Table of Content

15 November 2011 Volume 24 Issue 11

  

Articles

Research on and Design of a Satellite Communication Umbrella Antenna

GUO Dong-Yang, LI Ping, WANG Yi-Thong, LI Jun-Li

. 2011, 24(11):  1. 

Abstract ( 1398 )   PDF (864KB) ( 826 )  

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With the development of material science,the light,portable and foldable reflector antenna has been gradually popularized and replaced the metal reflector antenna of solid surface on some special occasions.In this paper,MOM and PO methods are used to design an offset reflector antenna with a gain of over 42 dB.The antenna is made from silver fabric,which has good electromagnetic wave reflection,on the basis of an umbrella structure.It provides a good method for the development of light,small,potable reflector antennas.

MIMO Radar Based on Ternary Complementary Sets

FENG Jun-Jie, ZHANG Tai-Rong, LIU Song-Hong

. 2011, 24(11):  3. 

Abstract ( 2157 )   PDF (668KB) ( 863 )  

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Multiple-Input Multiple-output radar uses multiple antennas to simultaneously transmit orthogonal or non-coherent waveforms and uses multiple receiving antennas to receive and separate the reflected signals.Optimization of the transmit signals can improve the performance of the MIMO radar.The binary spread spectrum code is easy to construct,but it has the drawbacks of high cross correlation and auto-correlation sidelobes.Ternary complementary codes,which have better correlation properties and zero range sidelobes,can be used for target imaging.

Design of an Ultra Wideband Radar Pulse Generator

LI Xiu-Gui, NI Yuan

. 2011, 24(11):  6. 

Abstract ( 1945 )   PDF (702KB) ( 2371 )  

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This paper mainly introduces the operating principle of human life detection system using UWB radar,and compares several methods on ultra-short pulses generating.Taking into consideration the avalanche transistor principle,this paper comes up with using the avalanche characteristics of the avalanche transistor to achieve ultra-wideband radar ultra-short pulse generating principle.Through researching and analyzing the typical pulse generating circuit,this paper works out the pulse signal generator circuit on detection system of human life.Experimental simulation results show that:the circuit can generate a pico-second bipolar pulse and peak-up of the narrow pulse can reach up to 2 V.It can meet the micro power impulse radar system which can be applied in the field of life signal detection requirements.

Frequency Refining Technology of Low Frequency Electromagnetic Signals

YANG Yong-Xia, TIAN Guanng-Ping

. 2011, 24(11):  9. 

Abstract ( 1301 )   PDF (755KB) ( 780 )  

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In the low frequency electromagnetic signal,in order to get the fine structure of a certain spectrum within the narrowband,improve the frequency resolution of spectrum,and meet the requirement of good real-timeness,this paper puts forward the frequency refining technology based on the fast Fourier transform algorithm.Through polyphonic system frequency refinement,we amplify a local spectrum to facilitate fast and accurate analysis for the low frequency electromagnetic signal spectrum.Matlab is used for simulation of the low frequency electromagnetic signal by the method of polyphonic system frequency refinement.The simulation results show that this method is more effective and feasible than the Chirp Z transformation algorithm.

Monopulse Radar Target Simulator Based on DDS

XIAO Kai-Jian, JING Wei, XIAO Zhan-Niu, LI Guo-Qing

. 2011, 24(11):  13. 

Abstract ( 1374 )   PDF (481KB) ( 897 )  

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The target simulator can help debug radar system and do operation training.In this paper,we adopt AD9857 to design a monopulse radar target simulator.By using digital intersection,we can obtain the operational parameters of DDS.Then the DDS directly produces the two channel IF (intermediate frequency) signals.We also propose continuous wave correcting and wave storage to solve the sign of the difference pattern.During the development of a radar,the validity of the simulator is validated.

Hardware Design and Implementation of the Signal Processing System in the GPS Adaptive Nulling Antenna

CHENG Zhen, JIA Wei-Jie

. 2011, 24(11):  16. 

