HC VIN CễNG NGH BU CHNH VIN THễNG BI GING TING ANH CHUYấN NGNH TVT (Dựng cho sinh viờn h o to i hc t xa) H NI - 2020 BI GING TING ANH CHUYấN NGNH TVT Biờn son : THS NGUYN QUNH GIAO THS NGUYN HNG NGA BI GING TING ANH CHUYấN NGNH TVT Mó s: 491ANH213 Chu trỏch nhim bn tho TRUNG TM éO TO BU CHNH VIN THễNG Lời nói đầu Ngày nay, tiếng Anh công cụ thiếu đợc nhà nghiên cứu, khoa học, nhà quản lý, học sinh, sinh viên để tích luỹ, học hỏi, nghiên cứu Có thể nói sử dụng thành thạo ngôn ngữ giành đợc lợi cạnh tranh lĩnh vực, đặc biệt ngành khoa học kỹ thuật Nhằm giúp cho sinh viên hệ đào tạo từ xa học tiếng Anh chuyên ngành điện tử viễn thông có hiệu quả, tập giảng tiếng Anh chuyên ngành viễn thông đợc biên soạn bao gồm kiến thức mạng, truyền dẫn vô tuyến hữu tuyến, chuyển mạch ứng dụng công nghệ thông tin viễn thông Tp bi ging gm 10 Unit, ũi hi 60 tit trờn lp, cú th tng ng 100 gi t hc i kốm vi cun sỏch, sinh viờn s cn b a i kốm giỳp vic hc t hiu qu cao hn Tập giảng rèn luyện đầy đủ kỹ năng: nghe, nói, đọc, viết v dịch Tập giảng cung cấp khái niệm, cỏc cách sử dụng thuật ngữ chuyên ngành viễn thông, tạo điều kiện cho sinh viên luyn cấu trúc ngữ pháp Phần thực hành ngôn ngữ gồm nhiều loại hình tập phù hợp giỳp sinh viên dễ dàng vic s dng cỏc kin thc vin thụng, cỏc thut ng ó tớch lu c Sau hc phn ting Anh chuyờn ngnh in t vin thụng, sinh viờn cú kh nng c, dch, vit, phõn tớch cỏc ti liu cú liờn quan n chuyờn ngnh Sinh viờn cú c phng phỏp nghiờn cu ti liu chuyờn mụn bng ting Anh nhm phc v tt cho cỏc mụn chuyờn ngnh hc ti Hc vin cng nh t nghiờn cu cụng vic hay nõng cao trỡnh sau ny Cỏc tỏc gi ó rt c gng nhiờn iu kin thi gian hn hp nờn nhng thiu sút quyn bi ging l khú trỏnh Chỳng tụi rt mong v xin cm n s úng gúp ý kin ca bn bố ng nghip v cỏc hc viờn Chỳng tụi cng xin chõn thnh cm n s to iu kin giỳp ca Ban giỏm c Hc vin Cụng ngh Bu chớnh vin thụng, Trung tõm o to Bu chớnh vin thụng 1, Khoa C bn v s khuyn khớch ng viờn ca cỏc bn bố ng nghip chỳng tụi hon thnh c ti liu ny Hà nội, năm 2007 Unit The Telephone Network Unit The telephone network I GII THIU Bi gii thiu v cỏc mng in thoi, mt mng quc gia v s phỏt trin m rng mng ni ht Mc ớch yờu cu Sau nghiờn cu bi 1, sinh viờn cn: Phõn bit c cỏc tỡnh s dng cỏc t ng ngha Thnh lp hi thoi vi cỏc cu trỳc c s dng khụng hiu li ngi núi, mun lm rừ hn hoc khng nh ngi nghe ó hiu Nm c cỏc c im ca mt mng in thoi quc gia Nm c cỏc cm t vit tt k thut vin thụng Túm tt ni dung be composed of/ consist of/ be made up of/ comprise be divided/ be broken down/ be separated into two- both/ two- one- the other/ one- another Interrupting Asking for clarification Giving clarification Checking understanding Mng in thoi quc gia gm mng ni ht, mng chuyn tip v mng chớnh (trung k) GSC- DSC- MSC- DP- CCP- TSC- PCM- RSS II NI DUNG READING The UK national network comprises: a/ The local network The lines between the subscriber and the local exchange b/ The junction network The circuits between a local exchange and another local exchange The circuits between a local exchange and a primary centre, sometimes termed a tandem exchange The circuits between a local exchange and a secondary centre, sometimes called a Group Switching Centre (GSC) c/ The main/ trunk network The circuits between GSCs Unit The Telephone Network The circuits between GSCs and tertiary centres, known in the UK as District and Main Switching Centres (DSCs and MSCs) Figure The national network In the local network, each subscriber is connected to a local exchange To reduce the number of cables, the local network is usually divided into three parts: a/ The subscriber circuit: this consists of the telephone set, in the customers premises, and a cable pair, often open-wire line, which is connected to a distribution point (DP) b/ The secondary circuit: this is made up of a number of pairs (a multi-pair cable) connected over or underground to a cabinet, sometimes called a cross connection point (CCP) c/ The primary circuit: this is composed of a number of multi-pair cables ( multi-unit cable) connected in ducts or in a cable tunnel to the main distribution frame in a local exchange Figure The local network In the trunk network, all non-local calls are set up via a GSC and the main network In the UK, 70% of all traffic is routed direct to another GSC, 24% via one other GSC The traffic which cannot be handled by these direct routings is carried by a new network, called the Transit Network This network, which also carried overseas