ABSTRACT
The Fourier transform is referred to as a frequency-domain transform to make solution, design, and analysis of linear systems simpler. It also gives some insights about the frequency contents of signals where these insights are harder to see in real-time systems. The chapter discusses the properties of the Fourier transform based on different solutions. Before one sends an information signal through a communication medium, the information signal is converted to another signal via a process called modulation. The chapter discusses the energy of nonperiodic signals and the energy spectral density of a linear system. Fourier series are limited as to their use. They only represent signals of periodic nature. Many important functions like the isolated pulse and the decaying exponential are nonperiodic and therefore cannot be represented by the Fourier series.
