Radio Communication

Radio communication is the transfer of high-frequency energy from the transmitter to the receiver without wires.

Radio is a device that transmits and receives signals and programs by electromagnetic waves. Since the process of radio communication includes transmission and recep­tion of signals, the necessary components of radio are a transmitter and a receiver.

The transmitter is a device that produces radio-frequen­cy energy. The main parts of a transmitter are a high-fre­quency oscillator including an oscillatory circuit and one or a few amplifiers.

The receiver is a device that receives waves sent out by a transmitter. Radio receiver demodulates these waves and they are heard as speech, music, or signals.

Electric oscillations produced in the antenna of the transmitter travel in all directions. Radio waves are waves of very high frequency; they travel through space at the speed of light. They differ from other wave forms only in frequency (number of vibrations pat second).

Vocabulary:

transfer – передача

to differ (from) –отличаться

since – так как

necessary – нeобходимый

space – пространство

speed – скорость

amplifier – усилитель

Task 2. Translate the following word combinations:

high and low frequency energy; necessary amplifier parts; bad reception;

oscillatory circuits; changing wave direction; wave modulation

Task 3. Read and translate the following words without a dictionary:

amplitude, crystal, station, plan, operation, idea, cycle, variant

Task 4. Read and translate the following sentences:

1. The necessary components of a transmitter are a high-frequency oscillator, an amplifier, and electron tubes.

2. Electron tubes...

— amplify currents.

— give greater transmitting range.

— give better reception.

3. A receiver...

— receives high-frequency energy.

— demodulates high-frequency energy.

4. Radio waves...

— travel through space.

— differ from other wave forms.

— travel at high speed.

—travel in different directions.

Task 6. Look at this picture and give the answer what do you think about it?

Task 7. Read the Text. The clockwork radio

T revor Baylis is an inventor. In 1991, he heard about the problem of bringing health information to people in rural Africa. Radio was the best way but people had no electricity and couldn't pay for expensive batteries. So he invented a radio which doesn't need mains power or batteries. Instead, it consists of a spring, gears, and a small generator.

So how does his clockwork radio actually function? As you turn the handle on the side of the radio, you wind up a spring. It's the same kind of steel spring used in car safety belts. It takes 60 turns to wind up the spring fully.

When the spring starts to unwind, the gears engage. There are three 1:10 step-up gears. The last step-up link is a pulley. Pulleys run more quietly than gears so this reduces noise. Each time the first gear turns, the generator turns one thousand times. As it turns, it generates electricity - a voltage of 3 V at about 30 mA. The spring has enough power to run the radio for 30 minutes before you have to wind it up again.

More than two million clockwork radios are in use all over the world. Trevor Baylis has also invented an 'electric shoe'. It charges batteries as you walk.

Методические рекомендации:

Для полного понимания текста следует просмотреть активную лексику, и если необходимо, обратиться к англо-русскому словарю. Затем провести аудиторную работу над текстом с аналитическим чтением, контролем понимания и закреплением с помощью упражнений.

Рекомендуемая литература:

осн .(стр. 48-50) ,9 осн.(стр 202-213)

Контрольные вопросы:

1. How is the telephone conversation carried on?

2. What is the number of long distance calls per year by statistics reports?

3. Are there any disadvantages of space satellites.

4. Which device produces high-frequency energy?

5. Is a microphone connected to the circuit of the transmitting antenna?

6. What necessary components of a radio do you know?

7. What means is the antenna grounded by?

8. What means is the transmitted sound reproduced by?

9. What kind of current produces oscillations?

10. Which device receives radio waves?

Практическое занятие 4

Theme: Crystal Radio Set

Task 1. Read the text .

Task 2. Find answers to the questions in the text:

1. Which device produces high-frequency energy?

2. Which device receives radio waves?

3. What necessary components has radio?

4. What are the parts of a transmitter?

Radio waves start traveling when a transmitter sends out a constant amplitude signal at a very high frequency. Radio waves are traveling but the transmitter makes no sound.

A microphone is connected to the circuit of the transmitting antenna. When we speak into the microphone its resistance varies with the audio frequency. An alternating current is established in the microphone and antenna circuits and its frequency is the same as the audio frequency. Oscillations of the same frequency are induced in the antenna and in the oscillatory circuit of a receiver. These oscillations are in fact a high-frequency current.

In order to reproduce the transmitted sound, this current modulated by audio frequency should be sent through a telephone. The high-frequency alternating current cannot pass through the telephone coils. In order to reproduce the transmitted sounds, a detector or rectifier should be connected to the telephone circuit. It passes (lie current only in one direction. Therefore the current in the rectifier and telephone circuits will not be alternating current but rectified current.

The audio frequency rectified current passes through the telephone and produces oscillations. These oscillations will reproduce the sounds produced at the transmitting stations.

