无线局域网环境中OFDM系统频偏综合估计

本文提出了一种针对IEEE802．11a OFDM系统频偏综合估计算法，该算法分两个过程对OFDM频偏进行估计；捕获过程和跟踪过程，计算机仿真表明，该算法在不降低估计误差均方差的情况下，相对于其它使用前导字进行频偏跟踪的算法能够提供更大的频偏估计范围，具有更高的频率和更低的计算复杂度。     

基于DM6437的运动目标跟踪系统研究

为了克服智能视频监控系统可视范围有限,单纯硬件改进增加系统成本的问题,提出一种运动目标跟踪系统,运用混合高斯背景模型的方法实现运动目标的提取,采用卡尔曼滤波器和均值漂移算法相结合实现运动物体的跟踪算法。使用TI公司达芬奇芯片中的DM6437对该算法进一步优化改进,并实现了运动目标跟踪系统,通过对运动小车跟踪测试可知,当小车和背景在RGB色彩空间中反差很大时,跟踪的效果理想;反差很小时,跟踪的失败率会有所提高,整体跟踪效果良好。     

无线光通信ATP演示实验系统

针对空间无线光通信中捕获、瞄准和跟踪（ATP）技术的粗跟踪系统对信标光斑实时准确跟踪需求,为项目进一步工作提供基础,搭建了无线光通信ATP演示实验系统,分别对粗、精跟踪子系统进行了详细的介绍,利用该系统进行了运动目标的模拟跟踪实验。结果表明：粗跟踪可将运动误差控制在200μrad之内,使光目标始终维持在精跟踪视场内,精跟踪可将系统误差控制在15μrad,可满足通信需求。     

时变WOC信道的二阶盲辨识与估计研究

时变及干扰严重是室内光无线通信应用的主要限制.本文引入基于二阶统计量的盲辨识信道估计与去噪策略,对WOC室内信道变化进行自适应跟踪.采用不同的WOC信道作为研究对象,完成了对噪声的估计及信道系数的预测.模拟中对SNR的跟踪范围达30dB,结果证明该方法对信道变化具有适应性.利用该方法对WOC进行改进,可以获得稳定、高效的WOC室内应用系统.     

一种具有听觉功能的智能视频监控系统

基于图像的智能视频监控系统由于视角有限,当目标不在摄像头视场范围时,易出现监控盲区,为了解决该难题,利用声源定位的优点,提出一种具有听觉功能的智能视频监控系统。首先采集传声器线性阵列,采用时延估计技术对声源进行定位,然后根据声源位置驱动摄像头,使其转动到声源位置并采集视频信息,最后采用图像检测程序对目标进行实时定位和跟踪,并通过仿真测试验证该系统的可行性,结果表明,该系统具有较好的定位和跟踪精度。     

基于跟踪微分器的模型参考自适应控制

为了处理二阶系统模型参数的大范围不确定性,提出了基于跟踪微分器的模型参考自适应控制,利用两个非线性跟踪微分器分别得到系统输出的微分信号和误差的微分信号,同时抑制了高频噪声放大效应。根据被控对象的数学模型,自适应调节律能自动实时调节控制律中的参数。实验结果表明,当雷达伺服系统被控对象模型的参数在较大范围内变化时,该新型控制器有效补偿了二阶系统参数的不确定性,提高了伺服系统稳态和动态跟踪精度,保证了系统的全局渐近稳定。     

智能娱乐园物联网系统的研究与开发

提出了一个集无线传感网技术、GPRS定位跟踪、视频监控、娱乐和管理于一体的智能娱乐园物联网系统。给出了系统的结构设计,阐明了工作原理、系统功能及软件结构;采用适合物联网(IOT)的系统设计方法、面向物联网的架构(TOA)和基于该架构的中间件(TOC)予以实现。系统实现了射频识别器(RFID)智能化识别、GPS定位跟踪、网络化视频监控、设备租赁管理、状态环境无线监测、娱乐的智能化管理等功能。     

基于增量学习神经模糊网络的机动目标跟踪

本文提出了基于增量学习神经模糊网络机动目标跟踪模型.当被跟踪目标发生机动时,该模型立刻检测到机动并对卡尔曼滤波器的自适应系统协方差进行精确估计,系统得到及时、正确的补偿.增量学习神经模糊网络能够随着环境变化,自动调整、找到最优的网络结构及参数,当发生机动时,总是能产生接近真实机动值的估计输出,从而提高跟踪性能及避免错误跟踪.仿真结果表明,该模型比传统的机动目标跟踪模型有更好的跟踪性能,并且该模型能动态的适应环境的变化,使系统更加实时,精确的跟踪机动目标.     

