Work Step by Step
Fourier discovered that any periodic wave pattern, no matter how complex, can be built up by adding sine waves of different frequencies. This is discussed on page 398. A Fourier analyzer decomposes (breaks up) a complex pattern into its sine wave components. The human ear can do that too; if a high-frequency piccolo is played alongside a low-frequency bass guitar, you can make out the individual pure tones that make up the complex soundwave.