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

МИНИСТЕРСТВО ОБРАЗОВАНИЯ И НАУКИ РОССИЙСКОЙ ФЕДЕРАЦИИ МИРЭА – РОССИЙСКИЙ ТЕХНОЛОГИЧЕСКИЙ УНИВЕРСИТЕТ Т.В. КУДИНОВА, Н.А.МИРОЛЮБОВА, Н.В.ДИДЫК АНГЛИЙСКИЙ ЯЗЫК Учебно-методическое пособие по английскому языку для специалистов и бакалавров 2 курса института РТС. Москва – 2019

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Кудинова Т.В., Миролюбова Н.А, Дидык Н.В. Английский язык: учебно-методическое пособие по английскому языку для специалистов и бакалавров 2 курса института РТС. / Кудинова Т.В., Миролюбова Н.А., Дидык Н.В. — М.: МИРЭА – Российский технологический университет, 2019. — 65 с.

Разработано в помощь специалистам и бакалаврам института РТС для развития навыков работы с английскими текстами по специальности, для улучшения монологической речи, практического овладения профессиональной терминологией.


Рекомендовано к изданию на заседании кафедры Иностранных языков, протокол № 8 от 17.04.2019г.
Авторский коллектив:

Кудинова Татьяна Викторовна, старший преподаватель кафедры иностранных языков РТУ МИРЭА

Миролюбова Наталья Алексеевна, старший преподаватель кафедры иностранных языков РТУ МИРЭА

Дидык Наталья Валерьевна, старший преподаватель кафедры иностранных языков РТУ МИРЭА

Рецензенты:

Склизкова Екатерина Владимировна

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, кандидат культурологических наук, доцент, зав. Кафедрой лингвистики и межкультурной коммуникации Института славянской культуры РГУ им. Косыгина

Васильев Андрей Георгиевич, доктор физико-математических наук, профессор, директор института Радиотехнических и телекоммуникационных систем.


Table of contents

Unit 1

Text A

Telecommunications
Telecommunication is the transmission of signs, signals, messages, words, writings, images and sounds or information of any nature by wire, radio, optical or electromagnetic systems.

Telecommunication occurs when the exchange of information between communication participants includes the use of technology. It is transmitted either electrically over physical media, such as cables, or via electromagnetic radiation. Such transmission paths are often divided into communication channels which afford the advantages of multiplexing.

The Latin term communication is considered the social process of information exchange, the term telecommunications is often used in its plural form because it involves many different technologies.
Key concepts

Modern telecommunication is founded on a series of key concepts that experienced progressive development and refinement in a period of well over a century.

Basic Telecommunication technologies may primarily be divided into wired and wireless methods.

Overall though, a basic telecommunication system consists of three main parts that are always present in some form or another:

• A transmitter that takes information and converts it to a signal.

• A transmission medium, also called the physical channel that carries the signal. An example of this is the "free space channel".

• A receiver that takes the signal from the channel and converts it back into usable information for the recipient.

For example, in a radio broadcasting station the station's large power amplifier is the transmitter; and the broadcasting antenna is the interface between the power amplifier and the "free space channel". The free space channel is the transmission medium; and the receiver's antenna is the interface between the free space channel and the receiver. Next, the radio receiver is the destination of the radio signal, and this is where it is converted from electricity to sound for people to listen to.

Sometimes, telecommunication systems are "duplex" (two-way systems) with a single box of electronics working as both a transmitter and a receiver, or a transceiver. For example, a cellular telephone is a transceiver. The transmission electronics and the receiver electronics within a transceiver are actually quite independent of each other. This can be readily explained by the fact that radio transmitters contain power amplifiers that operate with electrical powers measured in watts or kilowatts, but radio receivers deal with radio powers that are measured in the microwatts or nanowatts. Hence, transceivers have to be carefully designed and built to isolate their high-power circuitry and their low-power circuitry from each other, as to not cause interference.

Telecommunication over fixed lines is called point-to-point 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 low-power but sensitive radio receivers.