Abstract ( 1325 )   PDF (571KB) ( 872 )  

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For GPS interference problems,the common method in the signal processing system is to achieve interference using the adaptive nulling algorithm.This paper presents a signal processing system hardware implementation scheme together with an algorithm.First,the architecture of the GPS nulling antenna is described,then the paper gives the signal processing hardware design ideas and implementation of functional modules.Finally the results of the measured data show that the hardware modules can meet the requirements of the adaptive nulling algorithm.

Research on the Communication System of CAN Multi-point Real-Time Data Based on C8051

PANG Qian-Xiao

. 2011, 24(11):  19. 

Abstract ( 1764 )   PDF (656KB) ( 818 )  

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A communication system of CAN multi-point real-time date based on C8051 is designed to meet the needs of real-time monitoring multiple devices in industry.The system has the features of high-speed,low latency,low error rate and high stability.Compared with the traditional RS232 and 485 communications systems,the system has a unique non-destructive CAN-bus arbitration and message filtering.It makes communication between each device easy and fast.The result shows that the CAN system is better in communications quality than the traditional ones.It can be used for industrial real-time monitoring multiple devices.

Multiple Access Performance Analysis for DFH in AWGN

WANG Ai-Fen, XU Hua, ZHU Li-Li, WANG Rui-Jie

. 2011, 24(11):  22. 

Abstract ( 1258 )   PDF (515KB) ( 793 )  

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This paper presents a new hopping system,which is called the Differential Frequency Hopping(DFH) system.First it introduces the basic theory of the Differential Frequency Hopping(DFH) system,and studies the performance of the Differential Frequency Hopping(DFH) system and DFH networking.The performance in AWGN by using these two methods is analyzed respectively in theory,and the corresponding simulation results are given.Simulation results show that the smaller the number of the system users,a smaller error rate means a smaller interference at the corresponding SN ratio.

Optimal Design of Ku-band Waveguide Duplexer

SHAO Li, KANG Xiao-Ning, ZHANG Hui

. 2011, 24(11):  25. 

Abstract ( 1722 )   PDF (576KB) ( 820 )  

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A Ku-band waveguide duplexer together with the theory of the metal-septum filter is introduced.First,it is divided into two parts for theoretical analysis,the septum part and waveguide resonator part.Then HFSS software is used to optimize it.Finally,the consistence of the measurement obtained from the processed and assembled duplexer with the simulation result indicates that this duplexer has such features as high Q factor and interport isolation,small size,and etc.

RAT Transform Based Multi-LFM Signal Detection and Parameter Estimation

LEI Lei, HAN Hong-Na

. 2011, 24(11):  27. 

Abstract ( 1377 )   PDF (759KB) ( 836 )  

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This paper studies the technology of the correlative dechirp,and analyzes its existing shortcomings.Some differences between Wigner-Ville method and ambiguity function are compared when they are used to analyze the LFM signal.A new algorithm of using RAT transform and fast dechirp is proposed by comparing the difference.Finally we validate the effectiveness of the algorithm through computer simulation.This method solves the shortage of the correlative dechirp and decreases the high computation of the RWT method.It can also solve the problem that the pure RAT method can only estimate the frequency modulation rate.

Research on Low-Voltage Power Line Communication Technology

DING Guan-Jun, LIU Yan, WANG Kai, TIAN Qi, GUO Feng

. 2011, 24(11):  31. 

Abstract ( 1785 )   PDF (822KB) ( 798 )  

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First of all,based on the current major research directions of low-voltage power line communication technology expounded,the paper summarizes the latest research achievements and corresponding schemes of domestic and overseas scholars,including impedance characteristics,noise characteristic,attenuation characteristic of signal and channel models.Secondly,the modulation-demodulation technology of low-voltage power line communication is analyzed emphatically,which is regarded as the research highlight at present and consists of the frequency-hopping modulation/demodulation technology and orthogonal frequency division multiplexing technology (OFDM).Finally,the future research direction and development potential of low-voltage power line communication technology are prospected.

Design and Implementation of Short-wave Frequency Source Based on DDS Device

SHI Hua-Hu, ZHANG Ling-Di

. 2011, 24(11):  36. 

