视频点播系统VOD技术原理和应用

本从视频点播系统的结构及组成和在有线电视网络中VOD系统的结构模式与应用两个方面，详细阐述了如何利用有线电视网络实现视频点播。本主要从以下三个方面来介绍关于视频点播系统VOD技术：1、视频点播VOD的技术，2、视频点播系统的结构及组成，3、有线电视视频点播系统的结构模式与应用。     

利用有线电视网络实现视频点播

本从视频点播系统的结构及组成和在有线电视网络中VOD系统的结构模式与应用两个方面，详细地阐述了如何利用有线电视网络实现视频点播。     

VOD广播协议族

真视频点播(T—VOD)技术支持双向点播，点播延迟短，因而成为技术热点。但该技术带来的双向网络改造费用大，一般多用在局域网中。而准视频点播技术(N—VOD)无需改造网络即可实现视频点播，在有线电视等宽带网中应用广泛。以准视频点播技术为背景，通过对VOD广播协议族进行归纳和分析，从而加深人们对N—VOD技术的理解。     

有线电视视频点播技术解析

首先介绍了视频点播的三种类型及各自的优缺点,然后详细阐述了视频点播系统的结构及组成,有线电视视频点播系统的结构模式与应用,最后展望了我国VOD建设的前景。     

视频点播系统

多媒体技术是有线电视台发展的趋势，尤其VOD（视频点播）是众所关心的焦点之一。但是实现VOD需要大量的资金投入，要对设备以及线路进行改造，使得VOD技术不可能在短期内实现。以下所介绍的系统是依据国内有线电视台的实际情况，不需设备及线路的改造，只需少量的投资即可实现的视频点播，它实现了VOD的功能。1什么是视频点播视频点播是指电视台通过自动点播系统开辟一个频道或利用某个频道的空闲时段，自动播放用户通过电话点播的视频节目。它既可以利用一个频道，实现24小时自动制作和播放，也可以利用其它频道的某一时段实现自动制…     

VOD技术及其应用

随着用户对信息需求的逐步增长,用户已不满足单向被动的接受信息,交互成为视频领域的发展方向。VOD视频点播的应用,丰富了人们的文化生活。有线电视经过双向改造,可以让广大的电视用户通过有线电视网点播视频节目。随着VOD技术的不断进步,其广泛的应用对大众文化和商业运作模式都将产生强烈的影响。     

贵阳广电双向网络建设

本文从广电双向网络出发,重点介绍目前贵阳市广电网络公司正在开展的VOD高清视频互动点播的网络改造工作。介绍贵阳市目前VOD视频点播所采用的方式,以及相关的技术特点,并着重阐述采用1550nm技术实现VOD视频点播的技术要领,详细讨论利用1550nm直调制光发射机实现VOD点播的开通调试过程以及相应的故障处理方法。     

产品简介

B-1 VOD服务器 美国博路技术公司推出的B-1^TM视频服务器在实现基于网络的个人视频录像（nPVR）、时移电视（LivePause^TM）及电视点播（TOD）新业务的同时，也可使现有的视频点播业务利润最大化。这些具有可扩展能力、已被业界证明的VOD系统不仅可传输电信级的、高可靠性的、高性能的视频点播业务．而且可以为用户提供未来的娱乐业务．同时确保运营商的收益稳步增长。支持的主要应用模式为：VOD；TOD：nPVR：LivePause；音乐和音频点播；游戏和IPTV等。     

FOUNDVOD平台

近日，方正科技推出了基于IA架构服务器的方正圆明FOUNDVOD视频点播平台，并发布系列基于FOUNDVOD平台的解决方案。FOUNDVOD视频点播方案面向宽带互联网多媒体应用，用户可以直接选择FOUNDVOD视频点播功能服务器，也可以根据自身需要，在FOUND－VOD系统平台上二次开发适合自己应用的视频点播系统。FOUNDVOD系统可以同时支持几百到上千个用户的并发点播要求，用户可以根据需要点播不同的视频资源，并可自由地控制节目的播放进度；在FOUNDVOD系统中，针对远程教学和视频会议的应用特点，用户可通过一台视频采集工作站…     

