Table of Content

15 March 2010 Volume 23 Issue 3

  

Articles

Study of Inhomogeneous Spatial Distribution of Scattering Light Intensity

LIU Huan-Huan, CENG Xiao-Dong, CHENG Yin, FU Chao

. 2010, 23(3):  1. 

Abstract ( 1708 )   PDF (514KB) ( 2498 )  

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Derived from the wave equation and the principle of acoustooptic frequency shifter,coupledwave equations of Bragg acoustooptic interaction are obtained,on the basis of a model of the acoustic field which is built in view of the finite size of acoustooptic crystal.The spatial threedimensional distribution of scattering field is analyzed with finite difference method.It is shown that the diffractive light intensity will be influenced by the inhomogeneous distribution of acoustic amplitude.

Background Suppression for the Infrared Image Using the Local Structure Tensor

HU Hui-Ling, QIN Han-Lin, BAI Li-Ping, ZHOU Hui-Xin

. 2010, 23(3):  4. 

Abstract ( 2331 )   PDF (409KB) ( 2465 )  

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A background suppression algorithm for the infrared image based on the local structure tensor is presented,which combines the local structure tensor and bilateralfiltering.In the algorithm,the standard derivative of the local structure tensor is used as the criterion for whether the bilateralfiltering is executed,and the weighed coefficient with bilateralfiltering is adopted to achieve background estimation.The structured background suppression and the targetsignal enhancement are fulfilled.Experimental results show that the presented algorithm achieves better background suppression than the partial differential equation method and the twodimensional LMS filter.

Investigation of Generation of Terahertz with the Photoconductor Triggered by the Femo Second Laser Pulse

XIAO Jian, GAO Ai-Hua

. 2010, 23(3):  7. 

Abstract ( 1610 )   PDF (461KB) ( 2353 )  

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The terahertz (THz) radiation properties of the photoconductive antenna (PCA) are studied in order to improve the THz radiation efficiency.Maxwells equations and boundary conditions are adopted to calculate the field intensity of the near or far field.Using the finitedifference timedomain electromagnetic method and c language program in the matlab software,the spatial electromagnetic field distribution radiation of photoconductive dipole antenna is calculated and displayed on the computer in a pseudocolor graph.The visualization of the electromagnetic field provides a physical basis for the intuitive design and improvement of the antenna.

Effect of Fluctuation of Stochastic Phases on Coherent Laser Beam Combining

LIAN Tian-Gong, WANG Dan-Yu, GUO Zhen, LI Bing-Bin

. 2010, 23(3):  10. 

Abstract ( 1967 )   PDF (588KB) ( 1810 )  

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Based on the model of Gaussian beams with hexagonal distribution,the coherent combining intensity is calculated,and the effect of the fluctuation of stochastic phases on coherent combined intensity is analyzed.The propagation property of the combined beam is also studied.A conclusion is drawn that the effect of the fluctuation of stochastic phases is the main factor influencing the intensity and the propagation of the combined beam and that the coherent combination becomes incoherent combination when the deviation of the fluctuation of stochastic phases is greater than 20.

Study of TWAINbased CharacterImage Collection

ZHANG Shao-Hui, HUANG Xiang-Nian, BO Xiang, LIU Qin

. 2010, 23(3):  14. 

Abstract ( 1829 )   PDF (330KB) ( 1768 )  

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In the process of character recognition,wordimage collection is a very important step.In order to collect images efficiently with a good quality from external physical equipment and process them directly,this paper introduces the basic principles and working process of TWAIN,describes the wide application prospects of TWAIN and the advantages of using TWAIN to develop the scanner driver.The VC++ program is used to achieve the collection of character images on the scanner based on TWAIN.The experimental results show that the procedure by the TWAIN standard meets the expected requirements.

Design and Implementation of Configurable FFT/IFFT in WIMAX System

LIU De-Fu, LEI Tian-Min, MA Zhuo

. 2010, 23(3):  17. 

Abstract ( 2136 )   PDF (403KB) ( 2125 )  

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A variablepoint FFT/IFFT is proposed in consideration of the characteristics of the variablelength subcarrier in WIMAX system.A high speed and configurable FFT/IFFT is designed by using the mixed radix with radix2,radix4 based on pipelined pingpong architecture.It saves storage space since all the twiddle factors are stored in the same space and RAM is optimized.Furthermore,radix4 butterfly processor is optimized for reducing adder and multiplying unit.The simulation results show that the design proposed meets the needs of FFT/IFFT for different bandwidth in highspeed WIMAX system.

