数字数据

Digital Data Network is a data transmission network by using digital channel. By contrast with analog channel, it has some strongpoint, such as higher transmission quality, greater speed, better utilization factor of bandwidth and so on.

数字数据网是利用数字信道传输数据信号的数据传输网，利用数字信道传输数据信号与传统的模拟信道相比，具有传输质量高、速度快、带宽利用率高等一系列优点。

The system hardware design and software design are discussed in detail,and the theory of wireless data transmission with wireless digital transmission chip under the enhanced ShockBurst mode is analyzed.

介绍了一种利用无线数字传输芯片和单片机构成的无线数据传输系统，讨论了系统的硬件电路设计和软件编程，以及无线数字传输芯片在增强式突发传递模式下通过单片机的控制进行无线数据传输的原理，设计了在增强式突发传递模式下可实现半双工通信的通用电路，并讨论了无线数字传输芯片初始配置和数据发送程序开发的关键技术。

The development direction changed direction according to the four-wheeler, the domestic and international company changes direction organization to control to the four-wheeler currently main adoption of is a numeral control, this is owing to a lot of advantages of numerical control:the procedure turn a control, the controller carries on the processing of operation and numerical information according to the control regulation designed, mainly passing procedure to carry out, if change control regulation need to change software, but need not change the hardware structure of system: control the accuracy is high, in the emulation the control the system, the accuracy of the controller from the accuracy of the component but settle, numerical controller accuracy from word long decision;Stability good;The software replies to use, needing a hardware environment of using the homology realization in the emulation the system, the numerical controller is a procedure control, the sub- procedure mold piece which need to be designed and write to carry out its model, can immediately carry out several links of functions expediently.

目前各个厂家大多采用的是PLC、单片机应用于四轮转向控制器中，功能基本能够实现，相比较之下，信号处理能力较强的数字信号处理器各方面均性能优于以上三种处理器。DSP是新世纪数字化革命的核心。它是一种独特的微处理器，具有可编程性，且实时运行速度远远超过通用微处理器。强大的数据处理能力和高速的运行速度，是DSP最值得称道的两大特色。DSP芯片是一种特别适合进行数字信号处理的微处理器。它强调运算处理的实时性，因此除了具备普通微处理器所强调的高速运算和控制功能外，主要针对实时数字信号处理，在处理器结构、指令系统和数据流程上做了很大的改动。它具有灵活、精确、可靠性好、体积小、功耗低和易于大规模集成等优点。

First, mathematical foundation of synchronization, i.e. the theory of parameter estimation is introduced. Then, DA/DD or NDA timing synchronization methods based on the ML estimation of timing parameter are presented. They are all widely applied in actual digital communication systems. Interpolation theory in digital signal processing has application in timing synchronization, which makes the sampling clock independent of the timing control so that timing adjustment is realized completely through digital disposal. The issue of interpolation in timing synchronization is discussed.

首先，介绍了定时同步实现的数学基础，即信号参数估计理论；从定时参数的最大似然估计出发，介绍了基于数据辅助的定时同步方法和基于非数据辅助的定时同步方法，他们在实际的数字通信系统中均有广泛应用；论文探讨了数字信号处理中插值理论在定时同步中的应用，它使得接收端的采样时钟独立于定时控制，定时调整完全通过数字处理方法得以实现。

The main features of the system are: the communications line is not only used for data transmission but also responsible for the system control and management; only one analogue to digital converter is needed for the whole system; a digital trimmer which is analogous to the adjustable resister in function is installed to each sub—system.

本文所进行的数字型条干均匀度测试仪的系统设计，采用了多微处理器的分布式并行结构，提出了一种数字信号的总线结构，采取了数据预处理和数字微调等措施，其主要特点为：半双工异步通信线不但用于数据传输，而且还负责系统的控制和管理；整个系统只需一路模数转换器；各子系统均设有数字微调装置，其功能类似于模拟电路中的电位器，可独立进行参数调整。

Companies specializing in digital network monitoring, digital video and data communications product research and development and production, successful research and development Tigereye series, Cerberus series of MPEG-1, MPEG-4, H.264 network monitoring systems and digital audio and video acquisition card, SupeScan power, the environment and image monitoring system, JS series Guangduan Ji, data multiplexer, data-machine, E1/10Base-T/V3.5 converters, optical transceiver, communications transmission Access and interface protocol converter products.

