Satellite Technology: Principles and Applications, 3rd Edition

5Communication Techniques

In Chapters 1 to 4, after an introduction to the evolution of satellites and satellite technology, the principles of satellite launch, in-orbit operations and its functioning have been covered in detail followed by a detailed account of satellite hardware including various subsystems that combine to make the spacecraft. In Chapters 5, 6 and 7, the focus shifts to topics that relate mainly to communication satellites, which account for more than 80 % of satellites present in space, more than 80 % of applications configured around satellites and more than 80 % of the budget spent on development of satellite technology as a whole. The topics covered in the first of the three chapters, that is the present chapter, mainly include modulation and demodulation techniques (both analogue and digital) and multiplexing techniques, followed by multiple access techniques in the next chapter. Chapter 7 focuses on satellite link design related aspects. All three chapters are amply illustrated with a large number of solved problems.

5.1 Types of Information Signals

When it comes to transmitting information over an RF communication link, be it a terrestrial link or a satellite link, it is essentially voice or data or video. A communication link therefore handles three types of signals, namely voice signals like those generated in telephony, radio broadcast and the audio portion of a television broadcast; data signals produced in computer-to-computer communications; ...