англ_практикум

X.Complete the sentences with a word formedfrom the word in brackets. Use the following prefixes only once: over-, super-, under-, mono-, semi-, mal-, non-, sub-, out-, mis-.

1. Recent spectacular breakthroughs in			(conductor) may be compared
with the physics discoveries that led to electronics and nuclear power.
2.	The introduction of	(conductor)	technology revolutionized the
computer industry.
3.	You mast not	(estimate) how difficult it is going to be.
4.	From the	(set), Bill Gates was	confident that his computer
language, BASIC, would be a success.
5. To build a reliable hypersonic plane one has to			(come) a whole set
of technological and scientific difficulties.
6.	Most people prefer a colour screen to a		(chrome) screen.
7. If a printer		(function), you should check the interface cable.

8. The researchers used continuous superconducting crystals and shaped the gate

in such a way that a central area of the organic material is less exposed to the
electric field at the gate. This area remains		(conducting).
9. His comments were	(interpreted)	as a criticism of the project.
10. We	(contracted) the work to a small engineering firm.

XI. Read the text. Express the main idea of the text. Translate it.

The charge-coupled device

The charge-coupled device (CCD) is an integrated circuit comprising an array of minute semiconductor memory cells on a silicon chip that converts light received through a lens into a series of electrical charges that are directly related to the intensity of any given picture element (pixel). The CCD camera is a type of camera for converting light into electrical signals since it is based on semiconductors rather than on thermionic emission. The CCD comprises a light-sensitive array of metaloxide semiconductors on a silicon chip. It is much more sensitive than the vidicon tube and it is also able to store images in such a way that each pixel (picture element) in the image is converted into an electrical charge the intensity of which is related to the colour in the colour spectrum.

The charge is removed from the. array and processed to form an image by electrodes attached to the surface of the chip. The longer the light falls on the array, the larger the charge stored. Thus, the CCD is more sensitive than photographic film and enables light to be gathered from faint sources. For example, both amateur and professional astronomers use CCD cameras in place of the eye and photographic film to record images in their telescopes. For surveillance purposes, CCD images can be gathered in near darkness, and CCDs are used in digital cameras, camcorders, scanners and bar code readers. The word megapixel refers to the remarkable

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resolution (the amount of detail) of images taken by CCDs in digital cameras, one megapixel being, say, an image comprising 1024x 1024 pixel.

On the surface of the semiconductor chip making up the CCD is a long row of tiny metal electrodes that overlay a thin oxide layer formed on the surface of a p-type substrate. A three-phase clock network alternately activates the electrodes in turn by being switched from 0V to say +10V. If an electrode is pulsed to a positive voltage, it is capable of attracting a negative charge to the underside of the oxide layer beneath it. It is as if the positively charged metal electrode creates a kind of "buckef that can hold electric charge.

Charge-coupling is the technique by which signal charge can be transferred from the bucket under one electrode to the next bucket. This is achieved by taking the voltage on the send electrode also to 10V then reducing the voltage to 0V on the first electrode. Hence by pulsing the voltages on the electrodes sequentially between high and low levels, charge signals *can be made to pass down an array of very many electrodes. To achieve this, the electrodes are connected in sequence to a set of threephase drive pulses. Charge signals can then be stored under every third electrode in the array and will be transferred together along the array under the control of the drive pulses. The use of three phases ensures that the charges move in the right direction. By letting the presence or absence of a charge represent digital values of 0 and 1, and by providing amplifiers for injecting and detecting these charges, a very simple and compact type of computer memory device is possible. If a CCD used as an electronic sensor is a camera, the metal electrodes will be overlaid by surfaces that are optically sensitive.

A different type of light-sensitive semiconductor array is the Complementary Metal-Oxide Semiconductor (CMOS) sensor that is a rival to the CCD sensor. CMOS is a switching circuit based on the combination of n-channel and p-channel fieldeffect transistors.

Let us compare the CMOS sensor with the CCD sensor:

1.The CMOS sensor is more susceptible to electrical noise than the CCD sensor.

2.On condition that each pixel on a CMOS sensor has several transistors located next to it, its light sensitivity will be lower since many of the photons hit the transistors rather than the light-sensitive CMOS.

3.CMOS consumes up to 100 times less power than the CCD sensor.

4.CMOS is cheaper since it can be made on any standard production line making silicon chips.