Abstract ( 1404 )   PDF (474KB) ( 732 )  

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The structure and principles of direct digital synthesizer (DDS) are introduced,and key technologies of DDS are introduced into the frequency source.A low noise frequency source based on MCU+new DDS device is designed with a range of frequency of 46.5~75 MHz.Some relevant tests are carried out after the frequency source circuit finished.Experiments show that the frequency synthesizer has the features of precise resolution and low phase turning noise.

Circuit Analysis and Trouble-shooting of the Second Digital Tuner Measuring System DS7720i

HAN Ting, MA Ke-Jian, TAO Mou-Tong

. 2011, 24(11):  39. 

Abstract ( 1600 )   PDF (512KB) ( 827 )  

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With a view from the practice application,this paper briefly introduces the principle of TianJin DELI's Digital tuner measuring system,namely DS7720i,and summarizes the frequent typical trouble-shooting methods for our long term instruments maintenance for volume-production so that the trade reference to improve instrument's efficiency and prolong its life.

Application of the Measurement Receiver in the Holographic Measurement System

HU A-Li

. 2011, 24(11):  42. 

Abstract ( 1225 )   PDF (665KB) ( 846 )  

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The holographic measurement on the 25 m parabolic antenna by the Sheshan station of Shanghai Observatory and the application of the measurement receiver in it are introduced.The basic theories of the microwave holographic measurement technique and the composition of the Sheshan station measurement system are described with emphasis on the principle of the composition of the measurement system and its application in Sheshan station.The measurement result with the SinoSat satellite beacon signal as a measurement signal is given.The measurement receiver is stable.

Design of One-touch On-off Power Source Based on LP2951

ZHAO Peng-Tao, LIU Yan, WANG Jian

. 2011, 24(11):  45. 

Abstract ( 1112 )   PDF (394KB) ( 1181 )  

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Battery-powered supply is a common power supply in the portable smart devices.This paper presents a power circuit of one-touch and on-off based on LP2951.It described in detail the power chips,circuit scheme and on-off working principle.Experiments show that the power supply circuit has the advantages of simple structure,easy use,reliability and versatility.

Design of a Cathode High Voltage Power Supply for an Airdrop Type of Radar Transmitter

WEI Xin, JIANG Zhi, BAI Ying, LI Jian-Hua

. 2011, 24(11):  47. 

Abstract ( 1355 )   PDF (733KB) ( 821 )  

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The ripple of the cathode high voltage power supply is the key factor that influences the transmitter frequency spectrum.Aiming at the application environment of the airdrop type of radar,which includes the strong impact,the low atmospheric pressure and the limited installation environment,this paper proposes a design method of the cathode high voltage power supply for the airdrop type radar transmitter.It adopts the soft switching resonance technology to reduce the loss of the power switching tube,provides the output high voltage by the series cascade multiple voltage circuit,takes effective means to reduce the ripple of the output high voltage,and improves the reliability of the system.This method has good adaptability in the working environment that includes the strong impact and the low atmospheric pressure.This cathode high voltage power supply has good miniaturization effect,big power densities,and good adaptability to the transmitter's working ratio.It is propitious to the transmitter system,which improves its power capacity,working efficiency and quality of the transmitter frequency spectrum.It provides new ideas for the development of the transmitter high voltage power supply and has good application prospects.

Signal Simulation for RCS Dynamic Measurement

ZHOU Xia, ZHOU Jian-Jiang, LI Hai-Lin

. 2011, 24(11):  51. 

Abstract ( 1272 )   PDF (980KB) ( 805 )  

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A signal simulation system for RCS dynamic measurement is developed and designed based on the Microsoft SQL Server 2005 database management system,ADO.NET database access technology and Visual Studio 2008 development environment.It is built on the C/S (client/server) structure.It can store and manage radar cross section (RCS) simulation data for each radar target in the database.The trajectories of horizontal straight flying,radial flying and spiral flying are calculated by means of kinematics equations.The inevitable random wobble in the flight is taken into consideration and the results of the real time RCS with different poses and radar echoes are presented.The system achieves the goal of signal simulation for RCS dynamic measurement finally.The system designed in the paper has prevalent applicability.It can be used in different radars and different targets for dynamic measurement processing.

