Performance of multimedia broadcasting through ISDB transmissionsystem

Multimedia broadcasting has the benefits of versatile information representation, intelligent viewing environments, and economical systems. Integrated Services Digital Broadcasting (ISDB) presents a concept for future digital broadcasting systems. Full-scale multimedia broadcasting services can be realized by ISDB. There are two aspects in multimedia broadcasting from the viewpoint of ISDB. One is “transmission multimedia” and another is “presentation multimedia”. The former means that ISDB provides services by exploiting the characteristics of various types of broadcast channels. It also integrates all broadcast networks and is interoperable with communications and package media. The latter means that ISDB can flexibly combine and send various types of representation media that most appropriately convey the information. Multimedia broadcasting by ISDB is expected to achieve interactive viewing and to raise individual viewer satisfaction. ISDB will also make it possible to set up multiple small-scale broadcast stations and to provide a many-to-many information linking environment for transmitting information between an unspecified number of individuals     

MRG9000数字视频网络安全在电视台的应用

当前全国电视台纷纷投入大量资金搭建数字电视节目制作网络和播出网络,但是随之而来的病毒传播以及网络(黑客)攻击严重威胁电视台的正常运转,常规的网络安全措施难以满足广电网络的特殊要求,停播、漏播等事故时有发生,以致于很多电视台不敢将内部的各个局域网连接起来,使它们成为一个个数字孤岛,这样既降低了工作效率,又因为重复的上载损害了节目质量。为了克服防火墙在功能上的缺陷,借助目前网络安全领域中先进的隔离交换思想,富锦台应用MRG9000数字视频网络安全产品,部署在电视台各个安全网络的入口,在完成外部数据到内网的传输的同时,实现了数据资料的受控传输、内容审查、内网网络拓扑隐蔽、日志审计等安全功能,确保整个传输过程高速、安全、可控。     

浅谈数字播出通路与导播应急操作

电视节目的安全播出无疑是任何一个电视台最重要的工作之一,而导播对播出事故的判断及应急操作又是安全播出工作中最关键的环节.以广东电视台卫星频道为例,通过对数字播出通路的简介,阐述数字播出通路的结构、数字信号传输过程及与之相关的播出设备,进而说明熟悉数字播出通路结构对导播在事故判断及应急操作的作用,并提出改良建议.     

唐山广播电视台播控及传输系统安全设计

针对电视台传统播控环境出现的问题,唐山电视台结合当前网络快速发展的状况,在综合考虑播出安全和播出质量需求的基础上,引进设计了网络智能化全球播出系统。实际运营证明,这套系统既保证了播出质量又维护了播控安全。从配电系统、播出控制安全系统、视频服务器、数据存储安全、信号处理与传输、垫片系统、报警系统、时钟系统、同步系统等9个方面对该系统进行了讨论及阐述。     

Trends in digital communication by wire

The introduction and rapid spread of pulse code modulation must be examined in the framework of overall capability, efficiency, and cost. However, apart from television, the only field of application that can presently justify a massive investment in a new transmission system is telephony, because it represents the dominant communication market. Other communication services?such as data and facsimile transmission, telegraphy, broadcast sound, and closed-circuit television?must in general travel as passengers on telephony networks if they are to be economically feasible. Hence, the most fruitful approach to an examination of digital communication is to begin by studying PCM telephony and then to see how other services can be coordinated with it.     

