Файл: Учебнометодическое пособие по английскому языку для специалистов и бакалавров 2 курса института ртс. Москва 2019.docx

Text B

Radio
Radio means sending energy with waves. In other words, it's a method of transmitting electrical energy from one place to another without using any kind of direct, wired connection. That's why it's often called wireless. The equipment that sends out a radio wave is known as a transmitter; the radio wave sent by a transmitter whizzes through the air—maybe from one side of the world to the other — and completes its journey when it reaches a second piece of equipment called a receiver. When you extend the antenna (aerial) on a radio receiver, it snatches some of the electromagnetic energy passing by. Tune the radio into a station and an electronic circuit inside the radio selects only the program you want from all those that are broadcasting.

How radio waves travel from a transmitter to a receiver:

1) Electrons rush up and down the transmitter, shooting out radio waves.

2) The radio waves travel through the air at the speed of light.

3) When the radio waves hit a receiver, they make electrons vibrate inside it, recreating the original signal. This process can happen between one powerful transmitter and many receivers—which is why thousands or millions of people can pick up the same radio signal at the same time.

How does this happen? The electromagnetic energy, which is a mixture of electricity and magnetism, travels past you in waves like those on the surface of the ocean. These are called radio waves.
Analog radio

Radio waves carry energy as an invisible, up-and-down movement of electricity and magnetism. This carries program signals from huge transmitter antennas, which are connected to the radio station, to the smaller antenna on your radio set. A program is transmitted by adding it to a radio wave called a carrier. This process is called modulation. Sometimes a radio program is added to the carrier in such a way that the program signal causes fluctuations in the carrier's frequency. This is called frequency modulation (FM). Another way of sending a radio signal is to make the peaks of the carrier wave bigger or smaller. Since the size of a wave is called its amplitude, this process is known as amplitude modulation (AM). Frequency modulation is how FM radio is broadcast; amplitude modulation is the technique used by AM radio stations. Sending information by changing the shapes of waves is an example of an analog process. This means the information you are trying to send is represented by a direct physical change (the water moving up and down or back and forth more quickly).

The trouble with AM and FM is that the program signal becomes part of the wave that carries it. So, if something happens to the wave en-route, part of the signal is likely to get lost. And if it gets lost, there's no way to get it back again. That's why analog radios can sound crackly, especially if you're listening in a car. Digital radio can help to solve that problem by sending radio broadcasts in a coded, numeric format so that interference doesn't disrupt the signal in the same way. Let's lift the lid of an old-style analog transistor radio and see what we can find inside:

1. External, telescopic FM antenna: The one on this radio extends to about 30 cm (1 ft), which is plenty long enough to catch a good range of FM broadcasts. You can extend and swivel the telescopic antenna for better reception. Generally speaking, the longer the antenna (known as an aerial in the UK), the more signals you can pick up.

2. Battery compartment: This radio is either battery or AC powered. When you plug in an AC lead, a switch automatically cuts out the battery power.

3. Loudspeaker: There is only one loudspeaker, so this radio can reproduce only mono sounds. Generally, the bigger the loudspeaker the louder the radio (and the better the quality of sound it will make).

4. AC power input: A cable plugs into this socket so you can run the radio economically from a domestic power supply (mains electricity socket).

5. Transformer: The radio's electronic components operate on very small voltages (less than 6 volts), but the power that comes in from the AC outlet is typically 110 volts (in the USA), 240 volts (in the UK), or similar. The transformer's job is to scale down the AC voltage so it's safe and appropriate for the radio's delicate components.

6. Internal AM antenna: When you're listening to an AM (also known as MW or medium wave) broadcast, the external FM antenna is redundant. Instead, signals are picked up by this tightly coiled AM antenna concealed inside the case. If you're listening on AM, you have to turn the entire radio to reorient the built-in antenna and improve your signal reception.

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7. Transformer: A series of smaller transformers help the radio hone in on just the station you want by blocking out other, nearby stations.

8. Amplifier: This small chip boosts the signal strength so it's powerful enough to drive the loudspeaker. The amplifier is based on transistors, electronic components that take in a small current and put out a much larger one—scaling it up in size. Small radios are often called "transistor radios": it was the development of the tiny transistor, from the late 1940s onward, that made it possible to pack all the components of a radio into a small portable unit. Before transistors came along, radios were typically huge wooden boxes that stood in the corner of your home, as big as an old-fashioned TV (and often even bigger).

9. Earphone socket: You can plug a small mono earphone in here to listen in privacy. If you plug stereo headphones into the mono socket, you'll hear sound in only one of the two earpieces.

10. Volume control: This is the back of the volume knob. Turning the volume knob adjusts an electronic component called a variable resistor or potentiometer, which increases or decreases the electric current flowing to the loudspeaker. A bigger current makes a louder sound with more volume; a smaller current makes a quieter sound with less volume.

