Table of Content

15 March 2012 Volume 25 Issue 3

  

Articles

A Robust Pretreatment Algorithm for Low Contrast Images

ZHANG Jun-Sheng, WANG Ming-Quan, HOU Hui-Ling, CHEN Zhi-Qiang

. 2012, 25(3):  1. 

Abstract ( 1075 )   PDF (835KB) ( 1066 )  

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Due to illumination or the object itself,images often become low contrast or blurred in the acquisition process and need further pretreatment before they are used.Grayscale subsection linear transformation is an effective technology for contrast enhancement by means of the rational choice of subsection points.The maximum and minimum values are always used for subsection points,but this method does not work when the original image has wide dynamic range of gray value.Through the analysis of the original image histogram,a robust method is proposed which selects subsection points by setting thresholds in the accumulation of the gray histogram.Experimental results show that the method can enhance the region of low contrast and provide satisfactory images for further processing.

A Model for Simulating Deformable Objects Based on the Honeycomb Structure

WAN Wen-Zhang, LIU Xiong

. 2012, 25(3):  4. 

Abstract ( 1156 )   PDF (747KB) ( 907 )  

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A haptic model based on the honeycomb structure of cellular solids is developed to satisfy the requirements of real-timeness and authenticity for simulating deformable objects in the virtual surgery.Honeycomb units of cellular solids are employed to construct the deformable object,and the space affected by the surface pressure is refined to the honeycomb shape.Based on the standard beam theory in Structural Mechanics,an analytical expression of the relationship between deformation and force of honeycomb units is obtained,so as to achieve physical meaning-based simulation of the deformable object.Not only does the model have better real-time deformation calculation,but also a variety of linear and nonlinear deformation simulation can be achieved.A haptic feedback prototype system based on hand controller “Falcon” verifies the real-time and realistic effect of the model.

A Dual Watermarking Algorithm for Image Tamper Orientation and Recovery

LI Wen, LI Hong-Chang

. 2012, 25(3):  8. 

Abstract ( 1062 )   PDF (689KB) ( 942 )  

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The concept of virtual watermark is introduced.A new digital image algorithm of double watermark is proposed on the basis of such watermarking technologies as self-restoring and wavelet transform.After the second wavelet transforming of the original image,the low-frequency part turns into the first watermark,and the digital product company is labeled as the second watermark.Then,this algorithm takes advantage of the characteristic of the dual watermarking algorithm to set up a mapping between two watermarks.The experiment results show that the algorithm is simple and efficient,and has such functions as watermark recovery,authentication of copyright,tamper orientation and recovery.

Research on Data Sharing Strategy for Sensitive Service Systems in Private Networks

WANG Xin, QIN Hai-Long

. 2012, 25(3):  11. 

Abstract ( 1023 )   PDF (418KB) ( 887 )  

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Sharing of data in sensitive systems is a complicated step in the realization of university information management.In this paper,we take the acquisition of information from the fee payment system as an example to present a scheme for achieving practical,secure and efficient data sharing through the front-end processor.Research results show that the setting of the front-end processor both guarantees the security of the system and improves the quality of data exchange.

Community Detection Method Based on Minimum Entropy

SUN Xi-Ya

. 2012, 25(3):  13. 

Abstract ( 1278 )   PDF (1016KB) ( 1001 )  

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This paper proposes an efficient method based on minimum entropy for community detection in complex networks.First,an interaction network is denoted by a fuzzy relation,and the entropy is proposed to determine the membership grade of the relation,and the lower the entropy,the more similar the vertices.Then,the fuzzy relation is transformed into a minimal fuzzy relation by a novel composition rule of fuzzy relation that is presented here.Finally,this minimal fuzzy relation is partitioned into clusters based on the value of entropy.The results both in artificial networks and real-world networks show that our method is efficient in community detection.

Application of Compensation Matrix in the Monobit Digital Receiver

YANG Han

. 2012, 25(3):  17. 

