十大信誉单位英文翻译

第一篇：十大信誉单位英文翻译

APCA

This is to certify

……CO., Ltd

is hereby granted

TOP 10 CREDIT UNITS

in ……province

Approved by

Department of Commerce of …… province …… Academy of Social Sciences…… Credit Association

…… Administration for Industry&Commerce …… Consumers’ Association

EXP DATEDecember, 2015

第二篇：常用英文翻译十大技巧

常用英文翻译十大技巧

作者:netboy 日期:2007-07-27 字体大小: 小 中 大

英汉两种语言在句法、词汇、修辞等方面均存在着很大的差异，因此在进行英汉互译时必然会遇到很多困难，需要有一定的翻译技巧作指导。常用的翻译技巧有增译法、省译法、转换法、拆句法、合并法、正译法、反译法、倒置法、包孕法、插入法、重组法和综合法等。这些技巧不但可以运用于笔译之中，也可以运用于口译过程中，而且应该用得更加熟练，因为口译工作的特点决定了译员没有更多的时间进行思考。

一、增译法

指根据英汉两种语言不同的思维方式、语言习惯和表达方式，在翻译时增添一些词、短句或句子，以便更准确地表达出原文所包含的意义。这种方式多半用在汉译英里。汉语无主句较多，而英语句子一般都要有主语，所以在翻译汉语无主句的时候，除了少数可用英语无主句、被动语态或“There be…”结构来翻译以外，一般都要根据语境补出主语，使句子完整。英汉两种语言在名词、代词、连词、介词和冠词的使用方法上也存在很大差别。英语中代词使用频率较高，凡说到人的器官和归某人所有的或与某人有关的事物时，必须在前面加上物主代词。因此，在汉译英时需要增补物主代词，而在英译汉时又需要根据情况适当地删减。英语词与词、词组与词组以及句子与句子的逻辑关系一般用连词来表示，而汉语则往往通过上下文和语序来表示这种关系。因此，在汉译英时常常需要增补连词。英语句子离不开介词和冠词。另外，在汉译英时还要注意增补一些原文中暗含而没有明言的词语和一些概括性、注释性的词语，以确保译文意思的完整。总之，通过增译，一是保证译文语法结构的完整，二是保证译文意思的明确。如：

①、What about calling him right away? 马上给他打个电话，你觉得如何？（增译主语和谓语）

②、If only I could see the realization of the four modernizations.要是我能看到四个现代化实现该有多好啊！（增译主句）

③、Indeed, the reverse is true.实际情况恰好相反。（增译名词）

④、就是法西斯国家本国的人民也被剥夺了人权。

Even the people in the fascist countries were stripped of their human rights.（增译物主代词）

⑤、只许州官放火，不许百姓点灯。

While the magistrates were free to burn down house, the common people were forbidden to light lamps.（增译连词）

⑥、这是我们两国人民的又一个共同点。

This is yet another common point between the people of our two countries.（增译介词）

⑦、在人权领域，中国反对以大欺小、以强凌弱。

In the field of human rights, China opposes the practice of the big oppressing the small and the strong bullying the weak.（增译暗含词语）

⑧、三个臭皮匠，合成一个诸葛亮。

Three cobblers with their wits combined equal Zhuge Liang the mastermind.（增译注释性词语）

二、省译法

这是与增译法相对应的一种翻译方法，即删去不符合目标语思维习惯、语言习惯和表达方式的词，以避免译文累赘。增译法的例句反之即可。又如：

①、You will be staying in this hotel during your visit in Beijing.你在北京访问期间就住在这家饭店里。（省译物主代词）

②、I hope you will enjoy your stay here.希望您在这儿过得愉快。（省译物主代词）

③、中国政府历来重视环境保护工作。

The Chinese government has always attached great importance to environmental protection.（省译名词）

三、转换法

指翻译过程中为了使译文符合目标语的表述方式、方法和习惯而对原句中的词类、句型和语态等进行转换。具体的说，就是在词性方面，把名词转换为代词、形容词、动词；把动词转换成名词、形容词、副词、介词；把形容词转换成副词和短语。在句子成分方面，把主语变成状语、定语、宾语、表语；把谓语变成主语、定语、表语；把定语变成状语、主语；把宾语变成主语。在句型方面，把并列句变成复合句，把复合句变成并列句，把状语从句变成定语从句。在语态方面，可以把主动语态变为被动语态。如：

