Page 35 - Fundamentals of Communications Systems

Chapter
1

Introduction

The students who read this book have grown up with pervasive communica-
tions. A vast majority have listened to broadcast radio and television, used a
mobile phone, surfed the World Wide Web, and played a compact or video disk
recording. Hence there is no need for this book to motivate the student about
the utility of communication technology. They use it everyday. This chapter will
consequently be focused on the engineering aspects of communication technol-
ogy that are not apparent from a user perspective.

1.1 Historical Perspectives on Communication
Theory

The subject of this book is the transportation of information from point A
to point B using electricity or magnetism. This field was born in the mid-
1800s with the telegraph and continues today in a vast number of applications.
Humans have needed communications since prehistoric times for capitalistic
endeavors and the waging of war. These social forces with the aid, at various
points in time, of government-sponsored monopolies have continuously pushed
forward the performance of communications. It is perhaps interesting to note
that the first electronic communications (telegraphy) were sending digital data
(words were turned into a series of electronic dashes and dots). As the inven-
tion of the telephone took hold (1870s), communication became more focused
on analog communication as voice was the information source of most interest
to convey. The First World War led to great advances in wireless technology
and television and radio broadcast soon followed. Again the transmitted infor-
mation sources were analog. The digital revolution was spawned by the need
for the telephone network to multiplex and automatically switch a variety of
phone calls. A further technology boost was given during the Second World
War in wireless communications and system theory. The Cold War led to rapid
advances in satellite communications and system theory as the race for space

1.1
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