剑桥雅思9Test3阅读Passage3原文翻译inform

剑桥雅思9Test3阅读Passage3原文翻译information theory?the big idea，今天就来为大家分析这个问题。

information theory?the big idea

信息理论

剑桥雅思9 Test3 Passage3阅读原文翻译

引言

Information theory lies at the heart of everything―from DVD players and the genetic code of DNA to the physics of the universe at its most fundamental.It has been central to the development of the science of communication,which enables data to be sent electronically and has therefore had a major impact on our lives

信息理论是一切的核心-从DVD播放机和DNA的遗传密码到最根本的宇宙物理学。它一直是传播学发展的核心所在。它使数据能够以电子方式发送，并因此已经对我们的生活产生重大影响

段落A

In April 2002 an event took place which demonstrated one of the many applications of information theory.The space probe Voyager I,launched in 1977,had sent back spectacular images of Jupiter and Saturn and then soared out of the Solar System on a one-way mission to the stars.After 25 years of exposure to the freezing temperatures of deep space,the probe was beginning to show its age.Sensors and circuits were on the brink of failing and NASA experts realized that they had to do something or lose contact with their probe forever.The solution was to get a message to Voyager I to instruct it to use spares to change the failing parts.With the probe 12 billion kilometers from Earth,this was not an easy task.By means of a radio dish belonging to NASA’s Deep Space Network,the message was sent out into the depths of space.Even travelling at the speed of light,it took over 11 hours to reach its target,far beyond the orbit of Pluto.Yet,incredibly,the little probe managed to hear the faint call from its home planet and successfully made the switchover.

2002年4月发生了一起事件。它证明了信息理论的许多应用之一。于1977年发射升空的“旅行者1号”太空探测器文章来自老烤鸭雅思送回了木星和土星的壮观影像，然后飞离太阳系执行探索恒星的单程任务。暴露于深空的冰冻温度25年后，该探测器开始老化。传感器和电路位于崩溃的边缘。NASA专家意识到他们必须做些什么，否则的话就会永远与探测器失去联系。解决办法是向旅行者1号发送一条消息，指示其使用备用零件更换出现故障的零件。考虑到探测器距地球有120亿公里，这并非易事。通过属于NASA深空网络的无线电天线，该消息被发送到太空深处。即使以光速行进，也花了11个多小时才能到达目标，远远超出冥王星的轨道。然而，令人难以置信的是，这一小型探测器设法听到了来自其母星的微弱声音，并成功进行了转换。

段落B

It was the longest-distance repair job history,and a triumph for the NASA engineers.But it also highlighted the astonishing power of the techniques developed by American communications engineer Claude Shannon,who had died just a year earlier.Born in 1916 in Petoskey,Michigan,Shannon showed an early talent for maths and for building gadgets and made breakthroughs in the foundations of computer technology when still a student.While at Bell Laboratories,Shannon developed information theory but shunned the resulting acclaim.In the 1940s,he single-handedly created an entire science of communication which has since inveigled its way into a host of applications,from DVDs to satellite communications to bar codes―any area,in short,where data has to be conveyed rapidly yet accurately.

这是历史上跨越最长距离的修理，也是NASA工程师的胜利。但是，它也突显了一年前去世的美国通信工程师克劳德?香农（Claude Shannon）所开发的技术的惊人力量。香农于1916年在密歇根州的佩托斯基（Petoskey）出生。他从小就展现出数学和搭建小工具方面的天赋，并在还是学生的时候就在计算机技术的基础上取得了突破。在贝尔实验室时，香农提出了信息理论，但回避了由此产生的好评。在20世纪40年代，他一手创建了后来应用于各种领域的通信科学，从DVD到卫星通讯再到条形码。简言之，任何需要对信息进行快速而准确的传输的领域。

段落C

This all seems light years away from the down-to-earth uses Shannon originally had for his work,which began when he was a 22-year-old graduate engineering student at the prestigious Massachusetts Institute of Technology in 1939.He set out with an apparently simple aim:to pin down the precise meaning of the concept of‘information’.The most basic form of information,Shannon argued,is whether something is true or false―which can be captured in the binary unit,or‘bit’,of form 1 or 0.Having identified this fundamental unit,Shannon set about defining otherwise vague ideas about information and how to transit it from place to place.In the process he discovered something surprising:it is always possible to guarantee the information will get through random interference―‘noise’―intact.

