基于载波相移双边带调制的可调谐光电振荡器

设计了一种利用载波相移双边带调制(CPS-DSB)系统实现宽带频率可调谐的光电振荡器(OEO)。其中CPS-DSB系统由3dB耦合器、π偏置Mach-Zehnder调制器(MZM)及可变移相器(VPS)组成,并与线性啁啾光纤Bragg光栅(LCFBG)完成可调谐微波光子滤波器(MPF)的功能。通过调整VPS的相位可完成MPF中心频率的调谐,进而实现OEO振荡频率的调谐功能。理论分析和仿真实验表明,通过调谐VPS的相位可实现振荡频率大范围调谐。     

调谐二极管激光吸收光谱技术中的线形误差与校正

在调谐二极管激光吸收光谱(TDLAS)技术中,谱线线形的检测精度受激光器调谐非线性和调制幅度的影响,本文针对近红外分布反馈(DFB)激光器,通过激光器的调谐特性曲线定量分析了调谐非线性和调制幅度对吸收线形的影响,提出了调谐非线性校正和调制幅度补偿方法,并通过实验验证了方法的有效性.实验结果表明,调谐非线性校正可以提高谱...     

一种多参数光纤光栅波长调谐器的设计与研制

对基于应力、位移、空间角度的多参数可调谐的光纤光栅(FBG)波长调谐进行了理论分析和实验研究.根据推导出的波长调谐公式,数值模拟了光纤光栅波长受应力、位移、空间角度时的多种调谐关系.在模拟分析的基础上,设计了一种基于应力、位移、空间角度的多参数可调谐的光纤光栅波长调谐器,并进行了实验验证.实验表明基于应力、位移的调谐为线性调谐,各光栅调谐线性拟合度均达0.9975以上;基于角度的调谐近似满足正(余)弦调谐.理论分析和实验测量具有良好的一致性.     

面向业务的光波长可调谐OBS环网

本文结合声光可调谐滤波器(AOTF)和光突发交换(OBS)技术构建了基于固定发射调谐接收机制(FTTR)的面向业务的光波长可调谐环型传送网.并对采用令牌轮询协议(RR/TOKEN)的光波长可调谐OBS环网在性能方面进行了计算机仿真研究,深入分析了最大突发包长度以及传输距离等参数对它的影响.     

中红外可调谐量子级联激光器研究进展

量子级联激光器(QCL)是中红外波段重要的激光光源,其中,可调谐中红外量子级联激光器具有单纵模、频率可调谐的优点,成为目前研究的热点。可调谐中红外量子级联激光器主要通过分布反馈(DFB)光栅、分布布拉格反射(DBR)光栅、外腔衍射光栅等方法实现。本文介绍了中红外量子级联激光器的基本原理,分别归纳、总结了近年来DFB、DBR可调谐量子级联激光器以及外腔可调谐量子级联激光器的研究进展,讨论了各种可调谐方法的优缺点。最后,对可调谐量子级联激光器的发展趋势进行了展望。     

可调谐激光器的固体化趋势

本文综合性地评述了由于掺钛蓝宝石等固体可调谐激光器的问世,在可调谐激光技术领域出现的由液体(染料)可调谐激光器向固体(过渡金属离子,光参量振荡)可调谐激光器转变的发展趋势,以及全固化的发展方向。     

一种新型跨导-电容滤波器自调谐电路

提出了一种基于开关电容技术的跨导一电容(Gm-C)滤波器自调谐电路.与基于压控振荡器(VCO)和压控滤波器(VCF)的传统调谐电路不同,该自调谐电路具有更高的精度和更低的功耗,且电路结构简单.设计了一个9阶椭圆函数低通滤波器,通过该调谐电路,实现了截止频率的精确可调.     

基于可调谐真相移的可调谐光电振荡器

提出一种基于真相移(TPS)实现可调谐光电振荡器( OEO)的方案。只需通过调谐Mach-Zehnder 调制器(MZM)的偏置电压,就可以实现可谐滤波器的频谱响应的改变,即可实现TPS滤波器。 其中,两个抽头的可调谐滤波器是由双光源、双调制器以及叠印光栅来实现。OEO的输出频 率由二抽头可调 谐滤波器的峰值频率决定,而滤波器可调谐,这样就可以实现输出OEO的输出频率可调。 仿真结果表明,输出频率可以实现5～10GHz宽带宽可调谐。     

