前进中的国产局用程控交换机

随着国产大容量局用程控交换机陆续问世、通过鉴定并投入使用,打破了大容量局用程控交换机必须从国外引进的局面。他们在强手如林的世界局用程控交换机市场上争得了中国人应有的地位,并结束了国内“七国八制”的局面。 事实证明,我国大型程控局用交换机及其网上各种功能的实现和开发已不存在技术上的难题,我国自行研制生产的大容量局用程控交换机从技术体制的先进性、功能的完善程     

提高技术创新能力 振兴我国程控交换机产业

当1981年我国进口第一部数字程控交换机时,我国正在开发模拟程控交换机,尚未形成产业,而数字程控交换机产业则是一片空白。经过十几年的努力,我国自主开发的数字程控交换机已有多种机型,并且已初步形成产业,但是面对国外跨国公司的激烈竞争,亟需不断提高技术创新能力和国际竞争力,振兴民族程控交换机产业。 一、我国程控交换机产业现状 (一)我国程控交换机市场情况 改革开放以来,为解决通信急需,我国进口了一批国外程控交换机,并引进了生产线。使我国通信得到了迅速发展,但也造成了我国通信网多种机型并存的局面,主要机型已有     

学术会议消息

中国通信学会电话交换委员会定于1987年9月中旬在太原召开数字交换技术学术交流会。目前征文工作已经开始。征文范围包括对我国已开通使用的程控交换机的技术经济分析及有关开通、维护、使用的经验;引进程控交换机的消化、吸收及国产化经验以及关于程控交换机总体设计等方面     

发展我国程控交换机几个问题的探讨

我国程控用户交换机究竟如何发展，笔者根据自己从事程控用户交换机的维护工作经验，从国内市场需求的产品概况、制式、研究水平、管理及技术发展等几个方面的问题作了分析和论述。就目前我国使用程控用户交换机所存在的问题，提出了解决的办法和措施。     

基于综合数据服务的程控交换机应用探讨

只有将交换技术发展得更好,才能够让人们体验到信息时代所带来的便利。随着交换机的技术不断提高,其发展正趋向于数字程控交换机。文章首先介绍了程控交换机的作用、类型及其技术,进而探讨了数字程控交换机的工作原理以及未来的发展趋势,以期使读者更加了解程控交换机在信息发展中的重要地位。     

C＆C08数字程控交换机简介

Ｃ＆Ｃ０８数字程控交换机简介重庆市电信局王力进入８０年代以来，世界上数字程控电话交换机技术发展趋于成熟，并逐步取代模拟交换机。为了适应经济建设迅速发展对通信的急需，我国先后大量引进了国外大容量局用程控交换机和生产线。发达国家以其先进的技术、雄厚的资金...     

数字程控交换机在广播电视业务中的应用

1概述程控数字交换机是数字通信交换技术、计算机技术和微电子技术相结合的新技术产品。为了适应现代通信技术和实际通信业务的需要，我厅决定将新建成的电视大楼通信设备由原设计的纵横制总机改为程控交换总机。本文就程控数字交换机如何改善我厅的通信业务作一些技术说明，这些技术主要表现在：（1）以电视大楼程控交换机为中心组成了一个数字／模拟专用网。（2）程控交换机的功能开发。最后，本文就如何提高程控交换机的应用提出几点建议，以便在今后的工作中，做到最大限度地利用程控交换机。2程控交换机的选型与设备配置原设计中的纵横…     

浅谈程控交换机技术发展与趋势

目前,程控交换机在程度软件、控制方式、接入业务和话路网等方面均处于快速的发展过程当中。本文就程控交换机的结构特征,并从从分类角度和社会需求角度对程控交换机技术发展及趋势进行分析,以期能够为企业程控交换机技术的提升提供理论依据。     

程控交换机维护与管理

程控交换机曾是现代通信的主流设备,给人们的生活和工作带来通信的便利.随着移动通信技术的发展,程控交换机也呈现出边缘化,但程控交换机仍在人们生活、工作中占领一定的通信份额.对程控交换机的维护和管理工作,也应该结合设备技术特点,才能保证设备长期无故障运行.     

中国电子通讯产品市场容量大

自80年代以来,通过引进技术,引进设备及自行研制开发,目前我国程控交换机生产已达到相当规模,程控交换机年生产能力已突破1000万门,其中局用程控交换机与用户程控交换机之比为3∶2。截止1993年底,全国程控交换机总装机量已达到4059万门,电话普及率达到2.15％。预计到2000年我国电话交换机总容量达9600万门,若从现在起,每年生产供应交换机1000～1300万线,到2000年全国电话普及率也还只有5～7％。     

多业务宽带交换

网络交换经历着一系列发展演变;从电路交换到分组交换;从软件交换到硬件交换;从单一网络业务交换到多种业务交换。多业务宽带交换需要协议机制的支持,如业务类型划分,网络资源预约和用户业务最监控等。目前主要的宽带交换网技术有千兆比以太网,千兆比路由器网和ＡＴＭ网三种。文章最后论述了多业务宽带分组交换网的原理和结构。     