①、我们学院受教委和市政府的双重领导。

Our instituteis co-administrated by the States Education Commission and the municipal government.（名词转动词）

②、Too much exposure to TV programs will do great harm to the eyesight of children.孩子们看电视过多会大大地损坏视力。（名词转动词）

③、由于我们实行了改革开放政策，我国的综合国力有了明显的增强。

Thanks to the introduction of our reform and opening policy, our comprehensivenational strength has greatly improved.（动词转名词）

④、I’m all for you opinion.我完全赞成你的意见。（介词转动词）

⑤、The reform and opening policy is supported by the whole Chinese people.改革开放政策受到了全中国人民的拥护。（动词转名词）

⑥、In his article the author is critical of man’s negligence toward his environment.作者在文章中，对人类疏忽自身环境作了批评。（形容词转名词）

⑦、In some of the European countries, the people are given the biggest social benefits such as medical insurance.在有些欧洲国家里，人民享受最广泛的社会福利，如医疗保险等。（被动语态转主动语态）

⑧、时间不早了，我们回去吧！We don’t have much time left.Let’s go back.（句型转换）

⑨、学生们都应该德、智、体全面发展。

All the students should develop morally, intellectually and physically.（名词转副词）

四、拆句法和合并法

这是两种相对应的翻译方法。拆句法是把一个长而复杂的句子拆译成若干个较短、较简单的句子，通常用于英译汉；合并法是把若干个短句合并成一个长句，一般用于汉译英。汉语强调意合，结构较松散，因此简单句较多；英语强调形合，结构较严密，因此长句较多。所以汉译英时要根据需要注意利用连词、分词、介词、不定式、定语从句、独立结构等把汉语短句连成长句；而英译汉时又常常要在原句的关系代词、关系副词、主谓连接处、并列或转折连接处、后续成分与主体的连接处，以及意群结束处将长句切断，译成汉语分句。这样就可以基本保留英语语序，顺译全句，顺应现代汉语长短句相替、单复句相间的句法修辞原则。如：

①、Increased cooperation with China is in the interests of the United States.同中国加强合作，符合美国的利益。（在主谓连接处拆译）

②、I wish to thank you for the incomparable hospitalityfor which the Chinese people are justly famous throughout the world.我要感谢你们无与伦比的盛情款待。中国人民正是以这种热情好客而闻明世界的。（在定语从句前拆译）③、This is particularly true of the countries of the commonwealth, who see Britain’s membership of the Community a guarantee that the policies of the community will take their interests into account.英联邦各国尤其如此，它们认为英国加入欧共体，将能保证欧共体的政策照顾到它们的利益。（在定语从句前拆译）

④、中国是个大国，百分之八十的人口从事农业，但耕地只占土地面积的十分之一，其余为山脉、森林、城镇和其他用地。

China is a large country with four-fifths of the population engaged in agriculture, but only one tenth of the land is farmland, the rest being mountains, forests and places for urban and other uses.（合译）

五、正译法和反译法

这两种方法通常用于汉译英，偶尔也用于英译汉。所谓正译，是指把句子按照与汉语相同的语序或表达方式译成英语。所谓反译则是指把句子按照与汉语相反的语序或表达方式译成英语。正译与反译常常具有同义的效果，但反译往往更符合英语的思维方式和表达习惯。因此比较地道。如： ①、在美国，人人都能买到枪。