浅谈无功补偿方案在电力系统运行中的选择

本文简要介绍了传统单独使用电容器进行无功补偿的不足,并全面分析了调谐滤波方案(即带调谐电抗器的电容器组)的优点。着重介绍了调谐滤波解决方案,并以山西云海镁厂供电系统中调谐滤波方案的应用系统为例详细介绍了调谐滤波方案的设计原理,参数选型。     

微波单晶铁氧体器件再展雄风

本文叙述了微波单晶铁氧体器件——YIG调谐滤波器(YTF);YIG调谐振荡器(YTO);YIG调谐器件组件;YIG单晶薄膜及平面器件;磁光器件的概况及其发展方向。 微波单晶铁氧体器件已有近50年发展历史。YIG调谐滤波器(YTF),YIG调谐振荡器(YTO)是其典型产品,产品已经系列化。频率范围从0.5～40GHz,有点频、     

Novel fiber-optical interferometer with miniaturized probe for in-hole measurements

Today, micro-system technology and the development of new MEMS （Micro-Electro-Mechanical Systems） are emerging rapidly. In order for this development to become a success in the long run, measurement systems have to ensure product quality. Most often, MEMS have to be tested by means of functionality or destructive tests. One reason for this is that there are no suitable systems or sensing probes available which can be used for the measurement of quasi inaccessible features like small holes or cavities. We present a measurement system that could be used for these kinds of measurements. The system combines a fiber optical, miniaturized sensing probe with low-coherence interferometry, so that absolute distance measurements with nanometer accuracy are possible.     

Theoretical analysis of the relationship between the Brillouin gain coefficient and the strain in the optical-fiber sensors

The relation between the power of the Brillouin signal and the strain is one of the bases of the distributed fiber sensors of temperature and strain. The coefficient of the Bfillouin gain can be changed by the temperature and the strain that will affect the power of the Brillouin scattering. The relation between the change of the Brillouin gain coefficient and the strain is thought to be linear by many researchers. However, it is not always linear based on the theoretical analysis and numerical simulation. Therefore, errors will be caused if the relation between the change of the Brillouin gain coefficient and the strain is regarded as to be linear approximately for measuring the temperature and the strain. For this reason, the influence of the parameters on the Brillouin gain coefficient is proposed through theoretical analysis and numerical simulation.     

Towards Mobile Ubiquitous Service Environment

In this article we present a perspective on future vision of mobile communications and services which is referred to as Mobile Ubiquitous Service Environment (MUSE). Based on analysis of wireless communications and services, we exploit a conceptual model for MUSE via a top-down approach. The conceptual model consists of three major elements: Terminal Service Environment (TSE), Network Service Environment (NSE) and User Identity (UID). The concept of Always the Best Experience (ABE) is addressed as the hinge in design and development such that the user-centric services could be provided automatically and intelligently in the future diverse wireless world Based on these, we further discuss the issues on design and implementation of architecture of future wireless communication system. Requirements for architecture brought by the new features of MUSE are listed. Moreover, we also address several tradeoffs that should be taken into consideration in design. Finally, the deployment challenges for MUSE, such as reflectiveness of system, security and privacy, as well as peer-to-peer AAA are predicted.Ji Yang received PhD degree on Circuit and System, Bachelor degree on Telecommunication Engineering from Beijing University of Posts and Telecommunications (BUPT) in 2002 and 1993 respectively. Currently, he is an associate professor of BUPT, chief technical supervisor of Wireless Technology Innovation Institute, and vice manager of MTlab of Sino-Germany Software Institute. He leads the research on service and application in Future Forum in China. He also made much contribution to the China Communication Standardization Association (CCSA), including the vision of future Mobile Ubiquitous Service Environment, architecture of future B3G mobile terminal, etc. His research interests include architecture design for mobile ubiquitous networks, theory of self-organization, etc.Zhang Ping is now the professor of Beijing University of Posts and Telecommunications and director of Wireless Technology Innovation (WTI) Institute, BUPT. He has also served on the senior member of C3G Group, China MOST 863 future mobile communication FuTURE project, vice-chairman of China FuTURE Forum, and member of Vision Committee of World Wireless Research Forum(WWRF), he was vice chair of WWRF in 2005. He is also invited as the consultants for many domestic and oversea communication companies. He is very active on the international research activity on Beyond 3G area. He also participated in several European projects such as E2R and MOCCA. Until now, he has published 6 books, around 400 publications in journals and conferences in the area of telecommunications. His main research interests are theory and applications in wireless communication area. He was awarded by government, city of Beijing and Ministry of Information Industry several times for his great contribution to the industry and research activity in China.Hu Zheng is a PH.D candidate in mobile communications engineering in Wireless Technology Innovation Institute (WTI) at Beijing University of Posts and Telecommunications (BUPT). He received B.S degree from Nanjing University of Posts and Telecommunications in 2002, majoring in computer communications engineering. He currently works on serivce aspects of mobile ubiquitous communication system with focus on design and performance evaluation of interaction protocols and services in self-organized service environment.Wang Xu received the B.Tech. degree in electronic engineering from Beijing Polytechnic University (now named as Beijing University of Technology), Beijing, China, in 2002. Now he is working for his Ph.D. degree in Wireless Technology Innovation (WTI) Institute, Beijing University of Posts and Telecommunications (BUPT). His current interests include wireless communications in personal area, ad hoc networks and peer-to-peer system.Li Yinong received the BS degree major in Telecommunication Engineering in 1993 from Beijing University of Posts and Telecommunications, the MS degree and PhD degree major in Telecommunication and Electronic System in 1995 and 2003 from the Beijing University of Posts and Telecommunications. He is currently a lecture of STE (School of Telecommunication Engineering) of BUPT. His main research interests include service modeling, service composition approach, and intelligent service. In BUPT, he has given several lectures to both graduate and undergraduate students such as Information Theory, Speech Recognition, Pattern Recognition and Artificial Intelligence.     