天屹：50Ω基带同轴电缆和低烟、无卤、阻燃环保线缆

思迁数码科技（中国）有限公司在此次CCBN展会上．将展出既适合于单向网络又适合于双向网络的VOD系统。该系统既包含享有专利技术的SeaChange高性能视频服务器和指令中心、视频调制及网络传输以及STB客户端等硬件部分．也包括丰富的后台运营管理及客户端应用软件。其中单向VOD方案是通过一个自动电话系统（交互式语音应答系统）与用户交互，实现了VOD点播功能。用户只需拥有一台普通的数字机顶盒和一部电话就能够点播所需要的内容收视，实现视频点播功能。     

Development of the readout system for waveguide multilayer optical card

Waveguide multilayer optical card （WMOC） is a novel storage device of three-dimensional optical information. An advanced readout system fitting for the WMOC is introduced in this paper. The hardware mainly consists of the light source for reading, WMOC, motorized stages addressing unit, microscope imaging unit, CCD detecting unit and PC controlling ＆ processing unit. The movement of the precision motorized stage is controlled by the computer through Visual Basic （VB） language in software. A control panel is also designed to get the layer address and the page address through which the position of the motorized stages can be changed. The WMOC readout system is easy to manage and the readout result is directly displayed on computer monitor.     

Nanoimprint Lithography -A Next Generation High Volume Lithography Technique

IntroductionNanoimprint Lithography is a well-acknowl-edged low cost, high resolution, large area pattern-ing process. It includes the most promising methods,high-pressure hot embossing lithography (HEL) [2],UV-cured imprinting (UV-NIL) [3] and micro contactprinting (m-CP, MCP) [4]. Curing of the imprintedstructures is either done by subsequent UV-lightexposure in the case of UV-NIL or by cooling downbelow the glass transition temperature of the ther-moplastic material in case of HEL…     

Collinear phase-matching study of terahertz-wave generation via difference frequency mixed in GaAs and Inp

The collinearly phase-matching condition of terahertz-wave generation via difference frequency mixed in GaAs and InP is theoretically studied. In collinear phase-matching, the optimum phase-matching wave hands of these two crystals are calculated. The optimum phase-matching wave bands in GaAs and lnP are 0.95-1.38μm and 0.7-0.96μm respectively. The influence of the wavelength choice of the pump wave on the coherent length in THz-wave tuning is also discussed. The influence of the temperature alteration on the phase-matching and the temperature tuning properties in GaAs crystal are calculated and analyzed. It can serve for the following experiments as a theoretical evidence and a reference as well.     

Effects of the alloy compositions on the phonon-polaritons in ternary mixed crystals

Composition dependence of bulk and surface phonon-polaritons in ternary mixed crystals are studied in the framework of the modified random-element-isodisplacement model and the Bom-Huang approximation. The numerical results for Several Ⅱ - Ⅵ and Ⅲ- Ⅴ compound systems are performed, and the polariton frequencies as functions of the compositions for ternary mixed crystals AlxGa1-xAs, GaPxAS1-x, ZnSxSe1-x, GaAsxSb1-x, GaxIn1-xP, and ZnxCd1-xS as examples are given and discussed. The results show that the dependence of the energies of two branches of bulk phonon-polaritons which have phonon-like characteristics, and surface phonon-polaritons on the compositions of ternary mixed crystals are nonlinear and different from those of the corresponding binary systems.     

Influence of PVK ： NPB hole transporting layer on the characteristics of organic light-emitting devices

A doping system consisting of NPB and PVK is employed as a composite hole transporting layer （CHTL）. By adjusting the component ratio of the doping system, a series of devices with different concentration proportion of PVK ： NPB are constracted. The result shows that doping concentration of NPB enhances the competence of hole transporting ability, and modifies the recombination region of charge as well as affects the surface morphology of doped film. Optimum device with a maximum brightness of 7852 cd/m^2 and a power efficiency of 1.75 lm/W has been obtained by choosing a concentration proportion of PVK ： NPB at 1：3.     

