共查询到20条相似文献,搜索用时 93 毫秒
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阐述了智能天线的基本原理,指出码分多址系统基站中采用智能天线技术可能抑制多址干扰。在总结分析了目前各种波束形成技术的基础上,着重介绍了一种适用于移动无线通信环境的阵列权值调整准则-最大接收信号准则,利用此准则和相应算法。提出了一种带智能天线的新型最小均方误差多用户检测器,理论分析证明了采用新型检测器后系统容量显增加,仿真实验表明,新型检测器的误码性能大大优于改进前的检测器。 相似文献
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自适应阵列天线中的波束赋形技术是智能天线数字信号处理部分的核心,在介绍和比较常用波束赋形算法以及RLS算法的基础上,提出了-种改进的RLS算法以提高系统的性能。对于用自适应阵列天线改善GPRS基站系统,提高其容量、减少干扰信号、提高信噪比、提高系统频谱利用率有很大的现实意义。 相似文献
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自适应阵列智能天线(AdaptiveArrayAntenna) ,是一种起源于相控阵雷达的天线技术。自适应阵列智能天线利用基带数字信号处理技术 ,通过先进的算法处理 ,对基站的接收和发射波束进行自适应的赋形 ,从而达到降低干扰、增加容量、扩大覆盖和提高无线数据传输速率的目的。目前 ,自适应阵列智能天线已经成为智能天线发展的主流。本文主要介绍自适应阵列智能天线在3G中的应用 ,同时介绍了爱瑞通信公司 (ArrayCommInc)的IntelliCell技术技术方案。1 自适应阵列天线技术自适应阵列天线技术是近30… 相似文献
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在CDMA基站中采用自适应阵列天线技术可以克服多址干扰,提高系统容量。本文针对目前一种收敛速度较快的HLMS算法作了性能分析,仿真结果表明除特殊条件外,HLMS算法在加快收敛速度的同时也增大了噪声。 相似文献
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在对高铁视距SIMO (single-input multiple-output)下的直线多天线阵列接收进行三维建模的基础上,分析了车载N组阵列合并接收的信道容量,发现合并后的信道容量在基站附近会得到提升,但是存在抖动,而且很快衰减到香农容量,单纯地增加接收天线阵列组数N并不能获得平稳容量增益。研究还发现,调整阵列的参数并将阵列进行分组,适当改变每组阵列的权重值可获得稳定容量增益。计算机数值仿真结果也表明,适当的设置会使得列车在不同速度下克服驶过基站时的容量振荡,并获得平稳的信道容量。 相似文献
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在频率选择性衰落环境中,MIMO-OFDM系统能够极大地提高无线通信系统的容量和可靠性.发射/接收天线选择方法能以很小的性能损失换取射频成本的大幅度降低,使系统不完全受射频成本的限制.容量性能是天线选择当中的重要准则.现提出一种基于子系统的接收天线选择方法,降低了多载波系统的复杂度.仿真结果表明,系统的容量性能与传统方法相当,在接收信噪比为20dB、发射端采用两根接收天线的时候,12选2比无选择的情况得到近1.2比特/信道的容量增量,并且容量增益随着天线的增加而增加. 相似文献
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Meihua Shen Wilfred Pau Nicolas Gani Jianping Wen Shashank Deshmukh Thorsten Lill Jian Zhang Hanming Wu Guqing Xing 《半导体技术》2004,29(8)
This paper presents a brief overview of the Applied Centura(R)DPS(R)system,configured with silicon etch DPS Ⅱ chamber, with emphasis on discussing tuning capability for CD uniformity control. It also presents the studies of etch process chemistry and film integration impact for an overall successful gate patterning development. Discussions will focus on resolutions to key issues, such as CD uniformity, line-edge roughness, and multilayer film etching integration. 相似文献
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White organic light-emitting devices based on fac tris(2- phenylpyridine) iridium sensitized 5,6,11,12-tetraphenylnap -hthacene 总被引:1,自引:0,他引:1
We have fabricated the white organic light-emitting devices (WOLEDs) based on 4,4' -bis(2,2 -diphenyl vinyl)-1,1' - biphenyl (DPVBi) and phosphorescence sensitized 5,6,11,12,-tetraphenylnaphthacene (rubrene). The device structure is ITO/2T-NATA (20 nm)/NPBX (20 nm)/CBP: x%Ir(ppy)3:0.5% rubrene (8 nm)/NPBX (5 nm)/DPVBi (30 nm)/Alq(30 nm)/LiF(0.5 nm)/A1. In the devices, DPVBi acts as a blue light-emitting layer, the rubrene is sensitized by a phosphorescent material, fac tris (2-phenylpyridine) iridium [Ir(ppy)3], acts as a yellow light-emitting layer, and N,N' -bis- (1-naphthyl)- N,N' -diphenyl -1, 1' -biphenyl-4,4' -diamine (NPBX) acts as a hole transporting and exciton blocker layer, respectively. When the concentration of Ir (PPY)3 is 6wt%, the maximum luminance is 24960 cd/m^2 at an applied voltage of 15 V, and the maximum luminous efficiency is 5.17 cd/A at an applied voltage of 8 V. 相似文献
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Complete approach to automatic identification and sub-pixel center location for ellipse feature 总被引:1,自引:0,他引:1