Generation Method about Pseudo Random Sequence of Optional Cycle Based on DSP

DU Yun-Feng, LI Meng

. 2010, 23(3):  20. 

Abstract ( 2149 )   PDF (379KB) ( 4115 )  

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In many projects,it is a great advantage for designing and debugging systems to generate the pseudo random sequence by DSP.Based on the analysis of the linear congruential generator and TigerSHARC20XS of ANALOGDEVICES,this paper presents a method for generating the pseudo random sequence in optional cycle by addressing the sequence of descending length.Compared with traditional methods,the new method,which is innovative in optional cycle,solves the problem that the pseudo random sequence can only be in a fixed cycle of 2n(1≤n≤32) using DSP in traditional methods and is of value in the transmission of communication and antijamming of the frequency hopping radar.

Barcode Image Acquisition System Based on CIS and ARM9

XIA Zhen-Chun, DING Wan-Shan

. 2010, 23(3):  23. 

Abstract ( 2462 )   PDF (580KB) ( 2552 )  

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A barcode image acquisition system based on the contact image sensor which realizes dynamic adjustable image resolution is introduced.It uses CIS to achieve line scanning and completes image acquisition with a platform composed of the optical rotary encoder and reducing motor.It can adjust scanning length dynamically according to the barcode size to reduce the acquisition of useless information.This system can be widely applied in barcode recognition and serial number recognition and other situations and greatly improve the identification efficiency.

Implementation of Acquisition of the PNCode of DS Based on FPGA

JI Jie-Xian

. 2010, 23(3):  26. 

Abstract ( 2608 )   PDF (548KB) ( 2623 )  

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By analyzing the operational principle of PNCode acquisition and comparing traditional classical methods,a bunching and combining PNCode acquisition project of good performance and easy implementation is designed.A circuit of PNCode acquisition which is successfully applied in practice is given.The performance simulation results of the PNCode acquisition is given by modelsim.

The Design and Realization of the Data Sampling Board

DING Hai-Feng, ZHANG Zhi-Jiang, DIAO Jian-Cheng, NI Chao

. 2010, 23(3):  30. 

Abstract ( 2426 )   PDF (797KB) ( 3093 )  

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With the development of modern radar,the data sampling board used as the receiver of a system of radar signal processing must face the increasingly high requirements,and guarantee the reliability of posterior signal processing.The data sampling board is designed specially,which improves the generality and shortens the time for design,so that it has become the development trend of signal processing system design.This paper adopts FPGA and ADC to design a data sampling board for signal processing based on the CPCI Bus,which accomplishes eight channels of IF signal sampling and processing,and has been used in some radar systems.

Design and Realization of the Voice Recognition System for the Remote Distance Control Robot

LI Jia-Wang

. 2010, 23(3):  34. 

Abstract ( 1659 )   PDF (715KB) ( 1472 )  

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Based on the popular technique of speech recognition,this paper describes the communication of the server with the client and the use of the microphone to control the longdistance robots arm to finish all sorts of actions.Experimentation validates the accuracy and realtimeness of the motion of the intelligent robot remotely controlled by voice.

Simulation of Typical Physical Effects of the Infrared Imaging Sensor Based on OGRE

WANG Bo, HUANG Xi

. 2010, 23(3):  36. 

Abstract ( 2083 )   PDF (1211KB) ( 2799 )  

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Vignetting,spatial filtering,and nonuniformity introduced in the infrared imaging sensor are modeled,by the pixel processing method and modulation transfer function (MTF) respectively.On the basis of the above physical effects model,their corresponding textures are generated by adopting the texture generator.Finally,these physical effects texture are sampled and postprocessed through the OGRE rendering engine,and highspeed realtime physical effect rendering are implemented.

A Segmentation Method for the Missing Component of the PCB Board

ZHONG Wei-Quan, DENG Ji-Zhong, HE Fu-Chang, ZHONG Quan

. 2010, 23(3):  40. 

Abstract ( 1714 )   PDF (501KB) ( 1609 )  

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The traditional OTSU threshold method can detect effectively the gray images that have clear valley and twopeaks,but for the images that have clear twopeaks and an unclear valley,OTSU could not separate the target with the background easily due to the misjudgment of the target or background.Given the missing component of the PCB board,an improved OTSU threshold method based on the RGB color characteristics in the backlight condition is put forward.The result is superior to the traditional OTSU segmentation method.

