Text B. Telecommunications (2)

1. ____________________________

Telecommunication is the transmission of signals over a distance for the purpose of communication. In modern times, this process almost always involves the sending of electromagnetic waves by electronic transmitters but in earlier years it may have involved the use of smoke signals, drums or semaphore. Today, telecommunication is widespread and devices that assist the process, such as television, radio and telephone, are common in many parts of the world. There is also a vast array¹ of networks that connect these devices, including computer networks, public telephone networks, radio networks and television networks. Computer communication across the Internet, such as e-mail and instant messaging, is just one of many examples of telecommunication.

2. ____________________________

Telecommunication systems are generally designed by telecommunication engineers. Major contributors to the field of telecommunications include Alexander Bell who invented the telephone, John Logie Baird who invented the mechanical television and Guglielmo Marconi who first demonstrated transatlantic radio communication. In recent times, optical fiber has radically improved the bandwidth available for intercontinental communication, helping to facilitate a faster and richer Internet experience. And, digital television has eliminated effects such as snowy pictures and ghosting. Telecommunication remains an important part of the world economy and the telecommunication industry's revenue has been placed at just under 3% of the gross world product.

3. ____________________________

The basic elements of a telecommunication system are:

- a transmitter that takes information and converts it to a signal for transmission;

- a transmission medium over which the signal is transmitted;

- a receiver that receives and converts the signal back into usable information.

For example, consider a radio broadcast. In this case the broadcast tower is the transmitter, the radio is the receiver and the transmission medium is free space. Often telecommunication systems are two-way and devices act as both a transmitter and receiver or transceiver. For example, a mobile phone is a transceiver. Telecommunication over a phone line is called point-to-point² communication because it is between one transmitter and one receiver, telecommunication through radio broadcasts is called broadcast communication because it is between one powerful transmitter and numerous receivers.

4. ____________________________

Signals can either be analogue or digital. In an analogue signal, the signal is varied continuously with respect to the information. In a digital signal, the information is encoded as a set of discrete values.

5. ____________________________

The shaping of a signal to convey information is known as modulation. Modulation is a key concept in telecommunications and is frequently used to impose the information of one signal on another. Modulation is used to represent a digital message as an analogue waveform. This is known as keying and several keying techniques exist – these include phase-shift keying, amplitude-shift keying³ and minimum-shift keying⁴. Bluetooth, for example, uses phase-shift keying for exchanges between devices.

Comments:

1) ¹a vast array (of networks, technologies, etc.) – широкий спектр (сетей, технологий и пр.).

2) ²point-to-point – "точка-точка". Тип связи между устройствами в сети передачи данных (syn. monocast).

3) ³amplitude-shift keying – амплитудная манипуляция, АМн.

4) ⁴minimum-shift keying – манипуляция минимальным сдвигом, манипуляция с минимальным сдвигом.

1.7 Complete the chart with the key words from the text.

1.8 Match the terms with their definitions.

1.9 Underline the sentences that, in your opinion, contain the basic information and summarize the general ideas of the text.

1.10 Prepare a report and take part in the discussion on the topic “Uses of radio and communication”. Use any additional information you can find in other sources.

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