An improved parallel thinning algorithm with two subiterations

The parallel thinning algorithm with two subiterations is improved in this paper. By analyzing the notions of connected components and passes, a conclusion is drawn that the number of passes and the number of eight-connected components are equal. Then the expression of the number of eight-connected components is obtained which replaces the old one in the algorithm. And a reserving condition is proposed by experiments, which alleviates the excess deletion where a diagonal line and a beeline intersect. The experimental results demonstrate that the thinned curve is almost located in the middle of the original curve connectivelv with single pixel width and the processing speed is high.     

High Speed Curve Interpolating D/A Converter

This paper presents a design of high speed curve interpolating D/A converter. We improve 8-bit data to 12-bit data, so the data resolution increases 16 times than that of original 8-bit data. The curve interpolator is developed from the linear interpolator. The simulation speed curve interpolator is about 500 MHz. The chip is fabricated by 0.8 m double-metal single poly CMOS technology. The active interpolation size of chip is 1 × 1 mm². The power dissipation is 200 mWatts at 5volt and 500 MHz for simulation result and 80 mWatts at 5 volt and 50 MHz for measurement result. The errors of interpolating result of curve interpolators are about 20 times less than that of original signal.     

Status and Trends in Advanced SOI Devices and Materials

提供了一种用于安德鲁反射测量样品制备新方法. 该方法采用聚焦粒子束刻蚀和磁控溅射,可以获得可控的、干净的、无应力的纳米接触用于自旋极化探测. 所制备的样品中,磁性和非磁性材料样品的反射谱都表现出复杂的峰和谷结构,这些结构可能源于与界面相关的零偏压反常以及与激发态相关的准离子相互作用. 对另一个Co40Fe40B20合金样品采用简单的钕针尖压针方法进行了对比性测量,反射谱中没有观察到谷结构,但谱结构出现较明显的热扩展,这种热扩展可能来源于界面处的非弹性输运. 所有的反射谱目前还不能由现有的理论给出令人满意的解释. 利用点接触反射方法获得可靠的自旋极化信息还有赖于接触界面特征的进一步分析. 而一个更切合实际的、更完善的理论成为迫切的需要.     