Abstract ( 1291 )   PDF (530KB) ( 836 )  

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Compared with the traditional DFT receiver,the monobit digital receiver can achieve large wideband and high processing speed by adopting low bit A/D and simplifying the course of Fourier transformation.However,a problem of low two-signal instantaneous dynamic range has occurred for the monobit digital receiver.In this paper,we adopt a compensation technique to improve instantaneous dynamic range without more quantization precision.Simulation results show that this technique can enlarge the dual signal dynamic range.

Color Image Enhancement Based on Retinex Theory

YIN Hong-Ran, YU Hao, QIN Qing-Feng

. 2012, 25(3):  21. 

Abstract ( 1630 )   PDF (858KB) ( 994 )  

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A new enhancement algorithm for color images is proposed after an analysis of Retinex theory and its classic algorithm.This image retains some of the low frequency components of the image while enhancing the high-frequency components.Besides,the dynamic parameters,acquired according to the Gray World theory,are introduced to extend the dynamic range.The experimental results demonstrate that the proposed algorithm is efficient in color image enhancement.

Analysis of the Effects of Passive Location Based on the Extended Kalman Filtering Algorithm

MENG Xiang-Fei

. 2012, 25(3):  25. 

Abstract ( 1469 )   PDF (411KB) ( 1103 )  

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According to the observed coordinate,azimuth and elevation,the extended kalman filter algorithm is expanded from six to nine dimensions.A new extended kalman filtering algorithm is proposed,and its performance is better than the original ones.The conclusions are verified by theoretic analysis and simulations.

Implementation of Multiboot Based on Xilinx-Spartan6 FPGA

LIU Zhao, DU Yong-Feng, XU Zhi-Bo

. 2012, 25(3):  28. 

Abstract ( 1248 )   PDF (571KB) ( 879 )  

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Two implementation methods for Multiboot are introduced.Xilinx Spartan-6 FPGA's Multiboot feature allows the user to download multiple configuration files into Flash.According to the needs of different times,in the case of non-power-down restart,one file is chosen to re-configure the FPGA,to achieve different functions,to improve device utilization,to increase system security,and to reduce system cost.

Design and Realization of Network Video Servicer Based on MPEG 4 in Modern Mine

HE Ling-Ling

. 2012, 25(3):  32. 

Abstract ( 1062 )   PDF (646KB) ( 920 )  

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On the basis of a study on the improvement of the application architecture of the network monitor system,this paper proposes a new architecture with the front-end storage function,which can greatly improve the usability and reliability of the system.It also presents the design and implementation of a network video servicer with a hard disk.

Simulation and Realization of Viterbi Decoder with Matlab in the Communication System

MEN Lan-Ning, GE Chi-Heng

. 2012, 25(3):  35. 

Abstract ( 1328 )   PDF (483KB) ( 1040 )  

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The digital communication system plays an important role as a forward error correction technology convolutional code.And the message receiver has a higher requirement on the decoding of the convolutional code.This article comes up with a simulation scheme of convolutional code's decoding with Matlab,and realizes the convolutional decoding with Viterbi Decoding.The simulation indicates that viterbi decoding is a perfect means for convolutional code's decoding,and it provides a good reference for technical applications.

Operating System Security Assessment Method for the Mobile Intelligent Terminal

SHEN Lei

. 2012, 25(3):  38. 

Abstract ( 1303 )   PDF (669KB) ( 951 )  

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With the development of the mobile Internet,the mobile intelligent terminal has become one of the main ways to access the Internet.As the mobile terminal's capacity is limited,the available basic security methods cannot be applied directly to the mobile intelligent terminal.To solve the security issues of the mobile intelligent terminal,this paper proposes an operating system security assessment method for the mobile intelligent terminal with the characteristics of the mobile intelligent terminal considered.The process and method of testing the security function for the mobile intelligent terminal are presented.The proposed method has the advantages of low overhead and high security level,and can ensure the security of the mobile internet from the source.

Design of a Mall Temperature Control System Based on S7-300PLC

FU Ting

. 2012, 25(3):  42. 

