首页
外语
计算机
考研
公务员
职业资格
财经
工程
司法
医学
专升本
自考
实用职业技能
登录
外语
Telecommunications stand for devices and systems that transmit electronic or optical signals across long distances. Telecommunic
Telecommunications stand for devices and systems that transmit electronic or optical signals across long distances. Telecommunic
admin
2011-01-02
80
问题
Telecommunications stand for devices and systems that transmit electronic or optical signals across long distances. Telecommunications enables people around the world to contact one another, to access information instantly, and to communicate from remote areas. Telecommunications usually involves a sender of information and one or more recipients linked by a technology, such as a telephone system, that transmits information from one place to another. Telecommunications enables people to sand and receive personal messages across town, between countries, and to and from outer space. It also provides the key medium for delivering news, data, information, and entertainment.
Telecommunications devices convert different types of information, such as sound and video, into electronic or optical signals. Electronic signals typically travel along a medium such as copper wire or are carried over the air as radio waves. Optical signals typically travel along a medium such as strands of glass fibers. When a signal reaches its destination, the device on the receiving end converts the signal back into an understandable message, such as sound over a telephone, moving images on a television, or words and pictures on a computer screen.
Telecommunications messages can be sent in a variety of ways and by a wide range of devices. The messages can be seat from one sender to a single receiver (point-to-point) or from one sender to many receivers (point-to-multipoint). Personal communications, such as a telephone conversation between two people or a facsimile (fax) message (see Facsimile Transmission), usually involve point-to-point transmission. Point-to-multipoint telecommunications, often called broadcasts, provide the basis for commercial radio and television programming.
Telecommunications begin with messages that are converted into electronic or optical signals. Some signals, such as those that carry voice or music, are created in an analog or wave format, but may be converted into a digital or mathematical format for faster and more efficient transmission. The signals are then sent over a medium to a receiver, where they are decoded back into a form that the person receiving the message can understand. There are a variety of ways to create and decode signals, and many different ways to transmit signals.
Individual people, businesses, and governments use many different types of telecommunications systems. Some systems, such as the telephone system, use a network of cables, wires, and switching stations for point-to-point communication. Other systems, such as radio and television, broadcast radio signals over the air that can be received by anyone who has a device to receive them. Some systems make use of several types of media to complete a transmission. For example, a telephone call may travel by means of copper wire, fiber-optic cable, and radio waves as the call is sent from sender to receiver. All telecommunications systems are constantly evolving as telecommunications technology improves. Many recent improvements, for example, offer high-speed broadband connections that are needed to send multimedia information over the Internet.
Personal computers have pushed the limits of the telephone system as more and more complex computer messages are being sent over telephone lines, and at rapidly increasing speeds. This need for speed has encouraged the development of digital transmission technology. The growing use of personal computers for telecommunications has increased the need for innovations in fiber-optic technology.
Telecommunications and information technologies are merging and converging. This means that many of the devices now associated with only one function may evolve into more versatile equipment. This convergence is already happening in various fields. Some telephones and pagers are able to store not only phone numbers but also names and personal information about callers. Wireless phones with keyboards and small screens can access the Internet and send and receive e-mail messages. Personal computers can now access information and video entertainment and are in effect becoming a combined television set and computer terminal. Television sets can access the Internet through add-on appliances. Future modifications and technology innovations may blur the distinctions between appliances even more.
Convergence of telecommunications technologies may also trigger a change in the kind of content available. Both television and personal computers are likely to incorporate new multimedia, interactive, and digital features. However, in the near term, before the actualization of a fully digital telecommunications world, devices such as modems will still be necessary to provide an essential link between the old analog world and the upcoming digital one.
In this passage, "optical" can be understood as related to ______.
选项
A、light
B、audio
C、electronics
D、multimedia
答案
A
解析
转载请注明原文地址:https://kaotiyun.com/show/HJeO777K
0
专业英语八级
相关试题推荐
Videoconferencingisgraduallybecominganacceptedmeansinwhichtodobusiness.Foralongtimeissufferedfromtheimageo
SuccessPersonalityAccordingtoaGallupsurvey,anumberofqualitiesarecommonamongsuccessfulpeople.Herearefiveof
A、Differentculturalbackground.B、Lesslegislation,morelegislation.C、Differentprocesses.D、Socialistsociety,capitalistso
Norms:TypesandAcceptanceSociologistsfindthattounderstandaculture,itisveryimportanttounderstanditsnorms.Ⅰ.
Norms:TypesandAcceptanceSociologistsfindthattounderstandaculture,itisveryimportanttounderstanditsnorms.Ⅰ.
A、opposition.B、support.C、ambiguity.D、indifference.A考查同义词的掌握能力。考生听懂了disapprovedof这一词组即可从四个选项中找出与之表达同样概念的词。
A、Three.B、Six.C、Nine.D、Four.C
A、weapon-gradematerial.B、nuclearfuel.C、plutonium.D、spentfuel.C新闻的第一句即讲明Thorpefacility的功能是加工spentfuel,生产plutonium。本题题干的
C美国文学之作家概况。WaltWhitman是美国著名诗人,代表作为《草叶集》(LeavesofGrass),他是第一位使用自由体(FreeVerse)的诗人。
随机试题
国际政治
根据《劳动合同法》的规定,劳动者有下列哪些情形之一的,用人单位可以解除劳动合同()
最简单的甘油磷脂是
男,32岁。交通事故致头面部复合伤。伤后昏迷45min,造成吸人性窒息,正确的处理方法是
男,35岁。从高处跳下时,双下肢顿时感到无力。
私营企业主王某办公室的一台DVD播放机无法正常使用,遂通知工作人员刘某拿出去扔掉。刘某将该播放机修理好后拿回家使用。王某得知该播放机能够正常使用后,要求刘某返还。关于该播放机归属的说法,正确的是()。(2010年单项选择第5题)
下列不属于房地产经纪机构人力资源管理中的内部选拔的优点的是()。
在现行公开招标方式下,国债的销售价格是()。
辩证的否定观认为新事物必然取代旧事物,这是因为
若对n个元素进行直接插入排序,则进行第i趟排序过程前,有序表中的元素个数为______。
最新回复
(
0
)