5.CMOS can operate from a wide range of supply voltage.

Thus CCDs tend to be used in digital cameras if high-quality images are required with good light sensitivity.

Vocabulary:

array - множество

metal-oxide semiconductor - структура металл-оксид-полупроводник (структура МОП)

thermionic emission - термоэлектронная эмиссия

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surveillance - наблюдение

camcorders - портативная видеокамера со встроенным видеомагнитофоном bar code readers - устройство считывания штрихового кода

resolution - разрешающая способность substrate - подложка

underside - нижняя часть

to inject - инжектировать, вводить

to overlay - перекрывать, накладывать слой

CMOS (Complementary Metal-Oxide Semiconductor) - комплементарный металлооксидный полупроводник

XII. Find conditional sentences in the text and define their functions.

XIII. Read the text again and answer the questions.

1.What is the charge-coupled device?

2.What is the charge-coupled device used for?

3.What does the charge-coupled device consist of?

4.Describe the way how the charge-coupled device works.

5.What is charge-coupling?

6.What makes the charges move in the right direction?

7.What sensor does the CCD sensor compete with?

8.When are the CCDs used in digital camera?

XIV. Read the text again and complete the sentences.

1.The charge-coupled device is ...

a)more sensitive than the vidicon tube;

b)less sensitive than the vidicon tube.

2.The charge-coupled device gathers light

a)only from clear sources;

b)even from sources that can not be clearly seen.

3.The charge-coupled device

a)can not be used for surveillance purposes;

b)can be used for surveillance purposes.

4.Positively charged metal electrode

a)hold electric charge;

b)does not hold electric charge.

5.CCD sensor has ...

a)a lower consumption than the CMOS sensor;

b)a higher power than the CMOS sensor.

XV. Combine words from Box A with words from Box to make collocations.

	A		В
	thermionic		pulses
	photographic		layer
	oxide		sensor
	metal		film
	charge		coupling
	drive		sensitivity
	electronic		electrode
	light		emission
XVI. Connect the words with their definition.
	1. resolution		6. Complementary
2. substrate			Metal-Oxide Semiconductor
3. camcorder			7. electrode
4. charge-coupled device			8. thermionic emission
5. photon			9. bar code reader

10. pixel

a)an integrated circuit that converts light into a series of electrical charges that are related to the intensity of any given picture element;

b)the ability of a microscope or other optical instrument to produce separate images of closely placed objects;

c)any of a number of very small picture elements that make up a picture, as on a visual display unit;

d)the emission of electrons from very hot solids or liquids, used for producing electrons in valves, electron microscopes and X-ray tubes;

e)a video camera and recorder combined in a portable unit;

f)a switching circuit based on a field-effect transistor;

g)the semiconductor base on which other material is deposited, especially in the construction of integrated circuits;

h)a unit of electromagnetic energy;

i)a device which can read the information contained on a pattern of thick and thin lines that is printed on things you buy;

j)an element in a semiconducting device that emits, collects or controls the movement of electrons or holes.

XVII. Translate the following words, paying attention to prefixes then use them in sentences.

Underuse, outsource, overlay, misrepresent, undertake, overproduce, subdirect, supercharged, nonstandard, underachieve, mislay, misuse, outlay, outtake/

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XVIH. Find synonyms to the following words in the text.

To include, to find, to put into, to join, to produce, susceptible, strength, to form, base, to place.

XIX. Complete each sentence with a word from the box.

CCD, camcorder, pixel, surveillance, array, electrode, bar code reader, resolution,

substrate, CMOS		i			:
1. Each		is made up of three close dots of coloured phosphors of red,
green and blue.
2		are widely used in			security cameras, digital cameras and in

telescopes for detecting faint sources such as galaxies.

3. A wide range of digital devices, such as digital watches and microprocessors,

are based on			devices in integrated circuit form.
4		is used to make electrical contact with a circuit.
5.	To record pictures and sound amateurs usually buy a (an)					that can
be carried around.
6.	Professional video cameras typically have multiple image sensors to enhance
		and colour gamut.
7.	There	is a vast	of networks	that	connect devices,	including
computer networks, public telephone networks, radio and television networks.
8.	Closed-chcuit TV cameras are used for				purposes and	help	to
increase public safety.
9.	A thin oxide layer is deposited on the surface of a (an)					in	the
construction of integrated circuits.
10. A		common	alternative is the use of	a	(an) which may be capable

of reading the information on price tags and transferring of data to the computer.