数字电视多业务传输平台设计与实现

针对交互电视点播业务在广播电视领域里的快速推进,从组网技术的选择、网络结构、业务规划、保护方式等角度,全面介绍利用弹性分组环(RPR)技术建设数字电视多业务传输平台的设计方案,并通过案例证明了该技术方案能适应直播电视和交互电视传输需求,为广电行业组建数字电视SDH传输网络提供参考。     

An FM subcarrier data broadcast on bus transportation statusindication system

FM Subsidiary Communication Authorization (SCA) has been used to broadcast background music for a long time. Analog audio programs or digital data transmission services, utilizing SCAs, such as paging, stock market and headline news updates are common in people's daily life. Some demonstrations have been offered in the past to broadcast fax messages and some studies dealing with broadcasting video programs over the FM SCA channels. This paper focuses on using the FM SCA subchannel to transmit bus service status. This application provides the transmission of accurate status of public bus transportation services in order to offer better services. The status can be displayed on bus stations display boards or on personal computer receivers     

Coded orthogonal frequency division multiplex [TV broadcasting]

Technological evolution and the ever-increasing demand for higher-quality services give broadcasters a strong incentive to completely digitize their broadcasting networks. This digitization, which is already well advanced in many program production areas and transmission links, now has to be extended to complete the last link in the broadcast chain; i.e., from broadcast transmitter to consumer receivers. It is therefore necessary to develop wholly new techniques for the broadcasting of digitally coded TV programmes. Thus an efficient baseband digital coding must be combined with a robust digital modulation and channel coding scheme that can meet the requirements of every mode of broadcast reception. This article presents the research work related to the coded orthogonal frequency division multiplex (COFDM) technology, which has now been completed in the field of digital radio (DAB), and which is under progress in the field of digital terrestrial TV     

Two-step multipolling MAC protocol for wireless LANs

The IEEE 802.11 standard defines two coordination functions: distributed coordination function (DCF) and point coordination function (PCF). These coordination functions coordinate the shared wireless medium. The PCF uses a centralized polling-based channel access method to support time-bounded services. To design an efficient polling scheme, the point coordinator (PC) needs to obtain information about the current transmission status and channel condition for each station. To reduce overhead caused by polling frames, it is better to poll all stations using one polling frame containing the transmission schedule. In this paper, we propose an efficient polling scheme, referred to as two-step multipolling (TS-MP), for the PCF in wireless local area networks (WLANs). In this new scheme, we propose to use two multipolling frames with different purposes. The first frame is broadcast to collect information such as the numbers of pending frames and the physical-layer transmission rates for the communication links among all stations. The second frame contains a polling sequence for data transmissions designed based on the collected information. This frame is broadcast to all stations. Extensive simulation studies show that TS-MP not only overcomes the aforementioned deficiencies, but also help to implement rate adaptation over time-varying wireless channel.     

清远有线数字电视系统安全播出策略

介绍清远有线数字电视系统安全播出的规划建设,阐述在各个环节如何部署安全备份措施以实现数字电视的安全播出,希望通过清远有线前端的安全播出介绍,能够为各台搭建一个具有合理备份措施的数字电视播出平台提供一定的帮助。     

On the reliability and performance of real-time one-hop broadcast MANETs

Recently, broadcast communications in mobile ad hoc networks (MANETs) have been deployed in many mission-critical applications. So far, most investigations of such broadcast networks focus on multi-hop connectivity taking all one-hop links for granted. In this paper, the reliability and performance of real-time one-hop broadcast services in IEEE 802.11 based MANETs are investigated analytically and by simulation. Having specified possible applications and the features of IEEE 802.11 broadcast communication in dynamically self-organized networks under harsh communication environment, analyses are conducted to derive closed form expressions of the reliability and performance indices for both one-dimensional (1-D) and two-dimensional (2-D) broadcast MANETs: packet reception rate (PRR) and packet transmission delay. The proposed analytical models account for the impact of broadcast hidden terminal problem, message arrival interval, backoff counter process, space distributions of nodes, and fading transmission channel on the reliability and performance of the broadcast MANETs. As an example, the proposed models are applied to the evaluation of safety-related inter-vehicle communication on a highway. From the obtained numerical results under various offered traffic and network parameters, new observations and effective enhancement suggestions are given.     