Image Segmentation and Recognition Algorithm for the Fire Cannons Jet Trajectory

CHEN Jing, DIAO Min

. 2010, 23(3):  43. 

Abstract ( 1865 )   PDF (577KB) ( 1358 )  

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A segmentation and recognition algorithm based on the improved OSTU method and region growing is proposed for the fire cannons jet trajectory image.First,the method of OSTU is improved to obtain the optimal segmentation threshold of jet trajectorys difference image quickly.Then,the possible target areas are segmented by the region growing method.On the basis of indepth research on and analysis of jet trajectorys shape features,the real jet trajectory is identified from the possible target areas.The experimental results show that in the case of different lighting conditions and complex backgrounds,the method presented in this paper can eliminate the interference and identify the target accurately with a high processing speed.

Networked Electronic Load Monitor Controlling System Based on ARM

SUN Meng-Yu, ZHAO Min, TUN Yi-Jie, GU Jun-Jun

. 2010, 23(3):  46. 

Abstract ( 2465 )   PDF (552KB) ( 2172 )  

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A networked electronic load monitor controlling system based on ARM has been designed.The structure and composition of the embedded system hardware which uses Samsung s3c2440 as the core chip is described.To realize the connectivity between the RS232 bus and Ethernet the visual communication control software is developed by using Embedded VC++ based on Windows CE which is adopted as the platform of embedded system.Delphi is used as a development tool to design electronic load monitoring software on PC in order to achieve such functions as remote monitoring,multiple load control,data acquisition and analysis.

A Model for Ionizing Radiation Damage Correlating with Noise in Optoelectronic Coupled Devices

LIN Li-Yan, DU Lei, BAO Jun-Lin, HE Liang

. 2010, 23(3):  50. 

Abstract ( 1664 )   PDF (279KB) ( 1397 )  

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Defects generated by ionizing radiation damage in optoelectronic coupled devices(OCDs) is the origin of noise.Based on a summary of the noise mechanism in OCDs,a model of ionizing radiation damage correlating with 1/f noise in OCDs has been established.The experimental results agree well with the proposed model.The model analyzes the mechanism and provides the noise representation theory for ionizing radiation damage in OCDs.

The Digital Filter Separation Technology for Communication Signals Based on FPGA

SUN Jie, FENG Xiao-Ping, CUI Yu-Jiao

. 2010, 23(3):  53. 

Abstract ( 1827 )   PDF (614KB) ( 2481 )  

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Based on the background of the modern software wireless channeled theory and FPGA technology,this paper makes a study of the digital filter separation technology for communication signals.It is proposed that the function of the digital signal filtering separation be realized for the filterbank by a discrete Fourier transform (DFT).In the realization of DFT,the fast Fourier transform (FFT) is applied,Verilog HDL is used as a carrier and a modern FPGA tool——the ModelSim software is employed to realize the required DFT efficiently.Finally the test of DFT shows that it can realize the desired function.

Design of a GPS receiver Low Noise Amplifier

SHI Chao, SUN Bao-Hua, WEI Yun-Fei, ZHU Cheng

. 2010, 23(3):  56. 

Abstract ( 2069 )   PDF (449KB) ( 3243 )  

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A GPS receiver low noise amplifier is presented.Using the chip of Agilent EPHEMT ATF54143,the proposed low noise amplifier is built based on the method of lumped component matching network.With the optimized parameters simulated by Agilent ADS,the prototype of the proposed amplifier is constructed on a PTFE and measured.Over the whole operating frequency range (1 520-1 600 MHz),the measured results explore favorable operation with a low noise figure of less than 05 dB,gain of higher than 16 dB,good input VSWR of less than 2 and output VSWR of less than 15.It shows good agreement with the simulation results.

Study and Realization of a Signal Generator Based on the DDS Technology

HU De-Zhi, DING Cai-Cheng

. 2010, 23(3):  59. 

Abstract ( 2510 )   PDF (277KB) ( 3380 )  

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The basic principle of the DDS technology is introduced,on the basis of which a signal generator system is realized,using a single chip machine AT89S52 to control the AD9850 chip.The results of theoretical analysis and experiments show that the system can produce sine wave,triangular wave and square wave,of which the amplitude and frequency can be adjusted.The output signal has a wide frequency band,high precision and high stability.

Effects of Metal Components on Internal Planar Monopole Antenna Performance

HUANG Hong-Chun

. 2010, 23(3):  62. 