traffic to the International Gateway Exchanges, comprises 11 MSCs and 26 DSCs, known collectively as Transit Switching Centres (TSCs) Transmission on this network can be by coaxial cable or radio link Unit The Telephone Network Figure The analogue trunk network 1.1 Main phrases - in the customers premises: nh thuờ bao - transmission on the network: truyn dn trờn mng 1.2 Complete the labelling of Figures 1, and Figure : a network b network d e Figure : a c network f b c d e f g h i j k Figure : a b c d e f g 1.3 Answer the following questions What the following abbreviations stand for? a GSC b DSC c MSC d DP e CCP f TSC What is another term for? g the main network h a primary centre i a secondary centre j tertiary centre k a cabinet What other means of transmission are mentioned in the passage an open wire line l m n o p What types of traffic does the transit network carry? Unit The Telephone Network q r LANGUAGE PRACTICE 2.1 Phõn loi (Classification) a to be composed of to consist of to comprise to be made up of Nhng ng t v cm ng t trờn u cú ngha bao gm Trong mt bi vit, ngi ta thng dựng cỏc t ng ngha trỏnh lp li Tng t, ta cú cỏc cm t khỏc nhng u cú ngha c chia thnh to be divided into to be broken down into to be separated into Vớ d: The local network is divided into parts The local network is broken down into parts The local network is separated into parts ng t to be th hin s chc chn Nu khụng hon ton chc chn, ta dựng mt nhng ng t khim khuyt can, may, might Vớ d: The local network can be divided into parts The local network can be broken down into parts The local network can be separated into parts b two- both/ two- one-the other/ one-another There are two exchanges Both are traditional electromechanical exchanges. Both (c hai) thng c dựng vi cõu khng nh ch ngi, vt, ni cú cựng mt c im chung Tỡnh õy ch tng i v c u l tng i c in c truyn Khi ta mun din t ý ph nh thỡ thay both bng neither v cõu ú khụng cn dựng not Vớ d: Neither are digital ( C u khụng phi l tng i s) Khi tng s lng ta cp ti l nhng cú nhng c im khỏc thỡ ta dựng one v the other mụ t Vớ d: Two SPC exchanges are installed; one to extend the central area, the other to serve the new area There are two types of cables; one is fibre optic, the other is metallic Khi tng s hn m ta ch mun núi ti s ú ta dựng another Vớ d: 70% traffic is routed direct from one GSC to another GSC (70% lu lng c truyn thng t GSC ti GSC khỏc.) Unit The Telephone Network Vớ d tỡnh mua mỏy in thoi, ngi bỏn hng a cho bn chic nhng thy khụng va ý, bn cú th núi: May I see another one? Practice 2.1 Use the map to complete the sentences below The Newtown local telephone area a The Newtown telephone network secondary centres and b The Area into sub-areas: North, c There secondary centres are connected to the DSC in Sisley by radio link d There junction routes between the secondary centres: direct via a local exchange e Routing from local exchange to can be direct or via exchanges f Northern and Southern areas are served by local exchanges Cõu hi v tr li (Questions and responses) 2.1 Cú th hi li cho rừ ngi khỏc ang núi hoc din thuyt thụng qua bc: a Ngt li (Interrupting) Sorry to interrupt Excuse me b Hi cho rừ ý/ ngh gii thớch rừ (Asking for clarification) What you mean by ? I am not sure I understand So that means that ? 2.2 Quỏ trỡnh tr li ca ngi núi cng cú th thụng qua bc a Gii thớch rừ (Giving clarification) Ngi núi c hi cú th dng núi v ỏp li: Yes? Unit The Telephone Network Yeah? ri gii thớch: What I mean was Let me put it another way In other words Sau cỏc cm t trờn l phn gii thớch Khi gii thớch xong, ta cú th kim tra xem ngi nghe ó hiu cha b Kim tra (Checking understanding) Kim tra bng cỏch hi nhng cm t sau: Is that clear? Do you follow me? READING Read the following text carefully TOOLS OF TOMORROW'S TELECOMMUNICATIONS For some time yet, much of our telecommunicating will continue to depend on the existing web of thin copper wires that telephonically link most of our homes and workplaces Making it possible for that network to match the communications demand of the near future will require new technologies that widen the lanes on the information highway The standard telephone service is something we take for granted in today's modern world The public telecommunications network provides a reliable and highly accessible service - we have high expectations and react strongly when the service is unavailable To meet the demand for high reliability, and to