The Design and Implementation of a Portable Vibration Test Instrument

LI Qi, LIU Yan-Fei, LIU Yan, TIAN Qi

. 2011, 24(11):  55. 

Abstract ( 1397 )   PDF (1019KB) ( 931 )  

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To meet the requirement of information acquisition and data analysis for the state of industrial equipment,this paper develops a portable vibration test instrument.The system adopts portable embedded system architecture,uses the acceleration sensor to gain vibration signals and gains speed and displacement signals by the integrator analog circuit double improved.The MCU gathers and stores the information.This system has USB communication,Flash memorizer,48 bit authentication energy-saving power manager,LCD display and SD memory.The system has such functions as time-domain signal display and analysis,spectrum analysis,resonance vibration demodulation and trend analysis.Experimental results show that the system is stable and reliable,and data analysis  is accurate and fast,meeting the expectation.

Implementation of PCI Slave Interface Using CPLD

SHI Xiao-Bin, SONG Si-Sheng, HUANG Gen-Quan

. 2011, 24(11):  59. 

Abstract ( 1251 )   PDF (677KB) ( 871 )  

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This paper presents the implementation method of PCI slave interface using CPLD.This method is compliant with PCI specification revision 2.2.The auto configuration of resources is realized and burst transaction is also supported by this method.The experiment results have proved its validity;the speed of burst transaction may reach to 20 MB·s^-1.

Hardware Design and Implementation of Real-time Airborne Video Image Processing System Based on FPGA

YOU Li, XIA Wei-Jie, ZHOU Jian-Jiang

. 2011, 24(11):  63. 

Abstract ( 1294 )   PDF (660KB) ( 786 )  

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The hardware design of a real-time airborne video image processing system is studied in this paper.The system uses the XC5VFX70T FPGA as the core processor to implement the decoding,real-time processing and encoding of video signals of such formats as DVI and PAL.The circuit design of the system is concise,flexible and scalable.The paper introduces the overall hardware architecture of the system.The hardware plans of the decoding module,encoding module and video buffer module are also designed in detail in this paper.The final results of the experiments prove that the system can process the high definition video with 1 600×1 200 resolution,60 frames/s fresh rate,24 bit true color fluently,and the processing time of one frame high definition video is less than 3 ms,which can meet the real-time requirements of the system.

A Method of SAR Image Texture Feature Extraction Based on Co-occurrence Matrix

YANG Kai-Zhi, CHENG Ying-Lei

. 2011, 24(11):  66. 

Abstract ( 1953 )   PDF (761KB) ( 1183 )  

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To extract available information from SAR images effectively,this paper proposes a method of texture feature extraction based on co-occurrence matrix.This paper first analyzes the common attribute values of co-occurrence matrix and the influence of window size and displacement vector on texture feature.By comparing the distribution and mean value of different objects' texture,it obtains the best window size and displace vector used to calculate co-occurrence matrix,and determines practicable texture feature combination for classification.Finally,this paper gives methods for texture feature selection and extraction.The experiment results show that the features extracted by the method are effective in describing objects.

A New Camera Calibration Algorithm Based on B-dual-space

XU Lei, YANG Gang

. 2011, 24(11):  70. 

Abstract ( 1052 )   PDF (895KB) ( 885 )  

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For camera calibration,this paper presents an improved plan calibration algorithm based on B-dual-space.First,the concept of B-dual-space and its basic properties are introduced.Second,the paper creatively combines B-dual-space and Zhang's method,proposing an improved plan calibration algorithm.This algorithm also uses the second-order distortion model which is more elaborate than the first-order distortion model that Tsai's method uses.Finally,the efficiency of the algorithm is verified by the checkerboard experiment.A comparison with the other two classic calibration algorithms shows that the accuracy of the new algorithm is approaching to that of Zhang's method.

Design of a Video Collecting System Based on ADV7183A

HANG Juan, ZHANG Yao-Qin, WANG Yu-Fan

. 2011, 24(11):  74. 