Abstract ( 1184 )   PDF (496KB) ( 958 )  

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This paper introduces a mall temperature control system based on S7-300PLC.To provide customers with a comfortable shopping environment,it is necessary to keep the mall temperature appropriate.This system uses the computer monitoring system,intelligent sensors,programmable controllers,industrial field bus,and optical fiber communication technology to achieve automatic control and improve the economic efficiency of the system.

A Model Checking Method for Ada Concurrent Program

HUANG Chao, JIANG Guo-Hua

. 2012, 25(3):  44. 

Abstract ( 1194 )   PDF (575KB) ( 824 )  

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A model extraction method for Ada concurrent programs is proposed.The model checker SPIN is used to validate the model generated automatically,and it is found that concurrent errors such as deadlock exist in programs written with Ada language.Finally,the extraction method is verified through examples.The experimental results show that this method can successfully detect errors existing in Ada concurrent programs,and give the corresponding error path.

Medical Image Fusion Algorithm Based on Intuitionistic Fuzzy Reasoning

ZHAO Meng-Yang, NA Yan, LI Si-Tong

. 2012, 25(3):  48. 

Abstract ( 1515 )   PDF (773KB) ( 863 )  

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Aiming at the poor quality of the fusion image based on the fuzzy reasoning image fusion methods,a new algorithm based on the intuitionistic fuzzy reasoning(IFR) is presented.According to the definition of the Intuitionistic Fuzzy Set,using the advantage of the IFR in solving vague problem,to make the IFR rules to image fusion.Listing the steps of the new algorithm and experiment.The results show that the algorithm we presented is obviously superior to the algorithm based on the traditional fuzzy reasoning.

Building and Dynamic Generation Technology for the Virtual Equipment Based on Web3D

MA Qun, DU Bao-Jiang, GUO Jing-Jing, WEI Xiong

. 2012, 25(3):  51. 

Abstract ( 1278 )   PDF (715KB) ( 777 )  

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This article discusses the dynamic generation technology on the Web3D platform according to the parts of the virtual equipment that constitute the production line.First,the virtual device library is built and the virtual equipment is classified.According to the command,the virtual equipment is transferred into virtual scene and then generated in real time in virtools and web services with the loading speed guaranteed.

Reversible Watermarking Based on JND and Cellular Automata Transform

LIU Na

. 2012, 25(3):  55. 

Abstract ( 915 )   PDF (974KB) ( 899 )  

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A reversible watermarking method using JND and cellular automata transform (CAT) is proposed.Histogram adjustment technique is first adopted to change the grayscale values of the original images in order to prevent the overflow and underflow of pixels during embedding.Then,the original images are decomposed with the integer wavelet transform (IWT) to extract the high frequency sub-bands for embedding.By calculating the just noticeable difference (JND) of each coefficient,the embedding regions and strength can be controlled flexibly.Finally,the watermark image which is encrypted by CAT is embedded into the chosen wavelet coefficients using the spread spectrum technique.Experimental results show that the proposed method greatly improves the invisibility of watermarks while achieving good capacity.

Network Asynchronous Communication Programming Techniques Based on Windows

DU Yong-Feng, LIU Zhao

. 2012, 25(3):  59. 

Abstract ( 1388 )   PDF (464KB) ( 794 )  

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This paper introduces the basic processes and two common kinds of class of the WinSock network programming in the TCP/IP network and focuses on the features of asynchronous non-blocking class CAsyncSocket which is provided by MFC.The features include the creation of objects,the asynchronous selection mechanism,and the response to network events.Then with practical development experience,this paper introduces the communication process and basic framework of the network communication by using CAsyncSocket class.

Windows-based Distributed Real-time Simulation System

SUN Ya-Hong

. 2012, 25(3):  62. 