provide services economically, the public network is being progressively upgraded Yet consumers are still waiting for the widespread use of new services such as the video phone, which was first demonstrated 30 years ago What then is required to make new services such as video telecommunications possible and widely available? Apart from the availability of inexpensive video terminal equipment, the key requirement is increased bandwidth (that is, more available frequencies for transmission) which must be provided by the network at an affordable cost Understanding how this objective might be achieved requires a review of the existing telecommunications network and the new technologies that are expected to improve and extend its capacity The traditional telephone network consists of a pair of copper wires connecting the customer premises to a local exchange This is known as the customer access network The local exchange is connected to other local exchanges through a series of intermediate exchanges, using coaxial cable, microwave or satellite transmission links This part of the network is referred to as the core network Within the core network, a technique known as multiplexing is used so only a small number of physical connections are needed between each telephone exchange As a result, each transmission link may carry thousands of telephone conversations simultaneously Traditionally the telephone network used analogue switching and transmission techniques Since the 1970s, the core network has been progressively changed from an analogue to a digital In 1980 2000 2050 2100 will be satellite 2.2 T ch lng i vi danh t khụng m c All (tt c) ; Most (hu ht) Most equipment is modern Much / A lot of (nhiu) I've received a lot of good news Some; A little (mt s, mt ớt) Can I have some information on your latest series? Little (ớt) I've got little information on it No / None of (khụng) No information was given Note: Danh t khụng m c cú th mn mt danh t m c s dng lm n v Countable noun + of + Uncountable noun Four pieces of equipment One type of equipment Bng di õy hp cỏc t v ý ngha ca chỳng i vi danh t m c v danh t khụng m c Approx 100% Countable Uncountable every /all all most most many/ a lot of much/ a lot of some some several _ a few a little 5% few little 0% no/ none no/ none 85% Practice 2.2 A Fill in the sentences with appropriate words of quantifiers Examples: In 1980, a little information was transmitted by satellite In 2100, all information will be transmitted by satellite In 1960 1980 2000 2050 2100 was transmitted by satellite information will be B Choose the correct answers Examples: A lot of digital equipment will be used Much digital equipment will be used By the year 2000 digital equipment will be used a a lot of b much c both a and b information was given about that equipment a Little few b much piece of c few piece of The switchboard received calls from satellites a a little b a few c a little good weather can normally be expected in England during August a A little b Some c both a and b people think that knowledge is a good thing a Many / b much b A few / b a little c both a and b news came in concerning engineers a A lot of many b Many a piece of c both a and b 2.3 Prefixes, Suffixes, Affixes and Stems Nhiu t ting Anh cú th phõn thnh cỏc b phn: tin t (prefix), thõn t (stem) v hu t (suffix) Cỏc tin t v hu t cú th gi chung l ph t (affixe) Vic nm vng ý ngha ca ph t v thõn t cú th giỳp ta oỏn ngha ca nhng t l Example: SUB SCRIB ER PREFIX STEM SUFFIX Practice 2.3 Match the first two columns (1 and 2), basing on the suggestive examples in column Prefixes com-,con-, co- Meanings a in, into Examples co-operate, connect in-, im- b not invade, immerse impossible, In-, im-, ir-, il- c small illegal microscope, micro- d before microcomputer prepare, pre- pre- e back, again war re- f together, with return, re-read Stems Meanings Examples -audi-, -audit g study of audience, auditorium -chron- h hear chronological -dic-, -dict- i time dictation 10 -graph-, -gram- j say, speak telegram 11 -log-, -logy k write, writing biology 12 -phon- l sound telephone 13 -scrib-, -script- m write inscription 14 -spect- n look at inspect 15 -vid-, -vis- o see vision, video Suffixes Meanings Examples 16 -er, -or p forms noun teacher, spectator 17 -ist q a person who typist, biologist 18 -tion, -ation information READING Read the following text carefully The launching of the first satellite by the Russians in 