New insert layer structure OLEDs

An insert layer structure organic electroluminescent device（OLED） based on a new luminescent material （Zn（salen）） is fabricated. The configuration of the device is ITO/CuPc/NPD/Zn（salen）/Liq/LiF/A1/CuPc/NPD/Zn（salen）/Liq/LiF/A1. Effective insert electrode layers comprising LiF（1nm）/Al（5 nm） are used as a single semitransparent mirror, and bilayer cathode LiF（1 nm）/A1（100 nm） is used as a reflecting mirror. The two mirrors form a Fabry-Perot microcavity and two emissive units. The maximum brightness and luminous efficiency reach 674 cd/m^2 and 2.652 cd/A, respectively, which are 2.1 and 3.7 times higher than the conventional device, respectively. The superior brightness and luminous efficiency over conventional single-unit devices are attributed to microcavity effect.     

Analysis of error performance on Turbo coded FDPIM

Due to variable symbol length of digital pulse interval modulation（DPIM）, it is difficult to analyze the error performances of Turbo coded DPIM. To solve this problem, a fixed-length digital pulse interval modulation（FDPIM） method is provided. The FDPIM modulation structure is introduced. The packet error rates of uncoded FDPIM are analyzed and compared with that of DPIM. Bit error rates of Turbo coded FDPIM are simulated based on three kinds of analytical models under weak turbulence channel. The results show that packet error rate of uncoded FDPIM is inferior to that of uncoded DPIM. However, FDPIM is easy to be implemented and easy to be combined, with Turbo code for soft-decision because of its fixed length. Besides, the introduction of Turbo code in this modulation can decrease the average power about 10 dBm, which means that it can improve the error performance of the system effectively.     

A method for calculating the center position of collimated light

It is a key problem to accurately calculate beam spots＇ center of measuring the warp by using a collimated laser. A new method, named double geometrical center method （DGCM）, is put forward for the first time. In this method, a plane wave perpendicularly irradiates an aperture stop, and a charge couple device （CCD） is employed to receive the diffraction-beam spots, then the geometrical centers of the fast and the second diffraction-beam spots are calculated respectively, and their mean value is regarded as the center of datum beam. In face of such adverse instances as laser intension distributing defectively, part of the image being saturated, this method can still work well. What＇s more, this method can detect whether an unacceptable error exits in the courses of image receiving, processing and calculating. The experimental results indicate the precision of this method is high.     

Resolution Enhancement Technology:Integrated Process Solutions using OPC

DUV lithography, using the 248 nm wavelength, is a viable manufacturing option for devices with features at 130 nm and less. Given the low kl value of the lithography, integrated process development is a necessary method for achieving acceptable process latitude. The application of assist features for rule based OPC requires the simultaneous optimization of the mask, illumination optics and the resist.Described in this paper are the details involved in optimizing each of these aspects for line and space imaging.A reference pitch is first chosen to determine how the optics will be set. The ideal sigma setting is determined by a simple geometrically derived expression. The inner and outer machine settings are determined, in turn,with the simulation of a figure of merit. The maximum value of the response surface of this FOM occurs at the optimal sigma settings. Experimental confirmation of this is shown in the paper.Assist features are used to modify the aerial image of the more isolated images on the mask. The effect that the diffraction of the scattering bars (SBs) has on the image intensity distribution is explained. Rules for determining the size and placement of SBs are also given.Resist is optimized for use with off-axis illumination and assist features. A general explanation of the material' s effect is discussed along with the affect on the through-pitch bias. The paper culminates with the showing of the lithographic results from the fully optimized system.     

Cost-effective test solutions for smart card and other integrated flash applications

From its emergence in the late 1980s as a lower cost alternative to early EEPROM technologies, flash memory has evolved to higher densities and speedsand rapidly growing acceptance in mobile applications.In the process, flash memory devices have placed increased test requirements on manufacturers. Today, as flash device test grows in importance in China, manufacturers face growing pressure for reduced cost-oftest, increased throughput and greater return on investment for test equipment. At the same time, the move to integrated flash packages for contactless smart card applications adds a significant further challenge to manufacturers seeking rapid, low-cost test.