Abstract ( 1323 )   PDF (569KB) ( 794 )  

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FPGA is used to control ADV7183A so that ADV7183A can output the 8 bit 4:2:2 YCrCb video data.Then the data is sampled at every other point to produce the grayscale image data of 320×256.Finally,the data is transmitted to DSP.The sampled data displayed by DSP meets the demand of design and serves as good digital video data for later filtering.

Development of Control System for Steering Gear Based on RTX

ZHANG Bei-Lei, XIA Wei-Jie, ZHOU Jian-Jiang

. 2011, 24(11):  77. 

Abstract ( 1125 )   PDF (581KB) ( 799 )  

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This paper designs and develops a set of testing system for Steering Gear control of virtual flight test from 2.4 meter windtunnel based on RTX real-time extension module.The system which provides an important basis for the assessment of aerodynamic characteristics for flight major components collects Signals which are sent by Balance,Gyroscope,Steering Gear,photoelectric encoder.The paper introduces RTX real time module and hardware design firstly,and then describes the software design divided into 2 parts.Finally,in conjunction with a practical application,it is more time critical,more stable when running algorithm,higher accuracy and more user-oriented.

MSP430 Based Ecg Acquisition System

ZHANG Hai-Feng, REN Ai-Feng, TONG Xin, RUAN Hang

. 2011, 24(11):  80. 

Abstract ( 1547 )   PDF (740KB) ( 823 )  

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This paper designs a kind of simple ECG acquisition measuring system with the instrument amplifier and MSP430 single ship.The bioelectric signal is tiny and we obtain it through the standard leads.The tiny signal is amplified by the first level amplifier and then continues to be amplified by the second level amplifier because of the low level voltage of the signal.After the 50 Hz trap circuit,the signal can be passed into the MSP430 through a small circuit model.We use single input AD,the voltage of which ranges from 0mv to 600 mV,to measure the ECG signal.The signal can be displayed on 12 864 Liquid Crystal Display and can also be sent to the pc by the serial port.In the end we program a host computer system interface.This system can provide patient's heart data for the remote doctor.

A Method for Detection of Driver Eye Fatigue State Based on 3G Video

WANG Yu, HU Ji-Wen

. 2011, 24(11):  84. 

Abstract ( 985 )   PDF (542KB) ( 733 )  

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Fatigue driving has become one of the main contributing factors to traffic accidents.This paper presents a method for the detection of driver eye fatigue state based on 3G video.First,video frames are captured from the video stream via DirectShow,then the human face's position is located through the characteristics of skin colors,and the human eyes are tracked using grayscale information.Finally,the PERCLOS method can decide whether the driver is fatigue.By this method,it can prevent fatigue driving effectively.

Design of Testing System for Accelerometer Based on GP-IB

ZHAO Yuan, LIU Yan, CHENG Hong-Jie, GUO Feng

. 2011, 24(11):  86. 

Abstract ( 1445 )   PDF (698KB) ( 801 )  

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Through analyzing the situation of accelerometer testing system,there are several bottleneck factors such as various testing procedure,complicated operation,and easy to cause mishandling which have restricted the accelerometer's automatic testing capability.To calibrate the performance parameters better,the testing system for accelerometer based on GPIB is designed,and the composition of the system is introduced.According to the characters of high accuracy and faint feedback signals of accelerometer,the digital multimeter technique is applied to realize the accurate test of the accelerometer's faint output signals through its favorable signal processing and noise limiting capacity.At the same time,for the small sample of test data,double modified interpolation is used to process the obtained data,enlarge the sample size and solve the problem that it's difficult to build times-series model with a small sample.Comparing with operational testing system,advanced technology,comprehensive function and powerful data processing & analyzing capacity are main advantages of this testing system.The application indicates that this precise and steady testing system can meet the requirement of accelerometer calibrating & testing completely.

ABS Control System of Hybrid Electric Vehicle Based on the SAE J1939 Protocol

SHANG Bao-Wei, LIANG Tao-Nian, LI Xuan

. 2011, 24(11):  90. 

Abstract ( 1372 )   PDF (672KB) ( 765 )  

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The paper researches the energy recycle principle and braking course of hybrid electric vehicle,and then puts forward the braking control strategy and the realization of the energy recycle of hybrid electric vehicle at the condition of ABS system participate in the braking.According the detail content of SAE J1939 protocol,the massage format of communication in ABS control system is designed,which realizes the ABS controller share and communication data with the HECU (High Electronic Control Unit).

