基于DWT的数字音频水印技术研究

提出了一种基于小波变换的多分辨率数字水印隐藏与检测新算法,算法的优点在于其算法简单。利用小波变换的快速、简单和多分辨率特点,将水印信号隐藏在第1、2、3级的详细分量(细节信号)中保证了水印的稳健性,具有很强的抵御各种信号处理变换的能力,适用于数字语音等信号的版权保护。最后给出了计算机仿真实验结果,证明了本算法的有效性。     

圆感应同步器数显表检测方法研究

介绍了圆感应同步器数显表测角系统的工作原理,以及在静态和动态测角方法。提出了两种提高动态测量精度的方法。实验数据验证了方法的合理性。     

Extension of the range of resonator scanning spectrometer into submillimeter band and some perspectives of its further developments

Extension of the working frequency of modern resonator spectrometers into submillimeter wave range is described. Experimental record of atmospheric absorption spectrum covering 45-370 GHz range is demonstrated for the first time, and measured water vapor J′_{ka′, kc′}-J_{ka, kc} = 5_1,5-4_2,2 at 325 GHz line parameters are presented. For the first time pressure lineshift for the 325-GHz water vapor line is measured. Further extension of working range is discussed. New estimations of physical limits of time needed for measurements of absorption in the whole Backward Wave Oscillator (BWO) range are given for phase continuous synthesizer regime. Basic schemes of fast broadband continuous phase synthesized sources are discussed. Verification of the previous measurements of water vapor 3_1,3-2_2,0 at 183 GHz line parameters is presented. Comparisons with ringdown resonator spectrometers are given.     

A new microtensile tester for the study of MEMS materials with the aid of atomic force microscopy

An apparatus has been designed and implemented to measure the elastic tensile properties (Young's modulus and tensile strength) of surface micromachined polysilicon specimens. The tensile specimens are “dog-bone” shaped ending in a large “paddle” for convenient electrostatic or, in the improved apparatus, ultraviolet (UV) light curable adhesive gripping deposited with electrostatically controlled manipulation. The typical test section of the specimens is 400 μm long with 2 μm×50 μm cross section. The new device supports a nanomechanics method developed in our laboratory to acquire surface topologies of deforming specimens by means of Atomic Force Microscopy (AFM) to determine (fields of) strains via Digital Image Correlation (DIC). With this tool, high strength or non-linearly behaving materials can be tested under different environmental conditions by measuring the strains directly on the surface of the film with nanometer resolution.     

用于二聚物三能级蒸气激光系统的环形谐振腔设计

针对二聚物三能级蒸气激光系统增益相对于泵浦光方向显著的不对称特性,本文设计了一种稳定的能够充分利用介质增益特性的环形谐振腔,给出了象散和慧差补偿及泵浦激光与谐振腔匹配的条件。文中还给出了Na_2B~1Ⅱ_u-X~1∑_g~+跃迁激光谐振腔设计数据。     

双电极对双脉冲激光器结构分析

本文对双电极对双脉冲激光器的谐振腔结构进行了分析,结果表明采用双非稳腔和增大反射镜的曲率半径可分别获得单纵模和基横模输出。为使输出能量稳定,则双电极对的间距有一最小值的限制。     

从江苏苏南数字微波线路看广播电视专用网发展前景

新建微波干线电路采用高质量的数字微波设备是广电部科技工作会议的精神之一。本文介绍了江苏苏南数字微波线路，并从方案确定、技术实现、设备选型等方面进行分析比较，从而得到一个合理的整体方案。本文还着重阐述了数字传输的关键设备－编码器的现状与发展趋势，提出广播电视专用网多功能应用的设想。     

我国有线电视事业的现状和发展

本文详细系统地介绍了我国有线是视发展历史和现状，及其经营和管理方法。重点介绍了北美的ＣＡＴＶ技术发展动向。最后，指出我国ＣＡＴＶ事业发展中的应用重视的问题。     

美国高清晰度电视的发展与现状

本文作者根据对美国高清晰度电视（ＨＤＴＶ）现状考察的情况，详细系统地介绍了美国大联盟（ＧＡ）系统的形成及关键技术的确定，使用极化方式进行ＨＤＴＶ的频率规划，普通电视采用数字压缩技术的发展状况，以及美国目前正在讨论和实验的数字显频业务。     

任意型一维FIR数字滤波器设计新方法

本文介绍了一种设计任意型（宽带、窄带、低阶、高阶、低通、高通、带通、带阻）一维FIR数字滤波器新方法．给出设计不同类型滤波器的统一方法。各种类型滤波器脉冲响应的设计公式简单、计算方便。该方法消除了Gibbs现象．不仅克服了优化设计中收敛速度、设计精度及初值选取等问题，而且减少设计高阶滤波器的时间。最后，本文给出了各种类型滤波器设计的仿真结果。