《IPTV》实验指导书(模板).pdf

《《IPTV》实验指导书(模板).pdf》由会员分享，可在线阅读，更多相关《《IPTV》实验指导书(模板).pdf（12页珍藏版）》请在得力文库 - 分享文档赚钱的网站上搜索。

1、实验三 IPTV 一、实验目的 1、扩大通信技术的英语词汇量。2、熟悉通信行业、广播电视、可视电话等专业术语。3、了解科技文章的表达特点和掌握科技英语的翻译技巧 二、实验内容 文章翻译 IPTV Over the past few months,there has been increased interest in the use of IP networks to deliver broadcast-quality TV.IPTV is a relatively recent buzzword having emerged only three or four years ago.In a

2、 nutshell,it means the delivery of television over Internet Protocol(IP)networks.But for the telecommunication industry,which drives it to the market,IPTV means much more.For them,IPTV is an entirely new multimedia experience extending the borders of conventional broadcast television;it is an integr

3、ated,“all-embracing”media platform offering a bundle of diverse content and communication services from a single provider over a single network to a single user device-all with a single payment.Why use 30-year-old technology designed for slow,unreliable,unicast communications to transport video?The

4、answer is that IP is a magical platform to breed success and it has become totally pervasive.The second motivation is that IP can offer more functionality than traditional TV.The open,extensible nature of IP holds the promise of many more services in the future.IP infrastructure also can be leverage

5、d to provide video telephony and remote monitoring,as well as new uses of video within applications that havent been thought of yet.The final factor that is emerging is cost savings.There are diverging views about what IPTV really means.To broadcasters,IPTV is simply a new emerging platform for dist

6、ributing digital television channels to home consumers using a TV screen.To the telecom industry,IPTV is synonymous with a new broadband digital technology,offering voice,data and video.IPTV is complementary to existing satellite,cable and terrestrial systems,although in some cases it may become a v

7、igorous competitor to them.So far,the telecom industry has merely been providing telecommunication services such as voice connections between two points.The telecom companies were not at all concerned with the content of the information carried.They are now getting involved in IPTV as they facing de

8、creasing subscriber revenues from their traditional voice and broadband communication.They are in the process of moving into the content-providing domain with no real expertise and experience in providing television services to the general public,simply in order to improve their balance sheet and br

9、ing the customers back.Indeed,IPTV is beginning to look like a promising new business opportunity for telecom operators.However,telecoms will have to resolve some major technical challenges.One problem is the end-to-end transmission quality due to limited network bandwidth which decreases with the d

10、istance from the exchange cabinet.New modulation strategies such as ADSL2+and VDSL are being introduced,but the cost concerned is relatively high.The introduction of High-Definition Television(HDTV)may be quite a challenge,even if advanced coding technologies such as ITU/MPEG 4 or Microsoft VC1 are

11、used.Furthermore,Telecom networks do not generally serve the hundreds of thousands and even millions of simultaneous users.A lack of international standardization,which is currently the main obstacle to establishing horizontal markets and equipment inter-operability,is now being addressed by the Int

12、ernational Telecommunications Union.IPTV can potentially offer a myriad of new innovative services and applications to the user,many of which are already possible with digital television.The main differences come from the fact that IPTV uses a two-way communication channel,so the user can interact d

13、irectly with the content and service provider.The interactive link between the provider and the user enables sending individual video streams to individual devices in the home at the users request,in contrast to the broadcast model where all channels are sent to all users all the time.Such personali

14、zed services are becoming increasingly popular,particularly with entertainment and education.While the technical issues are not easy,they are not insurmountable.The legal and regulatory issues,however,are a real nightmare.One of the outstanding issues is to determine which national regulatory body i

15、s responsible for the regulation of IPTV services.This depends on the very definition of IPTV.Some countries consider IPTV a broadcast service and some a telecom service.Not only do the legal regimes vary from country to country,they are also different for telecoms and broadcasters.IPTV is still in

16、its infancy.Its market size is still small but it is growing rapidly.The prospects for the commercial success are great.The principle drivers for IPTV are the incumbent telecom and Internet companies.So far,broadcasters have been marginally involved in the IPTV process.It is now time to raise the aw

