Short-Term Autocorrelation Analysis and Correlatograms of Spoken Digits
R. Biddulph · The Journal of the Acoustical Society of America · 1954
Autocorrelation techniques provide a method of displaying speech sounds in a form which differs significantly from conventional sound spectrograms. The autocorrelation function ψ11(τ), of a signal I(t) is defined by ψ11(τ) = LimitT→∞1T ∫ 0T I(t)I(t-τ)dt. Delay τ introduced in the speech signal appears as ordinate in these displays, time t as abscissa, and magnitude of the resulting correlation function ψ11(τ) is shown by the density of the pattern. Characteristic features of the displays are discussed and evaluated in terms of the mechanism of the correlation process. Data considered are limited to the ten spoken digits one, two, ⋯ nine, “oh.”