Abstract ( 1365 )   PDF (324KB) ( 2214 )  

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A conventional planar monopole antenna is presented,and the effects on its performance of the relative position of the antenna to the metal components (speaker and battery) in a folded cell phone.HFSS optimetrics are used to find the optimal location of metal components based on effects of battery and speaker on resonation frequency,bandwidth and gain of internal planar monopole antenna.Simulation results are validated by real model test.

Application of Underrate Sampling and ZOOMFFT in Frequency Shift Detection

YUAN Wei, SUN Jing-Feng, FAN Wen-Xia

. 2010, 23(3):  65. 

Abstract ( 2336 )   PDF (434KB) ( 2975 )  

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Frequencyshift keying signal detection needs a relatively high frequency resolution.With the limit to the detection equipment memory and FFT calculated length in the detection algorithm,the useful frequency band needs to be selected and partially analyzed if we want to obtain a higher frequency resolution.This paper combines the underrate sampling technology and the spectrum refining technology,and simulates and verifies the detection algorithm of the homemade 18 information track circuit frequency shift signal based on the software Matlab.The simulation shows that the detection algorithm is totally feasible.This offers a method of direction for designing the track circuit frequency shift signal detection instruments.

Design and Realization of Radar Echo Realtime Simulating Means

LIU Peng, WANG Wei, YANG Ying-Ke, YANG Pei

. 2010, 23(3):  68. 

Abstract ( 1606 )   PDF (398KB) ( 1613 )  

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The Design method for a realtime radar echo simulators realization at intermediate frequency is introduced.The function of the radar echo simulating system and the relation of the radar with other systems are discussed in detail.The main mathematical model of the simulating system is given,and the application effect of the radar echo realtime simulating method is validated with an instance.

Collision Avoidance Radar for the Vehicles Based on the Theory of Highresolution Distance Estimation

ZHAO Shu-Tian, PENG Hao

. 2010, 23(3):  71. 

Abstract ( 1734 )   PDF (210KB) ( 2008 )  

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The highresolution Fourier transform method is adopted to make precise location estimation of the adjacent vehicles.Compared with the classical spectrum methods,the proposed method avoids the complex matrix computational load during the distance estimation,which can ensure the precise estimation via the iterative procedure.Since this method,which is only the expansion of the Fourier transform,can be easily realized,it can achieve the realprocess effect in the vehiclecarried system.The simulation experiments show the validity of the proposed method.

A New CFAR Detector Based on the Cell Approach

MA Jian, XU Yun-Shan

. 2010, 23(3):  73. 

Abstract ( 1419 )   PDF (213KB) ( 1680 )  

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A new CFAR detector based on censored mean (CM) and cell average (CA) is proposed.It uses the CM and CA estimations to produce local estimation,and compares the two local estimations with the detective cell,and then takes the local estimation which approaches the detective cell as a clutter power estimation.The analytic expressions of probability of false alarm and probability of detection are derived under Swerling Ⅱ and Gaussian clutter assumption.

Analysis of the Estimation of DOA for the MIMO Radar

WANG Yan-Peng, ZHANG Zhi-Bin, CHEN Juan, YANG Xiao-Yu

. 2010, 23(3):  76. 

Abstract ( 2066 )   PDF (587KB) ( 26113 )  

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A MUSIC algorithm,which is used to estimate the target direction of arrival of the MIMO radar is given on the basis of the signal model of the MIMO radar.Compared with the traditional phased radar,we can detect more targets with the MUSIC algorithm in the estimation of DOA in MIMO radar systems.Through computer simulation,this paper analyzes the factors influencing the precision in the estimation of the target direction of arrival by the MUSIC algorithm.

Research on the Discrimination of the Ballistic targets Based on MicroDoppler analysis

LIU Xi-Feng, LI Meng, DU Yun-Feng

. 2010, 23(3):  81. 

Abstract ( 1616 )   PDF (597KB) ( 1760 )  

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The characteristic in targets microdoppler that derives from the micromotion of the target is generally unique.Consequently,it can be utilized to automatic target recognition and classification.In this work,based on the principle of microdoppler,the mathematical model between missile and decoy is constructed,and characteristics in microdoppler are analyzed through simulation,thus distinguishing the target from heavy decoys and the missile.It offers a new reassuring way to the discrimination of the real or false targets.

Calculation of Effective Numbers of Bits for the Analogtodigital Converter

ZHANG Zhi-Jiang, RUAN Li-Ting, NI Chao, DIAO Jian-Cheng

. 2010, 23(3):  84. 

