4 Семестр

Unit 7

What is electronics?

Text 7.1

Read and translate the text.

Electronics is the branch of science which controls electricity in order to convey a signal using semiconductor materials. These signals represent numbers, letters, sounds, pictures, computer instructions or other information. Radio systems were developed to read and understand these signals and in 1920 radio broadcasting started, making it possible for electromagnetic waves to travel long distances.

More sophisticated devices were needed during the Second World War and the invention of radar (Radio Detection and Ranging) represented a further step in electronics, making it possible to determine the altitude, direction and speed of moving and fixed objects.

The invention of television in the 1920s was one of the most revolutionary and popular inventions in history and it showed the importance of electronics in certain branches of industry. For the first time in history it became possible to transmit images and sound over wire circuits.

The first computer appeared in 1946. This machine, which could solve a wide range of computing problems, was built over a period of three years by a team of American scientists working at the University of Pennsylvania. It was a huge machine weighing almost 50 tons.

The first transistor was assembled in 1957 by a team of scientists working at the Bell Laboratories in the U.S.A, and it was a real coming of age in the science of electronics because it replaced the use of valves. Transistors are very small, easy to handle, cheap, and they use little power.

The silicon chip - which followed the transistor in the 1960s - can contain up to several thousand transistors packed and interconnected in layers beneath the surface. It is really tiny (usually less than one centimetre square and about half a millimetre thick) and it has paved the way to microelectronics.

Electronics has influenced and improved the way information is stored, processed and distributed. Social and personal life has been deeply affected by these inventions and many financial, business, medical, education and political routines have been speeded up.

Read the text about the main inventions in electronics and complete the table with the missing information.

Invention	Year	Function
		read and understand electronic signals
Radar
	1920s

Text 7.2

Electronic circuits

Read and translate the text.

A conventional electronic circuit is made of separate components attached to a base called a printed circuit board (PCB). Before being finalised and manufactured, the electronic circuit must be tested many times on an experimentation board called a breadboard. It consists of a perforated block of plastic with several spring clips connected by copper wires. It doesn’t require soldering as its components can be pushed straight into the holes, so it is easy change connections and replace pieces. It is generally used to temporary prototypes and experiment with circuit design.

The integrated circuit, also known as a chip, is one of the most important inventions of the 20th century. Integrated circuits are used in almost all electronic equipment today, for example watches, calculators and microprocessors. It consists of millions of transistors and other electronic components combined to form a complex set on a thin slice of silicon or other semiconductor material. Chips are becoming tinier and tinier and they are produced in large quantities so that costs are reduced. Since signals have to travel a short distance, they work faster, consume less power and generate less heat. They are also more reliable given the limited amount of connections which could fail.

The microprocessor is the heart of any normal computer: it is a logic integrated circuit chip which can carry out a sequence of operations when it receives instructions from different input devices. As it doesn’t contain a large memory, it can’t work alone but needs to be supported by other integrated circuits to be connected with peripherals. Most microprocessors are found inside computers and are called the CPU (Central Processing Unit). In order to work properly, the microprocessor needs to receive instructions from a memory chip. These instructions are then decoded, executed and ' elaborated so as to get the results available. The most sophisticated microprocessors can contain up to 10 million transistors and run 300 million cycles per second. It means that the computer can perform about a billion instructions every second. As technology continues to evolve, microprocessors are becoming tinier and tinier.

Answer the questions.

1 What is a conventional circuit made of?

2 What does PCB stand for?

3 What is a breadboard?

4 What does a chip consist of?

5 What is a chip made out of?

6 What are the advantages of chips compared to conventional electronic circuits?

7 What is a microprocessor?

8 How many instructions can computers perform?

Read the text again and match the words with their definitions.

1 prototype a - to convert an electrical signal into another code

2 perforated b - the act of joining metallic parts

3 soldering с - an original model used to test a circuit or a product

4 to fail d - to perform ineffectively

5 peripheral e - having a series of holes

6 to decode f - an auxiliary device that works with a computer

Text 7.3

Read and translate the text.