这一切似乎与香农最初的应用相差很远。1993年他22岁，是著名的麻省理工学院工程学的研究生。他一开始的目的很简单：确定“信息”这一概念的确切含义。香农认为，基本的信息形式是判断事物正确与否，这可以用二进制单位“比特”以1或者0的形式来记录。香农确定了此基本形式后，便着手定义关于信息和信息跨地区传输的其他模糊概念。在这个过程中，他发现了一些令人吃惊事情：总是有可能使信息穿过随机的干扰-噪音-而保持完整。

段落D

Noise usually means unwanted sounds which interfere with genuine information.Information theory generalizes this idea via theorems that capture the effects of noise with mathematical precision.In particular,Shannon showed that noise sets a limit on the rate at which information can pass along communication channels while remaining error-free.This rate depends on the relative strengths of the signal and noise travelling down the communication channel,and on its capacity(its‘bandwidth’).The resulting limit,given in units of bits per second,is the absolute maximum rate of error-free communication given signal strength and noise level.The trick,Shannon showed,is to find ways of packaging up―‘coding’―information to cope with the ravages of noise,while staying within the information-carrying capacity―‘bandwidth’―of the communication system being used.

噪音通常表示会干扰到真正信息的多余声音。信息理论通过定理概括了这一概念。它以数学的精确度确定了噪声的影响。更确切的说，香农表示噪音在速度方面存在限制。在特定的速度上，信息可以通过通信频道并保持完整。该速度单位为比特/秒，是在给定的信号强度和噪音水平下，信息无误差传送的最大绝对速度。香农指出，提供这一速度的有效方法是在所使用的通信系统的传送能力（即带宽）范围内，找到将信息打包（即编码）的方式，来应对噪声的破坏。

段落E

Over the years scientists have devised many such coding methods,and they have proved crucial in many technological feats.The voyager spacecraft transmitted data using codes which added one extra bit for every single bit of information;the result was an error rate of just one bit in 10,000―and stunningly clear pictures of the planets.Other codes have become part of everyday life―such as the Universal Product Code,or bar code.Which uses a simple error-detecting system that ensures supermarket check-out lasers can read the price even on,say,a crumpled bag of crisps.As recently as 1993,engineers made a major breakthrough by discovering so-called turbo―which come very close to Shannon’s ultimate limit for the maximum rate that data can be transmitted reliably,and now play a key role in the mobile videophone revolution.

多年来，科学家们已经设计出许多这样的编码方法，也证明了它们对许多技术成就至关重要。旅行者号航天器利用编码传输数据，这些编码在每比特信息上都额外增加了一比特信息，使错误率仅为万分之一，得到清晰度惊人的行星图片。其他编码已成为日常生活的一部分，例如通用产品代码或条形码。它使用一种简单的错误检测系统，确保超市的激光结账设备甚至可以在皱巴巴的薯片袋上读取价格。就在1993年，工程师们取得了一项重大突破，发现所谓的Turbo码，这与香农提出的信息可以安全传送的最大速度极限非常接近。现在，Turbo码在移动可视电话变革中发挥着关键的作用，

段落F

Shannon also laid the foundations of more efficient ways of storing information,by stripping out superfluous(‘redundant’)bits from data which contributed little real information.As mobile phone text messages like‘I CN C U’show,it is often possible to leave out a lot of data without losing much meaning.As with error correction,however,there’s a limit beyond which message become too ambiguous.Shannon showed how to calculate this limit,opening the way to the design of compression methods that cram maximum information into the minimum space.

通过去除含有较少真实信息的多余数据，香农也会开发更有效率地储存信息的方式奠定了基础。正如手机短信“I CN C U”（I can see you的缩写）一样，有可能在省略了很多数据之后，基本意思保持不变。但是，正如纠错一样，省略存在一定的限制。超过该限制信息就会变得模糊不清。香农说明了如何计算这一限制，为设计信息压缩方法，从而将最多的信息塞进最小的空间开辟了道路。

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