1957 began what has become known as the "space race", the first stage of which culminated with the Americans landing on the moon twelve years later A whole range of satellites now orbit the Earth and are used for a variety of purposes Low orbit satellites, the typical height of which varies from 150 to 450 kilometres, are of little use for telecommunications for they are only in line of sight of each earth station for about 15 minutes Their rotation period around the Earth is about one and a half hours and their main use is for remote sensing, a field in which digital processing techniques are proving especially valuable A low orbit satellite, equipped with a multispectral scanner system (MSS), can observe the Earth in great detail providing us with extremely accurate information about agriculture, forestry, water resources and pollution patterns It also has a multitude of applications in such fields as weather forecasting, environmental monitoring, geology, oceanography and cartography There are important defence implications too, since they can be used to "spy" on the activities of a potential enemy Medium altitude satellites are used for telecommunications, especially in countries which cover a vast geographical area like the USSR They "fly" at a typical height of 000 to 18 000 kilometres, orbiting the Earth in a period of five to twelve hours They are in line of sight of the earth station for between two and four hours The most important type of satellite for telecommunications is the geosynchronous, or geostationary, satellite positioned over the Equator at a height of 35 800 kilometres Its rotation period is 24 hours, the same as the Earth's and consequently, seen from the Earth, this type of satellite appears to remain motionless in the sky It is within line of sight of an earth station for its entire life A communication satellite is, in essence, a microwave relay station which receives signals in a given frequency band and retransmits them at a different frequency to avoid problems of interference between the weak incoming signal and the powerful retransmitted signal The equipment which receives a signal, amplifies it, changes its frequency and then retransmits it, is called a transponder A satellite can handle large amounts of traffic which it can send over vast areas of the Earth It therefore represents a relatively cheap way of transmitting information over long distances For countries which not already have sophisticated cable or microwave networks the use of a satellite can be extremely beneficial as it can be used in their place The first satellites were seen as a way of communicating with people who lived in isolated area of the world As a result, earth stations began to appear in the remotest parts of the globe The cost of satellite communications began to fall steadily and consequently, satellites have to compete with submarine cables as a way of linking continents cheaply With the arrival of optical fibre undersea cables, however, a more balanced division of intercontinental circuits between the two is likely Satellites were soon used to broadcast TV programmes "live" from one side of the Earth to the other, and then to link up computer terminals in different parts of the world The use of digital transmission and multiplexing techniques has led to an enormous increase in the capacity of satellites The international organization INTELSAT was created in 1964 to provide international communication services by satellite In 1983 it operated and owned 16 spacecrafts in geosynchronous orbit representing an investment of over three billion US dollars In 1983 it handle two thirds of all international telephone and data communications and transmitted virtually all "live" international television broadcasts 109 nations are members of INTELSAT Between 1979 and 1983 INTELSAT's traffic doubled, yet its communications charges decreased, despite a 73% rise in the worldwide cost of living index Satellites are not simply replacements for point-to-point terrestrial lines They have several unique properties, among which the most important are: 270 millisecond propagation delay caused by the distance the signal has to travel (80 000 km - 300 000 km /sec = 0.27 seconds) the possibility of very high bandwidths or bit rates if the users can avoid local loops by having an antenna on his premises, or a radio link to an earth station antenna the special security problems that are