卫星寻呼网交叉覆盖区域信号时延分析

本文分析了通过卫星进行无线寻呼大区域同播时交叉覆盖区域信号的时延情况，并结合目前常用的几种编码速率和传输距离给出了具体的时延数据和结论。     

高标清电视同播技术研究

由于HDTV与SDTV信号格式的差异,使得先前高标清同播中存在一系列问题。针对HDTV和SDTV几种同播方式,分析了它们的性能,指出了保证同播质量的技术措施,对部分方式进行了仿真实验,并提出了一种可供选用的同播方案。     

多基站同播通信系统设计

本文讨论一种分区覆盖的广域通信系统-多基站同播通信系统,介绍了同播系统的特点,阐述了同播系统信号失真的机理和消除信号失真的方法。对基站发射频率的一致性、调制信号的幅频特性、相频特性的差异以及CTCSS信号对同播系统的影响进行了分析,并对这些影响因数给出了具体的要求及实现方法,本文还详细介绍了同播系统优化调节的方法及步骤。     

寻呼系统联网及其通信连接

区域覆盖同播与广域寻呼联风是无线寻呼系统目前发展的主要要方向。本文简述了寻系统中区域覆盖同播与广域联网的主要构成及功能，叙述了区域覆盖同播与广联网的最新通信信连接方法－－卫星链路控制技术与分级交换网，详细比较了区域同播和广域寻呼联网中各种通信连接的优劣。     

广西电视台总控系统高/标清同播改造

为达到卫视频道高/标清同播的要求,广西电视台对标清电视节目制作、播出和传输系统进行了较大规模的技术升级改造。本文对总控系统的高/标清同播改造作了详细的阐述,与原总控系统相比,新总控系统除具备高/标清同播的能力外,不同之处还有:播出矩阵也同时作为监视矩阵;监测系统和卫星接收系统首次用ASI矩阵与中频矩阵;监视矩阵与多画面分割器的结合使得电视信号源的监视变得既简单又灵活。     

高清卫星地球站设计、建设与思考

为提升青海省广播电视节目的传输质量和收视效果,广播电视台建设高清卫星地球站,与标清站一起将卫视节目采用高标清同播方式上星覆盖全国播出。本文介绍了青海省地球站按照广电总局发布的卫星相关技术标准、技术规范要求设计的建设方案,对上行系统、应急方案等进行了说明,总结了建设高清卫星地球站过程中的一些思考。     

广西台高标清同播总控系统介绍

本文介绍了广西台高标清同播总控系统的基本架构,对高清矩阵、周边设备、卫星接收系统、互锁式同步系统、多信源监视系统进行了介绍,分析了总控矩阵系统的特点和工程困难的应对措施。     

卫星高清电视远程加密技术实现探讨

本文阐述了数字电视加解密的基本原理,介绍了高清同播频道卫星传输远程加密技术试验的有关情况,讨论了卫星高清电视远程加密技术实现的可行性,总结了在实际应用中需要注意的问题,对高清卫视节目远程加密方式的应用具有参考作用。     

DRM数字与模拟节目同播问题探讨

为了实现由模拟到数字的平滑过渡,解决频率与设备的短缺,同一部发射机可以按照不同的方案同时播出DRM数字节目与模拟节目。本文分析了几种可能的同播方式与相关问题,讨论了同播时电压和功率分配与接收质量的关系,指出了DX系列发射机同播运行的优势。     

上海台电视播出高清化历程回顾与实现综述

本文对上海广播电视台十四年来的高清化历程分四个阶段进行回顾;对高标清同播的两种实现方式进行描述和比较,分四个层面介绍单平台高标清同播系统的实现;就高清化过程中遇到具体问题的解决方法进行总结。     

Endpoint detection for CMP

In spite of dramatic advances in oxide chemical mechanical polishing (CMP) process performance in recent years, there has been relatively little published data on semiconductor production line worthy endpoint detection (EPD) systems for interlevel dielectric (ILD) planarization.¹ In contrast, numerous EPD methods have been successfully developed for metal polishing, most notably friction sensing via motor current monitoring. However, these methods have so far not been proven to be 100% reliable. Semiconductor manufacturers have been searching for a viable method of either monitoring the dielectric removal rate or the planarization of the surface during the polish process, and for improved metal endpoint detection systems. A coustic methods have been patented, but to date no commercially viable acoustic based EPD system exists. A great deal of effort has been expended developing optical methods, and some success has been reported for STI structures. In this paper, we discuss many of the approaches that have been published. We categorize these approaches as being either global or local methods. We further categorize the methods as being either a direct or indirect assessment of events taking place at the surface of the wafer.     