In the United States, everyone can buy a gun.（正译）

In the United States, guns are available to everyone.（反译）

②、你可以从因特网上获得这一信息。

You can obtain this information on the Internet.（正译）

This information is accessible/available on the Internet.（反译）

③、他突然想到了一个新主意。

Suddenly he had a new idea.（正译）

He suddenly thought out a new idea.（正译）

A new idea suddenly occurred to/struck him.（反译）④、他仍然没有弄懂我的意思。

He still could not understand me.（正译）

Still he failed to understand me.（反译）

⑤、无论如何，她算不上一位思维敏捷的学生。

She can hardly be rated as a bright student.（正译）

She is anything but a bright student.（反译）

⑥、Please withholdthe document for the time being.请暂时扣下这份文件。（正译）

请暂时不要发这份文件。（反译）

六、倒置法

在汉语中，定语修饰语和状语修饰语往往位于被修饰语之前；在英语中，许多修饰语常常位于被修饰语之后，因此翻译时往往要把原文的语序颠倒过来。倒置法通常用于英译汉, 即对英语长句按照汉语的习惯表达法进行前后调换，按意群或进行全部倒置，原则是使汉语译句安排符合现代汉语论理叙事的一般逻辑顺序。有时倒置法也用于汉译英。如：

①、At this moment, through the wonder of telecommunications, more people are seeing and hearing what we say than on any other occasions in the whole history of the world.此时此刻，通过现代通信手段的奇迹，看到和听到我们讲话的人比整个世界历史上任何其他这样的场合都要多。（部分倒置）

②、I believe strongly that it is in the interest of my countrymen that Britain should remain an active and energetic member of the European Community.我坚信，英国依然应该是欧共体中的一个积极的和充满活力的成员，这是符合我国人民利益的。（部分倒置）

③、改革开放以来，中国发生了巨大的变化。

Great changes have taken place in China since the introduction of the reform and opening policy.（全部倒置）

七、包孕法

这种方法多用于英译汉。所谓包孕是指在把英语长句译成汉语时，把英语后置成分按照汉语的正常语序放在中心词之前，使修饰成分在汉语句中形成前置包孕。但修饰成分不宜过长，否则会形成拖沓或造成汉语句子成分在连接上的纠葛。如：

①、You are the representative of a country and of a continent to which China feels particularly close.您是一位来自于使中国倍感亲切的国家和大洲的代表。

②、What brings us together is that we have common interests which transcend those differences.使我们走到一起的，是我们有超越这些分歧的共同利。

八、插入法

指把难以处理的句子成分用破折号、括号或前后逗号插入译句中。这种方法主要用于笔译中。偶尔也用于口译中，即用同位语、插入语或定语从句来处理一些解释性成分。

如：如果说宣布收回香港就会像夫人说的“带来灾难性的影响”，那我们要勇敢地面对这个灾难，做出决策。

If the announcement of the recovery of Hong Kong would bring about, as Madam put it, “disastrous effects,” we will face that disaster squarelyand make a new policy decision.九、重组法

指在进行英译汉时，为了使译文流畅和更符合汉语叙事论理的习惯，在捋清英语长句的结构、弄懂英语原意的基础上，彻底摆脱原文语序和句子形式，对句子进行重新组合。

如：Decision must be made very rapidly;physical enduranceis tested as much as perception, because an enormous amount of time must be spent making certain that the key figures act on the basis of the same information and purpose.必须把大量时间花在确保关键人物均根据同一情报和目的行事，而这一切对身体的耐力和思维能力都是一大考验。因此，一旦考虑成熟，决策者就应迅速做出决策。

十、综合法

是指单用某种翻译技巧无法译出时，着眼篇章，以逻辑分析为基础，同时使用转换法、倒置法、增译法、省译法、拆句法等多种翻译技巧的方法。

如：How can the European Union contribute to the development of a European film and television program industry which is competitive in the world market, forward-looking and capable of radiatingthe influence of European culture and of creating jobs in Europe?

欧洲联盟应该怎样做才能对欧洲的电影电视工业有所贡献，使它在国际市场上具有竞争能力，使它有能力发挥欧洲文化的影响，并且能够在欧洲创造更多的就业机会呢？

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第三篇：单位证明英文翻译模版

单位证明

Embassy of [×××] in Beijing

[Address]

To whom it may concern,Subject: Tourist Visa Application

We certify that [Mr./Ms.××[Passport No.××] has been employed by [company name××] as a [title] since [month/year].We have approved [Mr./Ms.××]’s annual leave from [date/month/year] to

[date/month/year].[Mr./Ms.××] will resume [his/her] duties with the company on his/her return to Beijing.We are confident that [Mr./Ms.××] will return to work on time.The purpose of

