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Comparison of amplitude-optimised bit-edge equalisation with pulse-width modulation in high-speed wireline application

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ELECTRONICS LETTERS 2009年第3期45卷 189-191页

作者： Zhang, L. Kwasniewski, T. Carleton Univ Dept Elect Ottawa ON K1S 5B6 Canada

An amplitude-optimised bit-edge equalisation (BEE) scheme is presented and compared with pulse-width modulation for mitigating intersymbol interference in high-speed backplane applications. With transmitter pre-coding and pre-emphasis, this BEE uses an adaptive LMS algorithm as a receiver error convergence engine by adjusting error derivation points. The optimality of the proposed BEE scheme is discussed.

关键词： TELECOMMUNICATION MOTHERBOARDS (Microcomputers) pulse-width modulation pulse modulation (Electronics) RADAR transmitters

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Absolute phase retrieval for defocused fringe projection three-dimensional measurement

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OPTICS COMMUNICATIONS 2014年 312卷 302-311页

作者： Zheng, Dongliang Da, Feipeng Southeast Univ Sch Automat Nanjing 210096 Jiangsu Peoples R China Southeast Univ Key Lab Measurement & Control Complex Syst Engn Minist Educ Nanjing 210096 Jiangsu Peoples R China

Defocused fringe projection three-dimensional technique based on pulse width modulation (PWM) can generate high-quality sinusoidal fringe pattet ns. It only uses slightly defficused binary structured patterns which can eliminate the gamma problem (i.e. nonlinear response), and the phase error can be significantly reduced. However, when the projector is defficused, it is difficult to retrieve the absolute phase from the wrapped phase. A recently proposed phase coding method is efficient for absolute phase retrieval, but the gamma problem leads this method not so reliable. In this paper, we use the PWM technique to generate fringe patterns for the phase coding method. The gamma problem of the projector can be eliminated, and correct absolute phase can be retrieved. The proposed method only uses two grayscale values (O's and 255's), which can be used for real-Lime 3D shape measurement. Both simulation and experiment demonstrate he performance of the proposed method. (c) 2013 Elsevier B.V. All rights reserved

关键词： Three-dimensional measurement Fringe projection Absolute phase retrieval pulse-width modulation

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High-harmonic-generation spectroscopy is extended to new types of molecules

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LASER FOCUS WORLD 2014年第2期50卷 29-+页

作者： McGrath, Felicity Siegel, Thomas Austin, Dane Marangos, Jon Univ London Imperial Coll Sci Technol & Med Quantum Opt & Laser Sci QOLS Grp London England Univ London Imperial Coll Sci Technol & Med Dept Phys London England

High-order harmonic generation, a revolutionary tool for studying electronic and nuclear dynamics and molecular structure, is now being extended to new molecular species by optimizing pulse-duration diagnostics and pu... 详细信息

关键词： Technological innovations Harmonic generation Atomic spectroscopy Electronic structure Dynamics pulse-width modulation pulse compression (Signal processing) Diatomic molecules

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Stabilization of unstable vertical position of plasma in T-15 tokamak. II

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AUTOMATION AND REMOTE CONTROL 2014年第9期75卷 1565-1576页

作者： Mitrishkin, Yu V. Kartsev, N. M. Zenkov, S. M. Russian Acad Sci Trapeznikov Inst Control Sci Moscow Russia

The paper is devoted to the development and mathematical modeling of a stabilization system for unstable vertical plasma position in a T-15 tokamak (Institute of Tokamak Physics, NSC "Kurchatov Institute"). In the second part of the work, we give a comparison of linear systems for stabilization of vertical plasma position for two versions of the location of the fast coil for the T-15 tokamak's horizontal magnetic field (HFC-coil): a) between the toroidal coil and vacuum vessel, b) inside the vacuum chamber. We estimate parameters for control systems with impulse actuator in the pulse-duration modulation mode and relay mode. Our studies were done on a linear model of plasma in the T-15 tokamak obtained by linearizing the plasma-physical DINA code on the quasistationary stage of the discharge.

