用预滤波法改善直扩信号卷积／相关器输出信噪比

本文通过对快捕系统预滤波法的分析与公式的推导，提出了一种新的提高同步快捕系统相关器输出信噪比的方案，从而可在接收信号的信噪比较低的情况下，完成同步信号检测。     

快捕段格式编码提高相关处理增益

本文通过快捕段格式编码的分析，提出了一种适合于较低输入信噪比，短码相关器实现长码的捕获方法。     

一种高灵敏度GPS信号快速捕获算法

为了提高GPS软件接收机捕获算法的灵敏度和快速性,提出了一种高灵敏度GPS卫星 信号快捕方案。首先对GPS信号进行频率补偿,然后进行相干滤波提高卫星信号的信噪比, 从而提高捕获算法的灵敏度。再采用延迟、累积捕获结构寻找输入信号中各颗卫星的C/A码 起始点,引入延迟累加器实现各卫星多普勒频移成分的分离、估计,将传统的二维捕获过程 简化为两个一维搜索过程,捕获时间仅为传统FFT快捕算法的几十分之一,提高了捕获算法 的速度。分别通过实测和GPS数字中频信号发生器仿真生成的GPS数字中频数据对所设计的捕 获算法进行了验证,实验结果表明该捕获算法行之有效。     

黄鳝无土流水养殖法

黄鳝无土流水养殖与常规的静水有土养殖相比，具有生长快、成本低、产量高、起捕方便等优点，其主要养殖技术介绍如下：     

优化参数对CPM-PSWF信号性能的影响

基于椭圆球面波信号的连续相位调制（Continuous Phase Modulation Based on Prolate Spheroidal Wave Function,CPM-PSWF）方法是一种新颖的数字调制方式,调制参数的优化与其调制信号性能有着直接联系。分析不同调制参数对CPM-PSWF信号性能的影响,优化选择调制参数,对获得能量聚集性和功率效率都较高的CPM信号具有重要意义。首先,对基于椭圆球面波信号的CPM信号进行描述;其次,采用韦尔奇(Welch)谱密度估计法,对时间带宽积、调制指数、关联长度等不同参数对CPM-PSWF调制信号的功率谱密度和带宽特性的影响进行了仿真分析。实验结果表明,选用0阶椭圆球面波信号,小时间带宽积、调制指数和符号进制数越小,关联长度越大时,CPM-PSWF信号具有频谱带外高频滚降快、占用带宽小的特点。     

一种三维调制信号快速解调新方法

根据三维调制信号的特性,提出了一种新的三维调制信号的快速解调方法。该方法 基于MUSIC算法,首先利用单次快拍来建立阵列数据的协方差矩阵,然后根据调制信号的先 验信息对所得信号空间谱进行判决,来估计其极化辅角与极化相位角等信息,从而恢复出基 带信号。分析与仿真结果表明,所提方法不仅可以避免谱搜索,大大降低MUSIC方法的运 算量,而且适用于瞬时信号和快速运动信号的解调。     

电子技术在捕鳖上的应用

我国民间捕捉甲鱼,常用的方法有枪打、钩钓、中草药诱捕,潜水捕捉、鱼笼诱捕、掏洞捕、排叉探捕等等。 近年,湖北省一家公司成功地将电子技术和传感技术运用于捕捉甲鱼,开创了捕鳖的新方法。用新探鳖仪捕甲鱼,有如下优点:     

FFT辅助的部分相关码捕获技术的实现

FFT辅助的部分相关伪码快捕方法将沿码相位-多普勒频率的二维搜索简化为沿码相位的一维搜索,克服了多普勒频率的影响,大大缩短了PN码捕获时间,适用于中低轨卫星.文中介绍了该方法的基本原理、性能分析和实现方案.实验结果表明,在大多普勒频偏下FFT辅助的部分相关码捕获方法是一种性能优良的伪码捕获方法.     

ofcdm和mc-cdma在快衰落信道下的性能比较

第四代移动通信的目标是应用先进的技术来提供极高速的无线数据传输,尤其是在下行信道.本文讨论了正交额分码分复用(ofcdm)系统和多载波码分多址(mc-cdma)系统在快衰落信道下,在不同的调制方式下的ber性能比较,最后得出仿真结果.     

电捕焦油器在化工生产中的应用与改进

介绍电捕焦油器的特点,及其在济钢化工厂生产系统中的应用现状,提出电捕焦油器电气部分高压整流设备以及绝缘箱存在的安全隐患、整改方法以及整改后的实际效果,并且总结电捕焦油器的日常点检维护方法,有效的提高电捕焦油器的安全性以及稳定性。对于同类的电捕焦油器的改造和维护工作,具有较强的针对性和实用性,对于类似的电捕焦油器也具有借鉴意义。     

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,     

China's Auto Industry Steps Forward

Last year,the volume of China's auto trade reached US$66.878 bil- lion,of which imports accounted for US$25.982 billion,a year-on- year increase of 24.45 percent;while ex- ports totaled US$40.896 billion,growing by 45.31 percent.The China Association of Automobile Manufacturers(CAAM) predicts that the number of autos sold in 2008 will break the 1 million barrier for the first time in history,representing an increase of about 20 percent.     

Domino Effect on Electricity and Coal Prices

In the middle of last December, the key purchase contracts for coal used in power generation in 2008 were signed, reflecting a demand for more than 1.085 billion tons. It is important to note that the country＇s five biggest power producers, China Huaneng Group, China Guodian Corporation, China Power Investment Corporation, China Huadian Corporation and China Datang Corporation, had settled on the prices on their purchase contracts, and they are expected to consume 290 million tons of coal for generating electricity,