V.34调制解调器技术及DSP仿真

采用话带调制解调器数据信息传输,是目前广为人们采用的一种数据传输方式。本文首先介绍了Ｖ．３４建议的基本特点;然后,简单讨论在Ｖ．３４建议中为了提高信息传输速率而采用的新技术;最后,本文采用ＤＳＰ对Ｖ．３４Ｍｏｄｅｍ进行了仿真,并给出了仿真结果,     

超高速话带调制解调技术

采用话带调制解调数字信息传输具有价格低、方便、的优点，是目前广为人们采用的一种数据传输方式，最后通过的ＩＴＵ－ＴＶ，３４建议，命名话带调制解调器的速度达到了２８．８ｋｂ／ｓ，从此话带调解调器进入了超高速的新。本文论述了Ｖ．３４建议中的技术，并讨论了话带调制解调器的发展现状及未来趋势。     

V.34高速Modem的通信标准及其实现

本文扼要介绍使Ｖ．３４Ｍｏｄｅｍ数据传输速率大幅度提高的七种先进技术，并说明Ｖ．３４是如何组合这些先进技术实现Ｖ．３４发射机的。     

Co34Cu66颗粒膜的磁光性质研究

详细研究了Ｃｏ３４Ｃｕ６６颗粒膜在不同退火温度下的磁光性质．结果表明：未退火时在测量的能量范围内,位于３．８ｅＶ处有一θｋ峰．随着退火温度的升高,θｋ有不同程度的增加,当退火温度高于２００℃时,可以观察到在２．１ｅＶ附近出现一个θｋ的增强峰．其中２．１ｅＶ处的峰来源于Ｃｕ的带间跃迁,３．８ｅＶ处的峰来源于Ｃｏ．面内和极向Ｋｅｒｒ回线的测量表明：经退火后Ｃｏ颗粒变成平行于膜面的盘状     

可编程DSP调制解调器控制程序设计

可编程ＤＳＰ调制解调器控制程序设计刘丹谱，乐光新近年来，由于格状编码调制（ＴＣＭ）技术的应用，话路调制解调器在传输速率上有了极大的提高，目前符合ＩＴＵＴＶ．３４国际标准的２８．８ｋｂ／ｓ速率话带调制解调器已经开始投入商用。这些高速调制解调器的实现都需...     

光谱法求解析化聚合物薄膜的电子系数

提出了利用透过光谱法和吸收光地相结合测定聚合物电光系数的一种新方法,并求得了合成的聚氨酸薄膜在６３２．８ｎｍ处的电光系数为γ３３＝３４ｐｍ／Ｖ,γ１３＝５．４ｐｍ／Ｖ。     

Ka频段鳍线电调振荡器

介绍了一种由鳍线、耿氏器件和梁式引线变容管构成的混合集成电调振荡器电路及其设计方法．给出的ＶＣＯ电路结构简单,利用其等效电路模型,可方便地对振荡器在所需工作频率上的电调带宽进行优化设计．经优化设计的电调振荡器性能的测试结果为：在３４．９３ＧＨｚ的频率处,具有１．２ＧＨｚ的电调带宽,带内功率输出为２０．６５±０．５２ｄＢｍ．     

激光二极管泵浦的1.34μm及其腔内倍频红光Nd: YVO_4激光器

报道了激光二极管泵浦的１．３４μｍＮｄＹＶＯ４激光器，利用ＫＴＰ晶体腔内倍频，实现了６７０ｎｍ红光输出。计算了ＫＴＰ在１．３４μｍ的倍频参数，分析并提出了提高腔内倍频效率的有效途径。     

钛宝石激光泵浦的1.06μm和1.34μm高效连续掺钕氟钒酸锶激光器

利用钛宝石激光作为泵浦源,实现了掺钕氟钡酸锶（ＮｄＳＶＡＰ）晶体在１．０６μｍ和１．３４μｍ的高效连续激光运转。在１．０６μｍ和１．３４μｍ处得到的最低泵浦阈值分别为２ｍＷ和２．４ｍＷ,最高斜效率分别为４９．４％和３７．４％,最大输出功率分别为３３６ｍＷ和１６５ｍＷ。     