XX. Translate the sentences, paying attention to the meanings of highlighted words.

1. You should keep a record of you expenses. 2. Did you remember to record my favourite program for me? 3. She holds the world record for the 100 metres. 4. The airline has a good safety record. 5. He recorded the class rehearsing before the performance. 6. Tell me when the tape starts recording. 7. The band is back in the US recording their new album. 8. Record you goals if you want to achieve them. 9. The thermometer recorded a temperature of 40° C. 10. The place was overlaid with memories of his childhood. 11. The roar of the engines was overlaid by a loud banging. 12. To protect wood from rotting we overlaid it with paint. 13. An overlay showing population can be placed on top of the map.

XXI. Put the verbs in brackets into the correct tenses.

1. If you camera (have) a good resolution its quality (be) high.

2.If the charge-coupled devices (have) a lower power consumption they (be) more popular.

3.If the charge-coupled devices (can) be made on any standard production line they (be) cheaper.

4.If digital cameras (not have) an extended depth of field, objects at a larger range of depth (not be) in focus.

5.	The signal-to-noise ratio (decrease) if each pixel sensor (get) smaller, because
in this case it catches fewer photons.
6.	If the charge-coupled devices (not invent) cameras (not be able) to take images.

7.If the charge-coupled devices (not be) sensitive they (not can) gather light from faint sources.

8.The charges (move) in the right direction if they (transfer) under the control of the drive pulses.

XXII. Discussion. In pairs discuss the following questions.

1. Speak about different applications of the charge-coupled devices. 2. Paraphrase the following quotation. Express your opinion about it.

"A discovery is said to be an accident meeting a prepared mind". (Albert SzentGyorgyi).

Unit 10

1.Сослагательное наклонение (The Subjunctive Mood)

2.Сослагательное наклонение после безличных предложений

3.Сослагательное наклонение после глагола wish

4.Конструкции would rather и had better

5. Текст: «Fibre optics communications»

/. Translate the sentences, paying attention to the Subjunctive Mood after the verbs should, would, could, might, must.

1. Would you mind giving me your dictionary for a minute? 2. I would like to thank you for your help. 3. You could have done it in a different way. 4. One laser beam could carry all the radio, TV and telephone messages simultaneously. 5. It would be useful to read this article. 6. Many scientific problems might be solved with the help of mathematics. 7. There would be no life without atmosphere. 8. It would be a great discovery to find means to prolong man's life. 9. There would be no progress in science without observations. 10. The material in this book is out of date. The book must have been written a long time ago.

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II. Translate the sentences, paying attention to the Subjunctive Mood in subject clause.

1. It is desirable that he should be present here. 2. It is essential that a superconductor should be a solid material. 3. It is necessary that superconductor should be cooled to -273°C. 4. It is required that an airplane should be well-balanced dynamically. 5. It is possible that a compound should become a superconductor even if the chemical elements constituting it are not. 6. It is very important that we should discuss this problem. 7. It is suggested that we should realize this program. 8. It is required that all measurement be done beforehand. 9. It is necessary that the average acceleration of the moving body be determined accurately. 10. It is essential that the two rotors should be accurately spaced angularly, that is to say that they should be accurately at right angles to each other. 11. It is desirable that they should measure all the chemical substances they deal with. 12. It is extremely important that all the metal powders used during production should be uniformly mixed.

III. Translate the sentences, paying attention to the Subjunctive Mood after verbs: to order, to insist, to demand, to suggest, to advice.

1. We suggested that his project be discussed in detail. 2. The engineer insisted that all the experimental data obtained should be exact. 3. The scientist demanded that the test should be repeated. 4. We were ordered that we should take part in the discussion. 5. The majority of the committee advised that the research work should be postponed. 6. I insisted that she regularly should inform us of the results of her experiments. 7. He suggested that the equipment should be brought in a week. 8. The engineer demanded that the molecules should be heated in order to make them move very rapidly. 9. Brattain and Gidney (the physical chemist of the group) suggested that the semiconductor and the metal plate should be immersed in an electrolyte to overcome the blocking effects of the surface states. 10. He demanded that the process should be modified to fabricate devices with a higher gain performance.