The device called a crystal radio set uses the energy induced in the receiving antenna. Its operation will be the better, the more energy is received by its oscillatory circuit. The oscillatory circuit is also provided with a ground. It is important for good operation of the receiver. The antenna should be grounded by means of a switch.

Practice the following words from the text:

audio - звуковой, низкий rectifier - выпрямитель

alternating - переменный to rectify - выпрямитель

to establish – устанавливать the ... the - чем...тем

in order to - для того чтобы

Task 3. Read and translate the following word combinations:

direct and alternating current; rectified current; audio frequency rectified

current; constant amplitude signal; radio set operation.

Task 4. Complete the sentences:

1. Current in the rectifier...

• is not alternating current.

• is rectified current.

• is audio frequency rectified current.

2.All alternating current...

• should be rectified.

• is established in the microphone.

3. In order to produce oscillations…

- an oscillatory circuit is used.

- laser devices are used.

- steam engine is used.

Методические рекомендации:

Для полного понимания текста следует просмотреть активную лексику, и если необходимо, обратиться к англо-русскому словарю. Затем провести аудиторную работу над текстом с аналитическим чтением, контролем понимания и закреплением с помощью упражнений.

Рекомендуемая литература:

осн .(стр. 48-50) ,9 осн.(стр 202-213)

Контрольные вопросы:

1) What kind of current produces oscillations?

2) By what means is the antenna grounded?

3) By what means is the transmitted sound reproduced?

Практическое занятие № 5

Задание 1. Read the text : The birth of the radio

Guglielmo Marconi (1874-1937) Italian electrical engineer and Nobel prize winner, the inventor of the first radio-signaling system. Today we don't think twice when we turn on the radio, but when a 21-yeur-old Italian invented it over 100 years ago no one could believe their ears.

One day in 1895 in Bologna, Italy, Guglielmo Marconi sent the world's first radio signal. Using a simple radio transmitter and a receiver, he sent a signal from his attic room to his brother who was hidden in a field a kilometer away. When his brother received the signal he fired a gun. The Italian government showed no interest in young Marconi's invention, but his mother, Annie, who was Irish, believed he had a good idea. So in February of the following year, she sent him to England to meet her cousin who was an important engineer. It was a journey that would change the world.

In England, Marconi and his cousin were joined by two other inventors. In 1897 Marconi formed Marconi's Wireless Telegraph Company in London and started to transmit simple radio signals over long distances. In 1899 he sent the first wireless telegraph across the English Channel to France. This meant that ships were now able to send messages from ship to shore if they were in distress.

Marconi had always believed that radio waves could travel round the curve of the earth. By 1901 he had improved his radio system so much that on 12th December he astonished the world by sending the first radio signals across the Atlantic Ocean. They were transmitted from Poldhu in Cornwall, and were received 3,520 kilometers away in St John's, Newfoundland, using an aerial flown in the air by a kite. Marconi's system was soon adopted by the British and Italian navies. From now on, the Marconi company had the monopoly of wireless communication and Marconi became a multi-millionaire.

Marconi is one of the key figures of the twentieth century. He even recognized the military importance of radar and thought of the idea of sending radio signals out into space. When Marconi died in 1937, wireless stations all over the world closed down for two minutes as a mark of respect. Marconi made only one big mistake. He thought that television would never become popular.

Задание 1. Read the text and find words and phrases which mean the same as the following.

1 give something a second thought

2 in danger or difficulty

3 made better

4 amazed

5 total control

6 a person with a lot of money

Задание 2. Complete the notes about Marconi and the history of radio communication.

1874 Marconi was born

1895 …

1896 …

1897 …

1899 …

1901 …

1937 …

Задание 3. Use word endings to identify parts of speech

You can often guess the part of speech of a word from its ending. For example, words ending in -ment, -ion, -once, -ence, -ness are often nouns.

Задание 4. Noun formation with endings: -ment, -ion, -er, -ance

Make words by matching the first part of each word with the correct ending(s).

-ment -tion -er -ance

relation

1. relat- 6. achieve- 11. demonstrat-

2. transmit 7. invent- 12. import-

3. receiv- 8. equip- 13. perform-

4. educat- 9. winn- 14. entertain

5. communicat- 10. govern- 15.

Задание 5. Find as much information as you can about an inventor of your choice. Write about him/her using the text about Marconi as a model. Include:

1. when and where he/she lived.

2. what he/she invented.

3. why the achievement was important.

4. if it has made people's lives better or worse

Методические рекомендации: Be sure to discuss the question from the task 5 with your tutor and groupmate. Make a Discussion.

Рекомендуемая литература:

Контрольные вопросы:

1.Do you think radio and telecommunications inventions have improved the quality of our life today or not?

2. Who was Guglielmo Marconi? (Italian electrical engineer and Nobel prize winner,

the inventor of the first radio-signaling system)

3.hen and where he/she lived. (1874-1937)

Практическое занятие №6

Тема: Electronics