posed when information is broadcast through a satellite 3.1 Phrases - what has become known as: iu tr nờn c bit n nh l - a variety of purposes: nhng mc ớch khỏc - be of little use: ớt tỏc dng - cost of living index: ch s mc sng - in essence: v bn cht 3.2 Complete the key Earth Earth Earth a height: b rotation period: c time in line of sight of earth station: d use: a height: b rotation period: c time in line of sight of earth station: d use: a height: b rotation period: c time in line of sight of earth station: d use: e exact position: 3.3 Choose the right answers Which event sparked off the "space race"? a the Americans landing on the moon b The launching of the first satellite by the Russians in 1957 Which event ended the first stage of the "space race"? a In 1969 b In 1977 What does a transponder do? a It receives a signal, amplifies it, changes its frequency and then retransmits it b It receives signals Why are developing countries particularly interested in satellite communications? a They not already have sophisticated cable or microwave networks and the use of a satellite can be extremely beneficial b Satellites were seen as a way of communicating with people who lived in isolated area of the world What are the three main stages in the way satellites have been viewed? a Satellites are used as a way of communicating with people who lived in isolated areas; a way of broadcasting "live" TV programmes; a way of linking computer terminals b Satellites were used to broadcast TV programmes "live" and to link up computer terminals in different parts of the world 3.4 Match the two columns 1 Year of creation a two thirds Number of spacecraft owned and operated in 1983 b 109 Investment value of the above spacecraft d 16 Number of member nations e 1964 Proportion of all international telephone and data traffic handled in 1983 f doubled c over three billion US dollars INTELSAT's traffic between 1979 and 1983 WRITING 4.1 Writing letters Sau cuc núi chuyn qua in thoi bn v cụng vic, ngi th ký ca khỏch hng cú th vit th cho bờn bỏn hng khng nh li thụng tin Hóy c k cỏc thụng tin cn vit lỏ th ú Company: Swanford Tools Ltd., Address: Slingdon Road, Thurby TH2 SY3 To: Mr Bradley Main ideas: to confirm that Mr Davies will visit Mr Bradley at Bradfield Electronics (Date of meeting: Thursday 26th April at p.m.) Mr Davies hopes Mr Bradley will provide a demonstration of the mobile phone series to confirm that three other members from Sales department will be with Mr Davies From: Ms J Whitfield (Secretary) Put the jumbled letter from Mr Davies to Chris Bradley confirming the subject matters of their telephone conversation Example: Beginning: B Ending: A G Tel : 0432 - 53260 Ref : TD/368 Mr C Bradley Bradfield Electronics, Nutley, NU6 SR7 B Swanford Tools Ltd., Slingdon Road Thurby TH2 SY3 C Yours sincerely, D 19th April, E Following your telephone conversation yesterday with Mr Tom Davies, I should like to confirm that Mr Davies will visit you at Bradfield Electronics on Thursday 26th April at p.m F Mr Davies hopes that you will be able to provide a demonstration of the mobile phone series which is of great interest to Swanford Tools ltd G Ms J Whitfield, (Secretary) p.p Mr T Davies H I can also confirm that three other members of our Sales department will be present with Mr Davies 4.2 Writing fax Trong trao i cụng vic ta cng cú th dựng bn fax Hóy nghiờn cu tỡnh v lm bi On Monday, April 30th, Ms Whitfield received the following fax from Mr Tom Davies, who was on a business trip to Spain Note: Cỏc bn fax, telex cú th dựng mt s cm t vit tt thụng dng - ref: with reference to : tham chiu - tel: telephone: in thoi - re: regarding, on the subject of : v vic - pls: please: xin vui lũng - asap: as soon as possible (often "soonest"): cng sm cng tt - info: information: thụng tin Put the jumbled fax from Mr Davies to Ms J Whitfield, enquiring her to write a fax to Mr Bradley Example: Beginning: D Ending: A A T DAVIES 64032 SPANCOM 43751 SWANTOOL B Ref: My visit to Bradfield re mobile phone Pls send letter Bradley confirming: C Finalize details at meeting 29.5 at Swanford 15.30 D 43751 SWANTOOL Fax No3624 E Thanks, F Attention: J WHITFIELD G Interesting demonstrat Bradfield 26.4 confirm order ten mobile phones for salesmen H Hope above time and date convenient 4.3 Now you are Ms Whitfield Write a letter to Chris Bradley, including all the information in the fax and basing on the letter in Writing 4.1 (the