关键词： TOKAMAKS PLASMA confinement devices pulse-width modulation TOROIDAL magnetic circuits TRANSFER functions (Mathematics) MATHEMATICAL models

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Microsatellite Attitude Determination and Control Subsystem Design and Implementation: Software-in-the-Loop Approach

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MATHEMATICAL PROBLEMS IN ENGINEERING 2014年第1期2014卷 1-12页

作者： Shou, Ho-Nien Air Force Inst Technol Dept Aviat & Commun Elect Kaohsiung 820 Taiwan

The paper describes the development of a microsatellite attitude determination and control subsystem (ADCS) and verification of its functionality by software-in-the-loop (SIL) method. The role of ADCS is to provide attitude control functions, including the de-tumbling and stabilizing the satellite angular velocity, and as well as estimating the orbit and attitude information during the satellite operation. In Taiwan, Air Force Institute of Technology (AFIT), dedicating for students to design experimental low earth orbit micro-satellite, called AFITsat. For AFITsat, the operation of the ADCS consists of three modes which are initialization mode, detumbling mode, and normal mode, respectively. During the initialization mode, ADCS collects the early orbit measurement data from various sensors so that the data can be downlinked to the ground station for further analysis. As particularly emphasized in this paper, during the detumbling mode, ADCS implements the thrusters in plus-wide modulation control method to decrease the satellite angular velocity. ADCS provides the attitude determination function for the estimation of the satellite state, during normal mode. The three modes of microsatellite adopted Kalman filter algorithm estimate microsatellite attitude. This paper will discuss using the SIL validation ADCS function and verify its feasibility.

关键词： ARTIFICIAL satellite attitude control systems COMPUTER software pulse-width modulation ANGULAR velocity KALMAN filtering

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A Cascaded Multi-level Inverter Topology with Improved modulation Scheme

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ELECTRIC POWER COMPONENTS AND SYSTEMS 2014年第7期42卷 768-777页

作者： Odeh, Charles Ikechukwu Univ Nigeria Dept Elect Engn Nsukka 410 Nigeria

This article proposes a single-phase, cascaded multilevel inverter topology. Each of the cascaded unit cells is made up of a main inverting H-bridge leg and a level-clamping half-bridge circuit. The single-carrier, multilevel pulse-width modulation scheme is employed to generate gating signals fort he power switches. The modulation scheme is hybridized to enable the output voltage of the proposed inverter configuration, inherit the features of switching-loss reduction from fundamental pulse-width modulation, and good harmonic performance from multiple sinusoidal pulse-width modulation. A sequential switching scheme is embedded with the already employed hybrid modulation to overcome unequal switching losses among the power devices. A simple base pulse-width modulation circulation scheme is also introduced in this work to get resultant sequential switching hybrid pulse-width modulation circulation that balances power dissipation among the power modules. The proposed inverter configuration was subjected to a resistor-inductor load, and the respective numbers of output voltage level were synthesized. Fast Fourier transform (FFT) analyses of the output voltage waveforms were carried out. Analysis of the conduction power losses in the power semiconductor switches of the proposed inverter topology is given. Simulations and experiments are carried out on a 3.07-kW rated prototype of the proposed inverter for a resistor-inductor load.

关键词： switching loss pulse-width modulation multi-level inverter H-bridge

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On re-examining symmetry of two-level selective harmonic elimination PWM: Novel formulations, solutions and performance evaluation

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ELECTRIC POWER SYSTEMS RESEARCH 2014年第Mar.期108卷 185-197页

作者： Konstantinou, G. Agelidis, V. G. Univ New S Wales Australian Energy Res Inst Sydney NSW 2052 Australia Univ New S Wales Sch Elect Engn & Telecommun Sydney NSW 2052 Australia

This paper analyzes the half-wave symmetrical two-level SHE-PWM, proposes two formulations of the SHE-PWM waveform with multiple solutions and evaluates the solutions for different cases of eliminated harmonics. Previous work on SHE-PWM focused on algorithms for calculating the solutions and only considered the quarter-wave symmetry in the formulation. In this paper two different formulations to the problem are considered and solutions for a number of eliminated harmonics are presented. The different formulations increase the solution space of the problem and the number of acquired solutions. A comparison of the solutions in terms of harmonic performance is also presented. When compared with the quarter-wave symmetrical solutions, certain half-wave symmetrical solutions exhibit better performance and additional benefits can be acquired for two-level converters operated under SHE-PWM techniques. The HW symmetrical solutions are experimentally verified on a laboratory setup in order to confirm the validity of the solutions sets. (C) 2013 Elsevier B.V. All rights reserved.

