TEMIC射频卡的速率自适应读卡算法

提出种基于TEMIC射频卡Manchester编码的速率自适应读卡算法,并对该算法进行了说明和示例。     

类锂硅离子软X射线激光研究

在激光等离子体典型参数条件下，利用碰撞－辐模型计算了类锂硅离子５ｆ－３ｄ和４ｆ－３ｄ跃的粒子数反转比率和激光增益系数。讨论了不同热带条件和不同冷却速度下，激光增益系统数的变化。计算结果表明，高功率，短脉冲激光生产的高温等离子体在快速冷却条件下能产生软Ｘ射的线激光增益。     

Gain saturation in quantum-well heterostructures

The effect of radiation gain saturation in quantum-well heretostructures was investigated in the system GaAs—AlGaAs with regard to the spectral line broadening and the type of radiation polarization. Belarusian State University, 4, F. Skorina Ave., Minsk, 220050, Belarus. Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 64, No. 6, pp. 797–800, November–December, 1997.     

基于小波基优化和动态比特分配的数字音频压缩编码方案

提出了一种新颖的基于自适应小波基优化选择和心理声学模型相结合的数字音频信号的透明质量编码方法，保证固定失真水平上使每帧信号的变换系数的动态分配的比特数最少，并且利用动态码本的方法来消除音频信号的统计冗余，进一步压缩比特率，对于抽样率为４４．１ｋＨｚ每样值用１６比特线性码表示的光盘单声道音乐信号可以压缩到６４ｋＢＰＳ左右。     

Multiresolution coding techniques for digital television: A review

Multiresolution decompositions for video coding are reviewed. Both nonrecursive and recursive coding schemes are considered. In nonrecursive schemes, it is shown that pyramid structures have certain advantages over subband or wavelet techniques, and a specific spatiotemporal pyramid coding of HDTV is discussed in some detail. It is shown that recursive, DPCM like schemes will incur a slight loss of optimality due to a restricted form of prediction if multiresolution decomposition with compatible decoding is required. Compatibility and transmission issues are also discussed. Multiresolution transmission for digital broadcast TV is introduced. This, when combined with multiresolution source coding, achieves spectrum efficiency, robustness and graceful degradation under channel impairments.Invited PaperWork supported in part by the National Science Foundation under grants ECD-88-11111, MIP-90-14189 and Bell Communications Research.Work supported by the National Science Foundation under grants ECD-88-11111. K.M. Uz is now with David Sarnoff Research Center in Princeton, NJ 08543.     

Spectral Feature Analysis of Semiconductor Thin Disk Laser

The semiconductor thin disk laser is a new type of semiconductor laser. This work gives the basic operation function of the semiconductor disk laser, and analyses the heat effect by the experimentally measured photoluminescence spectrum of the laser chip at different pump power and different temperatures. We can see that: with increasing pump power, the thermal effect of the gain material becomes seriously and causes the saturation of carrier lifetime, so the electron-hole pair created in the absorbtion lay...     

模拟乘法器的简易分析方法

提出了一种模拟乘法器工作原理的简易分析方法，与通用的一般方法相比，这种方法避开了较复杂的数学推导，采用大学熟悉的公式从而使分析过程简便易懂。     

MPEG-4自然视频编码技术

对MPEG－4自然视频编码的关键技术作了详细的分析和阐述。首先介绍MPEG－4频语法结构，并对视频编码的框架概要分析。接着分析了自然视频编码中涉及到的关键技术，包括：VOP的产生；二值和灰度级α平面的编码技术；运动估计和补偿方法；纹理编码；基于对象的时间分级和空间分级；MPEG－4提供的再同步和各种错误掩盖，刷新方法，精 编码技术和零树小波基的静止图像编码技术。指出MPEG－4和MPEG－1，MPEG－2等标准的异同，突出MPEG－4的三个主要特点。最后给出MPEG－4技术在网络视频传输中的应用，并给出测试和分析。     

用拉盖尔-高斯激光对真空中电子直接加速

对用拉盖尔-高斯(LG)光束加速电子作了研究.结果表明，仅模指数为p和l=1的LG光束的纵向电场可用于加速电子.模指数为p和l=1的线偏振和圆偏振LG光束都对电子有加速效果.对轴上光场的相速度和群速度以及电子能量增益等物理特征作了讨论.给出了轴上光场的相速度和群速度、加速电位及电子能量增益等的解析表达式，并作了数值计算和分析. 关键词： 激光电子加速 拉盖尔-高斯光束 线偏振和圆偏振 能量增益     

加载单极子天线的时域辐射特性

基本的单极子天线由于其本身的特社会在天线内部对馈入的信号进行多次反射，严重,制约着它的辐射性能。采用时域有限差分法对比计算了加载与非加载单极子天线的时域辐射特性。计算结果表明，加载是改善单极子天线时域辐射性能的最佳选择，但需要以牺牲辐射效率为代价。