Page 52 - DCAP406_DCAP_207_Computer Networks

Yadwin University Unit 4: Physical Layer-2

Unit 4: Physical Layer-2 Notes

CONTENTS
Objectives
Introduction

4.1 Wireless Transmission
4.1.1 Radio
4.1.2 Very Low Frequency (VLF)

4.1.3 Microwave Transmission
4.2 Satellite Communication
4.3 Public Switched Telephone Network
4.3.1 Digital Channel
4.3.2 Trunk Lines

4.4 Mobile Telephone System
4.5 Cable Television
4.6 Summary

4.7 Keywords
4.8 Review Questions
4.9 Further Readings

Objectives

After studying this unit, you will be able to:

Describe the wireless communication media like radio, microwave, VLF, etc. and its
applications
Discuss general properties of the different types of wireless communication systems

Describe Satellite communication with its general properties and applications
Describe concepts of public switched telephone network, digital channel and trunk lines
Know the underlying technologies of cable television and cable modem

Introduction

As you know that there are various ways to transmit the signal. These ways can be broadly
categorized into guided and unguided media. The guided media includes all wired media, also
referred to as conducted or bounded media. You have already studied about the guided/bounded
transmission media in the last unit. Now in this unit you will learn about the second category
which includes all traditional wireless media, also referred to as radiated, or unbounded. In the
transmission of signal the data is encoded to energy and then energy is transmitted. Similarly at
the receiving end the energy is decoded back to data. This energy can be electrical, light and
radio, etc. Therefore, this transmitted energy is carried through some sort of medium, which

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