Parallel Imaging Algorithm of Synthetic Aperture Radar Based on GPU

ZHANG Xiao-Dong, KONG Xiang-Hui, ZHANG Huan-Yang

. 2011, 24(11):  94. 

Abstract ( 1258 )   PDF (434KB) ( 793 )  

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A parallel RD algorithm is achieved by the high speed GPU.A highly parallel and real-time method used in synthetic aperture radar ( SAR) is proposed.The result of the experiment shows that the method can meet the demand of real-timeness in SAR.Compared to the traditional method,this method can reduce the cost of hardware and shorten the time of software development.

Research on Security Access Control Based on SDT

ZHAO Yuan, WANG Huai-Jun, FANG Ding-Yi, TANG Zhan-Yong

. 2011, 24(11):  96. 

Abstract ( 1287 )   PDF (629KB) ( 772 )  

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The rapid development of network offers a wide range of channels for information acquisition,which brings a serious potential security danger at the same time.this paper puts forward a method of access control based on SDT,by which the incredible binary code is executed separately through software dynamic translation.In the dynamic fragment execution,SDT is responsible for adding the security polices to the executable code,and controls the access of system resources by security polices.This method is implemented by the strata(SDT common platform).

An Improved Algorithm of Whirlpool

LIU Fei, HUANG Yu-Hua, WU Kuang-Shi

. 2011, 24(11):  100. 

Abstract ( 985 )   PDF (473KB) ( 726 )  

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The use of the block cipher to construct a Hash function is a very common method.The most representative algorithm is Whirlpool.This algorithm has the same packet length as the output length,but its efficiency is half that of AES-128.We obtain a message extension improvement program of Whirlpool with the thought of AES-256,while increasing the iterative rounds.The efficiency of this algorithm is about 1.4 times higher than that of the original algorithm with the security of the algorithm remaining unchanged.

Study and Design of a High-bandwidth Digital Content Protection Receiver

JIANG Te-Lin, YANG Yu-Cai

. 2011, 24(11):  103. 

Abstract ( 940 )   PDF (494KB) ( 725 )  

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This paper focuses on the study and design of the receiver of High-bandwidth Digital Content Protection(HDCP).It also analyzes the basic structure of HDCP receiver and discusses the design method,including the design for four sub-modules,Cipher datapath,controller,register and I²C interface.HDCP is an IP core embedded in Digital Video Interface(DVI) or High Definition Multimedia Interface(HDMI) chips.The integration of the HDCP in DVI＼HDMI chips can ensure the legality and confidentiality of video data in its transfer between two devices.

Study on Modeling and Algorithm of a Digitalization Leveling Platform for a Radar

JIANG Yang, ZHENG Zhi-Jun, WANG Ke-Jun

. 2011, 24(11):  106. 

Abstract ( 961 )   PDF (603KB) ( 755 )  

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A mathematical model of a digitalization leveling platform for a radar is established and its corresponding algorithm is presented.Since the algorithm for traditional coordinate rotating transformation is complex,it is difficult to implement because of its heavy operand.Therefore,a novel algorithm is presented.This algorithm aims at dismantling the 3 dimensional mathematical model into the 2 dimensional model equivalently to carry out planar geometry parsing.Several simple equations are summarized after analysis so as to make the algorithm simple and easy to understand.This model can be applied in multiple fields such as phased array radars and gun firings,which are not leveled mechanically.

Engineering Implementation of the Frequency Estimation Algorithm on Speed Radar for Muzzle Velocity

WANG Yi, GAO Jian

. 2011, 24(11):  109. 

Abstract ( 1592 )   PDF (635KB) ( 826 )  

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The measurement result of radar signal frequency decides the precision of speed radar.This paper mainly introduces two methods of frequency estimation,and estimates the Doppler velocity in white gauss noise using FFT,MUSIC and ESPRIT algorithms.By Matlab simulation,it compares the estimating precision of the three algorithms under different conditions.The result indicates that MUSIC and ESPRIT algorithms can achieve high precision of frequency estimation at a certain SN ratio.