高速调制解调器中的多维格状编码和壳映射

采用话带调制解调器进行数据信息传输，特别是在接入环路中，具有价格低、方便、灵活的优点，是目前广为人们采用的一种数据传输方式，本文结合Ｖ．３４建议，讨论了两种高速调制解调技术－多维格状编码和壳映射技术，从理论上分析了它们改善调制调解调器性能，提高传统速率的机理；最后，本文给出了计算机的仿真结果。     

Alternative Schemes for Dynamic Secure VPN Deployment in UMTS

Three alternative schemes for secure Virtual Private Network (VPN) deployment over the Universal Mobile Telecommunication System (UMTS) are proposed and analyzed. The proposed schemes enable a mobile node to voluntarily establish an IPsec-based secure channel to a private network. The alternative schemes differ in the location where the IPsec functionality is placed within the UMTS network architecture (mobile node, access network, and UMTS network border), depending on the employed security model, and whether data in transit are ever in clear-text, or available to be tapped by outsiders. The provided levels of privacy in the deployed VPN schemes, as well as the employed authentication models are examined. An analysis in terms of cost, complexity, and performance overhead that each method imposes to the underlying network architecture, as well as to the mobile devices is presented. The level of system reliability and scalability in granting security services is presented. The VPN management, usability, and trusted relations, as well as their behavior when a mobile user moves are analyzed. The use of special applications that require access to encapsulated data traffic is explored. Finally, an overall comparison of the proposed schemes from the security and operation point of view summarizes their relative performance. Christos Xenakis received his B.Sc. degree in computer science in 1993 and his M.Sc. degree in telecommunication and computer networks in 1996, both from the Department of Informatics and Telecommunications, University of Athens, Greece. In 2004 he received his Ph.D. from the University of Athens (Department of Informatics and Telecommunications). From 1998–2000 was with the Greek telecoms system development firm Teletel S.A., where was involved in the design and development of advanced telecommunications subsystems for ISDN, ATM, GSM, and GPRS. Since 1996 he has been a member of the Communication Networks Laboratory of the University of Athens. He has participated in numerous projects realized in the context of EU Programs (ACTS, ESPRIT, IST). His research interests are in the field of mobile/wireless networks, security and distributed network management. He is the author of over 15 papers in the above areas. Lazaros Merakos received the Diploma in electrical and mechanical engineering from the National Technical University of Athens, Greece, in 1978, and the M.S. and Ph.D. degrees in electrical engineering from the State University of New York, Buffalo, in 1981 and 1984, respectively. From 1983 to 1986, he was on the faculty of Electrical Engineering and Computer Science at the University of Connecticut, Storrs. From 1986 to 1994 he was on the faculty of the Electrical and Computer Engineering Department at Northeastern University, Boston, MA. During the period 1993–1994 he served as Director of the Communications and Digital Processing Research Center at Northeastern University. During the summers of 1990 and 1991, he was a Visiting Scientist at the IBM T. J. Watson Research Center, Yorktown Heights, NY. In 1994, he joined the faculty of the University of Athens, Athens, Greece, where he is presently a Professor in the Department of Informatics and Telecommunications, and Director of the Communication Networks Laboratory (UoA-CNL) and the Networks Operations and Management Center. His research interests are in the design and performance analysis of broadband networks, and wireless/mobile communication systems and services. He has authored more than 150 papers in the above areas. Since 1995, he is leading the research activities of UoA-CNL in the area of mobile communications, in the framework of the Advanced Communication Technologies & Services (ACTS) and Information Society Technologies (IST) programmes funded by the European Union (projects RAINBOW, Magic WAND, WINE, MOBIVAS, POLOS, ANWIRE). He is chairman of the board of the Greek Universities Network, the Greek Schools Network, and member of the board of the Greek Research Network. In 1994, he received the Guanella Award for the Best Paper presented at the International Zurich Seminar on Mobile Communications.     