A cellular phone (or mobile phone) is designed to give the user freedom of movement while using a telephone. It uses radio signals to communicate between the phone and the antenna. The server area is divided into smaller areas called cells and an antenna is placed within each cell and connected by telephone lines. These lines connect cellular phones to one another: a computer selects the antenna closest to the telephone when a call is made. If the phone moves to one serving cell to another, the radio signal is transferred to the actual cell without interrupting the conversation.

The circuit board is the heart of the system. A chip translates the outgoing and incoming signals from analogue to digital and back from digital to analogue. The microprocessor handles all the functions for the keyboard, the display and the loudspeakers, and it controls the signal to the base station. Other flash memory chips provide storage for the operating system.

A cellular phone is not only a phone but it provides an incredible amount of functions:

• store information;

• use a calculator;

• send and receive emails;

• surf the Internet;

• play simple games;

• play music, take photos and videos.

Can you imagine your life without your mobile phone?

Decide if the following statements are true (T) or false (F).

1 Mobile phones use radio signals to communicate.

2 The server area is divided into smaller areas called stations.

3 An antenna is placed every two or three cells.

4 Communication with a mobile within a cell is independent from the base station.

5 There are interruptions when you move to one cell to another.

6 The antenna is the heart of the system.

7 The signal must be translated.

8 The flash memory handles all the functions.

Unit 8

Telecommunications and networks

Text 8.1

Read and translate the text.

Communication has always played a crucial role in human societies and over time its forms have evolved through the progression of technology, transforming itself into telecommunication. The telegraph, the telephone, the radio, the television, the radar, the fax and, more recently, the computer are all devices which were invented to communicate using electromagnetic waves. Thanks to them, we can transmit texts, pictures, sounds and images and reach everyone in any part of the world.

Telecommunication systems need means for the transmission of any information, which is translated into electromagnetic waves that connect the transmitter to the receiver.

These means can be physical media, such as cables, or radio waves, which are transmitted by air. Different kind of cables can be used. The simplest communication cables consist of a single pair of wires twisted together. Other types are coaxial cables and optical fibres. Radio waves need antennas to be transmitted and sometimes satellites are necessary for long-distance transmission.

Text 8.2

Read and translate the text.

Ground transmission

Wires provide a cheap and effective means of communication that was predominant in the past. Wires, which are made out of copper and insulated with plastic, can be single or twisted, and they are used mainly in telephone and computer networks.

Coaxial cables consist of an inner conductor insulated with plastic and surrounded by a woven copper shield. They are used in television and radio as these cables can support about 60 channels. The inner copper cable is insulated to protect the wires from bending and crushing and to reduce the noises.

Optical fibres are used in place of simple copper wires to carry larger amounts of information. They consist of strands of pure glass as thin as a human hair. Signals travel along fibres with less loss and without any electromagnetic interference. As they permit transmission over longer distances and at a higher speed, they are used in communication systems, in some medical instruments and in a wide variety of sensing devices.

Air transmission

Antennas were invented to capture radio signals and convert them into electrical signals through the receiver. They can also receive electrical signals from the transmitter and convert them into radio signals.

These electric devices, which provide information at a cheap rate, are essential to all equipment that uses radio. They are used in systems such as radio and television broadcasting, radar, mobile phones, and satellite communications, for which they are in form of dishes.

Satellites are machines launched into space to move around Earth or another celestial body. A communications satellite is basically a station which receives signals in a given frequency and then retransmits them at a different frequency to avoid interference problems. The first satellite was launched by the Soviet Union in 1957. There are different types of satellites: low-orbit satellites, which travel at about 300 km from the Earth and observe the planet, providing accurate information about agriculture, pollution and weather forecasting; medium-altitude satellites, which travel at about 9000-18000 km from the Earth and are used in telecommunications.

Complete the table

Means of transmission	Material	Function	Type of signal(ground or air)	Advantages
Wires
Coaxial cables
Optical fibres
Antennas
Satellites

Text 8.3

Read and translate the text.

A network is a group of computers linked together. It consists of at least two computers joined by cables on the same desk or same office, but it can also mean thousands of computers across the world. The users of a network can share hardware (scanner, printer, fax machine, etc.), access data in other people’s computers and run other programs stored in the network although not installed on their own computer.

A network consists of:

■ nodes, that is to say different computers and devices;

■ a connecting medium, such as cables or a wireless connection;

■ routers, which are special computers enabled to send messages;

■ switches, that is to say devices which help to select a specific path to follow.

Networks can be connected in different ways according to the area they cover.

A LAN (Local Area Network) is generally located in a limited space, such as a building or a campus.

On the contrary, a WAN (Wide Area Network) operates in a larger area and it can reach most of the world, so it could be described as a collection of LANs all over the world.

The exchange of information in a network is controlled by communications protocols, which define the formats and rules that computers must follow when talking to one another.

Well-known communications protocols are Ethernet, which is a family of protocols used in LANs, and the Internet Protocol Suite, which is used in any computer network.

Computer networks offer many advantages. For example, they facilitate communication, allowing people to send emails and texts, make phone/video calls and videoconference. Furthermore, networks allow people to share files, data, and other types of information as users may access data and information stored on other computers in the network.

On the other hand, networks may be difficult to set up and may be insecure as computer hackers can send viruses or computer worms to the net computer. They may also interfere with other technologies, as power line communication strongly disturbs certain forms of radio communication and access technology such as ADSL.

Answer the questions

1 What does a network consist of?

2 What is a router?

3 What is a LAN?

4 What is a WAN?

5 What is the function of communications protocols?

6 What is Ethernet used for?

7 What are the advantages of using a network?

8 What are the disadvantages of using a network?

Text 8.4

Read and translate the text.

Bus network

In a bus network all nodes are connected to a common medium, called backbone, as it happens with Christmas lights. Information sent along the backbone travels until the destination is reached. This kind of topology is generally used only for small networks, as it isn’t able to connect a large number of computers. The main advantage offered by this topology is that if a computer or device doesn’t work, it doesn’t affect the others.

Star network

In a star network all nodes are connected to a special central node called the hub. Once it has received a signal, the hub passes it to all the other nodes until it reaches the destination computer. This means that all the computers and devices are joined together. This topology is commonly used in businesses because it can grant rapidity and safety in exchanging data. Thanks to this topology, data is always up-to-date and if a computer doesn’t work, it doesn’t affect the others. The only disadvantage to it is that if the hub goes down, the whole network doesn’t work.

Ring network

In a ring network each node is connected to its left in a circle. There is no central hub that holds all the data, and communication is sent in one direction around the ring through the use of a token. As it requires fewer cables, this topology is less expensive. Nonetheless, because it provides only one pathway among the nodes, a single node failure may isolate all the devices attached to the ring.

Star bus topology

Star bus topology is the most common network topology used today. It combines elements of star and bus topologies to create a more effective network. Computers in a specific area are connected to hubs creating a star, then each hub is connected together along the network backbone.

The main advantage of this type of topology is that it can be more easily expanded over time than a bus or a star. On the other hand, this topology is more difficult to configure than the others and if the backbone line breaks, the whole network goes down.

Read the texts again and decide if the following statements are true (T) or false (F), then correct the false ones.

1 The topology chosen depends only on the location of computers.

2 All topologies use many cables and are very expensive.

3 In a bus topology all the buses are connected one after the other.

4 In a bus topology a server controls the flow of data.

5 In a star network data is always updated.

6 The hub doesn’t connect printers and other devices in a star topology.

7 In the ring topology each node is connected to the hub.

8 In the ring topology if the hub doesn’t work, the network goes down.

9 Star bus topology combines elements of bus and ring topologies.

10 In a star bus topology a backbone line failure affects the whole network.