Compensation Optimal Algorithm of Angular Attitude for Dynamic Slant Calibrating Sensor

GAO Jin, ZHOU Da-Zheng

. 2011, 24(11):  112. 

Abstract ( 1213 )   PDF (482KB) ( 730 )  

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The compensation optimal algorithm of angular attitude plays a very important role in the output operation model of the dynamic slant calibrating sensor.The performance of the algorithm determines the accuracy and real-timeness of output.This paper designs an attitude algorithm for the strapdown system taking advantage of the fact that the contributions to the coning compensation by the cross products of the two incremental angles having equal time intervals are the same under the condition of coning movement.If the coning compensation accuracy is the same,the calculation burden of this algorithm will be decreased.A compensation algorithm is also introduced,by which the angular increment in the former coning compensation period reduces the operation time and improves the compensating accuracy.

A General-purpose Algorithm for Natural Language Information Hiding

WU Jian-Tao, FANG Ding-Yi, JIN Yan-Ping, HE Lu

. 2011, 24(11):  115. 

Abstract ( 1124 )   PDF (781KB) ( 719 )  

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Natural language information hiding technology has been a research focus in the field of information security in recent years.Based on the analysis of the existing information hiding algorithms for natural language,we find that existing algorithms do not have enough hidden capacity and can not be applied to a variety of scenarios.In order to obtain a scheme with enough capacity and versatility,this paper presents a common abstract algorithm for natural language information hiding.With the concept of the cover unit as a link,the abstract algorithm divides the natural language information hiding algorithm into the cover control algorithm and hiding coding algorithm,and then realizes the abstraction of the existing algorithm.The abstract algorithm realizes the conjunctive use of a variety of cover control algorithms and effectively improves the hiding capacity.Because different embedded solutions can be flexibly applied to different scenarios,the versatility of the algorithm is achieved.Experimental results show that the abstract algorithm is versatile.

Effect of Several Defects on the Electronic Structure of Graphene

MIAO Ya-Ning, MIAO Wei, ZHENG Li, LI Yang, YUAN Jiang-Ni, ZHANG Zhi-Yong

. 2011, 24(11):  120. 

Abstract ( 1567 )   PDF (873KB) ( 900 )  

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First-principles calculations within the generalized gradient approximation(GGA) and density functional theory(DFT) are carried out on the electrical structure of eigen and defective Graphene supercell.Several defects,including Stone-Wales defects,single vacancy defects and double vacancy defects,and their effects on the electrical properties of Graphene are studied.It is found that the existence of the several defects are all accompanied with new energy states in the gap,and magnify the Graphene's band gap to a corresponding degree,and the density of state changes accordingly.Stones-wales defects add the Graphene's band gap up from 0e V to 0.637 eV,and single vacancy defects to 1.591 eV,and double vacancy defects to 1.207 eV.

Research on a Photoelectric Trigger System

WU Sha, LEI Zhi-Yong

. 2011, 24(11):  123. 

Abstract ( 1096 )   PDF (803KB) ( 782 )  

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In order to stabilize the work piece touch device of online automatic measurement in the vision measuring system and meet the camera's trigger function,this paper analyzes shot reflected light path and optical photoelectric detection performance of the trigger system based on the principle of synchronous photoelectric trigger mechanism.It designs the related signal processing circuit.According to the noise characteristics,it also analyzes the influence of the circuit background environment on the detection circuit.Through analysis,calculation,and experiment,this paper realizes the automatic testing function to meet the requirements of triggering for the measurement system.

Application of High Power Microwave Weapons in Air Defense

WANG Ren-Tao, WANG Yi, LI Bin

. 2011, 24(11):  128. 

Abstract ( 1326 )   PDF (986KB) ( 799 )  

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This paper briefly introduces the work and damage principle of HPMW,analyzes several possible modes for its application in air defense,presents its key technologies,points out its future development,emphasizes the importance of developing HPWM.

VSAT Broadband Satellite Communications Technology Based on DVB-RCS and its Applications

ZHI Qi

. 2011, 24(11):  132. 