Abstract ( 1362 )   PDF (816KB) ( 879 )  

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Two solutions for Windows-based distributed simulation are presented after an introduction to RTX-a real-time extension subsystem based on Windows,one being reflective memory network distributed simulation based on RTX,and the other being token ring distributed simulation based on Ethernet.A comparison of the differences in real-time performance between the two architectures and the traditional Windows solutions shows that the two solutions can offer flexible and reliable choice for different simulations while meeting the distributed simulation system's requirement of real-timeness.

Design of a High-Sensitivity LED Lamp of Sound-and-Light-Controlled Type with Micro-Power Consumption

JIN Yong-Gao, JIN Jie

. 2012, 25(3):  66. 

Abstract ( 1272 )   PDF (525KB) ( 857 )  

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On the basis of MK6A11P's characteristic of micro-power consumption,this paper designs an LED lamp with the characteristics of micro-power consumption,sound and light control and high sensitivity.It has a standby power consumption of less than 0.1 W and high sensitivity,thus overcoming the problem of the existing acoustic-control lamp of low sensitivity and also dealing with the problem that the lamp is always lighting when the sensitivity of acoustic control is high.The LED lamp can be widely used in public areas where the flow of people changes at random such as corridors,elevator entrance and public toilet.Experiments show that the LED lamp has the advantages of simple circuit structure,high operation stability and adjustable lighting time.

Secondary-Side Signal Processing of Fiber-Optic Current Transducer Based on LTC1068

GENG Jian-Ping, YANG Jian, YANG Hua-Lei

. 2012, 25(3):  69. 

Abstract ( 1386 )   PDF (545KB) ( 921 )  

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The basic principle of the fiber-optic current transducer based on the Faraday effect is introduced.The design of optical current transformer secondary-side signal processing using switched-capacitor filter LTC1068 is presented in detail.Finally the test results are given.Test results show that using LTC1068 to process secondary-side signals is practical and effective,and fully meets the measurement requirements.

Design and Simulation of Slow-Wave Structure and Beam-Wave Interaction for Space TWT

LIU Yi, RUAN Jiu-Fu, YANG Jun, DENG Guang-Sheng, LV Guo-Qiang, ZHANG Wen-Bing

. 2012, 25(3):  72. 

Abstract ( 1308 )   PDF (585KB) ( 830 )  

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The slow-wave structure of the Ka band helix-TWT is designed.Its color scattering characteristic curve and coupling impedance are analyzed.The high-frequency system is optimized.The results of Interaction from PIC simulation show that the output power is more than 73.5 W and distortion of gain is less than 2% at the working frequency.The test results show that this device has the output power of more than 45 W,the electronic efficiency of more than 12.5%,and the overall efficiency of more than 40% at the working frequency.The difference between the simulation result and test result is analyzed.

A Design Method for the DUAL Phase Lock-in Amplifier

SU Xin, LUO Wen-Guang, MA Chao, WU Zai-Qun

. 2012, 25(3):  75. 

Abstract ( 1632 )   PDF (674KB) ( 1048 )  

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In order to better abstract the weak signal submerged by noise,this paper analyzes the theory of the phase lock-in amplifier and designs a dual phase lock-in amplifier using CD4046 and AD630.Experimental results show that the amplifier can measure alternating-current less than 1 mA and it is a high-precision and practical phase lock-in amplifier with a sensitivity of 20 mV/mA and a precision of 0.05%.

Multi-output DC-DC Converter Based on LM2679

WANG Xian-Jiang, SHI Yu

. 2012, 25(3):  78. 

Abstract ( 1100 )   PDF (681KB) ( 883 )  

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It is found and proved that self-excitation may be avoided if each work module is isolated effectively in the design of multi-channel high-current DC-DC converters.This finding will help us design better multi-channel high-current DC-DC converters.This paper implements a three-way high-current DC-DC converter with the input voltage being 19~31 V,and output voltage 15 V/5 A,5 V/3 A,and 3.3 V/3 A.The results show that the method proposed in this paper meets the design requirement.

Design of the Digital Control Signal Source Based on FPGA and DDS Technology

SHEN Hui, WANG Shi-Kui, WEI Fu-Ya, ZHANG Dong, YU Rong-Zhi, ZOU Xiu-Lan

. 2012, 25(3):  82. 