[Mr./Ms.××]’s trip is only tourism.[He/She] will not seek any employment or residency in [country name: eg.Germany] and will comply with [eg.German] laws and regulations.We would be very grateful if you would approve [Mr./Ms.××]’s tourist visa application.If you have any questions, please do not hesitate to contact me on [Tel no.].Yours sincerely,[Company Name]

Sign by:[Name] and [Title]

Dated:

第四篇：英文翻译

Introduction: with the rapid development of the economy, China ‘smprehensive national power has been improved effectively.As a saying said;“Want to become rich first road”.So China has begun to build the high-speed rail since years ago.The building of the high~speed rail is suited to China's national conditions and help our country to run well in the strong competition of the world.大多数经济学家认为：交通基础设施的供应水平和能力必须适度超前，否则就会影响社会经济持续、稳定 和健康发展。这就意味着要加大对交通基础设施的投资，但是政府在加大交通基础设施投资力度的同时，用于改善民生的措施实际却在相对地减少。从中国目前的经济发展和人民的收入状况来说，我认为中国高 铁弊大于利.Most economists believe that: the supply and capability of transportation infrastructure must advance appropriately, otherwise it will affect the sustainable, stable and healthy development of social economy.This means that we have to increase the investment into transportation infrastructure,But while government increase the investment into transportation infrastructure, it will to some extent decrease the practical measures to improve people's livelihood.From China's current situation, I think it will do more harm than good to build high-speed railway in China.Piont1: Building too fast go against the laws of economic development, causing many problems, such as loan repayment, staff placement.And high-speed railway construction needs large investment, from the use of the actual situation, the possibility of short-term cost recovery do not, there is also the problem of capital wasting.建设速度过快，容易违背经济发展规律,同时面对的问题较多，例如贷款偿还，员工安置等。中国第一条高 铁客运专线——从北京到天津，它在 2008 年 8 月通车后一年就亏损了 7 个亿。武广高铁总投资约 1166 亿元，目前的线路至少能开 120 对车，但实际上只开了 33 对，而且还坐不满，这是资本的严重浪费。所 以说高铁建设不仅需要大笔的投资，而且从运用的实际的情况来看，短期收回成本的可能性根本就没有。The fast building speed will violate the rule of economic development, and at same time it faced many problems, such as loan repayment, staff placement.First high-speed railway of China-from Beijing to Tianjin, it was launched in August 2008, after one year it lossed 70 millions.The total investment of

Wuhan-Guangzhou high-speed rail was about 110 billions yuan, now it is able to drive at least 120 pairs of cars, but in fact only 33 to drive, and lots of seats are empty, this is a serious waste of capital.The high-speed railway not only requires large construction investment, but also, it is impossible to recovery the short-term cost based on its actural implement.Poiimnt2: The building of the high spee

d rail can drive the development of the industry related.for example, the building need many workers and the new technology, so it expand the employment and promiot the technological innovation.In another word through the building, more steel products are needed.Another important hand is transport during the Spring Festival.During this period of time, large numbers of people going home together.So the high speed rail can relieve the transportation pressure ectively 高铁的票价较高，例如京津高铁，它行驶 30 分钟，却要 69 元票价，让人望而生叹啊。中国的 GDP 总量 高居世界第二，但人均 GDP 在世界的排名却还在百名开外，穷人还是绝大多数。武广高铁开通后，原有 的一些客运列车停运，意味着中低收入者将被迫选择高铁，接受高票价。这种行为伤及了底层人民的最根 本利 e 而且建设过程中容易出现贪污腐败问题。The fare of high Speed Rail is higher, for example, the Beijing-Tianjin high-speed rail, it costs 69 yuan for only drive 30minuts.China's GDP ranks the second in the world, but per capita GDP still ranks out of hundreds in the world, the poor is the majority.When Wuhan-Guangzhou high-speed railway was used, the original passenger trains were stopped, which means low-incomer will be forced to choose high-speed rail and accept the high fares.This action has

