Reading and Speaking Practice Text a Networks

A collection of transmitters, receivers or transceivers that communicate with each other is known as a network. Digital networks may consist of one or more routers that route data to the correct user. An analogue network may consist 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 noise.

The shaping of a signal to convey information is known as modulation. Modulation can be used to represent a digital message as an analogue waveform. This is known as keying and several keying techniques exist.

Modulation can also be used to transmit the information of analogue signals at higher frequencies. This is helpful because low-frequency analogue signals cannot be effectively transmitted over free space. Hence the information from a low-frequency analogue signal must be superimposed on a higher-frequency signal (known as a carrier wave) before transmission. There are several different modulation schemes available to achieve this (two of the most basic being amplitude modulation and frequency modulation). An example of this process in action is a DJ's voice being superimposed on a 96 MHz carrier wave using frequency modulation (the voice would then be received on a radio as the channel “96 FM”).

Ex.3 Look through the text carefully and find if the statement above:

1. is not mentioned

2. is false

3. is true

1. A network consists of a number of devices sending and receiving signals and communicating with each other.

2. A DJ's voice being superimposed on a 96 MHz carrier wave using frequency modulation would then be received on a radio or television.

3. Used for long distances repeaters are to amplify or recreate the signal.

4. Almost any modulation scheme is able to transmit low-frequency analogue signals over free space effectively.

Ex.4 Answer the question: What can modulation be used for?

1. To transmit the information of analogue signals at middle frequencies.

2. To convert digital data into analogue form.

3. To route data to the correct user.

4. To superimpose on a higher-frequency signal before transmission.

Ex.5 Define the main idea of the text.

1. Types of network.

2. The components of digital networks.

3. The role of modulation in networks.

4. Different modulation schemes.

Text b Networking methods

Ex.1 Work in groups of three. Skim the passage and find information about:

Student A: Local area network

Student B: Wide area network

Student C: Wireless networks

Get ready to speak out in your group.

Networking is a complex part of computing that makes up most of the IT Industry. Without networks, almost all communication in the world would cease to happen. It is because of networking that telephones, televisions, the internet, etc. work.

One way to categorize computer networks are by their geographic scope, although many real-world networks interconnect Local Area Networks (LAN) via Wide Area Networks (WAN). These two (broad) types are: