Time Domain to Frequency Domain: Spectrum Analysis

Abstract

The concept of spectrum can be attributed to Isaac Newton, who, with the aid of a prism, discovered that sunlight can be decomposed into a spectrum of colors from red to violet in about 1700. This indicates that any light comprises numerous components of light of various colors (wave lengths). The earliest function most closely resembling the spectral density function was developed by Arthur Schuster, who investigated the presence of periodicities in meteorological [47], magnetic [48], and optical [49] phenomena. The spectrum provides a measure of the light’s intensity varied with respect to its wavelength. This concept has been generalized to represent many physical phenomena by decomposing them into their individual components.