关键词： Selective harmonic elimination Two-level converter pulse-width modulation Half-wave symmetrical PWM Power electronics

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A Multireceiver Null Microwave Radiometer with Prompt Regulation of the Measurement Range

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INSTRUMENTS AND EXPERIMENTAL TECHNIQUES 2014年第3期57卷 300-306页

作者： Filatov, A. V. State Univ Control Syst & Radio Elect Tomsk 634050 Russia

A multireceiver null radiometer, into which functions for prompt tuning to different measurement ranges are introduced taking nonidealities of the microwave components that are included in the input unit into account, is described. A simple algorithm of the radiometer calibration process is considered, which is automatically performed in all receivers under the control of a microcontroller. An expression is derived that establishes the relationship between the measured antenna signal and the duration of a pulse that controls the pulse-width modulation.

关键词： MICROWAVE radiometers CALIBRATION MICROCONTROLLERS pulse-width modulation ALGORITHMS ELECTRONICS ELECTROSTATICS

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Vibration of FG nanobeams induced by sinusoidal pulse-heating via a nonlocal thermoelastic model

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ACTA MECHANICA 2014年第12期225卷 3409-3421页

作者： Zenkour, Ashraf M. Abouelregal, Ahmed E. King Abdulaziz Univ Fac Sci Dept Math Jeddah 21589 Saudi Arabia Kafrelsheikh Univ Fac Sci Dept Math Kafr Al Sheikh 33516 Egypt Mansoura Univ Fac Sci Dept Math Mansoura 35516 Egypt

The vibration of functionally graded (FG) nanobeams subjected to a sinusoidal pulse-heating source is investigated. Material properties of the nanobeam are assumed to be graded in the thickness direction according to a novel exponential distribution in terms of the volume fractions of the metal and ceramic constituents. The upper surface of the FG nanobeam is pure ceramic, whereas the lower surface is pure metal. The generalized nonlocal thermoelasticity model based on Lord and Shulman's theory is used to solve this problem. An analytical technique based on Laplace transform is used to calculate the vibration of deflection and temperature. The inverse Laplace transforms are computed numerically using Fourier expansion techniques. A comparison between the obtained results from the nonlocal theory and those from the local theory of coupled thermoelasticity is presented. The effect of the nonlocal parameter, the pulse width of the sinusoidal pulse, is studied on the lateral vibration, the temperature and the displacement of the nanobeam. Additional results across the thickness of the nanobeam are presented graphically.

关键词： FUNCTIONALLY gradient materials VIBRATION (Mechanics) THERMOELASTICITY pulse-width modulation TEMPERATURE effect

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Field programmable gate array implementation of variable common mode injection PWM for three-level inverters

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COMPUTERS & ELECTRICAL ENGINEERING 2014年第4期40卷 1238-1252页

作者： Nageswari, S. Kumar, V. Suresh AC Coll Engn & Technol Dept Elect & Elect Engn Karaikkudi Tamil Nadu India Thiagarajar Coll Engn Dept Elect & Elect Engn Madurai Tamil Nadu India

This paper proposes implementation of variable common mode injection pulse width modulation (VCMIPWM) scheme using field programmable gate array (FPGA) for three-level inverters. The waveform quality of the inverter output can be improved using suitable PWM control technique. Optimal harmonic profile may be obtained by centring the middle space vectors in a switching cycle. If the expression of common mode voltage calculated for two-level inverter is applied to multilevel inverter, the middle vectors may not be centred. So, the harmonic performance is poor. There is a need to calculate the amount of common mode injection required to centre the middle space vectors in a switching cycle. The amount of common mode injection depends on the magnitude of the reference vectors. The common mode voltage is calculated for various cases and is injected with the sinusoidal reference vector to produce modified reference vectors. Harmonic performance of fixed common mode injection pulse width modulation (FCMIPWM) and VCMIPWM has been compared with the existing sinusoidal PWM (SPWM). In order to make use of the theoretical advantages of the VCMIPWM, this paper proposes the implementation of this PWM using FPGA. Simulation and experimental results are presented in this paper. (C) 2013 Elsevier Ltd. All rights reserved.

关键词： FIELD programmable gate arrays pulse-width modulation ELECTRIC inverters VHDL (Computer hardware description language) COMPUTER simulation ALGORITHMS

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