17、areness of broadcasters,so that they can play a more active role in the IPTV developments.三、实验步骤及要求 1、首先，打开手机，在应用市场上搜索可以翻译文档的软件，然后将翻译软件先下载到手机上，然后打开软件。软件分为三个功能：文档翻译、图片翻译、短句翻译。2、将翻译软件中的翻译参数设置为英译汉，将需要翻译成的语言调整为简体中文。3、利用翻译软件功能，采用一句原文，一句中文的方式进行翻译。4、将翻译后的汉语内容进行适当的句式调整,做到准确、完整、通顺和专业。四、实验设备 一部可以装有翻译软件的智能手机。五

18、、实验预习要求 阅读实验指导书内容，做好课前预习工作。六、实验报告要求 要求对文章进行翻译，书写的翻译内容要通顺、专业。实 验 四 Current Situation and the Future in the Telecommunication World 一、实验目的 1、扩大通信技术的英语词汇量。2、熟悉电电视信号、无线电波等专业术语。3、了解科技文章的表达特点和掌握科技英语的翻译技巧。二、实验内容 文章翻译 Current Situation and the Future in the Telecommunication World Todays telecommunication n

19、etworks are characterized by specialization.This means that for every individual telecommunication service at least one network exists that transports this service.A few examples of existing public networks are described below:The telex network transports telex information,i.e.messages of characters

20、,transported at very low speed.The characters are coded based on a specific 5-bit code.POTS(plain old telephone service)is transported via the public switched telephone network(PSTN).This ubiquitous network offers the customers classical two-way voice conversation.Computer data are transported in th

21、e public domain either by a packet switched data network based on X.25 protocols or in a very limited number of countries by a circuit switched data network based on X.21 protocols.Television signals can be transported in three ways:broadcast via radio waves using ground antenna,by the coaxial tree

22、network of community antenna TV network or recently via a satellite,using the so-called direct broadcast system.In the private domain,computer data are mainly transported by LANs(Local Area Network).The most famous ones are Ethernet,token bus and token ring(IEEE 802 series).Each of these networks wa

23、s specially designed for that specific service and is often not at all applicable to transport another service.For instance,the original CATV networks did not allow the transportation of POTS;or the PSTN does not transport TV signals;or the transfer of voice over an X.25 network is very problematic

24、because of too large end-to-end delay and jitter on this delay.Only in limited and special cases can service types other than the one the network was originally designed for be transported over it.This is for instance the case for the PSTN which is capable of transporting computer data at a limited

25、speed,if modems are provided at both ends of the network.An important consequence of this service specialization is the existence of a large number of often world-wide independent networks,each requiring its own design phase,manufacturing and maintenance.In addition,the dimensioning of each network

26、must be done for every individual service type.Even if resources are freely available in one network,they cannot be used by another service type.For example,the peak hours in the telephone network are between 9 a.m.and 5 p.m.,whereas the peak hours in the CATV network are during evening.Since resour

27、ce pooling is impossible each network must be dimensioned for its worst case traffic conditions which is the peak hour traffic.A first step,albeit a limited one towards a single universal network,is the introduction of NISDN in which voice and data are transported over a single medium.This network c

28、annot transport TV signals due to its limited bandwidth capabilities,so a special TV network is still required.Even in NISDN the integration of narrowband services such as data and voice can be considered as being rather limited:the user access to the network is fully integrated,either by a basic ac

29、cess or primary rate interface.However,inside the network there will still exist for some time a packet switched and a circuit switched network as two overlay networks incapable of transporting other traffic types and each dimensioned either for voice or X.25 data.Another important consequence of th

30、is service specialization is the inability of the network to benefit highly from the progress made in technology and coding algorithms.For instance,current digital NISDN switches are designed for 64 kbit/s voice channels.However,with the current progress in speech coding and chip technology,bit rate

31、s of 32 kbit/s,13 kbit/s and even lower will be used in the future.The existing switches and transmission systems are not directly suited and thus need an adaptation,or will not efficiently use their internal resources for these lower speed bit rates.When designing the future BISDN network,one must

32、take into account all possible existing and future services.Suppose a network is capable of transporting a specific service,e.g.a circuit switched service with a channel rate of 70 Mbit/s.Suppose also that it is specifically designed to transport this bit rate.Some years later a new teleservice of,f

33、or example,40 Mbit/s appears on the scene.This would mean that the network designed for that service(i.e.70 Mbit/s)will be capable of transporting the new teleservice,but with a large inefficiency:only 40 out of the 70 Mbit/s available will be used.This example is not unrealistic.It is very likely t

