza Attar
    2010 Volume 7 Issue 3 Pages 203-208
    Published: 2010
    Released: February 10, 2010
    JOURNALS FREE ACCESS
    In this paper, the problem of joint beamforming and power control is studied in the uplink of multiple-input multiple-output (MIMO)cognitive radio networks (CRNs). The objective is maximizing the minimum signal-to-interference-plus-noise ratio (SINR) of the secondary users (SUs). The CRN consists of a cognitive radio-base station (CR-BS) and a number of SUs. The proposed scheme uses genetic algorithm (GA) to solve the optimization problem by considering both the quality of service (QoS) constraints of the primary network and the maximum transmission power constraints of the CRN.
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  • Mehdi Sedighi, Sam Farrokhi
    2010 Volume 7 Issue 3 Pages 209-215
    Published: 2010
    Released: February 10, 2010
    JOURNALS FREE ACCESS
    Significant efforts have been put into optimization of GALS systems by considering locally synchronous modules as individual and independent islands of circuits. While existing approaches do improve some of the system characteristics, due to their limited scope, their achieved improvement is often limited too. This paper proposes an optimization approach in which a GALS system is optimized as a whole. The approach allows combinational or sequential sub-modules to move from one synchronous module to another while preserving the GALS system functionality. Experimental results show that if the movements are done properly, the proposed approach provides better results than the existing methods. The application of the proposed approach on benchmark circuits demonstrates 15.8% latency reduction with 3.3% area overhead in average.
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  • Yohei Sakamaki, Yusuke Nasu, Toshikazu Hashimoto, Kuninori Hattori, Ta ...
    2010 Volume 7 Issue 3 Pages 216-221
    Published: 2010
    Released: February 10, 2010
    JOURNALS FREE ACCESS
    We describe a technique for reducing the wavelength-dependent phase-difference deviation between in-phase and quadrature components in an 90° optical hybrid consisting of four 3-dB couplers and a phase shifter. We fabricated the 90° hybrid with our proposed technique, which uses silica-based planar lightwave circuit technology. The fabricated 90° hybrid exhibits a low phase-difference deviation from 90° of less than 0.7° over the C- and L-bands, and will be useful in a digital coherent receiver for transmission systems operating at 100Gbit/s or more.
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  • N. Kuga, K. Nemoto
    2010 Volume 7 Issue 3 Pages 222-227
    Published: 2010
    Released: February 10, 2010
    JOURNALS FREE ACCESS
    To provide a cost-effective low-PIM termination for impedance-matched PIM measurement systems, the design method of the termination using a high-PIM termination and linear attenuator is proposed. The validity of the concept is confirmed using a resistive termination and long semirigid cable as linear attenuator by experiment in 2GHz band. The result shows that a typical microwave resistive termination which has not been used in conventional PIM measurements is available as low-PIM termination using the proposed method. It is demonstrated that the method provides a cost-effective low-PIM termination.
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