XUE Ting WU Bin SUN Mei YE Sheng-hua 《光电子快报》2008,4(1):51-54
To meet the need of automatic image features extraction with high precision in visual inspection, a complete approach to automatic identification and sub-pixel center location for similar-ellipse feature is proposed. In the method, the feature area is identified automatically based on the edge attribute, and the sub-pixel center location is accomplished with the leastsquare algorithm. It shows that the method is valid, practical, and has high precision by experiment. Meanwhile this method can meet the need of instrumentation of visual inspection because of easy realization and without man-machine interaction. 相似文献
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Credence Systems Corporation 《半导体技术》2004,29(9)
Integrated circuits (ICs) intended for increasingly sophisticated automotive applications bring unique test demands. Advanced ICs for applications such as highly integrated automatic braking system (ABS) and airbag controllers combine high voltage digital channels, significant VI demands and precise timing capability. Along with continued missioncritical reliability concerns, the trend toward higher voltage operation and increased device integration requires specialized test capabilities able to extend across the wide operating ranges found in automotive applications. Among these capabilities, automotive test requirements increasingly dictate a need for a cost-effective versatile mixed-signal pin electronics with very high data rates reaching up to 50MHz with a voltage swing of-2 V to +28 V. 相似文献
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It is of interest to get appropriate information about the dynamic behaviour of rotating machinery parts in service. This paper presents an approach of optical vibration and deviation measurement of such parts. Essential of this method is an image derotator combined with a high speed camera or a laser doppler vibrometer (LDV). 相似文献
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正For a long time,optical and wireless systems/net-works are developed in separate communities witha few attempts for in-depth convergence.In fact,it prom-ises many advantages to combine the optical and wire-less technologies in the levels of systems and networks.Recently,both academia and industry have made manyefforts to enter a new phase of development to take op-tical and wireless systems as fully integrated networks.To provide high bandwidth and reliable service for bothfixed and mobile users,a well-designed network must 相似文献
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Zhang Xinsheng 《中国通信》2014,(1)
正Happy New Year!As we step into a new year,we take a look back at the key feature topics covered in China Communications over the past 12 months and set out our expecta- 相似文献
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正Cloud computing is a novel computing paradigm that utilizes remote cloud resources to achieve a high-performance computation.Cloud provides infrastructure,platform and software as different on-demand services.China has made remarkable progress in cloudbased products and operating system technology.The government,enterprises and research institutions are all active in the development of cloud computing-related projects.Despite the progress,many important problems 相似文献
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