IV. Open the brackets using the Subjunctive Mood.

Model: He (advise) them what to do, but he couldn't get in touch with them.

He would have advised them what to do, but he couldn't get in touch with them.

1.I (obtain) a datum quantity for direct current, but the galvanic element that I used failed.

2.The supply voltage must have been increased, more current (flow) through the

regulator tube.

3. Why did not you ask them to discuss your problem then? They (not postpone) it. .

4.It (be) wise of you to read scientific journals on your profession.

5.1think nobody (object) to discussing the results of our work tomorrow.

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6.She (buy) the disk, but she had no money.

7.It (be) impossible to determine the chemical composition of the metal without a laboratory analysis.

8.The heat (cause) mechanical troubles, but fortunately the temperature weren't raised above a certain limit.

9.1 (come) to the meeting, but I wasn't informed about it.

10. This method is not efficient otherwise it (introduce) long ago.

V. Complete the given phrases using the Subjunctive Mood.

1.We propose...

2.They insist...

3.The speaker demanded..^

4.I suggest...

5.The professor strongly advised ...

VI. Translate the sentences with the Subjunctive Mood after the following conjunctions: lest, so that, in order that, though.

1. One of the elements in a vacuum valve must be heated so that it will give off electrons. 2. In order that this method might be applied two conditions must be observed. 3. The sound level of the broadcast program sent to the transmitter must be carefully adjusted in order that the carrier be neither overnor undermodulated. 4. Electrical conductors are said to be in series if they are connected so that all the current which flows through one conductor must flow through each of the others. 5. Great attention is paid to ecological problems all over the world so that the air in large cities should be kept clean. 6. You must put down this formula lest you should forget it. 7. Metal parts are tested for defects lest they should fail in operation. 8. All kinds of safety devices for motor cars are being developed lest accidents should occur. 9. The video must be squeezed into a small package in order that it should be transmitted on top of the radio channels without affecting their reception. 10. We employ an asymmetric gate recess scheme lest source resistance and output conductance should be increased. 11. Though the calculations might be very complex, the computer will do them in a few minutes. 12. The digital stream takes up much less capacity in the airwaves, so that the space needed in the past for just one analogue channel can now carry five, six or seven different programs.

VII. Translate the sentences with the Subjunctive Mood after the following conjunctions: as if and as though.

1. If the elements lie near one another in the electromotive series they behave as '/they were of the same chemical species. 2. The distance is not measured on the curved surface of the Earth but is computed as if the line were passing through the Earth. 3. The Earth behaves as though it were an immense magnet. 4. They discussed

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the subject as though they had studied it before. 5. The fluid motion in the transition region may be treated as if 'the region were plain. 6. He looks at his new, compact and stylish mobile phone as though he were proud of it. 7. The classroom is so quiet as if there were nobody in it. 8. The mixture is combustible as though the fuel were uniformly mixed with the air. 9. He spoke as if he had been the witness of the incident. 10. A young scientist wrote a great work as if he had a large experience in his field.

VIII. Open the brackets and use the correct form of the Subjunctive Mood.

1. It seemed as though he (know) it long ago.

2.	He looked as if he (want) to say something but (be) afraid to begin his speech.
3.	It seemed as if he never (hear) of it before.
4.	She speaks English as if she (be) an Englishwoman.
5.	She looked very tired as if she (work) from early morning till night.

6.He looked pleased as though he (reach) his purpose.

7.Companies are beginning to show interest in the sector as though they already (calculate) their future revenue.

8. The telecommunication system is transmitting signals of different frequencies as if the bandwidth (be) high.

9. The student did the calculations in a few minutes as if they (not be) very complex.

lO.The gauge registers the pressure of the water as if it (act) directly downward. 11 .The weight of a body varied during the experiment as though it (place) in different localities.

12.The combustible mixture produced a lot of power as if it (compress) to a high pressure before it started to burn.

IX. Comment on the use of tenses in the following sentences after wish and if

only.

1. I wish I could drive a car. 2. If only I could have driven a car when I was young. 3. I wish I would be able to drive a car soon. 4. I wish they had introduced their friends to me at the party. 5.1 wish they would introduce their friends to me at the party. 6. I wish you had brought your video camera to the yesterday conference. 7. If only he brought his video camera to the conference. 8.1 wish you would bring your video camera tomorrow. 9. If only you had mentioned this fact to me before. 10. I wish you told me everything. 11. Mary wishes she had made a report yesterday. 12. Mary wishes she would make a report at the lecture tomorrow. 13. If only I could speak several languages. 14. I wish I would be able to speak several languages one day. 15.1 wish I had spoken Italian when I went to Italy. 16. If only you were better educated you would find a good job.

