共查询到20条相似文献,搜索用时 78 毫秒
1.
利用激光建立星间链路不仅具有极高的潜在通信数据率(可达100Gbps以上)、较小的终端体积和重量,并且具有很强的抗干扰能力和保密性,又可以减少地面站,因此各国都非常重视此项技术的研究.随着低轨小卫星数量的显著增加,需要高数据率、低功耗、体积小、价格低的星上通信终端,激光星间链路终端正是满足了这种需求. 相似文献
2.
3.
激光星间链路中振动补偿技术研究 总被引:5,自引:2,他引:3
提出了一种在激光星间链路过程中的卫星平台振动补偿方案。采用CCD探测器代替角度传感检测振动,简化了卫星光通信跟瞄系统。在激光星间链咯中,卫星平台角振动对光束的跟瞄有较大的影响,采用前馈补偿方式实现较好的抑制。在实验室中建立了卫星平台振动模拟装置和前馈振动补偿系统,针对卫星平台的实际振动情况进行了模拟实验。结果表明,对于100Hz卫星平台角振动,当CCD采样频率大于1kHz时,补偿后的瞄准误差与补偿前相比下降了71%。 相似文献
4.
5.
卫星间的第一条光学链路建于2001年11月,该链路使用激光作为信号载体。从那时起,卫星已能实时把图像从空间传输到地面,从而使数据的发送更为及时。 这条实验用的光学数据链路是由安装在法国地球观测卫星SPOT-4号上的“半导体激光器卫星间链路实验”(SILEX)通信终端提供的 相似文献
6.
7.
8.
9.
随着低轨卫星互联网的迅猛发展,星间激光通信链路成为低轨大型星座互联互通的关键,也是用户接入卫星互联网实现全球范围内端到端交互的基础。与地球同步轨道的星间环网不同,由于低轨卫星的高动态性,造成星间链路需要不断动态重构,由此带来空间节点的编址方式、交换路由方法等诸多技术难题,是目前该领域关注的热点。此外,用户终端通过微波链路接入卫星互联网,需要微波链路与激光链路之间的汇集和分发,也是迫切需要研究解决的重点难点问题。 相似文献
10.
通信研究实验室(CRL)已经开发了一种光学卫星通信系统,并计划进行基本的光学通信试验,试验拟采用将于1993年发射的日本工程试验卫星VI(ETS-VI)上的通信系统。目前,ETS-VI的光学通信载荷,即激光通信设备(LCE)正在研制中。装备直径1.5m望远镜的地面光学设施已经基本完成。在卫星通信试验中,将建立一个双向光通信链路,并且,一些基本的光学通信试验如光束定位/跟踪,数据传输,飞行器姿态精密确定和光通过大气层的传输等也将要开展。本文描述了试验计划的基本概况和在研系统的当前状况。 相似文献
11.
M. Arrigoni R. Madd 《International Journal of Satellite Communications and Networking》1988,6(2):197-207
Following a brief introduction reviewing various laser systems suitable for ISL, a typical link budget for an optical ISL with a Nd laser is calculated. Laser diode pumped Nd lasers are described, and several host materials are considered. Modulation formats and typical receiver performances for direct detection are examined in order to compute the minimum transmitted power required for the proposed link. Results show that laser diode pumped Nd laser systems are competitive for optical ISL. 相似文献
12.
13.
继传统的CO2激光器和YAG激光器之后,先进激光加工机于2001后陆续进入市场。LD泵浦的高功率YAG激光器、THGYAG激光器、半导体激光器、光纤激光器、飞秒激光器和盘形激光器统称为先进激光加工机。 相似文献
14.
机载激光器(ABL)是目前美国研发的各种定向能武器中较为成熟的一种。到2010年,ABL项目已经进入了实际拦截试验阶段。本文首先回顾了2010年内ABL的各次拦截试验情况,然后对ABL项目通过这些试验所取得的主要成绩进行了简单总结,并对该项目当前面临的主要问题进行了分析,最后简要介绍了ABL项目的现状及其未来前景。 相似文献
15.
给出了三维技术的定义,并给众多的三维技术一个明确的分类,包括三维封装(3D-P)、三维晶圆级封装(3DWLP)、三维片上系统(3D-SoC)、三维堆叠芯片(3D-SIC)、三维芯片(3D-IC)。分析了比较有应用前景的两种技术,即三维片上系统和三维堆叠芯片和它们的TSV技术蓝图。给出了三维集成电路存在的一些问题,包括技术问题、测试问题、散热问题、互连线问题和CAD工具问题,并指出了未来的研究方向。 相似文献
16.
有机电致发光 (OEL)元件又称为有机发光二极管 ,是一种面发光元件。它由直流低电压驱动 ,发光色从红、绿、蓝 (RGB)三原色到白色 ,自由度较大 ,因此有望成为新一代平板显示器。目前作为车载音响和手机的显示器已达到实用化 ,今后有望得到进一步发展。用于OEL元件的材料大体可分为两种 :一种是低分子量的荧光色素和金属络合物等小分子类材料 ;另一种则是将π共轭聚合物和色素高分子化的含色素聚合物等聚合物类材料。人类对小分子类的研究始于 2 0世纪 6 0年代初 ,对蒽单晶施加电压时观测到发光 ,后经薄膜化和层叠化处理提高了效率和亮度… 相似文献
17.