An efficient communication protocol for high-speed packet-switchedmultichannel networks

A media-access protocol for high-speed packet-switched multichannel networks that are based on a broadcast topology, such as optical passive star networks using wavelength-division multiple access, is described. The protocol supports connection-oriented traffic with or without bandwidth reservation, as well as datagram traffic to integrate transport-layer functions with the media-access layer. It uses the bandwidth efficiently while keeping the processing requirements low by requiring stations to compute their transmission and reception schedules only at the start and end of each connection. Analysis results show that low blocking probabilities for connections and high network throughput can be achieved     

ECAN电信运营级EoC技术的研究(本期优秀论文)

EPON+EoC已逐渐成为国内下一代广播电视网(NGB)双向改造的主流方案,而EoC同轴电缆接入技术是双向改造进程中最为关键的技术之一,即基于同轴电缆来承载以太网业务和其他各种综合业务,实现下一代广播电视网( NGB)的用户宽带接入.鉴于此,简要介绍各种EoC技术存在的缺点,通过与ECAN技术的分析,展示出了ECAN技术相比其他EoC技术的巨大优势,并探讨了ECAN广阔的应用前景.     

长电缆数字化传输系统的可靠性设计

纠错编码被广泛应用在各种数字通讯、数字广播和数据存储系统中。随着单片机、DSP和FPGA等器件的快速发展,越来越容易在各种通用硬件平台上实现纠错编码。在长电缆的地震数据数字化传输中,采用单片机和FPGA实现Reed Solomon编码和交织编码,保证恶劣传输条件下可靠的高速数据传输,就此传输系统的功能结构以及编解码方案做简要介绍。     

县级电视台播出机房数字化建设

播出机房是县级电视台重要的节目播出载体,不仅要保证播出质量,还要保证播出效率,因此应强化监管机制,利用数字技术,加快升级改造。     

全天候、全方位、高质量的数字音频传输系统

本文结合浙江广播电视集团广播数字直播车工程的建设,先简介了直播车的结构和功能,再重点介绍浙江广播电视集团广播数字直播车的创新点,通过对广播现场直播中播出信号传输功能的需求分析和方案优化选择,选用了全天候、全方位的数字音频传输系统,对同类工程建设具有一定的参考意义。     

无线Mesh网络技术在油田单位中的应用分析

通过油田数字化建设实现远程视频监控、闯入预警、功图法计量、电子巡井、数据采集等功能,建立起一套现代化的管理决策系统。如何保障数据从复杂的现场地理环境中传输到各个井站管理平台是信息网络建设的难点。通过对油区地理位置和各种网络传输技术分析研究,通过现场试验应用,选择无线Mesh网络组网技术为实现方案,并就无线Mesh网络技术在油田应用情况做以阐述。     

Reliable video broadcasts via protected Steiner trees

The introduction of the latest generation of ROADMs in the communication long-haul transport networks allows network planners to consider some new cost-effective design alternatives. Specifically, for video broadcast services ROADM wavelength drop-and-continue technology enables simple wavelength connections at each node via a tree-like topology, and the intelligent control plane permits the use of various shared protection schemes (with failure restoration switching times comparable to SONET BLSR). In this article we formulate models for reliable TV/video broadcast. We consider the network topologies based on minimum spanning trees. The objective is to minimize the total network cost while ensuring that the broadcast, originating in one (or two) source node(s), is delivered to a set of destination nodes and the network will tolerate at least one single link failure. The resulting protected tree networks are illustrated, and the cost of protection strategies is analyzed.     

创新的中国数字调频广播技术方案——CDRadio与HD Radio的简介与比较

数字化正对中国广播电视行业产生着深刻的影响,传统的FM音频广播也面临着数字化改造.在DAB,HD Radio,DRM及CDRadio几种先进数字音频广播技术方案中重点比较了HD Radio与CDRadio.中国数字调频广播技术方案CDRadio实现了真正的带内数模混叠同播,并通过使用非规则频谱分配、LDPC纠错编码、时...