impair interests of the low class people, and the corruption problem will be prone to easily during the process of building.新建高铁实际是在现有几种交通方式的基础上新增一种交通方式。建成之后会与高速公路、现有铁路、飞 机、船运形成竞争关系，在原有运力并不紧张的背景下必然形成运力过剩。新建的高铁主要是客运专线，因此高铁并不会加快货物与资金的周转速度，不会降低全社会运行成本。要修建如此庞大的高速铁路网，必将消耗大量的资金，必将挤占人们收入上涨的空间与企业利润空间（加重税负）如果将此财政投入医疗、。社保、教育、技术研究，则会消除人们存钱的预防养老动机从而扩大消费，利于中国经济可持续发展。综 上所述，在中国大规模修建高铁对中国经济的长远发展来讲是弊大于利，不利于扩大内需、不利于产业结 构调整 结论：The high-speed railway will compete with the existing highway, railway, aircraft, shipping after it consummation which will lead to a situation capacity.The new high-speed railway is mainly to carry passenger, so it will not speed up the turnover rate between cargos and the capital and will not decrease the costs of the whole social transportation.To build such a large network of high-speed rail will need a large amount of money, the government must increase the taxes of people and enterprise to raise the capital.If this financial investment used in health care, social security, education, tec

第五篇：英文翻译

Overview of the Global System for Mobile Communications 1 History of GSM During the early 1980s, analog cellular telephone systems were experiencing rapid growth in Europe, particularly in Scandinavia and the United Kingdom, but also in France and Germany.Each country developed its own system, which was incompatible with everyone else’s in equipment and operation.This was an

undesirable situation, because not only was the mobile equipment limited to operation within national boundaries, which in a unified Europe were increasingly unimportant, but there was also a very limited market for each type of equipment, so economies of scale and the subsequent savings could not be realized.The Europeans realized this early on, and in 1982 the Conference of European s Posts and Telegraphs(CEPT)formed a study group called the Group Special Mobile(GSM)to study and develop a pan-European public land mobile system.The proposed system has to meet certain criteria: ·Good subjective speech quality ·Low terminal and service cost ·Support for international roaming ·Ability to support handheld terminals ·Support for range of new services and facilities ·Spectral efficiency ·ISDN compatibility In 1989, GSM responsibility was transferred to the European Telecommunication Standards Institute(ETSI), and phase I of the GSM specifications were published in 1990.Commercial service was started in mid-1991, and by 1993 there were 36 GSM networks in 22 countries.Although standardized in Europe, GSM is not only a European standard.Over 200 GSM networks are operational in 110 countries around the world.In the beginning of 1994, there were 1.3 million subscribers worldwide, which had grown to more than 55 million by October 1997.With North America making a delayed entry into the GSM field with a derivative of GSM called PCS1900, GSM systems exist on every continent, and the acronym GSM now aptly stands for Global System for Mobile communications.The developers of GSM chose an unproven(at the time)digital system, as opposed to the then-standard analog cellular systems like AMPS in the United States and TACS in the United Kingdom.They had faith that advancements in compression algorithms and digital signal processors would allow the fulfillment of the original criteria and the continual improvement of the system in terms of quality and cost.The over 8,000 pages of GSM recommendations try to allow flexibility and competitive innovation among suppliers, but provide enough standardization to guarantee proper interworking between the components of the system.This done by providing functional and interface descriptions for each of the functional entities defined in the system.2 General Concepts 2.1 Analog Versus Digital Telephony Systems First-generation systems were analog.During the early 1980s these underwent rapid development in Europe.Although the NMT system was used by all the Nordic countries, and the TACS system in the United Kingdom and Italy, there was a variety of systems and no compatibility among them.Compared with these systems, the main advantages offered by GSM, which is the most important of the second-generation digital systems, are: ·Standardization;·Capacity;·Quality;·Security.Standardization guarantees compatibility among systems of different countries, allowing subscribers to use their own terminals in those countries that have adopted the digital standard.The lack of standardization in the first-generation system limited service to within the borders of a country.Mobility is improved, since roaming is no longer limited to areas covered by a certain system.Calls can be charged and handled using the same personal number even when the subscriber moves from one country to another.Standardization also allows the operator to buy entities of the network from different vendors, since the functional elements of the network and the interfaces between these elements are standardized.This means that a mobile phone from any manufacturer is able to communicate with any network, even if this network is built with entities from different vendors.This leads to a large economy of scale and results in cost reduction for both the operator and the subscriber.Furthermore, the phone cost is also reduced, because GSM is an international standard, produced quantities are greater and the level of competition is high.With respect to capacity, the use of the radio resource is much more efficient in a digital system such as GSM than in an analog system.This means that more users can be allocated in the same frequency bandwidth.This is possible with the use of advanced digital techniques, such as voice compression algorithms, channel coding, and multiple access techniques.Note that capacity gains are also achieved with radio frequency reuse, which had also used in analog systems.Frequency reuse means that a given carrier can be employed in different areas.The quality in digital transmission systems is better, thanks to the channel coding schemes that increase the robustness in the face of noise and disturbances such as interference caused by other users or other systems.The quality improvement is also due to the improved control of the radio link, and adaptations to propagation conditions, with advanced techniques such as power control or frequency hopping.This will be explained in greater detail in the next section.In terms of security, powerful authentication and encryption techniques for voice and data communications are enabled with GSM, which guarantees protected access to the network, and confidentiality.2.2 Cellular Telephony In mobile radio systems, one of the most important factors is the frequency spectrum.In order to make the best use of the bandwidth, the system is designed by means of the division of the service area into neighboring zones, or cells, which in theory have a hexagonal shape.Each cell has a Base Transceiver Station(BTS), which to avoid interference operates on a set of radio channels different from those of the adjacent cells.This division allows for the use of the same frequencies in nonadjacent cells.A group of cells that as a whole use the entire radio spectrum available to the operator is referred to as a cluster.The shape of a cell is irregular, depending on the availability of a spot for the BTS, the geography of the terrain, the propagation of the radio signal in the presence of obstacles, and so on.In dense urban areas, for instance, where the mobile telephony traffic is important, the diameter of the cells is often reduced in order to increase capacity.This is allowed since the same frequency channels are used in a smaller area.On the other hand, reducing the cell diameter leads to a decrease in the distance necessary to reuse the frequencies(that is, the distance between two co-channel cells), increasing co-channel interference.In order to minimize the level of interference, several techniques are used on the radio interface.A basic example of cluster organization is shown in Figure 1.In this example, we see a reuse attern for seven different frequencies, f1 to f7.These frequencies correspond to the beacon carrier of each cell, on which signaling information about the cell is broadcast(see Section 2.7).It can be seen from this figure that a given carrier can be reused in two separate geographical areas, as long as these areas are far enough from each other to reduce the effect of interference.With this technique of dividing the area in cells and clusters, the operator can increase the area it is able to cover with a limited frequency bandwidth.Figure 1 Example of a Cell Planning

