一种“北斗”B1C信号无模糊捕获算法

针对“北斗”B1C信号同步过程中存在的捕获模糊性问题,根据“北斗”B1C信号的信号特点,基于伪相关函数方法,设计了一种适用于“北斗”B1C信号的无模糊捕获算法。该算法采用数据分量和导频分量非相干组合的捕获策略,实现了B1C信号数据分量和导频分量的无模糊捕获,提高了捕获灵敏度。利用导航终端接收的卫星信号数据,对所提捕获算法进行了仿真验证,并分析了其无模糊捕获性能和捕获灵敏度。仿真结果表明,所提算法能准确且快速地捕获“北斗”B1C信号。     

基于时频分布迭代的跳频信号参数估计

提出了一种基于时频分布迭代的跳频信号参数估计新算法，利用时频平面最大值， 通过计算跳频信号与最优原子时频分布的残差逐次迭代获取匹配于跳频信号分量的时频参数 ，进而实现跳频信号参数估计。理论分析和仿真结果表明，与基于匹配追踪和粒子群优化的 跳频信号参数估计相比，基于时频分布迭代的参数估计算法在保证算法精度的情况下，有效 地降低了算法的计算复杂度，为跳频信号盲接收的实时实现提供了一种新方法。     

一种用于卫星通信的自适应编码调制信号接收方法

针对常规接收方法接收自适应编码调制信号时存在的接收过程易中断、数据不连续等问题,提出了一种适用于卫星信道的自适应编码调制信号接收方法。该方法通过采用统一的解调结构实现对不同调制信号的连续跟踪;利用接收端保存的帧同步字调制波形副本与接收信号中的帧同步字波形的相关结果,对解调方式切换时载波相位跳变值进行估计和补偿,解决了帧同步的连续跟踪问题。与现有方法相比,该方法不需要导频信号,可节省系统开销。     

基于FPGA的OBS边缘节点总线控制硬件设计

给出了一种OBS边缘节点总线控制的硬件设计方案。该方案采用循环四次握手的方式完成主模块与其它从模块的通信,用轮询的方式把几个可能引起时序上冲突的信号,按顺序分配到不同的时钟周期上。整个方案以FPGA芯片EP2C20F484C8为基础实现,在Quartus Ⅱ软件上编译通过。仿真结果显示:该方案不仅能够解决时序冲突的问题,而且最高工作频率达到340 MHz,在整个控制模块中占用的逻辑单元(LE)数目仅为0.9%。     

一种基于频移滤波器的混合信号盲恢复算法

针对单天线接收的频谱混叠的混合信号盲恢复问题,在频移滤波器结 构上,提出了一种基于相关函数误差准则的自适应频移滤波信号盲恢复算法。该算法利用滤 波 器输出信号和参考信号以及混合信号与参考信号之间的相关函数误差来调整自适应滤波器输 出权值。分析了该算法的稳态性能。仿真结果表明：在信噪比大于-5 dB的条 件下, 该算法对混合信号分量的恢复相似度达80%以上,并且该算法仅需已知混合信号分量的循环 频率,无需其它先验信息,具有计算量小、敛速度快的优点。     

JTIDS信号宽带接收方法及其FPGA实现

为了实现对联合战术信息分发系统(JTIDS)信号的宽带接收,设计了一种基于多相滤波器的信道化接收方法。该方法通过对JTIDS的模拟信道和数字信道进行合理划分,将宽带接收转化为多个窄带接收,然后再结合多相滤波器进行跳频频点检测,以实现全概率的JTIDS信号宽带接收。给出了此信道化接收模型的现场可编程门阵列(FPGA)实现方案,并对仿真和硬件测试结果进行对比分析。仿真与FPGA测试结果表明,该接收模型可以精确实时地接收JTIDS宽带信号。     

基于移频滤波的脉压雷达抗干扰方法

针对线性调频（LFM）脉冲压缩雷达易受移频欺骗干扰影响的问题,提出了基于移频检测的起始频率捷变LFM雷达抗干扰方法。通过分析匹配滤波器参考函数、目标回波信号和干扰信号在频域的相对位置,利用脉间LFM信号起始频率不同的特点,将接收信号进行移频,使得目标回波信号分量无脉压输出,从而确定干扰信号分量在时域的位置,通过时域选通对未进行移频的接收信号脉压结果中的干扰进行滤除达到抗干扰目的。仿真分析了移频检测抗干扰性能,结果验证了所提方法的有效性。     

PHS基站信号再生设备的设计与实现

介绍了一种新型PHS基站信号再生设备的设计与实现方法,完成了该系统的硬件模块设计和软件设计及编译,并对软件流程进行了详细的介绍。该系统主要采用小灵通基带芯片ML7338(ARM7TDMI核)和RDA5206射频模块,实现对射频信号的解调,同时对基带信号重新编码再调制发射,很好地解决了普通直放站射频干扰问题。所设计的信号再生设备能实现对PHS信号的变换与转发,能够有效解决当前小灵通网络的盲区问题。     

基于AD9361射频捷变收发器的GPS伪卫星设计

为了搭建用于室内定位的伪卫星室内定位系统,设计了一个伪卫星用于发射模拟GPS卫星定位信号。从伪卫星的硬件结构的角度详细说明了该伪卫星的各部分硬件组成以及相应的功能。该伪卫星使用了AD9361射频捷变收发器将时钟小数分频、数模转换、信号调制、上变频融为一体,简化了伪卫星的硬件结构。介绍了该伪卫星生成的信号的具体结构,采用时分多址（Time Division Multiple Access,TDMA）技术使得接收机接收伪卫星信号时不会被阻塞。利用示波器、频谱仪和嵌入式逻辑信号分析仪Signal Tap对伪卫星进行测试,包括时钟频率、伪码、BPSK调制、TDMA技术等,结果表明伪卫星工作正常,其信号能被ublox正常接收,可以利用其进行下一步伪卫星组网用于室内定位。     