11. Tuning control: This is a variable capacitor that tunes the radio in to a specific station.
Digital radio

You're driving along the freeway and your favorite song comes on the radio. You go under a bridge and—buzz, hiss, crackle, pop—the song disappears in a burst of static. Just as people have got used to such niggles, inventors have come up with a new type of radio that promises almost perfect sound. Digital radio, as it's called, sends speech and songs through the air as strings of numbers. No matter what comes between your radio and the transmitter, the signal almost always gets through. That's why digital radio sounds better. But digital technology also brings many more stations and displays information about the program you're listening to (such as the names of music tracks or programs):

– The transmitter sends program signals broken into fragments and coded in numbers (digits).

– The transmitter sends each fragment many times to increase the chances of it getting through.

– Even when things interrupt or delay some of the fragments, the receiver can still piece together fragments arriving from other places and put them together to make an uninterrupted program signal.

To help avoid interference, a digital radio signal travels on a huge, broad band of radio frequencies about 1500 times wider than those used in analog radio. This wide band allows a single digital signal to carry six stereo music programs or 20 speech programs in one go. Blending signals together in this way is called multiplexing. Part of the signal might be music, while another part could be a stream of text information that tells you what the music is, the name of the DJ, which radio station you're listening to, and so on. Switch on your digital radio and it:

– Collects fragments of radio signals flying through the air.

– Sorts through and reassembles the fragments in order to make a complete radio signal—and thus the program you want to hear.

It takes a digital radio some time to process incoming signals. Put a digital radio and an ordinary analog radio next to one another and tune them both into the same station. You'll find the sound from the digital radio lags noticeably behind the sound from the analog radio because of the time it takes to reassemble the digital signal.

Band/use	Wavelength	Frequency
LW (Long wave)	5km–1km	60kHz–300kHz
AM/MW (Amplitude modulation / medium wave)	600m–176m	500kHz–1.7MHz
SW (Short wave)	188m–10m	1.6MHz–30MHz
VHF/FM (Very high frequency / frequency modulation)	10m–6m	100MHz–500MHz
FM (frequency modulation)	3.4m–2.8m	88MHz–125Mhz
Aircraft	2.7m–2.2m	108–135MHz
Cellphones	80cm–15cm	380–2000MHz
Radar	100cm–3mm	0.3–100GHz

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If you look at the table, you'll notice that the wavelength and the frequency move in opposite directions. As the wavelengths of radio waves get smaller (moving down the table), so their frequency gets bigger (higher). But if you multiply the frequency and wavelength of any of these waves, you'll find you always get the same result: 300 million meters per second, better known as the speed of light.

Task 1. Read and translate text B.

Task 2. Answer the following questions.

1. What is modulation?

2. What’s the difference between FM and AM?

3. What does analog radio consist of?

4. How does digital radio work?

5. If you put a digital radio and an analog radio next to one another and tune them both into the same station, what will you notice?

6. If you multiply the frequency and the wave length of any of radio waves, what result will you get?

7. What is multiplexing?

Task 3. Say whether the sentences are true or false. If they are false, correct them.

1. The electromagnetic energy, or magnetism, travels past you in waves like those on the surface оf the ocean.

2. A program is transmitted by adding it to a radio wave called a carrier.

3. Generally, the bigger the loudspeaker the louder the radio (and the better the quality of sound it will make).

4. The transformer’s job is to scale up the AC voltage so it’s appropriate for the radio’s components.

5. If you multiply the frequency and wavelength of any of radio waves, you’ll find you always get the same result: 300 million meters per second.

Task 4. Use the text and find antonyms for the following words.

1. Wired

2. Visible

3. Tiny

4. Internal

5. To worsen

6. To increase

7. To receive

Task 5. Find the English equivalents for the following words and word combinations.

Динамик, воспроизводить, розетка, встроенный, внутренний, усилитель, качество, ток, настроить, конденсатор переменной емкости, избегать, увеличить, полоса частот, источник питания, несущая.

Task 6. Match the term with the right definition.

Broadcast, fluctuation, amplifier, interference, to tune, switch, carrier, capacitor, frequency, amplitude.

1. To adjust a circuit to oscillate at a particular frequency.

2. To transmit radio or TV signals.

3. Radio wave used to carry audio or video signals.

4. How often a pattern is repeated every second.

5. Small change above or below a fixed level.

6. Size of a wave at any given time.

7. Electrical component for opening and closing a circuit.

8. Electronic circuit for increasing the size of a signal.

9. Electronic component that stores charge.

10. Unwanted signals.

Task 7. Read the text and translate it into Russian.

The block diagram of a radio is shown below. The tuner selects the required RF wave from those picked up by the aerial. The selected RF wave is amplified and passed to the detector, which separates the audio modulation from the RF carrier wave. The audio frequency amplifier then amplifies the audio signal to make it strong enough to drive the loudspeaker.

