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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.

  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 It’s 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 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 (GaInAsP) 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 ILD sources should be used with stepped-index mono mode fibres. Furthermore, ILDs can launch between 0.5mW to 5mW of infrared power into a fibre, compared with the smaller 0.05μmW to 0.3μmW for an LED. GaAlAs ILDs and LEDs generate infrared in the 0.8μm to 0.9μm range, while GaInAsP 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 0.9μm.

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

cross

low

glass

plastic

armoured

infrared

B

cladding

cable

loss

talk

wavelengths

coating



XIX. Connect the words with their definitions.

    1. cross-talk f) reflection

    2. eavesdropper g) dispersion

    3. attenuation h) photodiode

    4. refractive index i) infrared

    5. cladding j) core

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

  1. The act or an instance of interfering;

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

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

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

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

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

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

  8. 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;

  9. 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 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 multi-mode 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.: КАРО, 2005. – 508с.

    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.


УДК 42 (076)

Н.Н. Клещина. Английский язык: Практикум по грамматике, чтению и переводу с английского языка. / СибГУТИ. – Новосибирск, 2008г. – 96 стр.

Практикум представляет собой сборник упражнений и текстов, составленных на основе разнообразного материала, в том числе и оригинальных источников – журналов: «The Economist. Technology quarterly», «Spectrum», учебников: «Upstream», «FCE Use of English», и книги Dr. Malcolm Plant «Electronics».

При работе с данным учебным материалом студенты должны приобрести знания по грамматике, расширить свой лексический запас, совершенствовать навыки перевода и устной речи.

Рекомендуется для работы студентов первого и второго курсов технических специальностей как для аудиторной, так и самостоятельной работы.

Кафедра иностранных и русского языков

Список литературы – 17 наим.

Рецензент: кфн. Е.И. Мартынова

Рекомендовано РИС СибГУТИ в качестве практикума по грамматике, чтению и переводу.

© Сибирский государственный университет

телекоммуникаций и информатики, 2008г.



Клещина Наталья Николаевна

АНГЛИЙСКИЙ ЯЗЫК

Практикум

по грамматике, чтению и переводу

с английского языка



Редиктор:

Корректор: Т.С. Пузанова


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