通信性能评估的仿真实验研究

研究了流量控制和差错控制对通信性能的综合影响，着重分析了停止-等待协议和连续ARQ协议的优缺点，讨论了信道利用率和帧长的关系。介绍了几种多点接人技术的基本原理，如CSMA和CSMA／CD，并给出了各自相应的性能仿真曲线。所设计的通信性能评估实验，仿真界面形象丰富，与实验知识点紧密结合，可以大大提高实验教学的效率和质量。     

UC3875在超声电源功率控制系统中的应用

根据超声波发生器的功率控制系统原理 ,阐述了移相控制策略对超声波发生器输出电压波形的影响 ,介绍了移相控制专用芯片UC3875的电路结构和使用设计方法。     

实时Motion JPEG2000视频编码系统设计

介绍了基于ADV202 JPEG2000编码芯片的Motion JPEG2000视频编码系统,该系统可实现SMPTE274M的实时编码,支持失真/无失真编码,与标准完全兼容.给出了系统硬件结构和软件流程设计,提出了一种利用帧间相关性减少编码计算量的码率控制方法.     

单片机控制下液晶显示器的使用

介绍液晶显示器EDM12864B的原理及其在单片机控制下的简单应用。     

混合动力电动汽车用电机及驱动控制器的电磁兼容设计

电机及驱动控制器作为电动汽车的关键部件,其电磁兼容设计对于保证电动汽车的可靠运行非常重要.介绍了国家十五项目中某混合动力轿车用电机及控制器系统的电磁兼容措施,分别从控制电路、信号电缆、功率电路及屏蔽机箱等工程角度进行了分析和设计.该系统的电磁兼容性符合GB/T17619-1998的要求,且已应用于实际混合动力电动汽车,运行情况良好.     

采用RF2607的WLAN自动增益控制设计

介绍了宽动态变化范围的新型可变增益放大器RF2607的特性、功能,给出了利用RF2607设计无线局域网(WLAN)通信中自动增益控制部分的实用电路.     

A call admission and rate control scheme for multimedia support over IEEE 802.11 wireless LANs

Quality of service (QoS) support for multimedia services in the IEEE 802.11 wireless LAN is an important issue for such WLANs to become a viable wireless access to the Internet. In this paper, we endeavor to propose a practical scheme to achieve this goal without changing the channel access mechanism. To this end, a novel call admission and rate control (CARC) scheme is proposed. The key idea of this scheme is to regulate the arriving traffic of the WLAN such that the network can work at an optimal point. We first show that the channel busyness ratio is a good indicator of the network status in the sense that it is easy to obtain and can accurately and timely represent channel utilization. Then we propose two algorithms based on the channel busyness ratio. The call admission control algorithm is used to regulate the admission of real-time or streaming traffic and the rate control algorithm to control the transmission rate of best effort traffic. As a result, the real-time or streaming traffic is supported with statistical QoS guarantees and the best effort traffic can fully utilize the residual channel capacity left by the real-time and streaming traffic. In addition, the rate control algorithm itself provides a solution that could be used above the media access mechanism to approach the maximal theoretical channel utilization. A comprehensive simulation study in ns-2 has verified the performance of our proposed CARC scheme, showing that the original 802.11 DCF protocol can statically support strict QoS requirements, such as those required by voice over IP or streaming video, and at the same time, achieve a high channel utilization. Hongqiang Zhai received the B.E. and M.E. degrees in electrical engineering from Tsinghua University, Beijing, China, in July 1999 and January 2002 respectively. He worked as a research intern in Bell Labs Research China from June 2001 to December 2001, and in Microsoft Research Asia from January 2002 to July 2002. Currently he is pursuing the PhD degree in the Department of Electrical and Computer Engineering, University of Florida. He is a student member of IEEE. Xiang Chen received the B.E. and M.E. degrees in electrical engineering from Shanghai Jiao Tong University, Shanghai, China, in 1997 and 2000, respectively, and the Ph.D. degree in electrical and computer engineering from the University of Florida, Gainesville, in 2005. He is currently a Senior Research Engineer at Motorola Labs, Arlington Heights, IL. His research interests include resource management, medium access control, and quality of service (QoS) in wireless networks. He is a Member of Tau Beta Pi and a student member of IEEE. Yuguang Fang received a Ph.D degree in Systems and Control Engineering from Case Western Reserve University in January 1994, and a Ph.D degree in Electrical Engineering from Boston University in May 1997. From June 1997 to July 1998, he was a Visiting Assistant Professor in Department of Electrical Engineering at the University of Texas at Dallas. From July 1998 to May 2000, he was an Assistant Professor in the Department of Electrical and Computer Engineering at New Jersey Institute of Technology. In May 2000, he joined the Department of Electrical and Computer Engineering at University of Florida where he got the early promotion with tenure in August 2003 and has been an Associate Professor since then. He has published over one hundred (100) papers in refereed professional journals and conferences. He received the National Science Foundation Faculty Early Career Award in 2001 and the Office of Naval Research Young Investigator Award in 2002. He is currently serving as an Editor for many journals including IEEE Transactions on Communications, IEEE Transactions on Wireless Communications, IEEE Transactions on Mobile Computing, and ACM Wireless Networks. He is also actively participating in conference organization such as the Program Vice-Chair for IEEE INFOCOM’2005, Program Co-Chair for the Global Internet and Next Generation Networks Symposium in IEEE Globecom’2004 and the Program Vice Chair for 2000 IEEE Wireless Communications and Networking Conference (WCNC’2000).     

IGCT 综合型电荷控制 模型的建立和仿真

以电荷控制方程而建立的IGCT综合型电荷控制模型，经关键性的关断电流和关断电压进行了仿真分析，所得结果与实际结果吻合。因此该模型是有效的，可用于IGCT的开关特性分析和集成门极电路设计。     

具有控制项的限定记忆卡尔曼滤波器

在已有的限定记忆卡尔曼滤波器的基础上 ,将确定性先验信息作为控制项加以应用 ,推导出了完整的限定记忆卡尔曼滤波公式 ,从而在记忆长度确定的情况下 ,有效地减小了模型不准的误差 ,降低了滤波总误差。仿真同样表明了该方法的有效性     

Scheduling Algorithms for Packet-Oriented MAC Protocols in Wireless Multimedia Systems

Future generation wireless multimediacommunications will require efficient Medium AccessControl (MAC) protocols able to guarantee suitable Qualityof Service (QoS) levels for different traffic classes whileachieving a high utilization of radio resources. This paperproposes a new scheduling technique to be adopted at the MAClevel in wireless access systems, named Dynamic Scheduling-Time DivisionDuplexing (DS-TDD), that efficiently managesvideo, voice, Web and background traffics. A theoretical approachis proposed in this paper to evaluate the DS-TDD performance withvoice and Web traffics. Simulation results have permitted tohighlight the following promising characteristics of the DS-TDDscheme: (i) a high capacity of real-time traffics isattained with a QoS insensitive to Web and background trafficloads; (ii) a high throughput can be guaranteed whilepreserving the QoS levels of the different traffic classes;(iii) heavier downlink traffic loads do not modify the QoSof uplink traffics. Finally, extensive comparisons with differentscheduling schemes proposed in the literature have permitted tohighlight the better performanceof DS-TDD.