基于MMX指令实现G.728定点算法优化

ITU-T建议是国际电信联盟于1992年制定的比特率为16kb/s的低延时CELP类语音编码器.G.728AnnexG是其补充定点算法建议.该文首先介绍了G.728定点算法的特点和Intel MMX技术,然后详细讨论了用MMX指令对G.728的LD-CELP定点算法实现优化一些关键技术,最后给出了优化前后算法速度的对比.     

基于直接控制光纤长度的RoF系统色散管理

基于色散引起的双边带调制信号周期性功率衰落,提出了一种直接控制光纤长度来避免光纤色度色散对接收信号功率影响的新方法.从理论上证明了这个方法的可行性,并通过仿真分析比较了四种色散管理的方法,仿真结果表明,与其他三种方法相比,提出的直接控制光纤长度的方法不仅改善效果显著而且对光源中心频率和调制频率波动并不敏感,是解决WDM...     

简易数字存储示波器电子综合实验项目设计

设计了一个电子综合实验项目简易存储示波器,让学生利用低频,数字电路、单片机技术、EDA技术等相关专业技能,完成方案设计,电路制作、直到最后的调试验收整个项目开发过程。培养学生应用已学的专业基础知识,进行项目设计和开发的能力。     

Early SKIP mode decision for MVC using inter-view correlation

In the joint multiview video model (JMVM) proposed by JVT, the variable block-size motion estimation (ME) and disparity estimation (DE) have been employed to determine the best coding mode for each macroblock (MB). These give a high coding efficiency for multiview video coding (MVC), however, they cause a very high computational complexity in encoding system. This paper proposes to reduce the complexities of the ME and DE processes with an early SKIP mode decision algorithm based on the analysis of prediction mode distribution regarding the corresponding MBs in the neighbor view. In this method, the mode decision procedures of most of MBs can be early terminated, and thus much of computation for ME and DE can be greatly reduced. Simulation results demonstrate that our algorithm can achieve computational saving of 46–57% (depending on the tested sequences) with no significant loss of rate-distortion performance.     

数字粮库的展望

以计算机技术、多媒体技术和大规模存储技术为基础,以宽带专用网络为纽带,运用粮情测控技术、全球定位系统、地理信息系统、虚拟现实等技术,对国内所有粮库及其存粮情况进行多分辨率、多尺度、多时空和多种类的数字描述。即利用信息技术手段把有关粮库的所有信息在网络上进行数字化虚拟实现,以便于粮库的监测和管理,同时也是为国家粮食管理部门提供一个粮食政策的决策支持平台。     

基于计算机技术的广播电视仿真综合培训平台的设计与实现

为保障广播电视节目的安全播出,对值班人员的日常培训和考核十分重要。针对目前在播出设备上实际操作练习的弊端,本文设计并实现了一种基于计算机技术的广播电视仿真综合培训平台,该平台构建了一整套无线发射台站的仿真系统,通过在计算机上模拟真实设备的操作,达到培训和考核值班人员的目的。     

信息化管理在商贸流通企业中的应用和效果

信息化管理是以信息化带动工业化,实现企业管理现代化的过程。随着市场经济的发展和变革,竞争激烈,科技进步,产品更新换代,需求趋于多样化,需要企业尽快适应市场变化,为用户提供适销产品和优质服务。信息技术和应用的发展推动并促进了企业在市场竞争中博弈能力。文章从市场经济发展和企业提高竞争能力的客观需要出发,阐述了信息化管理在企业中的应用过程和实际效果。     

Carrier dynamics in high-speed (f/sub -3 dB/>40 GHz) 0.98-/spl mu/m multiquantum-well tunneling injection lasers determined from electrical impedance measurements

Carrier capture times in InGaAs-AlAs-GaAs 0.98-/spl mu/m multiquantum-well tunneling injection lasers with f/sub -3 dB//spl sim/43-48 GHz have been determined from analysis of high frequency electrical impedance measurements. The capture times range from 14 ps, at biases around threshold, to about 1 ps, at 50-mA bias. The small capture times agree well with tunneling times obtained directly from pump-probe measurements. The impedance measurements also suggest that the carrier lifetime in the well is much less than the escape time from the well, consistent with the cold carrier distribution associated with a tunneling injection mechanism.     

Generalized fourier series expansion method for determining cutoffs in optical waveguides

In weakly guiding analysis of cutoff frequencies in general optical waveguides, the proposed generalized Fourier series expansion method in elliptical coordinates has advantages in terms of generality, accuracy, efficiency and simplicity. Numerical data of higher mode cutoffs in elliptical and rectangular optical waveguides show the excellent agreement between the present method and the finite element method.