公司专业从事数字网络监控、数字视频和通信数据产品的研发与生产，成功地研发Tigereye系列、Cerberus系列MPEG-1、MPEG-4，H.264数字网络监控系统及音视频采集卡，SupeScan动力、环境及图像监控系统，JS系列光端机、数据复用器、数据交叉机、E1/10Base-T/V3.5转换器、光纤收发器等，通信传输接入、接口协议转换器产品。

The design includes many new technologies in data exchange and data security, they are: Converting non-XML data to XML in order to apply the XML security technology to more data types; Using the technology of XKMS and PKI to manage the public key in order to overcome the shortage of complexity and difficulty in using PKI and improve the efficiency of the public key management; Using Diffe-Hellman algorithm combining with the public key technology to exchange secret key in order to furthest increase the security of the key; Using the technology of XML digital signature algorithm to ensure the integrity, message authentication and signer authentication of the data; Using the technology of XML encryption to ensure confidentiality of the data; Defining delegable access rules on the structure and content of the XML documents to provide fine-grained access control. According to the XML security framework, a XML security library is designed and implemented.

在对XML及其安全技术主要包括XML加密技术、XML数字签名、公钥管理、密钥产生和交换进行研究的基础上，结合传统密码技术和XML安全技术提出了一种基于XML的数据安全模型，模型中包含了目前网络数据交换和安全领域的一系列最新技术，主要有：将非XML格式数据转换为XML格式数据的方法，以保证现有的大部分网络数据能够应用XML安全技术；使用XML公钥管理技术结合PKI技术管理公钥，以克服PKI技术实施和部署复杂、难度大等问题，提高公钥管理的效率；使用Diffie-Hellman算法结合公钥技术交换密钥，以最大限度保证密钥的安全；使用XML数字签名技术保证数据的完整性、不可否认性和发送方身份认证；使用XML加密技术保证数据的机密性；根据XML文档的内容和结构定义授权访问规则进行良好的访问控制。

The DTM for automatic-design of thruway was put forward by Prof. Miller in 1956. Since then , the DEM is used for design of various circuit diagram, and for account of area, cubage, gradient of various project, and for estimating visibility from point to point; for rendering contour, grade-graph, aspect-graph, solid model; for making orthographic image and repair map in the Topography; for assistant data to classify in the Remote Sensing; as basic data in the GIS, for analysis and layout actuality of using soil, for disaster prediction; for navigation, guiding missile in the military affairs.

美国麻省理工学院Miller教授为了高速公路的自动设计于1956年提出了数字地面模型的概念后，DEM被用于各种线路的设计及各种工程的面积、体积、坡度的计算，任意两点间可视性判断及绘制任意断面图；在测绘中被用于绘制等高线、坡度坡向图、立体透视图，制作正射影像图与地图的修测；在遥感中可作为分类的辅助数据；它是地理信息系统的基础数据，可用于土地利用现状的分析、合理规划及洪水险情预报等；在军事上可用于导航及导弹制导；在工业上可利用数字表面模型DSM或数字物体模型绘制出表面结构复杂的物体的形状[2]。

The acquisition date of ETM+ is October 29, 1999. We get digital elevation model data from (1∶)250 000 topography map of Minhe area. The format of DEM is MapInfo exchange format *.mif which converted to coordinate. After primary treatment of the raw data, the DEM data is derived from the contour line. The ETM+ scenes are rectified using the DEM and sun-illumination model. NDVI and other three indexes from Tasseled Cap transform were calculated from RS data.

