International fixed satellite systems in synchronous digital hierarchy transport networks

This paper discusses functional and architectural aspects and suitable networks scenarios for the integration of international fixed satellite systems, such as the INTELSAT system, in and between digital networks implementing the new CCITT synchronous digital hierarchy (SDH). The paper presents SDH transmission network functional requirements, and combines them with current and anticipated future FSS operational requirements. It is shown that integration permits the use of SDH functions and features for enhanced network service provisioning by FSS in the international network fabric, and leads to new FSS system design criteria.     

The impact of synchronous digital hierarchy on digital microwaveradio: a view from Australasia

The recently agreed upon synchronous digital hierarchy (SDH) standard, which will provide a means to manage, multiplex, and access various forms of digital traffic in an economical and efficient manner, is described, and it is explained how radio systems can be deployed in SDH networks. This is followed by a discussion on the technical requirements for SDH digital radio relay system equipment. Frequency planning issues are considered. Gross transmission capacities that can be realized for various options of modulation schemes and RF channel spacing are discussed     

The synchronous digital hierarchy. II. Survival of the fittest

For pt.I see ibid., vol.37, no.5, p.185-9, 1991. The authors explain how the synchronous digital hierarchy (SDH) offers a solution the problems caused by the digitalisation of the world's telecommunications networks. The principles and the pros and cons of SDH are also outlined     

The synchronous digital hierarchy. I. The origin of the species

Throughout the world, public network operators are set to begin trials of what are known as synchronous transmission systems. The authors look at plesiochronous digital hierarchy, its successor, and describe the nature of the new transmission systems, indicate why they are needed, and identify some of the benefits they will bring to operators and users alike     

北京-廊坊-天津DAB同步网的发射系统

DAB(数字音频广播)是以数字化和网络化为基础的新一代全数字化广播体制,是继调幅和调频广播后的第3代广播,与传统的模拟广播相比,具有许多新的特点和优势。主要有：(1)音质可达到CD质量;(2)传输系统的抗干扰能力强,适用于移动接收;(3)频谱利用率高,可以实现单频网广播;(4)与传统的调频广播相比,为覆盖同样大小的区域,DAB的发射功率小得多;(5)既可传送声音广播节目,又可传送数据业务和静止图像,是新的多媒体广播系统。     

A video conference network management system

Setting up either one or multiple conferences and managing the various devices can be a very difficult task. In this article a newly developed distributed video conference management system is explained and tested. © 1998 John Wiley & Sons, Ltd.     

A digital rights management system for digital broadcasting based on home servers

This paper presents a digital rights management (DRM) system for digital broadcasting based on home servers (DBHS) using receivers with large-capacity storage devices. DBHS will enable viewers to enjoy 'television anytime/anywhere' by utilizing these storage functions. Our proposed DRM system is suitable for broadcasting, and allows both rights protection and advanced access to content held on home storage devices (in terms of validity, usage and charge conditions, and so on). We developed a prototype DRM system using a Pentium3 personal computer (1 GHz) in order to evaluate the nonlinear playback and 'trick-play' modes of encrypted content on the hard disk drive (HDD). Using this prototype, we confirmed that the nonlinear playback of content encrypted using the proposed DRM system could be processed in real time. The functionality in terms of trick-play modes was equal to that of commercially available hard disk recorders. In addition, we developed a security module for the DRM system in the form of a smart card with a built-in processor. We confirmed that the proposed DRM system utilizing the new smart card could be applied to DBHS.     

数字网络型光纤振动传感系统

设计了一种新型光纤振动传感系统,该系统借鉴光通信中的无源光网络(PON)技术、光纤时分和波分混合复用传感侦测技术组建了数字网络型无源传感网络,系统传感单元的最大容量为32×8,有效地扩大了传感范围,实现了多传感单元系统化的集中管理,在处理算法中采用动态阈值自适应管理,可以根据环境变化实时改变阈值.在报警处理中,采用声、...     

数字集群系统的虚拟专网

自信息产业部公布我国数字集群系统标准以来,数字集群通信系统网络的规划与实施已引起多方面的关注与探讨。我国模拟集群通信系统的使用和欧美等国相比并不晚,但是使用情况和用户数量不理想。主要问题有多种制式、信令不一、互不相通;频谱效率低、系统容量小;功能单一、只有语音调度;干扰大、盲区多。为了克服模拟集群投资分散,各自管理,系统规模小,用户发展规模有限等弊端,提出了数字集群“共网”概念,它充分发挥数字集群系统的高质量语音;频谱利用率高;系统容量大;以及无线分组数据传输及应用等优势。为了满足网内各专网用户…     

Total network management in the British Telecom digital public switched telephone network

The benefits of an integrated digital network are well known but such a network requires careful monitoring and management to obtain the full service and cost benefits. This paper describes the strategy that British Telecom has adopted to manage its long distance digital network.     