Current status and future trends of SiGe BiCMOS technology 总被引:8,自引:0,他引:8
Harame D.L. Ahlgren D.C. Coolbaugh D.D. Dunn J.S. Freeman G.G. Gillis J.D. Groves R.A. Hendersen G.N. Johnson R.A. Joseph A.J. Subbanna S. Victor A.M. Watson K.M. Webster C.S. Zampardi P.J. 《Electron Devices, IEEE Transactions on》2001,48(11):2575-2594
The silicon germanium (SiGe) heterojunction bipolar transistor (HBT) marketplace covers a wide range of products and product requirements, particularly when combined with CMOS in a BiCMOS technology. A new base integration approach is presented which decouples the structural and thermal features of the HBT from the CMOS. The trend is to use this approach for future SiGe technologies for easier migration to advanced CMOS technology generations. Lateral and vertical scaling are used to achieve smaller and faster SiGe HBT devices with greatly increased current densities. Improving both the fT and fMAX will be a significant challenge as the collector and base dopant concentrations are increased. The increasing current densities of the SiGe HBT will put more emphasis on interconnects as a key factor in limiting transistor layout. Capacitors and inductors are two very important passives that must improve with each generation. The trend toward increasing capacitance in polysilicon-insulator-silicon (MOSCAP), polysilicon-insulator-polysilicon (Poly-Poly), and metal-insulator-metal (MIM) capacitors is discussed. The trend in VLSI interconnections toward thinner interlevel dielectrics and metallization layers is counter to the requirements of high Q inductors, potentially requiring a custom last metallization layer 相似文献
18.
Transmission of electric power at ultra-high voltages: Current status and future prospects 总被引:4,自引:0,他引:4
《Proceedings of the IEEE. Institute of Electrical and Electronics Engineers》1985,73(8):1252-1278
The ability to transmit larger amounts of electric power over longer distances increases with the transmission voltage. Historically, this relationship--in conjunction with its associated economies of scale--provided the basic impetus for the technological drive to utilize increasingly higher voltages for the transmission of electric power: from "high voltage" (HV) transmission at 100, 138, 161, and 230 kV to "extra-high voltage" (EHV) transmission at 345, 400, 500, and 765 kV. For the past several years, research has been under way--in this country and abroad--to bring about transmission of electric power at "ultra-high voltage" (UHV), i.e., voltage in the range of 1000 to 1600 kV. This paper reviews the present status of UHV transmission research and development and discusses current prospects for the introduction of UHV technology in the commercial transmission of electric power. 相似文献
19.
ASIC design methodologies are assessed from the system designer's point of view by comparing the entire IC-related product cost, design schedule, functionality, and risks to that of designs containing standard devices. ASIC methodologies include programmable logic devices, gate arrays, standard cells, and full custom, all primarily in 2-µm CMOS, at production volumes of 1 to 100K units per year and at complexities of 5OO to 20 000 gates per device. It is shown that "gates per pin" is the key determinant of total IC-related cost. Products containing ASIC cost less than those containing SSI/MSI, since ASICs raise the number of gates per pin from 2 to a range of 40-200. More surprising, products using ASIC devices cost less than products containing combinations of standard LSI/VLSI and SSI/MSI, if their gates per pin is 2-3 times that of the products containing standard devices. Each design methodology has regions, or market segments, where it is competitive. But there are large regions of small cost differences between two ASIC methodologies. Currently, these regions use primarily the older methodologies, i.e., gate arrays at low production volumes and full custom at high volumes. They also provide future opportunities for standard cells. Currently, IC manufacturing cost accounts for about 15 percent of the logic-related total cost, field maintenance for 17 percent, device and system development for 11 percent, and systems related manufacturing cost for 57 percent. These percentages are expected to migrate to 17, 20, 13, and 50 percent, respectively, by 1990. Our ASIC techno-economic assessment is summarized in 27 nomograms, figures, and charts. 相似文献
20.
Laser application in neurosurgery was slow initially but now one-fifth of the neurosurgeons in the United States use it. Lasers offer many advantages and have few drawbacks. The CO laser is widely used for ablation of tumors and the Nd: YAG laser is useful for coagulation and sutureless blood vessel anastomosis. A variety of delivery systems are available, as well as adapters for microsurgery. Certain complications have occurred with the use of the Nd:YAG laser but these can be prevented by using proper equipment and adequate training. Current research is being conducted in the tissue effects of lasers and the laser catheter approach to vascular lesions. Lasers have a definite role in the neurosurgery of the future, which will be micromanipulative, automated, and computerized. Close cooperation between engineers and surgeons will play an important role in this development. 相似文献