蓝牙与IEEE802.11g系统的共存

蓝牙与IEEE802.11g无线局域网(Wireless Local Area Network,WLAN)都工作在2.4GHz频段上,因此它们之间存在一定的干扰。分析了蓝牙与IEEE802.11g通信系统之间的干扰,并提出了解决这一问题的两种方法:自适应跳频和删除标记法,并对两种方法的性能做了比较。     

电厂燃料桥式抓斗（行车）变频自动化控制

在分析了火电厂燃料桥式抓斗（行车）运行特性基础上。采用变频控制技术对原有控制系统进行了改造，优化了控制系统。解决了调速范围小、速度稳定性差、无法长时间低速下吊重物、故障率高等缺点。     

Layered Wyner-Ziv video coding.

Following recent theoretical works on successive Wyner-Ziv coding (WZC), we propose a practical layered Wyner-Ziv video coder using the DCT, nested scalar quantization, and irregular LDPC code based Slepian-Wolf coding (or lossless source coding with side information at the decoder). Our main novelty is to use the base layer of a standard scalable video coder (e.g., MPEG-4/H.26L FGS or H.263+) as the decoder side information and perform layered WZC for quality enhancement. Similar to FGS coding, there is no performance difference between layered and monolithic WZC when the enhancement bitstream is generated in our proposed coder. Using an H.26L coded version as the base layer, experiments indicate that WZC gives slightly worse performance than FGS coding when the channel (for both the base and enhancement layers) is noiseless. However, when the channel is noisy, extensive simulations of video transmission over wireless networks conforming to the CDMA2000 1X standard show that H.26L base layer coding plus Wyner-Ziv enhancement layer coding are more robust against channel errors than H.26L FGS coding. These results demonstrate that layered Wyner-Ziv video coding is a promising new technique for video streaming over wireless networks.     

掺杂室沉积本征微晶硅材料及其在太阳能电池中的应用

在掺杂P室采用甚高频等离子体增强化学气相沉积（VHF—PECVD）技术,制备了不同硅烷浓度条件下的本征微晶硅薄膜．对薄膜电学特性和结构特性的测试结果分析表明：随硅烷浓度的增加,材料的光敏性先略微降低后提高,而晶化率的变化趋势与之相反;X射线衍射（xRD）测试表明材料具有（220）择优晶向．在P腔室中用VHF—PECVD方法制备单结微晶硅太阳能电池的i层和p层,其光电转换效率为4．7％,非晶硅／微晶硅叠层电池（底电池的p层和i层在P室沉积）的效率达8．5％．     

Multi‐constrained Shortest Disjoint Paths for Reliable QoS Routing

Finding link‐disjoint or node‐disjoint paths under multiple constraints is an effective way to improve network QoS ability, reliability, and so on. However, existing algorithms for such scheme cannot ensure a feasible solution for arbitrary networks. We propose design principles of an algorithm to fill this gap, which we arrive at by analyzing the properties of optimal solutions for the multi‐constrained link‐disjoint path pair problem. Based on this, we propose the link‐disjoint optimal multi‐constrained paths algorithm (LIDOMPA), to find the shortest link‐disjoint path pair for any network. Three concepts, namely, the candidate optimal solution, the contractive constraint vector, and structure‐aware non‐dominance, are introduced to reduce its search space without loss of exactness. Extensive simulations show that LIDOMPA outperforms existing schemes and achieves acceptable complexity. Moreover, LIDOMPA is extended to the node‐disjoint optimal multi‐constrained paths algorithm (NODOMPA) for the multi‐constrained node‐disjoint path pair problem.     

阵列波导光栅复用/解复用器光栅孔径对器件性能影响的数值分析

阵列波导光栅复用 /解复用器中波导光栅孔径是器件重要的结构参数 .波导光栅孔径数值有限 ,部分光场将因未被耦合进而损失掉 .同时引起输出波导接收端焦场变形 ,增加了器件串扰 .本文详细分析和计算了由于波导光栅孔径有限引起的光场损耗和信号串扰 ,选择适当孔径参数可使其引入的信号损耗和串扰降到足够低 ,以优化设计器件     

平面阵列光学波导模式特性及其光强传输分析

分析了平面阵列波导的模式特性.其导波模式为周期性调幅的平面波(Bloch波).阵列波导输入/输出波导结构是影响其传输特性的重要因素.采用扇形过渡波导结构以提高阵列波导输入/输出端口芯区宽度与波导周期宽度的比值,可降低阵列波导光强的传递损耗.并可改善布里渊区入射/出射波的损耗非均匀性.采用低折射率差的波导芯区/包层结构可降低波导对光波的限制,提高光强的传输效率     

基于ZEMAX的半导体激光准直仿真设计

为了压缩905nm的半导体激光,以用于远程测距,采用几何光路原理,设计了由两个相互垂直的椭圆柱面透镜组成的准直系统,并在ZEMAX软件的非序列模式下实现仿真。半导体激光器快慢轴的初始发散角为30°和15°,经过柱面透镜后,半导体激光器两个方向的发散角都大大压缩;经准直后,激光束的快慢轴发散角分别为4.4mrad和3.6mrad,基本满足了远程测距的要求。结果表明,椭圆面柱透镜对半导体激光有很好的准直作用。     

用于以太网的40Gbit/s CFP光模块设计

为了满足传输容量日益增长的需求和降低通信系统的成本,介绍了一种用于城域网的40Gbit/s CFP(百吉比特可热插拔)光模块,该模块采用波分复用技术来实现4路不同波长的10Gbit/s载波信号在一根光纤中传输。它主要由发射单元、接收单元和控制单元3大部分组成。重点介绍了各个部分的工作原理及具体设计方案,按照IEEE 802.3.ba标准对样机进行了测试,结果表明该模块满足40Gbit/s以太网的应用要求。     

天文光电观测系统实时信息处理机的设计与实现

针对地基天文光电观测系统获取图像数据量大、实时处理难度高等特点,设计并实现了以高可靠CPCI工控机为平台、基于FPGA+双DSP TMS320C6455的实时信息处理机。详细介绍了实时信息处理机硬件结构,深入分析了实时信息处理机的设计特点。针对实时信息处理机实时图像获取和实时图像处理的主要任务,重点描述了工程实现过程中图像获取及处理流程、弱小目标检测算法实现、DSP任务分割和速度优化等。外场实验及大量实测数据处理结果验证了该处理机的实时性和处理能力,满足了天文光电观测系统的要求,为高分辨率图像的处理运算提供了可靠的硬件平台。