在80 年代初期期间，模式手机系统在欧洲体验迅速增长，特别在斯堪的那

维亚和英国，以及法国和德国。每个国家开发了它自己的系统，在设备和操作 上是互不相容的。这是一个不受欢迎的情况，因为不仅移动通信设备被限制在国 界之内，这在统一的欧洲是越来越不重要的，而且每种类型的设备都只有一个非 常有限的市场，因此经济尺度及随后的储蓄不可能体会。

欧洲人早就意识到了这点，并且在1982 年欧洲邮电管理联合会(CEPT)上形 成了移动通信特别研究组(GSM)来研发一个能在全欧洲大陆通用的移动通信系 统。提出的系统必须符合以下标准： 〃通话质量好

〃终端及服务费用低 〃支持国际漫游

〃能够支持可随身携带的终端 〃支持一系列新的服务和设备 〃效率高

〃与ISDN 兼容

1989 年，GSM 的责任转移了到欧洲电信标准学院(ETSI)，并且GSM 规格的

第一阶段也在1990 年出版了。商业服务在1991 年中期开始了，截至1993 年有 36 个GSM 网络在22 个国家诞生了。GSM 不仅仅是欧洲标准，尽管它是在欧洲 规范化的。现已有200 多个GSM 网络在全球110 个国家和地区运行。1994 年初 期全球有1,300,000 用户，截至1997 年10 月已突破55,000,000 用户。随着美国