Abstract ( 2046 )   PDF (828KB) ( 858 )  

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The paper introduces the design of the digital control signal source based on FPGA and DDS technology.Each functional module is designed with VHDL.The design can output sine wave,quadrate wave and trigonal wave.The frequency of each wave can be adjusted by the digital control method.This signal source has the advantages over the traditional signal source of better quality,higher precision,simple design,and easy implementation,extension and maintenance.

Research on MIMO OFDM Synchronization Technology

SHAO Feng

. 2012, 25(3):  85. 

Abstract ( 1457 )   PDF (810KB) ( 911 )  

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As a multi antenna and multi carrier technology,MIMO OFDM has the advantages of high spectrum efficiency,strong anti-interference capability,high transmission speed and large transmission capacity.MIMO OFDM has become one of the most popular standards for 4G technologies.However,due to the sensitivity of the MIMO OFDM system to the frequency offset and timing,the study of synchronization is of great importance.This paper analyzes the current mainstream synchronization methods.

Research on Voltage Source PWM Rectifier Based on DSP Control

SHEN Jian-Dong, ZHAO Yong

. 2012, 25(3):  90. 

Abstract ( 1341 )   PDF (463KB) ( 752 )  

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According to the work principle of the PWM rectifier,this paper analyzes its control method.Through the hysteresis control of the current,it builds a two closed loop automation system of the voltage source PWM rectifier with TMS 320F2812 as the controller.Experiment results show that the system has good static performance and dynamic performance and provides a theoretical foundation for designing PWM rectifiers.

Oil Well Communication System Based on the Power Line Carrier Communication

ZHANG Chao, FENG Yu-Feng, SUN Xue-Jun

. 2012, 25(3):  93. 

Abstract ( 1524 )   PDF (781KB) ( 888 )  

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To fully learn the situation in the underground part of the oil well,real time supervision over parameters such as temperature and pressure is necessary in the process of oil exploitation.In this paper,a method of data communication appropriate for the underground oil well condition is proposed.The core of the method is the use of SSC P485 spread spectrum chip and SSC P111 amplifying chip to implement data communication through the power line in the oil well by the low power line carrier technology.Experiments show that this method facilitates the acquisition of data and the knowledge of what happens underground.

Design of the LED Edge-lit LCD TV Backlight Module

HE Sheng-Bin

. 2012, 25(3):  97. 

Abstract ( 1250 )   PDF (835KB) ( 1112 )  

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As a key factor in the design,the LCD TV backlight module is experiencing a transformation from the LCD module to the LED module and from small size LED module to large size LED module.What is important in backlight design is how to transform the LED light source into uniform surface light source while ensuring the necessary light energy utilization.Especially in the large-size backlight module,each component of the backlight module must be considered and computed in the early design to reduce costs.Simulation results show that the central scale≥420 cd/m²,the light uniformity≥76％,and other indexes such as color coordinator,visual angle and painting quality meet the design requirement.

LDPC-Based MIMO Satellite Spreading Communication Systems

WANG Chen, YANG Feng-Fan

. 2012, 25(3):  101. 

Abstract ( 1322 )   PDF (615KB) ( 804 )  

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MIMO technique,namely the multiple-input-multiple-output technique,is widely used in various communication systems as it can enlarge channel capacity.In satellite communication systems,there are mainly two problems,co-channel interruption and noise,confronting MIMO application.In this paper,the MIMO linear detection system used in satellite communications aiming at overcoming co-channel interruption is introduced.Spreading and the Shannon-limitation-approaching LDPC encoding are introduced at input,while at output dispreading and decoding are done.Thus,both the co-channel interference and noise are significantly reduced and a good performance for this system is reached.

Applications of Fiber-Optic Transmission Technology in Radar Signal Record&Replay System

LIU Zhi-Ying, SUN Gao-Jun, WU Guan

. 2012, 25(3):  104. 