无铅覆铜板增韧技术概述及表征

阐述了近年来应用于无铅覆铜板的几种增韧技术,通过对增韧技术的综合运用,制备出一款具备良好韧性的高Tg无铅覆铜板,对其韧性进行定性表征,提出了快速简便的覆铜板韧性测试方法。     

A multilevel solver for boundary value problems

Multilevel methods have been studied extensively for solving certain partial differential equations, and such equation solvers have been successfully applied to major computational problems of physical interest and technological importance. KLEV is a collection of routines for solving theN times Nsystem of linear equationsAz = gwhenAandgare discretizations of some partial differential equation. The current release includes a direct method, iterative methods, and multilevel methods. A brief review of multilevel methods and an overview of the implementation are presented.     

二极管泵浦Nd∶YVO_4倍频激光器使用的光学薄膜

讨论了二极管泵浦 Nd∶ YVO4 激光器中使用的一系列光学薄膜 ,膜系类型涉及截止滤光片、增透膜等。根据设计对称匹配膜层的分析 ,利用计算机膜系设计优化软件对膜系进行优化 ,得到损耗小、利于制备、重复性好的膜系设计。用于实际制备 ,取得较好的效果     

用于雷达反隐身的低可探测目标电磁散射高效数值分析

本文介绍基于多层快速多极子方法（MLFMA）分析框架下的高效处理新方法和相关研究成果,重点讨论用于厚介质层散射分析的电流磁流混合场积分方程（JMCFIE）、用于多薄层介质散射的多层薄介质层（TDS）边界条件方法及其应用等;最后介绍了所研发的P-UEST软件及其在隐身飞行目标散射特性计算中的应用成果。     

任意折射率的均匀混合膜的获得——实用气相混合蒸镀技术之一

自然界拥有数不清的物质,然而能提供给薄膜工作者使用的材料却很寥寥.目前常用的膜料只不过二、三十种,折射率值的匮乏常使膜系设计人员感到困惑.为了弥补这个缺陷,人们做过不少尝试.     

Comparison of generalized Q- function algorithms (Corresp.)

Several methods have been proposed for calculating the generalizedQ-functionQ_{m}(alpha, beta), but only isolated comparisons of the various techniques have been reported. The accuracy, range, and execution time of prominent methods for computing theQ-function are compared, and limitations of the algorithms are identified.     

Comparison of test methods for the characterization of shielding ofboard-to-backplane and board-to-cable connectors

We present the work carried out in the SOBITS project executed within the framework of the European Measurement and Testing program. The goal of the project was to compare different methods for characterization of the shielding performance of board-to-backplane and backplane-to-cable connectors used in telecommunication and computer systems. Four measurement methods have been selected. Dedicated test samples have been designed and developed in order to enable the measurement of the shielding characteristics of the connectors under test with all methods. Different shielding configurations were considered, in order to determine the influence of the quality of the shield. Single-ended as well as differential excitations have been considered. Among the test samples, a nonshielded version was designed for each signal/ground configurations. This sample was used as a reference. The definition of the quantities that describe the shielding performance is different for each of the measurement methods. Conversion formulas between these quantities have been formulated. They were verified by measuring a reference device that is easy to measure by all methods. Thus we were able to compare the relative shielding effectiveness of the various shielded board-to-backplane and backplane-to-cable connectors for all four measurement methods. The relative shielding effectiveness of a shielded connector was calculated with respect to the nonshielded version. We also compared the different shielding performance results obtained with each measurement method individually     

An approximate-analytic solution for the forward-biased stepjunction

Approximate-analytic methods for analyzing semiconductor samples containing junctions complement purely numerical solutions by providing added physical insight. These methods have proved useful, but have been applicable primarily to samples at equilibrium. A technique for applying these methods to forward-biased junctions is described. The equations obtained are compatible with previously published work     

Design strategies of metal free-organic sensitizers for dye sensitized solar cells: Role of donor and acceptor monomers

A series of metal free organic sensitizers have been designed and their optoelectronic properties for DSSC applications have been systematically investigated using density functional theory (DFT) and time dependent density functional theory (TD-DFT) methods. The role of donor/acceptor monomers on the electron donating/withdrawing abilities has been discussed and promising donor–acceptor combinations are screened. Based on this screening, some of novel metal free sensitizers have been designed and their electronic and spectral properties have been investigated using DFT/TDDFT methods. Our results show that the designed molecules are promising candidates to provide good performances as sensitizers in the DSSC applications.