无线电管理信息网络系统建设浅析

无线电管理信息系统承载着国家极其重要的无线电管理业务，保证无线电管理信息系统的网络系统、主机系统、业务应用系统的稳定、高效运转，以及关键数据的可靠性是我们必须重点解决的问题。本文针对无线电管理信息系统的运行维护需求．提出了无线电管理信息系统的网络管理系统建设思路。文中提到的网络管理是广义的网络管理．涵盖了网络、主机、业务系统和关键数据等。[第一段]     

A multimedia front-end for an expert network management system

A multimedia natural-language interface for an expert network-management system is described. The different media discussed are speech, text, and graphics. An object-oriented, multimedia interaction language called Milan is used to describe the multimedia information. Application of the multimedia interface to a digital data services (DDS) network is illustrated. It is believed that such multimedia front ends will play a major role in the design of intelligent human-machine interfaces     

基于FPGA的数字复接系统帧同步器设计与实现

介绍了应用FPGA技术进行帧同步器设计的实现原理、系统框图及设计中需要注意的问题，给出了用VHDL描述的几个模块的源代码。     

基于集中式网络液压同步顶升控制系统的设计

针对连云港某高速路段高架桥改造工程的需求以及旧设备存在同步性不好的问题,采用腾控T-910 PLC和触摸屏TK6070iH完成子系统的数据采集、显示及控制,采用EMW1016、1008MV光纤交换机完成各子系统与工控机之间的数据传输,采用研华网际组态软件WebAccess作为工控机的人机交互界面,结合系统顶升与带载下降实验,得出基于集中式网络液压同步顶升控制系统精度可达到0.1 mm,其同步性更好且更加稳定。自2014年9月投入使用以来,该系统运行良好。     

E-linac数字化设计管理系统分析

直线加速器设计的信息化和网络化是今后加速器的发展趋势,文章在进行电子直线加速器(E-linac)数字化设计的基础上,构建了E-linac数字化设计管理系统,以解决设计管理中存在的信息共享、资源统筹差、工作协调不够等问题,提高设计管理的效率和加速器数字化设计的研究水平,以信息化推进加速器数字化设计管理体系和设计现代化,为直线加速器数字化设计变革创新奠定基础。     

ROADM设备网管系统的实现

可重构的光分插复用(ROADM)设备是光传送网的重要节点,通过软件配置,可以灵活实现波长上下,使网络具备重构功能.建立基于SNMP协议的网元管理系统是保证ROADM设备稳定灵活工作的前提,文章简述了ROADM设备的功能结构,并讨论了设备网管系统的建立和配置功能的软件实现.     

Implementing a flexible synchronous network

The SYNET project, undertaken by Deutsche Telekom to modernize its transmission network, is discussed. The SYNET technology is based on the synchronous digital hierarchy (SDH), which uses synchronous transport modules of 155 Mbit/s (STM-1). The latter include a maximum usable bit rate of about 50 Mbit/s as well as a variety of additional information intended for network management. Since the transmission network is divided into several network levels characterized by different traffic loads and structures, a range of synchronous components geared to the requirements of the different network levels have been developed. The major differences between the trunk network and the local networks are described. The implementation of SYNET is reviewed     

分布式光纤振动传感技术研究

分布式光纤振动传感技术具有精度高、动态范围大、响应频带宽、隐蔽性好等优于传统振动传感器的鲜明特点,可用于大坝、桥梁、地矿监测、车辆及机械运行监测、火灾报警、管道泄漏报警及重要区域安防报警等领域,应用前景广阔。本文主要介绍了分布式光纤振动传感器相关技术及种类,并对分布式振动传感技术的发展方向和应用领域进行展望。     

控制网络的综合调度及其在双缸同步控制中的应用

为提高网络调度的工程可操作性,基于对传输任务与被控对象的分析提出一种不依赖于控制模型的综合调度方法.通过估计网络负载和引入频谱能量分析法粗拟出多个回路的采样周期范围,针对争用式网络协议采用非抢占RM算法进行带宽分配,采用带宽预留的概念全面考虑周期任务和猝发任务.最后以工程机械中常见的顶推系统双缸同步控制为例,对所提出的综合调度方法进行仿真研究,验证该方法的有效性.