接收机畸变对辐射源指纹识别的影响

在辐射源个体识别技术应用中，接收机指纹和发射机指纹相互影响相互耦合，造成辐射源指纹库依赖于特定接收机，无法在不同接收机之间通用。针对此问题，对典型超外差接收机的滤波器、放大器畸变分量对接收信号指纹的影响进行了理论分析与实验验证。理论分析证明发射机和接收机的滤波器、放大器分量对于接收信号整体的畸变影响是等价的；实验中，利用两台超外差接收机对5台发射机进行个体识别测试验证，更换接收机前后，滤波器、放大器特征识别正确率分别从100%、95.5%降到20%，证明了接收机畸变分量对发射机指纹识别具有严重影响。该研究成果可为后续辐射源个体识别接收机设计以及接收机畸变校正提供理论依据。     

Brown＇s Blossom in Britain-China

The overall strategic relationship between U.K. and China is ＂better than ever＂, China- Britain relations have maintained good momentum, with increased high-level exchanges and the reinforcement of strategic mutual trust, with more room for growth in the future.     

Challenge and Opportunity Go Hand in Hand——What Global Economic Agitation Brings to the China's Economy?

Domino effects of the global finance agitation As the origin of the subprime crisis,US financial institutions lost USS45 billion last year,accounted for over half of the total US,EU & Japan loss.Since January 15th,Chtigroup released its financial statement of the 4th quarter,showing a net deficit of USS9.83 billion,which marked the hisoric high of its quarterly deficit.     

Sinosteel：Extraordinary Moves in Industry Chess

Among the Fortune 500 firms,more and more images from China emerge out.On the 2008 list,Sinosteel Corporation,a landmark group of China industries quietly squeezes into the candidate line.As the largest steel service ＆ trade enterprise,its sales reached at RMB 111.24 billion,with a year-on-year increase of 83.03 percent,and the profit grew by 180.03 percent.On the Sinosteel 2008 Work Meeting,the president Huang Tianwen uttered,＂In the coming year,we will work for US$20 billion sales,and look forward to getting a position in Fortune 500 firms for ourselves.＂     

Walk Through Unusual Five Years—— An Exhibitor＇s Canton Fair Course

When the 103rd Canton Fair is approaching, an old friend of Canton Fair, Li Ying from Jiangsu prov-ince recollected his past five years＇ experiences to the grand trade meeting. Each year is special, with some unforgettable memories colored by the year.     

Jean-Pierre Duprieu： Willing to Be A Legate of Sino-French Business

Estaing, former French president, Valery Giscard d＇Estaing attended Sino-French Economic Seminar held in Shanghai in early April and said that the world center has shifted from the west to the east with many European and US companies entering into Asia, and China has the ability to play an important role in the world stage. Estaing, naming himself＂French Confucian＂, then said in Chinese that a cook-group includes 10 people in ancient Chinese soldier system and the cook is in charge of cooking for them. And people who belong to the same cook are actually ＂Partners＂.     

China''''s Stock Market Wave

The annual meeting of the World Economy Forum was held in Davos,a little town in Switzerland,on January 23rd to the 27th this year,with the theme"the Power fo Collaborative Innovation",over 2500 celebrates from ture political and cconomic circles of more than 80 countries and challengred logether to talk about the future of the global economy in 2008,A Forum for the problems and challenges that face whole world,some of the keywords which drew attention during the event were:the U.S.subprime mortgage crisis,soaring energy prices,the economic slowdown in the U.S.ermerging economic bodies,authority funds and the general unpredictable nature of the global economy.     

Trade Promotion from Neighborhood

If you are considering to trade with companies in Japan or expanding your .business to Japan, we are ready to help from the very beginning.＂ You will find this greeting at the first sight on the Chinese website of Japan External Trade Organization （JETRO）. JETRO has committed itself in delivering highly efficient and quality services to meet the demand of internal and external customs including Japanese companies, hence winning a good reputation in the international trade arena. In recent years, with its priority in advancing business cooperation in South and East Asia, JETRO has made great achievement in promoting trade between China and Japan. Therefore, China＇s Foreign Trade interviewed Mr. Yoichi Maine, Deputy Director General of JETRO BEIJING.     

Auto Parts Market Potential Coming into Surface

Looking at the increasingly fierce competition in the world auto market. global automobile manufacturing industry, taking Europe, the U.S. and Japan as representatives, is gradually forming a new type of relationship, mutual cooperation between whole vehicle and parts manufacturers. We can clearly see that auto parts manufacturers have become independent from the whole vehicle manufacturing companies, which means that the former structure of auto industry has greatly changed, and a new relationship,     

Public Financial Expenditure——A Reflection of the Livelihood Improvement

In recent years.China's public finance put social construction high on the agenda and attaches more importance on livelihood insurance and improvement.The 2003-2007 public financial expenditure reflects a fact that the government isputting more emphasis on livelihood andissues concerning the people.     

Voices from the MPC and CPPCC

"Crucial for economic growth.energy utilization has its role in all economic sectors and every aspect of people's daily life.Now we are in dire need of a new profession,namely energy manager.We not only need to have passion and responsibility,but also a scientific approach to conserve energy and cut emissions.APpropriate legislation should be in place.and a special profession should be introduced to ensure the implementation of these laws and regulations."