Chapter 5 – Communications

Publisher Summary This chapter focuses on electromagnetic amplitude and phase as well as frequencies and wavelengths. Amplitude represents the amount of energy or power the wave contains, and phase indicates where along the wave form one is at any particular time. Electromagnetic waves are used for communication purposes to carry out information between locations. This chapter discusses these properties and phenomena that also apply to remote sensing and satellite navigation. Modulation is the means by which information is impressed on electromagnetic radiation so that it may be transmitted from one location to another. There are at least two different components of a communications signal, the carrier wave and the baseband signal. The baseband information must be impressed onto the carrier wave for propagation between stations. In all cases, some characteristic of the carrier wave, such as amplitude or frequency is modified to represent the baseband information whether it is in analog or digital form. It discusses modulation techniques using analog baseband signals and digital communication techniques.