Telecommunications in which multiple transmitters and multiple receivers have been designed to cooperate and to share the same physical channel are called multiplex systems. The sharing of physical channels using multiplexing often gives very large reductions in costs, Multiplexed systems are laid out in telecommunication networks, and the multiplexed signals are switched at nodes through to the correct destination terminal receiver.

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Analog versus digital communications.

Communications signals can be sent either by analog signals or digital signals. There are analog communication systems and digital communication systems. For an analog 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 (for example, a set of ones and zeros). During the propagation and reception, the information contained in analog signals will inevitably be degraded by undesirable physical noise. (The output of a transmitter is noise-free for all practical purposes. ) Commonly, the noise in a communication system can be expressed as adding or subtracting from the desirable signal in a completely random way. This form of noise is called additive noise, with the understanding that the noise can be negative or positive at different instants of time. Noise that is not additive noise is a much more difficult situation to describe or analyze, and these other kinds of noise will be omitted here. On the other hand, unless the additive noise disturbance exceeds a certain threshold, the information contained in digital signals will remain intact. Their resistance to noise represents a key advantage of digital signals over analog signals.
Telecommunication networks.

A telecommunications network is a collection of transmitters, receivers and communication channels that send messages to one another. Some digital communications networks contain one or more routers that work together to transmit information to the correct user. An analog communications network consists of one or more switches that establish a connection between two or more users. For both types of network, repeaters may be necessary to amplify or recreate the signal when it is being transmitted over long distances. This is to combat attenuation that can render the signal indistinguishable from the noise. Another advantage of digital systems over analog is that their output is easier to store in memory, i.e. two voltage states (high and low) are easier to store than a continuous range of states.

Communication channels.

The term “channel” has two different meanings. In one meaning, a channel is the physical medium that carries a signal between the transmitter and the receiver. Examples include the atmosphere for sound communications, glass optical fibers for some kinds of optical communications, coaxial cables for communications by means of the voltages and electric currents in them, and free space for communications using visible light, infrared waves, ultraviolet light, and radio waves. Coaxial cable types are classified by RG type or “radio guide”, terminology derived from World War II. The various RG designations are used to classify the specific signal transmission applications. This last channel is called the “free space channel”. Sending radio waves from one place to another has nothing to do with the presence of an atmosphere between the two. Radio waves travel through a perfect vacuum just as easily as they travel through air, fog, clouds, or any other kind of gas.

The other meaning of term “channel” in telecommunications is seen in the phrase communications channel, which is a subdivision of a transmission medium so that it can be used to send multiple streams of information simultaneously. For example, one radio station can broadcast radio waves into free space at frequencies in the neighborhood of 94.5 MHz (megahertz) while another radio station can simultaneously broadcast radio waves at frequencies in the neighborhood of 96.1 MHz. Each radio station would transmit radio waves over a frequency bandwidth of about 180 kHz (kilohertz), centered at frequencies such as the above, which are called the “carrier frequencies”. Each station in this example is separated from its adjacent stations by 200 kHz, and the difference between 200 kHz and 180 kHz (20 kHz) is an engineering allowance for the imperfections in the communication system.

In the example above, the “free space channel” has been divided into communications channels according to frequencies, and each channel is assigned a separate frequency bandwidth in which to broadcast radio waves. This system of diving the medium into channels according to frequency is called “frequency-division multiplexing”. Another term for the same concept is “wavelength-division multiplexing”, which is more commonly used in optical communications when multiple transmitters share the same physical medium. Another way of dividing a communications medium into channels is to allocate each sender a recurring segment of time (a “time slot”, for example, 20 millisecond out of each second), and to allow each sender to send messages only within its own time slot. This method of diving the medium into communication channels is called “time-division multiplexing” (TDM), and is used in optical fiber communication. Some radio communication systems use a hybrid of TDM and FDM.

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Task 1. Read and translate text A.

Task 2. Give the Russian equivalents of the following expressions:

radio broadcasting station, power amplifier, the transmission medium, broadcasting antenna, interference, broadcast communication, sensitive radio receivers, combat attenuation, frequency-division multiplexing, wavelength-division multiplexing, time-division multiplexing, to convey information

Task 3. Complete the following sentences using text A.