beginning and the ending have been done for you) Tel: 0432 53260 Swanford Tools Ltd., Slingdon Road, Thurby 16th May, Mr C Bradley, Breadfield Electronics, Nutley, NU6 SR7 Dear Mr Bradley, Yours sincerely, Ms, J Whitfield (Secretary) p.p Mr T Davies 4.4 Organizing sentences and parts of sentences Sau õy l cỏc cõu v cỏc phn ca cõu t mt on núi v cỏc u im ca cỏc n v nghiờn cu v phỏt trin c lp Hóy nghiờn cu chỳng v lm bi Organize the sentences and parts of sentences into a paragraph Example: h There are several reasons for separating research and development work a) One reason is that routine technical work on established systems b) offers a less bureaucratic and more creative environment to work in c) These three factors contribute to a shorter time lapse d) from production and from administration e) can be separated from research into entirely new products f) thus eliminating duplication of work on similar research programmes g) Another reason is that a smaller company devoted exclusively to development work h) There are several reasons for separating research and development work i) Finally the technical resources and expertise of the parent companies are merged j) between an idea being conceived and a marketable product emerging III TểM TT Cú cỏc loi v tinh nh Low orbit satellites, Medium altitude satellites v Geostationary satellites Mi loi v tinh cú nhng c im cao khỏc v ng dng khỏc Thụng tin v tinh cú cỏc c im chung: quay quanh trỏi t, Tm hot ng rng Cỏc t ch s lng, lng b ngha cho cỏc danh t Mt s ch kt hp vi danh t m c hoc khụng m c Mt s kt hp vi c hai loi danh t Cỏc bn (fax, letter) trao i cụng vic dựng ngụn ng trnh trng Cỏc bn fax, telex cú s dng nhng thut ng vit tt chuyờn dng VOCABULARY beneficial adj cú li buffer memories n b nh m counteract v trung hũa, lm mt tỏc dng culminate v lờn n cc im delay (echo) n tr (ting vng) earthbound adj hng v mt t, quanh mt t echo-suppressor n b nộn ting vng Equator n ng xớch o float v trụi ni geostationary adj a tnh index n ch s isolated adj hoang vng, xa xụi live adv trc tip, ti ch local loop n mch vũng mainland n t lin motionless adj bt ng multispectral scanner system n h thng quột a ph multitude n vụ s obstacle n tr ngi orbit n qu o positioned adj c nh v propagation n s truyn lan reminiscent adj lm nh li, gi nh rotate v quay, xoay quanh rotation period n chu k quay spacecraft n tu v tr spy v transponder n b phỏt ỏp unique adj nht virtually adv thc s, mt cỏch chớnh thc, hu nh ANSWER KEYS Reading H THNG V TINH Trong th gii truyn thụng vụ tuyn, thụng tin v tinh xut hin hng ngy Chỳng ta nhn c nhng bn tin tng thut t ton th gii thng vo phũng khỏch Cú th ớt ngi s chỳng ta nhn rng liờn lc bng in thoi cng s dng cỏc tuyn ni v tinh Tuy nhiờn, cụng ngh v tinh ũi hi chi phớ ban u cao, v chỳng cú lói, ớt nht phi cú c vi s nhng im sau: Liờn lc qua khong cỏch di gia mt s trm Tr ngi a lý gõy nờn chi phớ thm tn kộm hn nu kt ni tng ng trờn mt t Tp trung lu lng cao gia cỏc trm mng v tinh Phõn phi im ti a im Quay quanh trỏi t Truyn thụng v tinh gi ngh n mt tuyn ni vụ tuyn bỡnh thng Nhng thay vỡ t tt c cỏc trm trờn khp mt t, chỳng ta a mt s lờn khụng trung Cỏc v tinh thụng tin quay vũng quanh trỏi t vi tc gn y ht nh trỏi t qu o gi l a tnh Tm hot ng rng V tinh cú tm hot ng ỏng k V mt lý thuyt m núi, gn na trỏi t cú th nm tm bao ph ca ch mt v tinh V tinh c s dng c mng quc t v quc gia Cỏc gin khoan cng s dng v tinh thụng tin liờn lc vi t lin c tớnh truyn dn Cỏc c tớnh truyn dn ca tuyn ni v tinh rt tuyt, v rt ớt s c Tuy nhiờn, khong cỏch xa gõy nờn s tr (ting vng), iu cn phi x lý bng cỏch dựng b nộn ting vng Cn luụn nhn rng õy l truyn thụng gia hai vt th ni khụng trung Luụn cú mt s di chuyn tng i gia trỏi t v v tinh, iu cú th gõy nờn li truyn dn s Tuy nhiờn iu ny cú th c bự bng s lu tr thụng tin trung gian b nh m 1.2 Choose TRUE or FALSE F T F F T F F T F 10 F Language Practice Practice 2.1 Fill in the sentences with appropriate words of quantifiers no few many most all Practice 2.2.A Fill in the sentences with appropriate words of quantifiers no little much most all B Choose the correct answers c b b c c a Practice 2.3 Match the first two columns (1 and 2), basing on the suggestive examples in column f a b c d e h i j 10 k 11.g 12 l 13 m 14 n 15 o 16 q 17 q 18 p Reading Vic phúng v tinh u tiờn ca ngi Nga nm 1957 ó bt u cho cuc chy ua v tr, m kt thỳc ca gian on u l vic ngi M t chõn lờn mt trng 12 nm sau ú Hin tt c cỏc v tinh bay theo qu o trỏi t ang c s dng cho cỏc