Abstract ( 1486 )   PDF (944KB) ( 887 )  

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This paper describes the principles of VSAT data networks,satellite communication systems and the development trend of the broadband DVB-RCS open standard.Through the introduction of VSAT DVB-RCS based broadband satellite communication system in an engineering application examples,including system operations and characteristics,and the basic configuration of the subsystem,it can be concluded that along with broadband networks and services,VSAT satellite communication systems are transforming from the narrowband to broadband system.In the existing technology,based on DVB-RCS standard which has the advantages of openness and low cost,the VSAT broadband satellite communications system will have broad market prospects,especially in the vast remote rural areas.It will be one of the major solutions to the communication problem of the rural areas.

Application of Portable Satellite Communications Earth Station in Emergency Relief

SU Yuan

. 2011, 24(11):  135. 

Abstract ( 1298 )   PDF (601KB) ( 629 )  

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In emergency relief,to maintain smooth communication is an important condition for reducing disaster losses.Satellite mobile communications is an effective means to ensure smooth communication.Portable satellite communications station,an economic,practical,and reliable emergency communications,is an effective complement of satellite mobile communication applications in emergency relief.This paper discusses the composition and characteristics of the portable satellite communications station and its applications in emergency relief.

Review of the Airborne Ku and Ka-band Satellite Communication System

AI Wen-Guang, ZHAO Da-Yong, DENG Jun

. 2011, 24(11):  138. 

Abstract ( 2015 )   PDF (702KB) ( 1274 )  

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This paper reviews the Ku-band and Ka-band airborne satellite communication system both at home and abroad,cites a few typical satellite communication system specifications,and outlines matters that deserve our attention and some technical approaches in the development of airborne satellite communications systems,including choosing the form of antenna system,reasonably allocating system indicators,and eliminating the impact of the Doppler effect.

Cloud Computing the Key Technology and Application Prospects

CAO Yuan-Yuan

. 2011, 24(11):  141. 

Abstract ( 1403 )   PDF (741KB) ( 672 )  

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Cloud computing is considered to be another major change at electronic information technology field following PC and Internet.This article describes the development of cloud computing,analyzes its development trends,introduces the key technologies,finally,based on the cloud computing trends and key technologies,prospects our cloud computing applications and the industry development.

Study on Intrusion Detection System in Wireless Sensor Networks

CUI Jie, XU Lei, WANG Xiao-Dong, XIAO Hong

. 2011, 24(11):  144. 

Abstract ( 1868 )   PDF (410KB) ( 643 )  

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Wireless sensor networks are different from traditional networks,so traditional intrusion detection can not be applied efficiently to them.This paper first analyzes the security threats of the wireless sensor network,then summarizes the existing intrusion detection approaches in the wireless sensor network,and finally proposes a hierarchical intrusion detection system based on a synthesis of the existing approaches.This architecture can detect most of the security threats by reducing the false positive alarms.

Research on the Military Application of Cyberspace Technology

LIAO Xiao-Yang, CHEN Xu-Fei, YU Xin-Gang, LIAO Yong, WANG Zheng-Qiang

. 2011, 24(11):  147. 

Abstract ( 3182 )   PDF (618KB) ( 1125 )  

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Based of the concept of cyberspace,this paper summarizes the four distinctive features of the modern military applications of cyberspace,analyzes the four elements of the application of cyberspace in future wars,and proposes four inspirations and countermeasures.It is concluded that more efforts are needed both in the formulation of strategies for  adapting to cyberspace new network technology requirements and in the study of key cyberspace technologies.The relationship between the ability target and technical feasibility needs to be considered in advance.

Application of the Notion of Green Chemistry in the Analytical Chemistry Experiment

WANG Jian-Kun, LIANG Yan-Ping

. 2011, 24(11):  150. 

Abstract ( 1322 )   PDF (414KB) ( 595 )  

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In order to improve students' comprehensive capabilities and deepen their sense of green chemistry,experimental contents and teaching methods are reformed in analytical chemistry experiment teaching according to the concept of green chemistry.All these measures have promoted the student's awareness of environmental protection.