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June‐Young Chang Won‐Jong Kim Young‐Hwan Bae Jin Ho Han Han‐Jin Cho Hee‐Bum Jung 《ETRI Journal》2005,27(5):497-503
In this paper, we present a performance analysis for an MPEG‐4 video codec based on the on‐chip network communication architecture. The existing on‐chip buses of system‐on‐a‐chip (SoC) have some limitation on data traffic bandwidth since a large number of silicon IPs share the bus. An on‐chip network is introduced to solve the problem of on‐chip buses, in which the concept of a computer network is applied to the communication architecture of SoC. We compared the performance of the MPEG‐4 video codec based on the on‐chip network and Advanced Micro‐controller Bus Architecture (AMBA) on‐chip bus. Experimental results show that the performance of the MPEG‐4 video codec based on the on‐chip network is improved over 50% compared to the design based on a multi‐layer AMBA bus. 相似文献
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3G手机时代的来临给PCB的制造技术带来了巨大的挑战,文章介绍了3G手机对PCB行业的影响、PCB高密度化的要求、CCL高性能化的要求、PCB加工技术的要求。 相似文献
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基于EDGE技术原理的分析,通过调研中国联通EDGE业务在现网中的覆盖情况,从业务启动条件、系统升级需求、覆盖区域设计、频率规划等方面详细介绍了网络建设中的典型问题。此外,还分析了业务启动后对网络的影响,最后进一步阐述了EDGE业务的开展建议。 相似文献
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文章在分析了OLAP大规模海量多维数据特点的基础上,针对当前一般规模关系数据库处理海量多维数据能力的不足,通过使用数据库分区技术和并行磁盘组技术,设计并实现了一种高效的、面向OLAP应用的数据存储管理结构。并针对传统查询优化器对于大规模海量数据统计信息更新不及时的问题,设计了一种基于分区技术的统计方法。实验证明,该设计可以对百TB级的多维海量文本数据进行有效的管理。 相似文献
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基于椭圆曲线加密体制的实现 总被引:1,自引:1,他引:1
使用椭圆曲线作为公钥密码体制的基础,是定义在有限域上椭圆曲线上的点构成的阿贝尔群,并且使定义其上的离散对数问题的求解非常困难。在选取适合密码系统的安全椭圆曲线和基点算法的基础上,给出了两种明文在椭圆曲线上表示方法的算法以及基于这两种方法的椭圆曲线加密体制。 相似文献
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研究了利用GaAs作为衬底的HgCdTe MBE薄膜的表面缺陷,发现其中一类缺陷与Hg源中杂质有关。采用SEM对这类缺陷进行正面和横截面的观察,并采用EDX对其正面和横截面进行成分分析。并设计了两个实验:其一,在CdTe/GaAs衬底上,低温下用Hg源照射20min,再在其上继续高温生长CdTe;其二,在CdTe/GaAs衬底上,一直用Hg源照射下高温生长CdTe。两个实验后CdTe表面都出现与HgCdTe表面相比在形状和分布上类似的表面缺陷,采用光学显微镜和SEM对CdTe表面缺陷进行了观察,通过CdTe表面缺陷和HgCdTe表面缺陷的比较,我们证实了这类表面缺陷的成核起源于Hg源中杂质。 相似文献
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Ge-on-Si approaches to the detection of near-infrared light 总被引:1,自引:0,他引:1
We review our recent results on Ge-based near-infrared photodetectors grown on silicon. We fabricated metal-semiconductor-metal photodetectors based on epitaxial pure-Ge grown on silicon by chemical vapor deposition. Material characterization and device performances are illustrated and discussed. Exploiting a novel approach based on evaporation of polycrystalline-Ge on silicon, we also realized efficient near-infrared photodiodes with good speed and sensitivity. Finally, multiple-element devices were designed, fabricated, and tested, such as a voltage-tunable wavelength-selective photodetector based on a SiGe superlattice and a linear array of 16 photodetectors in poly-Ge on Si 相似文献
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《Microwave Theory and Techniques》1993,41(6):1037-1043
The quasi-TEM characteristics of a class of cylindrical microstrip lines are rigorously determined. The class of microstrip lines considered consists of multiple infinitesimally thin strips on a multilayered dielectric substrate on a perfectly conducting wedge. Expressions for the potential distribution inside and outside the dielectric substrate, charge distribution on the strips, and capacitance matrix of the microstrip lines are derived. The problems of a microstrip line on a cylindrically capped wedge and on a cylindrical dielectric substrate on perfectly conducting core are also considered as special cases. Sample numerical results based on the derived expressions are given and discussed 相似文献
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基于3GPP紧急定位标准流程,为实现隐私鉴权提出了优化建议,并在核心网不支持3GPP流程时,提出了基于信令分析控制设备实现紧急定位的方案。 相似文献
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Ledoux P. Auge J. Boniort L.Y. Dupont P. Goudeau J. Saugrain J.M. Rousseau J.C. Mohanna Y. 《Lightwave Technology, Journal of》1989,7(8):1270-1274
The authors point out the formation mechanism of axial stress, describes the method and the apparatus used for measurements, and presents the results obtained during a study of loss reduction on trapezoidal core 1.55-μm dispersion-shifted fibers manufactured by the MCVD technique. It is concluded that the stress measurements on fiber are less accurate than those on preform (experimental dispersion reaches 15% instead of 5%). The various observations made from measurements on preform show that the axial stress is related to the index profile and that the core axial stress increases with the GeO2 content. The measurements performed on fiber show that the level of stress is linearly dependent on the drawing tension and that the stress profile is related to the glass-transition temperature of the different materials. Furthermore, this method of stress measurement is complementary to the more standard index profile measurement on fiber or on preform 相似文献
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In this paper, recent literature on the discussion on high-speed backplanes with optical, electrical, and mixed solutions, as well as on polymer-waveguide systems suitable for implementation on printed circuit boards (PCBs), is reviewed from the point of view of their optical losses. The reevaluation of the optical power budget for realistic high-speed optical polymer-waveguide links on backplanes showed that signal amplification is necessary to boost the signal, which resulted in an additional literature review on advances in optical amplifiers based on silicon bench technology available. Finally, a concept study of an active optical waveguide amplifier device, based on planar optical waveguide amplifiers and semiconductor optical amplifiers, was performed. The amplification device can be flip-chip mounted on the backplane to compensate for optical losses due to signal routing, which increases the overall degree of freedom in waveguide routing on high-density interconnects for backplanes. The hybrid concept design guarantees compatibility with the processes of the PCB industry. 相似文献
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利用两步生长法在蓝宝石纳米图形衬底(NPSS)上生长得到高质量的氮化镓薄膜。通过XRD和SEM对薄膜质量的表征和研究发现,为得到高质量的氮化镓(GaN)薄膜,在NPSS上生长时得到的最优缓冲层厚度为15nm,而在微米级尺寸的图形衬底(MPSS)上得到的最优缓冲层厚度远大于15nm。同时,在NPSS上生长氮化镓薄膜的过程中观察到一个有趣的现象,即GaN在NPSS上生长的初始阶段,氮化镓晶粒主要在图形之间的平面区域生长,极少量的GaN在衬底图形的侧面上聚集生长。这一有趣的现象明显不同于GaN在MPSS上的生长过程。接着,又在NPSS上生长了GaN基LED结构,并对其光电性能进行了研究。 相似文献