On Fixed-Mobile Network Convergence

As the convergence in digital industry takes shape, the digital networks, both wireline and wireless, are also converging to offer seamless services and enhanced experience to the user. With the arrival of the mobile Internet the mobility is also moving into new areas, e.g., imaging, games, video, multimedia, and across different types of networks. In this paper we explore why, what, and how of the network convergence, and identify how the industry viewpoints align and differ. We also identify the key barriers to achieving true network convergence. We then discuss the role of the Internet Protocol (IP) as the common thread that enables network convergence, and the key industry and standards initiatives to actually provide solutions and the equipment to implement a cost-efficient and high performance converged network. Sudhir Dixit joined Nokia Research Center in 1996, where he is currently a Research Fellow and works on next generation wireless networks. From 1996 to 2003 he was a Senior Research Manager, focusing on IP/ATM, wireless, content networks, and optical networks. Prior to that he worked at NYNEX Science & Technology (now Verizon), GTE (now Verizon), Codex Motorola, Wang, Harris, and STL (now Nortel Europe Labs). He has published or presented over 150 papers, published three books, and holds 14 patents. He is on the Editorial Board of the IEEE Communications Magazine, Springer's Wireless Personal Communications Journal, and KIC's Journal of Communications and Networks. He received a B.E. degree from MANIT, Bhopal, India, an M.E. degree from BITS, Pilani, India, a Ph.D. degree from the University of Strathclyde, Glasgow, Scotland, and an M.B.A. degree from Florida Institute of Technology, Melbourne. He is a Fellow of IEE (UK) and IETE (India). He represents Nokia on the Steering Board of the Wireless World Research Forum, and is also Chair of the SIG on Self-Organization of Wireless World Systems.     

Wireless IP and Its Challenges for the Heterogeneous Environment

The tremendous momentum toward building a mobile wireless Internet using the Internet Protocol (IP) has thrust many challenges upon the technology developers and the operators. These challenges encompass the 2.5G, 3G, and future solutions and standards. Some of the key issues deal with supporting IP traffic across different wireless and MAC protocols, end-to-end QoS and mobility, traffic engineering and scalability, protection/restoration, operations and management, authentication/privacy/security, billing, and content and context aware networking. This article addresses the drivers, the issues, and solutions (wherever possible) in the above areas, and concludes with a summarization of the challenges that lie ahead.     

单目图像序列光流三维重建技术研究综述

由单目图像序列光流重建物体或场景的三维运动与结构是计算机视觉、图像处理与模式识别等领域的重要研究内容,在机器人视觉、无人机导航、车辆辅助驾驶以及医学影像分析等方面具有重要的应用。本文首先从精度与鲁棒性等方面对单目图像序列光流计算及三维重建技术近年来取得的进展进行综述与分析。然后采用Middlebury测试图像序列对HS、LDOF、CLG-TV、SOF、AOFSCNN 和 Classic ＋NL 等典型光流算法以及 Adiv、RMROF、Sekkati 和DMDPOF等基于光流的间接与直接重建方法进行实验对比分析,指出各对比方法的优点与不足,归纳各类方法的性能特点与适用范围。最后对利用分数阶微分模型、非局部约束、立体视觉以及深度线索解决亮度突变、非刚性运动、运动遮挡与模糊情况下光流计算及重建模型的局限性与鲁棒性问题进行总结与展望。     

A Novel Local-Dielectric-Thickening Technique for Performance Improvements of Spiral Inductors on Si Substrates

A novel local-dielectric-thickening technique is presented for performance improvements of Si-based spiral inductors.This technique employs the processes of deposition,photolithography,and wet-etching,to locally thicken the oxide layer under the inductor,which can decrease the substrate loss and improve the inductor performance.Both the structures and processes are compact,economical,and compatible with CMOS processing.Several square spiral inductors with different inductances are fabricated,and the quality factors and the self-resonant frequencies both increase clearly with this proposed technique:for the 10,5，and 2nH inductors,the peak quality factors are effectively improved by 46.7%,49.7%，and 686%,respectively;however,the improvement percents of the selfresonant frequencies are more significant,which are 92.1%,91.0%,and no less than 68.1%，respectively.     