mc ớch khỏc Cỏc v tinh qu o thp cú cao in hỡnh phm vi t 150 - 450 km, ớt c s dng vin thụng bi vỡ chỳng nm tm quan sỏt ca mi trm mt t khong 15 phỳt Chu k quay ca chỳng quanh trỏi t khong gi ri v chỳng c s dng chớnh cho vic cm bin t xa, l lnh vc m k thut s lý s ang c bit chng t l cú giỏ tr V tinh qu o thp c trang b vi h thng mỏy quột a quang ph (MSS), cú th quan sỏt Trỏi t rt chi tit cung cp cho chỳng ta thụng tin cc k chớnh xỏc v nụng nghip, lõm hc, ngun nc v s ụ nhim Ngoi nú cú rt nhiu ng dng cỏc lnh vc nh d bỏo thi tit, iu khin mụi trng, a lý, hi dng hc v v bn Cng cú nhng ng dng quan trng quc phũng, vỡ chỳng cú th c s dng cỏc hot ng ca i phng Cỏc v tinh cú cao trung bỡnh thng c s dng vin thụng, c bit nhng quc gia cú v trớ a lý rng ln nh Liờn Xụ c Chỳng bay vi cao c thự t 000 n 18 000 km theo, bay quanh trỏi t vi chu k ti 12 gi Chỳng nm tm quan sỏt ca trm mt t khong t n ting Loi v tinh quan trng nht cho vin thụng l v tinh ng b v mt a lý hay v tinh a tnh, v tinh c nh v trờn xớch o vi cao 35 800 km Chu k quay ca nú l 24 gi, cựng vi chu k quay ca trỏi t, v ú, nhỡn t trỏi t, cỏc v tinh loi ny cú v nh ng bt ng trờn bu tri Nú nm tm quan sỏt ca mt trm trỏi t sut thi gian tn ti Mt v tinh liờn lc, v thc cht, l trm tip súng vi ba vi vic thu tớn hiu t mt di tn cho trc v phỏt li chỳng cỏc tn s khỏc nhm trỏnh can nhiu gia tớn hiu thu yu v tớn hiu phỏt mnh Thit b thu tớn hiu, khuych i, i tn v sau ú phỏt li c gi l thit b phỏt ỏp Mt v tinh cú th iu khin mt lng ln lu lng v cú th gi chỳng trờn nhng vựng rng ln ca trỏi t Vỡ vy, nú i din cho cỏch truyn thụng tin tng i r khong cỏch ln i vi nhng quc gia khụng sn cú mng cỏp tinh xo hoc súng vi ba, vic s dng v tinh cú th em li li nhun to ln vỡ v tinh cú th dựng thay th cho cỏc mng ú Cỏc v tinh u tiờn c c xem nh l phng thc liờn lc vi nhng ngi sng nhng vựng bit lp trờn th gii Kt qu l cỏc trm mt t ó bt u xut hin nhng phn xa nht ca a cu Cc phớ thụng tin v tinh ó gim u v ú cỏc v tinh phi cnh tranh vi cỏp bin lm mt phng thc r kt ni lc a Tuy nhiờn, vi s xut hin ca cỏp quang bin, cú v cú s phõn nh cõn bng hn gia hai loi mng kt ni xuyờn lc a Ngay sau ú v tinh bt u c s dng truyn cỏc chng trỡnh vụ tuyn trc tip t mt ni n ni khỏc ca trỏi t, v ri c s dng kt ni cỏc u cui mỏy tớnh nhng ni khỏc trờn th gii Vic s dng k thut truyn dn v ghộp kờnh ó lm tng rt nhiu kh nng ca v tinh T chc quc t INTELSAT thnh lp vo nm 1964 nhm cung cp cỏc dch v liờn lc quc t bng v tinh Nm 1983 t chc ny hot ng v s hu 16 tu v tr qu o a tnh, u t hn t ụ la M Vo nm 1983, t chc ny iu hnh 2/ tng s in thoi quc t, truyn thụng d liu v truyn i tt c cỏc chng trỡnh truyn hỡnh quc t phỏt ti ch 109 quc gia l thnh viờn ca INTELSAT T 1979 n 1983, lu lng ca INTELSAT tng lờn gp ụi, song cc phớ vin thụng gim, mc dự ch s sinh hot ca ton th gii tng 73% Cỏc v tinh khụng d thay th cho cỏc ng dn im ni im trờn mt t Chỳng cú mt s c tớnh riờng, ú nhng im quan trng nht l: tr ng truyn 270 mili giõy khong cỏch m tớn hiu phi truyn qua (80.000 km - 300.000 km/giõy = 0,27 giõy) Kh nng t di thụng rng hoc tc bit rt cao nu ngi s dng cú th trỏnh mch vũng cc b bng cỏch s dng mt anten trờn núc nh hoc cú mt kt ni vụ tuyn ti anten ca trm mt t Cỏc bo mt c bit c t thụng tin c truyn i qua mt v tinh 3.2 Complete the key a low orbit satellite a 150 - 450 km b about 1/2 hours c about 15 minutes d remote sensing a medium altitude satellite a 9000 - 18000 kilometres b - 12 hours c - hours d telecommunications a geosynchronous satellite a 35800 km b 24 hours Equator c the satellites entire life d telecommunications e over the 3.3 Choose the right answers b a a a a 3.4 Match the two columns e c a d b f 4.1 Writing letters B D A E F H C G 4.2 Writing fax D F B G C H E A 4.3 Write a letter to Chris Bradley (model answer) Dear Mr Bradley, Following the most interesting demonstration of your equipment at Bradfield Electronics on 26th April, I should like to confirm that Swanford Tools intended to buy ten sets for their salesmen In order to finalize the exact details of this order, Mr Davies suggests you visit him at Swanford Tools on Wednesday, 29th May at 3.30 I hope that the date and time are convenient for you Yours sincerely, Ms, J Whitfield (Secretary) p.p Mr T Davies 4.4 Organize the sentences and parts of sentences into a paragraph h d a e g b i 8.f c 10 j TI LIU THAM KHO Kim Bng, Trng Thc, Tin Dng, Nguyn Qunh Giao Cụng ngh vin thụng s Nh xut bn bu in 2002 Eric H Glendinning & John Mc Ewan Oxford English for Information Technology Oxford