依据其理论方法，对青海省民和地区的遥感数据--ETM+进行了分类，选用的ETM+数据为1999年10月份数据，数字高程数据来自于1：25万民和幅地形图，数据格式为MapInfo通用格式MIF，数据进行了坐标转换，对原始数据进行了处理，从等高线中提取数字高程。

Specialized introduction: This specialized raise has the electronic technology and the information system elementary knowledge, can be engaged in each kind of electronic installation and the information system research, the design, the manufacture, the application and the development higher project technology talented person Main curriculum: The signal and the system, the digital signal processing, the correspondence principle, the microcomputer principle and the connection technology, the monolithic integrated circuit principle and the application technology, the DSP technology and the application, the EDA technology, the construction of data, embedded Linux using the programming, the feeling measure technical, the electric circuit theory series curriculum, the computer technology series curriculum and so on individual hobby * software and hardware research and development computer correspondence literature ping pong photography The experience and the personal experience * 2006.6.29-7.8 compile the staff management system management system using the C language, its basic service activity includes: The staff information warehousing, the revision, the inquiry, the insertion, deletes the staff information and so on * 2006.7.10-7.20 monolithic integrated circuit curriculum design period completes the stopwatch the design, namely the initialization timer is 99:99, 0 starts using the monolithic integrated circuit timer fixed time, fixed time arrives when 0s to transmit the signal to cause the buzzer bell, and may realize suspends, the continuation and the replacement function * 2007.7.2- 7.8 practises in Luoyang Big dragon Peony Communication facility Limited company, does has liquid crystal display monitor telephone one, simultaneously visited has served under somebody's banner the correspondence company, and studied has simulated the telephone the design electric circuit, had understood its basic principle * 2007.7.4- 7.18 completed the DSP curriculum in the school to design, realizes the FIR numeral filter, namely transmitted 25 from DSPThe height level, after advocates AC01 D/A to transform the simulation square-wave, then passes to again from AC01 carries on A/D to transform, produces the data signal, after the DSP numeral filter, finally produces the sine wave * 2008.8.1-8.15 to practise in the Zhejiang Jiang hua abundant power tool limited company, studies the computer software and hardware maintenance.

专业介绍：本专业培养具备电子技术和信息系统的基础知识，能从事各类电子设备和信息系统的研究、设计、制造、应用和开发的高等工程技术人才主要课程：信号与系统、数字信号处理、通信原理、微机原理与接口技术、单片机原理与应用技术、DSP技术及应用、EDA技术、数据结构、嵌入式Linux应用编程、感测技术、电路理论系列课程、计算机技术系列课程等个人爱好＊软硬件研发计算机通信文学乒乓球摄影实践经验及个人经历＊ 2006.6.29-7.8 利用C语言编写员工管理系统，其基本业务活动包括：员工信息入库，修改、查询、插入、删除员工信息等＊ 2006.7.10-7.20 单片机课程设计期间完成秒表的设计，即初始化定时器为99：99，利用单片机定时器0开始定时，定时到0s时发送信号使蜂鸣器响铃，并可实现暂停、继续和复位功能＊ 2007.7.2- 7.8 在洛阳巨龙牡丹通信设备有限公司实习，做有液晶显示屏电话机一部，同时参观了旗下通信公司，并学习了模拟电话的设计电路，懂得了其基本原理＊ 2007.7.4- 7.18 在校完成DSP课程设计，实现FIR数字滤波，即从DSP发送25个高低电平，经主AC01 D/A 转换成模拟方波，然后再传给从AC01进行A/D转换，生成数据信号，经DSP数字滤波，最后生成正弦波＊ 2008.8.1-8.15 在浙江华丰电动工具有限公司实习，学习电脑软硬件维护。

The split between the two groups can hardly be papered over.

这两个团体间的分歧难以掩饰。

This approach not only encourages a greater number of responses, but minimizes the likelihood of stale groupthink.

这种做法不仅鼓励了更多的反应，而且减少跟风的可能性。