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
39
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.
According to the passage, ______ has become the driving force for the development of telephone system?
选项
A、information technologies
B、Internet
C、PC
D、convergence of telecommunications technologies
答案
C
解析
转载请注明原文地址:https://jikaoti.com/ti/xnuYFFFM
0
专业英语八级
相关试题推荐
Inordertogetyourpointacrossinyourtargetlanguage,youhavetolearnplentyofwords.Howdoyousetaboutit?Dr.Paul
ThefollowingarethefoundingfathersoftheAmericanRepublicexcept______.
Extraordinarycreativeactivityhasbeencharacterizedasrevolutionary,flyinginthefaceofwhatisestablishedandproducing
Arab-Israelibloodshedhasincreasedbecause______.
Norms:TypesandAcceptanceSociologistsfindthattounderstandaculture,itisveryimportanttounderstanditsnorms.Ⅰ.
ThenumberofscientistsandengineersgoingtoAmericatostudyandworkisdroppingprecipitously.Animportantreasonisthe
A、howB、whenC、whyD、whereA考查分析重要细节的能力。新闻中有这样一句话:Butatoncesharpdivisionshaveemergedoverthebestpathtoachieveit.即意见
ThirtyyearsagoIturnedonourfamily’sblack-and-whiteconsoleTVtowatchanorchestraconductornearlyashyperactiveasI
Northernmarshesarebeingturnedintoempty,desecratedmudflatwasteland.Theculprit?Snowgeese.Thesemarshesaretheb
随机试题
人们将管理引申到企业的生产与经营活动中,是在
A.高渗性脱水B.低渗性脱水C.等渗性脱水D.高钾血症E.低钾血症肌乏力最早出现的疾病是()
根据我国刑法的规定,下列说法正确的是?()
一般情况下,利率下降,期货价格( )。
产出增长率在成长期较高,在成熟期以后降低,经验数据一般以()为界;到了衰退阶段,行业处于低速运行状态,有时甚至处于负增长状态。
2014年3月,母公司以每件1万元的价格(不含增值税额)将其生产的商品100件销售给其全资子公司作为存货。该产品每件成本为0.7万元,未计提跌价准备。至2014年末子公司已对外销售90件。适用的所得税税率为25%,存货的初始入账价值与其计税基础相同。编制2
甲公司银行存款账户的期初余额(借方)为8万元,本期借方发生额4万元,期末余额(借方)为9万元,则该公司本期贷方发生额为______。
逢年过节,单身人士(尤其是大龄单身女青年)总会被亲戚朋友询问个人的婚恋情况,看起来整个社会都在给大龄单身女青年施加着巨大的压力,但是心理学家的研究表明,整个社会对于单身人士这一群体的歧视是隐秘而深刻的,大龄单身女青年只是其中最为突出的受害者而已。以下哪项
下面关于概化理论的描述正确的是()。
______,Mr.Wellsisscarcelyinsympathywiththeworkingclass.[2005]
最新回复
(
0
)