Memory Performance Optimizations For Real-Time Software HDTV Decoding

Pure software HDTV video decoding is still a challenging task on entry-level to mid-range desktop and notebook PCs, even with today’s microprocessors frequency measured in GHz. This paper shows that the performance bottleneck in a software MPEG-2 decoder has been shifted to memory operations, as microprocessor technologies including multimedia instruction extensions have been improving at a fast rate during the past years.Our study exploits concurrencies at macroblock level to alleviate the performance bottleneck in a software MPEG-2 decoder. First, the paper introduces an interleaved block-order data layout to improve CPU cache performance. Second, the paper describes an algorithm to explicitly prefetch macroblocks for motion compensation. Finally, the paper presents an algorithm to schedule interleaved decoding and output at macroblock level. Our implementation and experiments show that these methods can effectively hide the latency of memory and frame buffer. The optimizations improve the performance of a multimedia-instruction-optimized software MPEG-2 decoder by a factor of about two. On a PC with a 933 MHz Pentium III CPU, the decoder can decode and display 1280 × 720-resolution HDTV streams at over 62 frames per second.This work was done while the author was a Ph.D. candidate in the Computer ScienceHan Chen is a research staff member in IBM T.J. Watson Research Center. His research interests include distributed computing systems, scalable display system, and multimedia. He received his Ph.D. degree in 2003 and his M.A. degree in 1999 from Princeton University. He received his B.S. degree from Tsinghua University of Beijing, China in 1997.Kai Li is a Charles Fitzmorris professor at the Computer Science Department of Princeton University. His research interests include operating systems, computer architecture, distributed systems, and scalable display systems. He received his Ph.D. degree from Yale University in 1986. Prior to that, he received his M.S. degree from University of Science and Technology of China, Academy of Sciences of China in 1981 and a B.S. degree from Jilin University in China in 1977. He was a visiting faculty member at University of Toronto in 1988 and a visiting professor at Stanford University during his sabbaticals in 1996 and 2000. He has served on dozens of program committees and served as chair or vice chair several times. He has been elected as an ACM fellow in 1998.Bin Wei received a Ph.D. in Computer Science from Princeton University in 1998 and joined the research community at AT&T Shannon Laboratories since then. His research interests are in the areas of high-performance computer systems, multimedia, and service platforms for mobile users. He received a BS in Computer Science from Tianjin University, China in 1983 and an MS in Computer Science from the Institute of Computing Technology, Chinese Academy of Sciences, in 1989.     

一个具有附益性及保序性算子的形态学非局部拓展

近年，形态学非局部拓展工作在图像处理领域受到众多关注.而附益性算子是经典形态学的最基本形式，也是形态学分析方法最重要的变换工具.为此，一些研究者就形态学非局部拓展中如何保持算子的附益性开展工作.本文从理论及实例两个方面说明，相关拓展工作为保持算子的附益性而丢失了保序性的不足；进一步，通过设计非局部权值的获取过程，并结合现有工作，本文提出了一个新的形态学非局部拓展，并定理证明了所得算子同时具备附益性及保序性两个重要性质；人工合成图像及自然图像上的仿真实验也表明了本文所提算法的有效性.     

Energy-efficient resource allocation model for device-to-device communication in 5G wireless personal area networks

In general, there are several many devices that can overload the network and reduce performance. Devices can minimize interference and optimize bandwidth usage by using directional antennas and by avoiding overlapping communication ranges. In addition, devices need to carefully manage their use of resources, such as bandwidth and energy. Bandwidth is limited in wireless personal area networks (WPANs), so devices need to carefully select which data to send and receive. In this paper, an intelligent performance analysis of energy-efficient resource optimization model has been proposed for device-to-device (D2D) communication in fifth-generation (5G) WPAN. The proposed energy-efficient resource allocation in D2D communication is important because it helps reduce energy consumption and extend the lifespan of devices that are communicating with each other. By allocating resources in an efficient manner, communication between two devices can be optimized for maximum efficiency. This helps reduce the amount of energy needed to power the communication, as well as the amount of energy needed to power the device that is communicating with another device. Additionally, efficient resource allocation helps reduce the overall cost of communication, as the use of fewer resources results in a lower overall cost. The proposed efficient resource allocation helps reduce the environmental impact of communication, as less energy is used for communication. The proposed energy-efficient resource allocation model (EERAM) has reached 92.97% of energy allocation, 88.72% of power allocation, 87.79% of bandwidth allocation, 87.93% of spectrum allocation, 88.43% of channel allocation, 25.47% of end-to-end delay, 94.33% of network data speed, and 90.99% of network throughput.     

基于WDM的设备驱动程序设计和实现

设备驱动程序是硬件设备连接到计算机系统的软件接口。Windows驱动程序模型(WDM)是Windows平台的新一代设备驱动程序模型,WDM的研究对设计优良设备驱动程序有重要指导作用。文章分析WDM的工作原理和机制,着重介绍WDM设备驱动程序的设计和实现方法,并给出一个通用串行总线(USB)设备驱动程序的设计实例。该设计将USB驱动程序分为即插即用(PnP)、电源管理、USB初始化和USB设备输入/输出(I/O)等功能模块,具有结构清晰、易移植、复用性好等优点,在USB驱动程序设计中具有良好的应用价值。