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X. Paraphrase the following sentences using	the Subjunctive Mood after the
verb wish.
Example: My students are not always in time	for	class.
I wish my students were always in time		for class.

1.My director is too bossy and demanding.

2.My brother couldn't fix our new TV yesterday.

3.I have too much work to do.

4.I live far from the university.

5.We are upset that our plan failed.

6.The scientist was disappointed that he couldn't fulfill his experiment.

7.Unfortunately I was not able to do all the calculations yesterday.

8.The experiment is prepared carefully. I hope I shall get good results.

9.I do not speak French.

10.1forgot my PIN number that is why I did not take money out of the ATM.

11.1cannot afford to buy a car.

12.1have to attend lectures, but they are so boring.

13.1missed the bus this morning and was late for work.

14.1did not print the report yesterday because the electricity was cut off.

15.1left my umbrella on the bus.

XI. Translate the sentences paying attention to the phrases would rather and had better.

1. I would rather Ann worked with you. 2.1 would rather we had left earlier, than we would not have been caught in the rush hour traffic. 3. I would rather John finished the article before he leaves. 4 . 1 would rather the plumber came tomorrow, because I don't want to wait around for him today. 5.1 would rather they tried to fix the computer themselves before they asked me to do it. 6. Would you rather I called you or sent you a text message? 7. You had better work harder in order to pass your exams. 8. You had better do some revision work. 9. You had better get out your calculator and tot it up. 10. You had better send e-mail instead of writing a letter.

XII. What would you do in the following situations. Express your advice using constructions: would rather and would better.

Model; Your record player is too loud.

You had better turn it down.

1.You drive too fast.

2.The student talks too much at the lecture.

3.Your friend lost his passport.

4.Your mobile phone is discharged and you don't have a charging device with you, but you have to make an urgent phone call.

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5. Your brother is going to rent a video for you both to watch. He suggests either a comedy or a horror film.

XIII. Comment on the use of the Subjunctive Mood after the expression Ifs

high time.

1. It's high time you took part in this work. 2. It's high time you thought of your future. 3. It's high time you earned your own living. 4. It's high time you called an electrician. 5. It's high time you got down to business. 6. It's high time we provided the solution to the problem. 7. It's high time we finished the theoretical research and proceeded directly to the experimental stage. 8. It's high time you finished your project. 9. It's high time you used flash memory instead of diskette. 10. It's high time you should realize that times have changed.

XIV. Read the text. Express the main idea of the text. Translate it.

Fibre optics communications

For a long time light has been used to send messages. Our ancestors lit beacons when invaders threatened. A hand-held mirror, the heliograph, was first used by the ancient Greeks to reflect the Sun's rays and flash coded signals over great distances. And lighthouses and traffic lights use light to warn us of danger. But fibre optics communications is an altogether more sophisticated way of sending messages from one place to another: it makes use of long thin glass fibres along which information is sent as pulses of laser light. Fibre optics communications is now a well-established technology and it holds great promise for the future of telecommunications systems. But why should optical fibres be so superior to conventional copper cables? Well, for one thing cables made from optical fibres are cheaper, lighter and easier to install than copper cables. Furthermore, they are completely free from electromagnetic interference since data on a light beam cannot be corrupted by electrical machinery, thunderstorms and "noisy" power lines. Consequently, there is no interference or "cross-talk" between neighbouring fibres, a quality that also means that signals carried by optical fibres are much less liable to be detected compared with electrical signals in copper cables, i.e. the information is effectively secure from eavesdroppers. Safety, too, is an important reason for using optical fibres since broken fibres are not a fire hazard as the escaping light is harmless. The strongest justification for using optical fibres is their potential for carrying considerably more information than copper cables. Since light waves have frequencies about 10000 times higher than the highest frequency radio waves, considerably greater bandwidth is available. Indeed conventional copper cables are hard pressed to keep up with the mounting speed of development in communications and information technology. However, before fibre optics communications could become a reality, two high technology inventions, the laser and low-loss fibre optic cable were needed.