Abstract ( 2371 )   PDF (197KB) ( 6409 )  

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It is a common practice to convert analog signal to digital signal before signal processing.Analogtodigital converter (ADC) is very important in digital signal process board,so calculation of the effective numbers of bits (ENOB) is of great importance for evaluation of system performance.Two testing methods of ENOB,namely noise testing method and SNR testing method,are discussed in this paper,both are then simulated and analyzed.

Design and Analysis of a Novel Triaxis Capacitive Accelerometer

WANG Shou-Meng, HONG Jie-Min

. 2010, 23(3):  86. 

Abstract ( 1775 )   PDF (692KB) ( 2749 )  

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A novel concept of the triaxis micro capacitive accelerometer is proposed.This accelerometer consists of two inertial mass blocks to detect the horizontal and vertical acceleration simultaneously.The asymmetrical comb removes the vertical interference with the horizontal acceleration from the zaxis and the support of the beam of the zaxis significantly minimizes the coupling from the lateral acceleration.In order to improve the detection performance of the accelerometer,differential capacitance is proposed.Static and modal analysis with Ansys verifies the feasibility of the structure in theory.

DSP Algorithm and the Implementation of the Digital AM Demodulator

DIAO Xiao-Yan

. 2010, 23(3):  90. 

Abstract ( 2193 )   PDF (400KB) ( 4231 )  

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The AM demodulator generally uses an envelope detector composed of analog components,and is therefore unstable and difficult to implement.This paper uses the digital Hilbert filter to realize a digital envelope detector based on the principle of the equivalent lowpass representation of the bandpass signals,and implements soft debugging in CCS.In the course of the implementation,LinkforCCS and DSPLIB are utilized not only to reduce the time of development but also to improve the efficiency of the algorithm.

 

One of the Web Service Key Technologies——SOAP Protocol

ZHANG Xian-Wei, ZHANG Jing

. 2010, 23(3):  93. 

Abstract ( 1619 )   PDF (404KB) ( 1997 )  

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The Web service represents a new generation software framework mode——application of software by the internet framework.Three roles exist in the Web service environment,service provider,service asker and service registry.Corresponding to the Web service are three key technologies:SOAP,WSDL,UDDI.This paper puts emphasis on one of the Web service key technologies——SOAP protocol with its main content,information format and work mechanism as well as some SOAP examples introduced.

The Simulation of Control Systems in the Small World Network

DAI Tu, LI Dun-Min, SUN Yun-Beng

. 2010, 23(3):  97. 

Abstract ( 2042 )   PDF (428KB) ( 1552 )  

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This paper focuses on the work principle and simulation mechanism of Networked Control Systems(NCSs) as well as the implementation process by using a NS2 simulator in the small world network.Given the great programming generality and function extendibility of the NS2 simulator,we realize realtime solution for differential functions of control systems by a programming fashion analogous to C++ in the NS2 simulator.Finally,we present the simulation results.

Design of the Home Security System Based on ADSPBF533

LI Li-Jun, ZHANG Pei, ZHANG Xiao-Xi

. 2010, 23(3):  101. 

Abstract ( 1603 )   PDF (363KB) ( 1714 )  

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Design of the home security system based on ADSPBF533 is described with the system scheme,the design of hardware circuit and the realization of software given in detail.This system is used mainly in the field of home security.Using the technology of infrared detection,GSM wireless communication and video compression based on MPEG4,the system realizes a series of functions,such as infrared detection,GSM alarming,images acquisition and storage etc.

Design of and Research on Payment for Electricity Services through Mobile Phones Based on Mobile Networks

AN Xin

. 2010, 23(3):  104. 

Abstract ( 1421 )   PDF (468KB) ( 1762 )  

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With the current services of mobile operators,the characteristics of mobile phones to pay for electricity services and its processes as the starting point,this paper analyzes the method for the implementation of mobile phones to pay for electricity services through the mobile networks,social benefits,and issues to be addressed after the implementation of the project.

Research on and Prospect of Cooperation Diversity

XING Tian-Zhang, CHEN Tian, BAI Ying-Qi

. 2010, 23(3):  107. 

Abstract ( 2416 )   PDF (207KB) ( 2446 )  

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The general multipleinput multipleoutput system is impractical in the wireless communication terminal due to the distance between the antennas.The cooperation diversity technique enables the single antenna mobiles to share their antennas,so that a virtual multiple antenna system is formed.The basic protocols of cooperation diversity are presented.The new research status is discussed,and some schemes are analyzed.The problems which should be solved in the future are also discussed.