Fourier’s heat-transfer theorem now underpins all periodic signal analysis

Evidence

Jean Baptiste Joseph Fourier (1768–1830) worked on a mathematical model of heat transfer in solid bodies (among many other topics). His thesis On the Propagation of Heat in Solid Bodies was published in 1807 and contained a novel idea for expanding a continuous function as a trigonometric series. Although Fourier developed this as a part of his model for heat transfer, it has a much wider application. Fourier’s Theorem is now usually stated as: Any periodic function can be represented as an infinite sum of harmonic sinusoids multiplied by appropriate coefficients. — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 2732

Categorization

• XREF: Connects the psychoacoustics of harmonic spectra straight back to a purely physical problem of heat diffusion — a historical lineage worth tracing.