By "low loss" is meant glass so pure you could see through a 35 km thick block of it as clearly as through a window pane! Such high purity means that information

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travels through optical fibres for long distances without having to be repeatedly amplified on the way - it is said to have low attenuation. The raw material for such optically clean fibres is a special kind of sand called silica. An optical fibre is a solid rod of silica, finer than a human hair and surprisingly flexible. It is manufactured in the cleanest of atmospheres to ensure that no speck of dust or fingerprint can mar its purity.

The basic construction of an optical fibre comprises a glass core totally enclosed by a glass cladding. A plastic coating covers the cladding and core to prevent dust and moisture from reaching the glass core. Light is guided along the core by being reflected back from the outer cladding to the core, bouncing along from side to side of the core. No light is lost as it bounces from the cladding; at each bounce it is all reflected back to the core. What makes this happen is the relative optical properties of the core and the cladding. The cable is designed so that the refractive index of the core is higher than the refrective index of the cladding. This ensures that light meeting the boundary between the core and cladding at an angle greater than a certain "critical" angle is totally reflected back into the core. This is called total internal reflection. A fibre optics cable is an armoured cable designed both to protect the bundle of fibres from contact with moisture and chemicals, and to strengthen it.

Two light sources (or transmitters) are eminently suitable for the job of sending pulses of light down these slender optical fibres: light-emitting diodes (LEDs) and injection-laser diodes (ILDs). Both sources generate light when excited by electricity, and they are the only sources of light capable of being switched on and off fast enough to be modulated by low power analogue or digital signals. Their physical dimensions are compatible with optical fibres and they have the reliability and long life needed in telecommunications systems. Gallium arsenide (GaAs), gallium aluminium arsenide (GaAlAs) and gallium indium arsenide phosphide (GalnAsP) are the materials used in their construction. They convert electricity in to infrared energy efficiently, and the special glass used in fibre optics is more transparent at infrared wavelengths. Infrared LEDs are suitable for use with stepped-index multi-mode fibres since they emit a relatively wide beam of light with a fairy large spectral bandwidth. ILD sources radiate a much narrower beam of infrared with a much narrower spectral width. It is desirable that ELD sources should be used with steppedindex mono mode fibres. Furthermore, ILDs can launch between 0.5mW to 5mW of infrared power into a fibre, compared with the smaller 0.05/imW to 0.3/imW for an LED. GaAlAs ILDs and LEDs generate infrared in the 0.8/tm to 0.9/im range, while GalnAsP devices generate infrared in the 1.3m to 1.6m range where attenuation and dispersion by fibres is very low.

A photodiode is generally used to convert the modulated infrared light back into electrical signals at the end of the fibre. The photodiode is reverse-biased so that when it absorbs infrared, a small current flows between its cathode and anode terminals. The current is virtually proportional to the amount of light it absorbs. Photodiodes are generally based on silicon. Infrared emitting diodes and photodiodes are available as spectrally-matched pairs: the LED emits maximum infrared radiation at the wavelength to which the photodiode is most sensitive. This wavelength is typically 0.9/rni.

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Vocabulary:

interference - взаимное влияние, помехи cross-talk - помехи

eavesdropper - оператор перехвата (подслушивания) сообщений fire hazard - источник пожароопасности

attenuation - ослабление, затухание silica - кварц, кремнезем

core - сердечник, ядро

cladding - покрытие, оболочка, плакировка refractive index - коэффициент преломления armoured cable - армированный кабель

stepped-index mono-mode fibre - волокно со ступенчато-изменяющимся показателем преломления с режимом передачи одного звукового сигнала в цифровом потоке

stepped-index multi-mode fibre - волокно со ступенчато-изменяющимся показателем преломления с режимом передачи нескольких сигналов в цифровом потоке

coating - обшивка, покрытие

XV. Read the text again and find all sentences with the Subjunctive Mood.

XVI. Answer the questions.

1. How were signals transferred in ancient times?

2. What are the advantages of optical fibres over copper cables?

3.What material is used for optically clean fibres?

4.What does the optical fibre look like?

5.What does the optical fibre consist of?

6.What is total internal reflection?

7.What is fibre optics cable designed for?

8.Which transmitters are suitable for sending pulses of light through optical fibres?

9.Compare LEDs and ILDs.