Abstract ( 1365 )   PDF (515KB) ( 912 )  

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The application of the fiber-optic transmission technology based on Stratix GX series FPGA in radar signal record&replay system is introduced.The advantage of fiber-optic transmission and its possibility of technical realization are analyzed.Emphasis is put on the structure of the fiber-optic transmission system and its particular application.The chip type  used is also given.It is shown that this technology has stable performance.

InSAR Imaging Technology

ZHANG Yue, WAN Die

. 2012, 25(3):  107. 

Abstract ( 1021 )   PDF (662KB) ( 829 )  

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This paper introduces the principle of InSAR imaging and discusses the procedure of measuring height with emphasis on flat removal and two phase unwrapping algorithms,and finally makes simulations of Gauss Hill for both the two algorithms of Branch-cut and Least-squares.Finally it makes a brief analysis of the result.The analysis shows that the Branch-cut phase unwrapping algorithm has better effect and retains the precision of the original phase and that the Least-square algorithm has a worse phase error than the Branch-cut phase unwrapping algorithm but it has higher computation efficiency.

The VC++ Implementation and Analysis of the Velocity Detection of Pulse Doppler Radar

LIU Zhen

. 2012, 25(3):  110. 

Abstract ( 1019 )   PDF (491KB) ( 814 )  

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This paper expounds how pulse Doppler radar uses the Doppler Effect to detect the velocity of the target.It also analyzes the characteristics of the Doppler filter group.Then it gives the engineering simulation method in VC++,the problems that emerge and their solutions.Finally,it transforms the data into an image in Matlab analyzes it.

Design of CCD Analog Front End Circuit for KAI-02150

LI Xiao-Yu, ZHAO Min

. 2012, 25(3):  113. 

Abstract ( 1487 )   PDF (754KB) ( 887 )  

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A dual-channel analog front end circuit for KAI-02150 CCD image sensor is designed.Specific circuits for each module of AFE are presented according to the KAI-02150 parameters.After AD9920A register's configuration accomplished through the SPI interface,a variety of working modes can be switched from one to another.Compared with the traditional analog front end solution,this design is more flexible,simple,stable and reliable.Tests show that the output for clock-driven timing of the design can meet the requirements of KAI-02150.After the correlated double sampling and A/D conversion,digital video signals can be output.

Large Capacity Storage Arrays Based on Flash Memory

CAO Xiao-Man, LIN Sen, FANG Huo-Neng

. 2012, 25(3):  117. 

Abstract ( 1837 )   PDF (755KB) ( 805 )  

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Large capacity,high speed,high density,low power consumption,low cost,high reliability and flexibility are always the primary research areas and goals of the information storage technique for the data record equipment.This paper analyzes the implementation of a high-speed solid storage system with large capacity based on NAND flash memory.The fruit of the thesis establishes a firm foundation for the actual development of flash memory based SSR used on the satellite and is very useful for reference.

The Modulation and Demodulation of 2FSK Signal Based On FPGA

ZHOU Zhi-Fa, AI Wen, ZHANG Yao-Qin

. 2012, 25(3):  121. 

Abstract ( 1385 )   PDF (529KB) ( 843 )  

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A variety of FPGA-based modulation and demodulation of the digital signal the to include 2ASK,2FSK,2PSK,described in the 2FSK signal modulation and demodulation,and the power spectrum of the signal.Provided at the end of the verification results to prove that the simulation results meet the requirements.

Applications of the Communication Access Network in the Railway

GAO Yu-Hong

. 2012, 25(3):  124. 

Abstract ( 878 )   PDF (549KB) ( 827 )  

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Railway communication technology has developed rapidly due to the vast expansion of the railway network over recent years.Considering such factors as long distance,numerous different railway lines,and many railway stations located in remote mountainous areas,the railway communications network has developed specialized centralized management plus a decentralization of its communications network system,achieved by providing considerably more sophisticated digital technology and integrated communication services.This article focuses on the methods for accessing the communications network and the important issues that require attention throughout the management of the railway's audio signalling and automatic services.