ABSTRACT
In 1822, the French mathematician J.B. Fourier, while studying problems in the ¯ow of heat, showed that any arbitrary periodic function could be represented by an inšnite sum of sinusoids of harmonically related frequencies. Several words in this sentence need clarišcation at this point. A continuous function f(t) is said to be periodic with period T if f(t) = f(t + T) for any T. Several functions that fulšll this requirement are shown in Figure 7.1.
