基于零均值特性的改进G-SVSLMS算法

为解决改进的基于Sigmoid函数变步长最小均方（G SVSLMS）算法步长更新公式易受 噪声干扰的问题,根据高斯白噪声的零均值特性,对G SVSLMS算法进行改进,提出基于零 均值特性的改进G SVSLMS算法,使算法的抗噪声干扰能力明显增强。理论分析和仿真结果 表明：若两算法选取相同参数α、β,则基于零均值特性的改进G SVSLMS算法相 对于G SVSLMS算法具有小的稳态误差;在保证算法收敛的条件下,基于零均值特性的改进G SVSLMS算法相对于G SVSLMS算法具有较快的收敛速度。     

基于小波变换变步长LMS自适应信道均衡的新方法

结合变换域最小均方（LMS）和变步长LMS算法的优势,提出了一种基于小波变换 的变步长LMS自适应均衡方法。该方法中步长调整函数采用了改进的Sigmoid函数,该函数具 有简单且误差信号接近零时变化缓慢的特点。并且,在训练模式、判决引导模式以及混合模 式下,将提出方法和传统均衡方法进行了仿真比较。结果表明,所提出的方法比传统的线性 LM S算法、变步长LMS以及小波变换LMS收敛更快、性能更优。     

GSM无源探测中基于空域宽零陷的DPI抑制新算法

强直达波干扰（DPI）抑制是GSM无源探测系统中的首要问题。根 据系统中DPI与目标回波的特征差异,提出了一种新的宽零陷空域DPI抑制算法。该算法基于 干扰和回波的DOA信息,采用改进的最小约束最小方差准则来实现特定方位上的空域滤波, 能够在对目标回波进行波束赋形的同时有效抑制DPI。仿真结果表明,该算法能获得不低于5 5 dB的抑制增益。     

基于相关特性的改进G-SVSLMS算法

为解决改进的基于Sigmoid函数变步长最小均方（G-SVSLMS）算法步长更新公式易受噪声干扰的问题,根据高斯白噪声相关性比较差的特性,对G-SVSLMS算法进行改进,提出基于相关特性的改进G-SVSLMS算法,使算法的抗噪声干扰能力明显增强。理论分析和仿真结果表明：若两算法选取相同参数,则基于相关特性的改进G-SVSLMS算法相对于G-SVSLMS算法具有小的稳态误差;在保证算法收敛的条件下,基于相关特性的改进G-SVSLMS算法相对G-SVSLMS算法具有较快的收敛速度。     

传输线小反射信号正交分解和对消技术

介绍一种基于信号正交分解和对消原理消除传输线上小反射信号的技术.通过在传输线上引入两个间隔1/8波长的可调不连续性电抗,实现任意相位的小反射信号消除.对该技术的工作原理进行了描述,建立了电路的数学模型并进行了理论分析.分析结果表明,采用适当的电路形式并通过调整电路参数,可对反射信号达到近乎完全的对消,回波损耗可改善40 dB以上.仿真和实验验证了该技术的有效性和理论分析的正确性.     

基于迭代次数变步长的LMS算法在ECG信号提取中的应用

介绍一种基于迭代次数变步长的LMS算法,通过自适应噪声抵消系统,对心电信号中的工频干扰进行抑制。实验结果表明,基于迭代次数变步长的LMS算法滤波效果最好,信噪比提高了46.0149dB,同时收敛速度也是最快的,并且具有好的实时性,验证了该算法在抑制工频干扰方面的有效性和优越性,有重要的理论意义和实用价值。     

计算电离层VLF波传输特性的时域有限差分算法

在星载甚低频（VLF）通信技术中,研究甚低频信号在电离层中的传输特性具有重要意义。现有的利用时域有限差分（FDTD）算法研究电离层传输特性大多基于高频脉冲信号,且传播模型相对粗略,计算存在一定误差。为此,建立了更为精确的电离层各向异性传播模型,对常规的FDTD算法引入变步长因子,并用该算法对VLF波在电离层中的场强衰减进行了数值计算,研究了昼夜变化及频率对其传输特性的影响。仿真结果与卫星实测数据对比表明：与常规的FDTD算法以及全波分析方法相比,引入变步长因子的FDTD算法精度更高;在VLF频段,降低频率有利于电磁波穿透电离层,且白天的衰减明显大于夜间;VLF波在射入电离层并穿透D层时衰减严重（30~40 dB）,约为F1层中衰减的3倍。     

多帧相参积累检测前跟踪方法

为了提高雷达对微弱目标的检测能力,提出了一种多帧相参积累的检测前跟踪（TB D）方法。通过对多帧时间内运动目标回波的分析,建立了相参积累的回波信号模型,其中 目标回波出现距离单元走动和多普勒单元走动。利用目标回波的空-时相关性,采用速度匹 配法和离散Chirp-Fourier变换（DCFT）联合估计目标径向速度、多普勒频率和调频斜率, 补偿距离单元走动和多普勒单元走动,实现多帧时间内目标能量的相参积累。最后,采用仿 真实验验证了信号模型的正确性和算法的有效性。     

一种用于自适应噪声抵消的变步长LMS算法

为了提高LMS自适应滤波算法的性能,在分析已有变步长算法的基础上进行了一些改 进。改进算法用误差信号的自相关来调节步长以实现对不相关噪声的更好抑制,且采 用先固定后变化的方法控制步长,兼顾了暂态和稳态性能。利用改进算法进行了自适应噪声 抵消的仿真实验,结果表明,基于改进变步长LMS算法的自适应噪声抵消器 能有效抵制噪声干扰,对含噪信号具有良好的消噪能力。     

一种改进的数字同频直放站自适应反馈干扰抑制算法

基于数字地面电视广播(Digital Terrestrial Televisi on Broa dcasting,DTTB)同频直放站的回波干扰抑制,提出了一种变步长块LMS(Variable Step-siz e Block Normalized Least Mean Square,VSSBNLMS)自适应算法。此算法的目的是为了提 高传统回波干扰抑制的自适应算法的收敛速度和降低计算复杂度。其将输入信号分为长度相 等的块,在每一个数据块内,权值向量只更新一次,有效地降低了计算复杂度。〖JP2〗另 外,该算 法通过输出误差控制更新步长的变化,与传统的归一化LMS (NLMS)和块LMS (BLMS)算法相比 ,提高了收敛速度。仿真结果表明,该算法具有良好的收敛速度和回波干扰抑制性能。     

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."