1. Telecommunication is the transmission of…

2. Such transmission paths are often divided into…

3. In a radio broadcasting station the station’s…

4. The free space channel is…

5. Telecommunication over fixed lines is called…

6. Communications signals can be sent…

7. Commonly, the noise in a communication system can be …

8. A telecommunication network is a collection of…

9. In one meaning, a channel is the physical…

Task 4. Make up your questions to text A, ask your partners.

Task 5. Using the material of the text above, write the main points. Use the following conversation phrases:

I think it is important…, Generally speaking…, It is interesting to know…

Task 6. Write the summary of text A.

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Text B

Principles of Wireless Communications
Wireless communications begin with a message that is converted into an electronic signal by a device called a transmitter. The transmitter uses an oscillator to generate radio waves. The transmitter modulates the radio wave to carry the electronic signal and then sends the modified radio signal out through space, where it is picked up by a receiver. The receiver decodes, or demodulates, the radio wave and plays the decoded message over a speaker. Wireless communications provide more flexibility than wire-based means of communication. However, there are some drawbacks. Wireless communications are limited by the range of the transmitter (how far a signal can be sent), and since radio waves travel through the atmosphere, they can be disturbed by electrical interferences (such as lightning) that cause static.

Wireless communications systems involve either one-way transmissions, in which a person merely receives notice of a message, or two-way transmissions, such as a telephone conversation between two people. An example of a device that sends one-way transmission is a pager, which is a radio receiver. When a person dials a pager number, the pager company sends a radio signal to the desired pager. The encoded signal triggers the pager circuitry and notifies the customer carrying the pager of the incoming call with a tone or a vibration, and often the telephone number of the caller. Advanced pagers can display short messages from the caller, or provide news updates or sports scores.

Two-way transmissions require both a transmitter and a receiver for sending and receiving signals. A device that functions as both a transmitter and a receiver is called a transceiver. Cellular radio telephones and two-way radios use transceivers, so that back-and-forth communication between two people can be maintained. Early transceivers were very large, but they have decreased in size due to advances in technology. Fixed-base transceivers, such as those used at police stations, can fit on a desktop, and hand-held transceivers have shrunk in size as well. Several current models of hand-held transceivers weigh less than 0.2 kg (0.5 lb).
Modes of Wireless Communications

Wireless communications systems have grown and changed as technology has improved. Several different systems are used today, all of which operate on different radio frequencies. New technologies are being developed to provide greater service and reliability.

Air Transceivers

Radio operators still monitor distress channels, but maritime and aviation telecommunications systems now use high-frequency radios and satellites capable of transmitting speech, rather than wireless telegraphy, to send messages. Aircraft pilots use radios to communicate with air traffic controllers at airports and also to communicate with other pilots. Navigation beacons are equipped with transmitters that send automated signals to help ships and aircraft in distress determine their positions. While high-frequency radio can transmit signals over long distances, the quality of these signals can be diminished by bad weather or by electrical interference in the atmosphere, which is often caused by radiation from the sun.
Hand-Held Radio Transceivers

Police, fire, and other emergency organizations, as well as the military, have used two-way wireless radio communication since the 1930s. Early vehicle-based radios were large, heavy units. After the invention of the transistor in 1948, radios shrank in size to small hand-held radio transceivers, which civil authorities now use to communicate with each other directly. Public two-way radios with several frequency options are widely available as well. Usually limited in range to a few miles, these units are great aids for such mobile professionals as construction workers, film crews, event planners, and security personnel. Simpler two-way radios, called walkie-talkies, have been popular children's toys for years.
Shortwave

Long-range broadcast services and frequencies, in what is known as the shortwave radio band (with frequencies of 3 to 30 megahertz), are available for amateur or ham radio operators. Shortwave radio broadcasts can travel long distances because of the concentration of ionized, or electrically charged, particles in the layer of the atmosphere known as the ionosphere. This layer reflects radio signals, sending signals that are transmitted upward back to earth. This skipping of waves against the ionosphere can greatly increase the range of the transmitter. The degree of reflectivity of the ionosphere depends on the time of day.

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