34、hat in the future new services will emerge which have not yet been identified,and of which the requirements are unknown today.As can be concluded from the above examples,the networks of today are very specialized and suffer from a large number of disadvantages,the most important being:Service Depend

35、ence Each network is only capable of transporting one specific service for which it was intentionally designed.Only in a limited number of cases and by using additional equipment(e.g.a modem)and with an inefficient use of its resources can it be adapted to other services.Inflexibility Advances in au

36、dio,video and speech coding and compression algorithms and progress in Very Large Systems Integration(VLSI)technology influence the bit rate generated by a certain service and thus change the service requirements for the network.In the future,new services with unknown requirements will appear.For th

37、e time being it is yet unclear,e.g.what the requirements in terms of bit rate for HDTV will be.A specialized network has great difficulties in adapting to changing or new service requirements.Inefficiency The internal available resources are used inefficiently.Resources which are available in one ne

38、twork cannot be made available to other networks.Taking into account all these considerations on flexibility,service dependence and resource usage,it is consequently very important in the future that only a single network exists and that this network of the future(BISDN)is service-independent.This i

39、mplies a single network capable of transporting all services,sharing all its available resources between the different services.A single service-independent network will not suffer from the disadvantages described above,but it will have the following main advantages:Flexible and future-safe Advances

40、 in the state of the art of coding algorithms and VLSI technology may reduce the bandwidth of existing teleservices.A network capable of transporting all types of services will be able to adapt itself to changing or new needs.Efficient in the use of its available resources All available resources ca

41、n be shared between all services,such that an optimal statistical sharing of the resources can be obtained.Less expensive Since only one network needs to be designed,manufactured and maintained,the overall costs of the design,manufacturing,operations and maintenance will be smaller.三、实验步骤及要求 1、首先，打开

42、手机，在应用市场上搜索可以翻译文档的软件，然后将翻译软件先下载到手机上，然后打开软件。软件分为三个功能：文档翻译、图片翻译、短句翻译。2、将翻译软件中的翻译参数设置为英译汉，将需要翻译成的语言调整为简体中文。3、利用翻译软件功能，采用一句原文，一句中文的方式进行翻译。4、将翻译后的汉语内容进行适当的句式调整,做到准确、完整、通顺和专业。四、实验设备 一部可以装有翻译软件的智能手机。五、实验预习要求 阅读实验指导书内容，做好课前预习工作。六、实验报告要求 要求对文章进行翻译，书写的翻译内容要通顺、专业。实验五 Next Generationa Network 一、实验目的 1、扩大通信技术的英语

43、词汇量。2、熟悉电信行业相关专业术语。3、了解科技文章的表达特点和掌握科技英语的翻译技巧。二、实验内容 文章翻译 Next Generationa Network The market for information and communications technology is currently undergoing a structural change.The classic telecommunication networks were planned and implemented for the transfer of specific data such as telepho

44、ne calls or pure data packages.The recent growth in competition,new requirements for the market and technological developments have fundamentally changed the traditional attitudes of the telecommunications industry.The present industry is characterized by the rapid growth of broadband connections,th

45、e convergence processes of various network technologies and the emergence of a uniform IP standard for individual and mass communications.Traditional telecommunications operators find themselves confronted with a host of new challenges.In particular,their previously successful fixed-network business

46、 is coming increasingly under pressure.New communication possibilities,such as telephoning via the Internet,and also growing market shares in mobile telephony are causing a great deal of concern.To counteract these losses,the network operators are investing more strongly in broadband，the growth driv

47、er.The traditionally familiar market boundaries between fixed networks,mobile telephony and data networks are disappearing more and more quickly.This gives the customer the advantage that he can call on an extremely wide range of services,regardless of his access technology.This development requires

48、 a meta infrastructure beyond the existing,subordinated networks-a core network for all the access networks.This new network is called the Next Generation Network.The Internet Protocol is the most significant integration factor because it is available globally and,at least in principle,it can use al

49、most all the services and applications in all the networks.In face,Next Generation Network（NGN）is a broad term to describe some key architectural evolutions in telecommunication core and access networks that will be deployed over next 5-10 years.The general idea behind NGN in that one network transp

50、orts all information and services(voice,data and all sorts of media such as video)by encapsulating these into packets.Like it is on the Internet,NGN are commonly built around the Internet protocol,and therefore the term“all-IP”is also sometimes used to describe the transformation towards NGN.Accordi