S-VDR设备安装与维护的研究

从S-VDR配备要求、结构和功能入手,介绍了S-VDR设备安装及检验与实验要求,并结合设备的日常维护与保养对操作过程进行了总结。     

程控交换设备安装与维护教学内容的设计

实践教学是理论教学的有效补充,是专业技能的具体表现。在理论教学的基础上,结合现场工作的实际步骤,分析了程控交换设备的安装、业务开通及程控交换设备的维护三个业务情景的具体内容,最终使学习者掌握专业技能的具体流程和工作要点。     

VSAT与USAT

VSAT通信是卫星通信的一种,Vsat是Very SmallAperture Terminal的英文缩写,意思是甚小口径卫星通信终端(地球站),通常指终端天线口径在1.2米-2.8米左右的卫星通信地球站.它是在80年代初期开发出来的一种卫星通信终端设备,并在近些年来得到广泛的发展.     

VSAT data networks

The use of satellite channels for very small-aperture terminal (VSAT) data networks such as spread spectrum and ALOHA is reviewed. Certain basic aspects of the architecture of VSAT data networks are discussed. Although spread spectrum and ALOHA have different origins and are sometimes represented as competing technologies, they can in fact be characterized as different ways of viewing the same low-dimensional signals in a high-dimensional signal space. After a brief introduction to the architecture of VSAT networks, it is shown how a simple linear transformation of conventional ALOHA packets called spread ALOHA leads to signals identical in all respects to the most common form of spread-spectrum signals. Two practical consequences of this theoretical result are discussed. First, for the case of small earth stations it is not possible to find an Access technique with a higher throughput than spread ALOHA. Second, the use of different spreading sequences for different users in a packet network using spread spectrum is not necessary for user separation     

浅析机房设备安装与日常维护的管理

为提高中心机房设备安装与日常维护工作效率,借助外协单位和自有技术人员的优势,文章就机房设备安装调试与日常维护方案实施进行概述,力求保证中心机房系统设备安全、稳定、可靠运行。     

VSAT卫星通信技术的发展与应用

本文从VSAT卫星通信系统的参数、特点、优点、网络构成及连接方式。VSAT通信网的通信规程协议。VSAT通信网的网络管理，VSAT卫星通信的发展趋势。VSAT卫星通信存在的问题，中国VSAT卫星通信未来的对策等方面。详细地介绍了VSAT通信技术的应用与发展。     

VSAT的未来

秉承以色列精益求精的传统．秉承Gilat高科技的血统．Gilat在VSAT这个并不宽广的领域，打拼出了自己的天空。问及VSAT的未来．Rudy认为VSAT会随着通信产业的发展而发展．不会消亡．而且市场会非常稳定，同时在3G时代．地面网络的高速发展也离不开卫星通信这个助手。     

发展中的VSAT技术

介绍ＶＳＡＴ最新技术及发展趋势。帮助用户合理规划和选用ＶＳＡＴ系统。     

VSAT的技术进展

本文从传输技术、多址接入方式、网络管理和网络体系结构等方面综述了甚小口径卫星地球站在技术上的最新进展。     

VSAT communications networks-an overview

The very-small-aperture-terminal (VSAT) fixed satellite communication network is a star network in which many dispersed micro terminals attempt to send data in a packet form through a random access/time-division multiple-access (RA/TDMA) satellite channel with transmission delay. The basic concept of the VSAT and its service potential are discussed. Two classes of traffic are addressed, namely business-oriented low-rate-data traffic and bulk data traffic of corporate networks. Satellite access, throughput, and delay are considered. The size of the network population that can be served in an RA/TDMA environment is calculated. User protocols are examined. A typical VSAT business scenario is described     

电视广播机房设备安装与日常维护探讨

随着科技的发展和社会的进步,广播电视这一娱乐活动走进千家万户。对于广播电视来说,广播电视机房就是整套系统的核心,它控制着信号的转换和发射,所以广播电视机房设备的安装和日常维护显得十分重要,它决定着用户的收看节目的质量。本文对广播电视设备安装和日常维护做了深入探讨并提出相应的措施。     

话音VSAT网管系统

现有的ＶＳＡＴ系统大都是用来传输数据的。研制以话音为主兼有数据传输功能的ＶＳＡＴ系统，较符合中国目前的国情，预计会产生很大经济效益。本文介绍了话音ＶＳＡＴ网络管理和控制系统议下简称网管系统Ｊ的总体设计以及实施。     

走向宽带化的VSAT卫星通信

受数据音频视频广播、计算机卫星宽带交互接入和音视频会议等业务的推动,VSAT卫星通信网向宽带业务发展巳成为必然趋势。分别对应以上业务的VSAT卫星通信网也日益趋于融合成一个统一的宽带VSAT通信网。发展宽带VSAT通信网的关键技术涉及到宽带数据广播、宽带多址接入、卫星通信规程、网络综合管理和宽带虚拟子网等。     

宽带VSAT网络中的多址技术

多址技术是宽带VSAT网络中的关键技术，先分析讨论了目前宽带卫星网络中提出的多种多址技术，业务使用的多址方式．它对用户的QoS要求和卫星信道的利用率都有重要的影响．文中首指出它们各自在应用中可能存在的问题：然后具体分析了ATM各类     

一种自组织VSAT卫星通信系统

针对传输话音业务的小型VSAT网络系统,提出了一种基于FDMA/SCPC的无主站自组网方法。在该方法中,网内各站点能力相同、全网状连接,共享业务信道频率资源。站点通过扫描业务信道获取频点实时忙闲信息。当需要通信时,站点通过自发自收测试占用空闲信道,并发起通信申请。介绍了这种自组网方法的网络构成、频率配置和通信过程,并通过Matlab仿真对网络的呼损率、信道利用率等性能指标进行了分析。     

VSAT networking concepts and new applications development

The authors present some innovative very small aperture terminal (VSAT) technology that can be used to support new applications. The first of these applications explores the possibility of realizing a VSAT-based satellite wide area network (SWAN) to provide flexible interconnection between local area networks (LANs) and metropolitan area networks (MANs) as well as gateway access to centralized information databases and computing services. A second application deals with the potential provision of ISDN-compatible services via VSATs in conjunction with existing satellites as well as future advanced satellites (ADSATs) having onboard switching and processing capabilities. The use of VSATs to solve backhaul interconnection/internetworking problems associated with evolving mobile satellite (MSAT) communication networks is discussed     

VSAT系统软故障分析及解决方法

从频率配置和电平配置两个方面论述了某些VSAT站在硬件设备无故障的情况下,系统却无法正常工 作的原因。并根据理论分析和实践经验提出了解决这种软故障的方法。     

广播影视VSAT

广播影视VSAT网因其业务复杂，涵盖多种技术体制，而明显地区别于国内其它专用VSAT网。本文简要介绍了该网的规模和功能，对网络的技术体制、频带利用情况等进行了深入的分析，并在文章最后对网络的应用前景做了展望。     

Next generation multiservice VSAT networks

Very-small-aperture terminal (VSAT) satellite networks have so far been successful in the provision of specific communication services to geographically dispersed users. However, user demands are becoming more complex and VSAT networks are expected to provide a much wider range of services (voice, data and multimedia). This paper investigates how this service integration could be achieved and shows that performance improvements are possible if efficient multi-access protocols and speech compression with voice-activity-detection techniques are used. It also discusses the future role that VSATs could play in the provision of access to the integrated broadband communication network to remote users. It is shown that it could be possible to use VSATs for ATM service provision, but there are limitations on the system's performance from the satellite delay and limited link capacity