University Press 2003 Hong c Hin, Nguyn Qunh Giao Bi ging ting Anh chuyờn ngnh in t vin thụng Hc vin Cụng ngh Bu chớnh Vin Thụng 2000 Nguyn Quc Hựng Hng dn k thut dch Anh - Vit Nh xut bn khoa hc xó hi 2005 Tp Bu chớnh Vin thụng v Cụng ngh thụng tin B Bu chớnh Vin thụng 2000, 2004 Tng cc Bu in English for the Telecommunications Nh xut bn bu in 2001 VN-Guide English for Computer Communications Nh xut bn thng kờ 1999 157 MC LC UNIT THE TELEPHONE NETWORK UNIT THE DATA NETWORK 18 UNIT THE BASIC TRANSMISSION SYSTEMS 31 UNIT OPTICAL FIBRES 44 UNIT HISTORY OF TELEPHONE EXCHANGES 56 UNIT DIGITAL TELEPHONE EXCHANGES 71 UNIT COMPUTER COMMUNICATIONS 88 UNIT INTERNET AND COMPUTER 106 UNIT RADIO COMMUNICATIONS 124 UNIT 10 SATELLITE COMMUNICATIONS 141 TI LIU THAM KHO 158 MC LC 159 158 [...]... Student B: Now, the rest of the network - that is the primary circuits from the exchanges to the Lecturer: Student C: Lecturer: Giảng viên: Sinh viên A: Giảng viên: Sinh viên A: Giảng viên: Sinh viên B: Giảng viên: Sinh viên B: Giảng viên: Sinh viên B: Giảng viên: Sinh viên C: Giảng viên: cabinets- remain analogue That's the big difference in the third solution shown in Figure 1f Here the two areas, that... thoại đồng thời Trước đây mạng điện thoại sử dụng kỹ thuật truyền dẫn và chuyển mạch tương tự Từ những năm 1970, mạng lõi đã nhanh chóng chuyển từ mạng tương tự sang số Công nghệ số đem lại chất lượng tốt hơn, với khả năng tái tạo linh hoạt tín hiệu gốc thậm chí cả khi bị chìm trong tiếng ồn không mong muốn Điều xung mã (PCM) là quá trình trong đó tín hiệu điện thoại tương tự được biến đổi thành tín hiệu... are true or false 1T 2T 3F 4F 5F 6F 7T 8F 9F 10T Unit 2 The Data Network Unit 2 The data network I GIỚI THIỆU Bài 2 giới thiệu về một mạng số liệu công cộng, các tiện ích của mạng số liệu và hệ thống SPC (Hệ thống điều khiển bằng chương trình lưu trữ) 1 Mục đích yêu cầu Sau khi nghiên cứu bài 2, sinh viên cần: 1 Nắm vững hơn cấu trúc chủ động và bị động 2 Nắm được các đặc điểm của một mạng số liệu... routed an exchange which uses microchip technology 7 8 9 10 Unit 3 The Basic Transmission Systems UNIT 3 THE BASIC TRANSMISSION SYSTEMS I GIỚI THIỆU Bài 3 giới thiệu về các hệ thống truyền dẫn cơ bản trong mạng điện thoại 1 Mục đích yêu cầu Sau khi nghiên cứu bài 3, sinh viên cần: 1 Nắm được cách mô tả một quá trình 2 Thành lập câu sử dụng cấu trúc so sánh để giải thích các mối tương quan giữa các yếu... n lưu lượng transit network n mạng chuyển tiếp transit switching centre (TSC) n trung tâm chuyển mạch chuyển tiếp/ quá giang transmission n truyền dẫn ANSWER KEYS 1 Reading 1 Mạng quốc gia Vương quốc Anh bao gồm: a/ Mạng nội hạt: * Các tuyến nối giữa thuê bao và tổng đài nội hạt b/ Mạng chuyển tiếp: * Các mạch nối giữa một tổng đài nội hạt và một tổng đài nội hạt khác * Các mạch nối giữa một tổng đài... một tổng đài nội hạt và trung tâm thứ cấp, đôi khi còn gọi là trung tâm chuyển mạch nhóm (GSC) c/ Mạng chính/ trung kế: * Các mạch nối giữa các GSC * Các mạch nối giữa các GSC và các tổng đài cấp 3, ở Anh được coi là các trung tâm chuyển mạch khu vực và trung tâm chuyển mạch chính (DSC và MSC) Trong mạng nội hạt, mỗi thuê bao được nối với một tổng đài nội hạt Để giảm số lượng cáp, mạng nội hạt thường... nhiều sợi) chạy trong đường ống cáp hoặc cống cáp đến giá phối dây chính trong tổng đài nội hạt Ở mạng trung kế, tất cả các cuộc gọi đường dài được thiết lập thông qua một GSC và mạng chính Tại Vương quốc Anh, 70% tổng lưu lượng cuộc gọi được định tuyến trực tiếp tới một GSC khác, 24% chuyển qua một GSC khác nữa Lưu lượng mà không thể được thiết lập bằng các tuyến trực tiếp sẽ được tải trên một mạng mới... đến hàng trăm kilômét 4 Truyền tin với thế giới bên ngoài Cự ly truyền trong phạm vi từ vài kilômét đến hàng nghìn kilômét Chúng ta thấy rằng điển hình mà nói, khoảng 50% tổng số liên lạc văn phòng khoanh vùng trong một khu vực địa lý và 70% tổng số liên lạc nằm trong một công ty Chỉ 30% là vượt quá phạm vi một công ty ra thế giới bên ngoài, ví dụ tới các khách hàng và các nhà cung cấp 3.1 Answer the... những đòi hỏi cao và sẽ phản ứng mạnh nếu dịch vụ không sẵn sàng đáp ứng Nhằm đáp ứng những nhu cầu về độ tin cậy cao, và nhằm cung cấp các dịch vụ một cách kinh tế, mạng công cộng đang được nâng cấp nhanh chóng Tuy nhiên các khách hàng vẫn đang trông đợi việc sử dụng rộng rãi các dịch vụ mới như điện thoại thấy hình, vốn đã được trưng bày từ cách đây 30 năm Tiếp theo cần phải có điều gì để khiến cho