10.What is a photodiode used for?

XVII. Read the text again and decide whether these statements are true or false.

1.Optical fibres are more expensive to install than copper cables.

2.Optical fibres are not liable to interference.

3.Copper cables cannot carry so much information as optical fibres.

4.Injection laser diode is not compatible with optical fibres.

5.Photodiodes are used at the beginning of the fibre.

XVIII. Combine words from Box A		with words from Box B to make
collocations.
	A	В
	cross	cladding
	low	cable
	glass	loss
	plastic	talk
	armoured	wavelengths
	infrared	coating

XIX. Connect the words with their definitions.

a) cross-talk	f) reflection
b) eavesdropper	g) dispersion
c) attenuation	h) photodiode
d) refractive index	i) infrared
e) cladding	j) core

1. The part of the electromagnetic spectrum with a longer wavelength than light but a shorter wavelength than radio waves;

2. The act or an instance of interfering;

3. The loss of energy suffered by radiation as it passes through matter, especially as result of absorption or scattering;

4.The process of protecting one metal by bonding a second metal to its surface;

5.A light-sensitive diode that has twp terminals, an anode and a cathode, and that responds rapidly to changes of light;

6.The separation of electromagnetic radiation into constituents of different wavelengths;

7.A measure of the extent to which radiation is refracted on passing through the interface between two media;

8.A process in which light, electromagnetic radiation, sound, particles, etc. are thrown back after impinging on a surface;

9. A piece of magnetic material, such as soft iron, placed inside the windings of an electromagnet or transformer to intensify and direct the magnetic field; lO.People who listen secretly to what other people are saying.

XX. Translate the sentences paying attention to the Subjunctive Mood.

1. It is necessary that the cladding and core should be covered with plastic coating to prevent dust from reaching the glass core. 2. It's high time you read about basic optics. 3. It seems as if refractive indices were different. 4. In order that greater bandwidth might be available light waves must have frequencies about 10000 times higher than the highest frequency radio waves. 5. There would be no fibre optics communication without two high technology inventions, the laser and low-loss fibre

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optics cable. 6. I wish you knew more about fibre optics communication. 7. It is important that glass should be pure, otherwise information could not travel through optical fibres for long distances. 8. Infrared LEDs are used with stepped-index multimode fibres so that they emit a wide beam of light with a large spectral bandwidth.

XXI. Practice the Conditional and the Subjunctive Mood while discussing the following ideas.

1.What if the telephone had not been invented?

2.What if printing had not been invented?

3.What if everybody in the world spoke the same language?

4.What if optical fibres had never been discovered?

5.If you had only one day to live, what would you do?

Список литературы

1.Куклина И.П. Energy is the Source of life. - СПб.: KAPO, 2005. - 508c.

2.Орловская И.В., Самсонова Л.С., Скубриева А.И.Учебник английского языка для студентов технических университетов м вузов. - М.: МГТУ им. Н.Э. Баумана, 2002. - 310с.

3. Романова Л.И. Практическая грамматика английского языка. - М.: Рольф, 2000.-376с.

4.Соболева Н.М. Пособие по английскому языку для заочных технических Вузов. - М.; Высшая Школа, 1998. - 228с.

5.Oxford Advanced Learner's Dictionary. - Oxford University Press, 2004. - 1540c.

6.The Economist. Technology Quarterly. December, 2007. - C. 5-26.

7.The Economist. Technology Quarterly. - C. 7-20.

8.The Economist. Technology Quarterly. - C. 6-16.

9.IEEE Spectrum. July, 2002. - C. 24-36.

10.IEEE Spectrum. November, 2007. - C. 15-34.

11.IEEE Spectrum. May, 2008. - C. 34-56.

12.IEEE Spectrum. March, 2008. - C. 45 - 67.

13.Dr. Malcolm Plant. Electronics. - London.: Hodder Headline, 2007. - 342c.

14.Virginia Evans, Jenny Dooley. Upstream. Intermediate. - Express Publishing, 2003.-222c.

15.Bob Obee, Virginia Evans. Upstream. Upper-Intermediate. - Express Publishing, 2003. - 264c.

16.Virginia Evans, Lynda Edwards. Upstream. Advanced. - Express Publishing, 2003.-236c.

17.Virginia Evans. FCE Use of English. - Express Publishing, 2004. - 236c.

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