基于MSP430F169单片机和红外的多点温、湿度无线监测系统的设计

温度、湿度是工农业生产中重要的环境参数,对其进行实时准确地测量显得尤为重要。文章采用MSP430F169单片机对温、湿度进行监测,使用红外作为无线传输方式,设计了一种精度高、功能强、体积小、价格低、简单灵活的多点温、湿度无线监测系统。当监测的温湿度参数超出设定的范围,系统会发出报警信号。该设计将具有较好的实用价值和推广前景。     

车载血库温度监控系统的研究及实现

为了有效控制车载血库的温度,使血库内的温度保持在(5±1)℃,设计了一套用于车载血库的温度监控和报警系统.该系统利用DS18B20数字温度传感器测量血库内外温度,当血库内温度超过上限时,单片机启动制冷压缩机降温,当低于下限时,关闭制冷压缩机,从而控制血库内的温度.与传统温度监控系统相比,该系统在血库外增加了一个温度传感器,解决了外界温度对血库内的温度控制的影响,提高了精度;此外,该系统还增加了打印和无线短信模块,能够打印时间和温度,便于工作人员的观察和记录.实验表明,在室外不同温度范围时,该系统能使单片机在血库内相应的温度时控制报警系统和制冷压缩机的开关,使血库温度保持在有效范围内.     

Cost-effective test solutions for smart card and other integrated flash applications

From its emergence in the late 1980s as a lower cost alternative to early EEPROM technologies, flash memory has evolved to higher densities and speedsand rapidly growing acceptance in mobile applications.In the process, flash memory devices have placed increased test requirements on manufacturers. Today, as flash device test grows in importance in China, manufacturers face growing pressure for reduced cost-oftest, increased throughput and greater return on investment for test equipment. At the same time, the move to integrated flash packages for contactless smart card applications adds a significant further challenge to manufacturers seeking rapid, low-cost test.     

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.     

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.     

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.     

Teleportation of an arbitrary unknown N-qubit entangled state under the controlling of M controllers

A new quantum protocol to teleport an arbitrary unknown N-qubit entangled state from a sender to a fixed receiver under M controllers(M < N) is proposed. The quantum resources required are M non-maximally entangled Greenberger-Home-Zeilinger (GHZ) state and N-M non-maximally entangled Einstein-Podolsky-Rosen (EPR) pairs. The sender performs N generalized Bell-state measurements on the 2N particles. Controllers take M single-particle measurement along x-axis, and the receiver needs to introduce one auxiliary two-level particle to extract quantum information probabilistically with the fidelity unit if controllers cooperate with it.     

Diode-end-pumped Nd:YVO4/LBO lasers with 4.2W continuous-wave output at 457 nm

A continuous-wave (CW) 457 nm blue laser operating at the power of 4.2 W is demonstrated by using a fiber coupled laser diode module pumped Nd: YVO4 and using LBO as the intra-cavity SHG crystal With the optimization of laser cavity and crystal parameters, the laser operates at a very high efficiency. When the pumping power is about 31 W, the output at 457nm reaches 4.2 W, and the optical to optical conversion efficiency is about 13.5% accordingly. The stability of the out putpower is better than 1.2% for 8 h continuously working.     

Call for Papers

正Wireless Body-area Networks The last decade has witnessed the convergence of three giant worlds:electronics,computer science and telecommunications.The next decade should follow this convergence in most of our activities with the generalization of sensor networks.In particular with the progress in medicine,people live longer and the aging of population will push the development of wireless personal networks     

Call for Papers—Feature Topic,Vol.12,No.7,2015

正Information Centric Networking Information-Centric Networking(ICN) is an emerging direction in Future Internet architecture research,gaining significant tractions among academia and industry.Aiming to replace the conventional host-to-host communication model by a data-centric model,ICN treats data content as the first     

JOURNAL OF ELECTRONICS(CHINA)

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NEXT GENERATION WIRELESS NETWORKS–ESPECIALLY THE USE OF MILLI-MICROWAVE BANDS

The global bandwidth shortage of wireless communications has motivated the exploration of the naillimeter wave （ram-wave） frequency spectrum for the next generation wireless communications. Recent advances in RF CMOS technology and high speed baseband signal processing technologies have enabled tile extensive research and development of turn-wave wireless communications. The multi gigabit per second data rate of ram-wave system will lead to applications in many important scenarios, such as WPAN, WLAN,back-haul for cellular system. And the frequency bands include 28 GHz, 38 GHz, 45GHz, 60GHz, E-BAND and even beyond 100 GHz. The propagation and the imitation of the RF circuits design in these frequency bands make the directional antennas be inevitable for mm-wave communications.