Unparalleled Dielectric-Switching Effects Caused by Dual Polarization Synergy

Dielectric switching materials are prospective candidates for smart electronic/electrical applications, and high dielectric switching ratios are crucial for their practical applications. However, the substantial improvement of the dielectric switching ratio is limited by the available dielectric switching mechanisms, and obtaining high dielectric switching ratios is a major challenge. Here, an unparalleled dielectric switching effect is reported in a water-in-oil emulsion system, caused by dual polarization synergy below the dielectric transition temperature in concert with suppression of the electrode polarization above the dielectric transition temperature. The synergistic dielectric switching effect of interfacial polarization and electrode polarization endows the emulsion with unprecedentedly high dielectric switching ratios. The highest room temperature dielectric switching ratio of this emulsion system up to 2.86 × 10⁶ at 20 Hz, is four orders of magnitude higher than the highest switching ratio reported so far. The unparalleled high dielectric switching ratio, reliable cycle stability, good frequency adaptability, and satisfactory scalability make the inorganic salt solution/octadecane emulsions potentially excellent candidates for high-sensitivity room-temperature smart switching or sensing devices.     

Optical switching technology comparison: optical MEMS vs. other technologies

Optical switching technologies are very crucial to future mobile broadband all-optical IP networks. Many different optical switching technologies are currently available or under development. The main purpose of the article is to conduct performance comparisons on optical switching technologies in terms of basic performance, network requirements, and system requirements based on a literature survey. The technologies include switching based on optical microelectromechanical systems (MEMS), thermal optical switching, electro-optic switching, and acousto-optic switching technologies. Each optical switching technology has unique performance characteristics specific to the utilized optical phenomena. It might be crucial to integrate some technologies together to achieve a better solution for optical switching. Optical switching is a very hot topic attracting much research effort. Optical MEMS-based switching technology might be one of the most promising approaches at present. Many new optical switching technologies might be created in the near future. Through the impact of nanotechnology, some innovative approaches to optical switching might emerge.     

Semiconductor devices in photonic switching

Three types of photonic switching networks have been proposed, namely, optical space-division switching, optical wavelength-division switching. Optional function devices required for each switching network are as follows: optical switch matrix for space-division switching; optical memory and optical write/read gate for time-division switching; and tunable wavelength filter and wavelength converter for wavelength-division switching. Recent progress in semiconductor functional devices such as modulators, switching devices, bistable devices, and wavelength control devices, which would be key devices to build switching networks, is reviewed     

宽带光交换技术

光交换是一种宽带交换技术。本文简述了空分、时分、波分、码分光交换技术的原理、结构、特点，并阐述了目前光交换技术的发展水平和研究进展。     

宽带ISDN与ATM交换技术：第三讲 ATM交换技术

本文介绍了ＡＴＭ交换的基本原理，研究了ＡＴＭ交换结构的分类，并讨论了几种典型的ＡＴＭ交换网络，包括ＢＳＳ交换结构、Ｂｏｘａｎｎｅ交换单元和交换机构以及Ｂａｔｃｈｅｒ－Ｂａｎｙａｎ多级互连网络。     

Optimization of multi-branch switched diversity systems

A performance optimization based on the optimal switching threshold(s) for a multi-branch switched diversity system is discussed in this paper. For the conventional multi-branch switched diversity system with a single switching threshold, the optimal switching threshold is a function of both the average channel SNR and the number of diversity branches, where computing the optimal switching threshold is not a simple task when the number of diversity branches is high. The newly proposed multi-branch switched diversity system is based on a sequence of switching thresholds, instead of a single switching threshold, where a different diversity branch uses a different switching threshold for signal comparison. Thanks to the fact that each switching threshold in the sequence can be optimized only based on the number of the remaining diversity branches, the proposed system makes it easy to find these switching thresholds. Furthermore, some selected numerical and simulation results show that the proposed switched diversity system with the sequence of optimal switching thresholds outperforms the conventional system with the single optimal switching threshold.     

光突发交换技术

光突发换是近几年出现的一种光交换技术 ,它交换的单元粒度介于电路交换和分组交换之间 ,比电路交换灵活 ,带宽利用率高 ,又比光分组交换易于实现 ;全面介绍了这种交换技术 ,并对它与电路交换和光分组交换性能进行了比较。另外 ,还对光突发交换的关键技术进行了讨论 ,结合下一代互联网的技术趋势 ,对光突发交换的前景进行了评价。     

低损耗软开关Boost变换器

介绍一种新的软开关Boost变换器。传统的Boost变换器在开通和关断时将产生开关损耗,因此使整个系统的效率下降。新的Boost变换器利用软开关方法增加了辅助开关管和谐振电路。这样,相比硬开关情况下,变换器减小了开关损耗。这种变换器可以应用在光伏系统、功率因子校正等装置中。详细分析电路的工作原理以及实现软开关的条件,利用Pspice9．2软件进行仿真验证。仿真结果表明,该变换器的所有开关器件都实现了软开关,从而使效率得到提高。     

Reduced banyan-type multiplane rearrangeable switching networks

The new concept of the multiplane rearrangeable switching network is presented. The new switching network's architecture is based on the well-known baseline network (the log₂(N, 0, 1) switching network). This new architecture can easily be obtained from the baseline network by the removal of some switching elements. It is therefore called the reduced baseline switching network and is denoted by log^r ₂((N, 0, 1). The new multiplane rearrangeable reduced baseline switching network requires fewer switching elements and crosspoints than the multiplane switching network which is based on the plain baseline network.