一种智慧协同网络多参数的多路径路由算法

多路径路由技术采用多条路径同时传输,作为优化资源配置和负载均衡的重要技术,在路由可靠性、QoS路由、传输效率等多方面比单路径传输具有优势.现有互联网网络资源配置和路由机制相对静态和僵化,导致多路径技术的发展存在发展的局限性.现有多路径技术考虑在路由层面不利于多路径路由选择和计算,难以保证传输性能,降低网络传输效率.智慧协同网络能够动态感知网络需求,灵活适配网络资源,更好的支持路由可扩展性.本文在智慧协同网络架构下提出了一种智慧协同网络多参数的多路径路由算法.该算法制定了智慧协同网络多参数的多路径路由协议,对网络性能参数CPU占用率、往返时延(RTT)、带宽进行加权计算得到路径权重值,根据权重值进行流量分配.采用图论理论对网络流量分配及模型进行了分析.并在Mini-Net平台上进行了开发和实验,结果表明,该算法能够优化网络配置,减小往返时延,提高网络吞吐量,从而提高网络性能,实现负载均衡.     

攀枝花广电工程项目管理策略与方法运用

工程项目管理就是要求工程建设任务在规定的时间和成本控制范围内达到预期的各项管控目的,它贯穿于项目的设计、施工准备与施工、使用与维护3个阶段,重点是施工准备与施工阶段的安全、质量、成本、进度、合同方面的控制与管理。结合工作实践,介绍了攀枝花市广电工程建设项目在施工准备与施工过程中的管理策略及其方法运用。     

卫星遥感温室气体的大气观测技术进展

全球、区域及城市的碳浓度、碳源汇信息是应对气候变化、达成双碳目标、完善国际谈判、支持治理政策制定与执行的重要依据。国际认可的“自上而下” 方法将卫星观测作为基础的通量计算技术, 是验证温室气体排放清单的重要手段。系统介绍了温室气体的卫星探测载荷原理、类别和发展, 以及反演、估算CO2、CH4 和N2O 的浓度和排放通量的方法, 还有探测缺失和误差存在的影响因素等; 分析了对卫星探测温室气体能力提高的迫切需求, 浓度反演和排放量估算精度不足, 以及N2O、氟化物等其他温室气体遥感研究缺乏、地基遥感验证能力薄弱等问题; 最后总结了我国温室气体卫星遥感技术的发展趋势, 主要是面向主被动高时空分辨率卫星的研制应用、高精度多尺度排放量估算(特别针对城市、小区域和点源尺度)、氟化物遥感评估等主题, 以加强对碳排放的量化观测, 并增强对碳循环的理解, 提高感知和应对气候变化的能力。     

基于声卡的虚拟示波器设计

随着现代科学和信息技术的不断进步,示波器作为一种电子测量处理仪器也在不断发展并且已经变的越来越精密,也越来越智能.传统的模拟示波器受到低频响应能力和带宽限制等多方面因素影响在很多领域已显得力不从心,虚拟示波器的出现很好的解决了这些问题.本文以LabVIEW18版本为开发平台,设计制作了一款基于声卡的虚拟示波器.重点介绍...     

机动6m抛物面天线车结构总体方案探讨

文章遵循策划、分解、综合及优化的总体方案研究思路,根据要求,提出了三个机动6 m抛物面天线车结构总体备选方案;针对系统结构组成,详细分析了天馈线、天线座、拖车以及系统标定等子系统所有可能的结构方案;最后综合权衡研究三个备选方案在技术、质量、成本、周期等多方面的优劣,选择了最佳结构总体方案,确保了所选方案具有合理性、可行性、经济性、先进性和科学性。实践证明,所选方案用户满意,实施效果良好。