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AF power amplifier

AF amplifier

Detector

RF amplifier

RF tuner

Aerial


A typical radio tuner circuit consists of an inductor and capacitor connected in parallel. The size of the aerial inductance coil can be kept small by winding it on a ferrite rod core.

The RF waves fed to the tuner cause the circuit to oscillate. The impedance of the circuit is smallest and the oscillation is greatest at a particular frequency known as the resonant frequency. This frequency is determined by the values of the inductance and the capacitance. By using a variable capacitor, the circuit can be tuned to the required radio frequency, and the selected RF wave passed on to the RF amplifier.

Task 8. Explain what happens at each stage in this flowchart, which shows how a radio works. Use the information from the text in Task 7.

Component Function

1. 
   Aerial
   
2. 
   RF tuner
   
3. 
   RF amplifier
   
4. 
   Detector
   
5. 
   AF amplifier
   
6. 
   Loudspeaker
   

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Text C

History of Radio
The history of radio begins in the mid 1800s with theoretical discussions that electricity and magnetism were related. The telegraph system was the first direct commercially viable technology to be developed from this discovery, although telegraph required fixed wire cables and could only be transmitted from point to point, and needed human operators to retransmit a signal over long distances.

The first true wireless experiments weren’t carried out until after James Maxwell had developed his own theories and incorporated the experiments of Michael Faraday into the unified theory of electromagnetism in 1865. Over the next decade several amateurs and physicists such as William Henry Ward, Mahlon Loomis, and Thomas Edison patented methods of sending and receiving a wireless telegraph system but none of these people ever demonstrated a working system.

This all changed in 1884 when Temistocle Calzecchi-Onesti invented a device which was subsequently refined and then named a coherer by Edouard Branly in 1886. The coherer became the enabling technology that allowed early radio signals to be received. The coherer is a glass tube filled with metal filings and connected to an electrical current which produced an audible click in a sounder whilst the signal was being received.

By 1887 Heinrich Hertz had refined a system that allowed him to experiment with sending wireless signals to a wireless receiver and is credited with being the first person to intentionally transmit and also receive a wireless signal. Strangely Hertz had no interest in the technology and was simply experimenting with practical electromagnetic waves to advance his theories, but his research paved the way for other, and more commercially attuned inventors. In 1933 Hertz was honored when the unit of measure of radio and electrical frequencies was named in his honor as part of the new International Metric System.

A Serbian-Croatian immigrant to the US Nikola Tesla in 1892 demonstrated the first complete radio transmitter and receiver system, and in so doing was the very first person to successfully invent radio. Sadly, Tesla suffered a fire in his laboratory in 1895 just as he was about to demonstrate radio over a distance of 50 miles in New York. That experiment never happened but by 1898 Tesla demonstrated the first radio controlled boat and filed a series of patents for radio in the early 1900s.

Guglielmo Marconi, a young man from Bologna in Italy had been fascinated by the idea of wirelessly transmitting a telegraph signal and in 1894 succeeded in inventing a spark transmitter with an antenna that he used to broadcast a signal across his parents garden and then across a distance of a mile in the countryside. The Italian Postal Service which controlled telegraph services weren’t interested in Marconi’s experiment so in 1896 he made his way to England and successfully demonstrated his technology to the English Post Office who immediately secured his services.

The following year Marconi established the Wireless Telegraph and Signal Company and was selling his patented invention to shipping companies. So successful was Marconi’s invention that Queen Victoria herself had one installed on a ship that her son the Prince of Wales was using whilst he recovered from illness. In 1898 Marconi also established the American Marconi Co recognizing that the US was quickly becoming one of the world’s most important merchant navy operators.

Whilst Marconi’s inventions were outstanding his real genius lay in commercializing his technology, an act that started with demonstrating a successful broadcast across the Atlantic in 1901, an event which progressed the development of radio broadcasting far more than any other single act. Marconi was related to British nobility who were powerful investors in his companies and in the emerging markets in the US.

So powerful were his backers that Marconi managed to have a patent for the invention of radio registered even though Tesla had a pre-existing patent. A legal dispute between the two started in 1915 and wasn’t finally settled until 1943 when the US Supreme Court finally upheld Tesla’s patent number 609,154 and confirming his role as the inventor of radio.

Another American Reginald Fessenden had heard of Marconi’s success but was convinced the enabling technology could be redesigned and be both more efficient, but also allow audio broadcasts, and in 1900 demonstrated his new technology which would afterwards be used by the weather department for sending time and weather information to ships at see. In 1906 or 1909, nobody knows for sure since Fessenden only wrote his notes 25 years later, the very first audio transmission was carried out by Fessenden playing a violin and reading a few passages from the Bible.

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