后来在GSM 领域制造了一个词条PCS1900 作为GSM 的拓展,GSM 系统已发展至 各大洲,并且缩写词GSM 现在已可以代表移动通信的全局系统。

GSM 开发商选择了一个当时未经证明的数字系统，与后来的标准模式蜂窝系 统相对，就象美国叫AMPS，而英国叫TACS 一样。他们坚信能够推进压缩算法 和数字信号处理器使其能够根据质量和费用将原始标准和系统连续改善。GSM 推荐8,000 页设法使得在与供应商竞争之中体现灵活性和创新，但提供 足够的标准来保证在系统的组分之间适当配合工作。完成提供功能和接口描述的 功能个体在系统中都有定义。

第一代系统是模拟的。上个世纪80 年代初期在欧洲迅速发展。虽然所有北 欧国家使用TACS 系统，英国和意大利使用NMT 系统，它们之间还有各式各样 的系统不兼容。和这些系统相比，GSM 提供的更重要的第二代数字系统主要优势 体现在： 〃标准化； 〃容量； 〃质量； 〃安全。

标准化保证了不同国家系统之间的兼容性，允许采取了数字化标准的国家的 订户使用他们自己的终端。在第一代系统中缺乏标准化的有限服务为在国家的边 界之内。流动性被改进，漫游不再被限制到某一系统包括的面积之内。既使当用 户从一个国家移动到另一个国家，电话也可以使用同一个个人号码。因为网络的功能元件和这些元素之间的接口被规范化，操作员可以从不同的 供营商购买。这意味着所有制造商的移动电话能与任何网络沟通，即使这个网络 是由不同的供营商的功能元件建立的。这为操作员和订户带来费用成本的降低。此外，电话费用也降低了，因为GSM 是国际标准，生产数量大，竞争水平高。能力方面，数字系统如GSM 比模拟系统使用的无线资源更有效。这意味着 更多的用户可以使用同一频带。这就有可能利用先进的数字技术，如语音压缩算 法，信道编码和多址接入技术。请注意，无线电频率复用也取得了一定增益，这 也已用于模拟系统。频率复用意味着同一载波可以在不同的地区重复使用。由于这种信道编码方案，提高了可靠性及对噪音和其他用户或系统的干扰能 力，数字传输系统的质量更好了。质量改进的原因还在于改善了对无线连接的控 制，并适应传播条件下，使用先进的技术，如电源控制或跳频。质量改进的原因 还在于使用先进的技术如电源控制或跳频改善了无线连接的控制,，传播条件的适

应性等。这些将在下文中做更详尽的解释。

在安全方面，GSM 具有语音和数据通信的强大的认证和加密技术的功能，保 证了保护接入网络和保密性。

在移动通信系统中，一个最重要的因素就是频谱。为了最有效地利用带宽，系统设计的目的是通过基站的服务区到周边小区，理论上是一个正六边形。每个 小区有一个收发基站（BTS），其中，以避免相邻小区的不同无线信道在运行时 产生相互干扰。这样可以在不相邻的小区使用同一载频。一组小区，作为一个整 体，给运营商提供整个无线电频谱是指一个区群。小区的形状是不规则的，这取 决于是否有现成的基站，地理地形，无线电信号传播中存在的障碍，等等。例如，在人口密集的城市地区，移动电话的通行非常重要，小区的直径往往 会减小，以提高其通行能力。

这是允许的，因为同一频道只在一个较小的地区内使用。另一方面，小区直 径的减小导致使用同一频率的小区间的距离（即两个公共通道小区间的距离）缩 小了，增强了各频道之间的相互干扰。为了尽量提高抗干扰的能力，无线接口使 用了一系列技术。

一个基本的区群组织的结构如图1 所示。在这个例子中，我们看到了一个复 用模式的7 个不同的频率，f1 至f7。这些频率对应于每个小区的信标载波，整个

小区的信号信息就靠它们被传播出去（见第2.7 节）。从图中可以看出，某一载 波可在两个不同的地理区域重复使用，只要这两个地区离的足够远，相互之间的 干扰足够小。这一技术把地区分成小区和区群，经营者可以利用有限的带宽增加 覆盖区域的面积。