# Translations:Illustrations of spectra/1/en

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Let us now illustrate the spectra of different dipoles. We start with the *unit spike*: the coefficient 1 at time index 0. In terms of a two-length causal wavelet, the unit spike is (1, 0). The Fourier transform of (1, 0) is 1 for all . Hence, the amplitude spectrum of the unit spike is equal to one for all frequencies or, in other words, the amplitude spectrum is white. If we write 1 = 1 + 0 *i*, we see that the phase-lag spectrum of the unit spike is , which is zero for all . In other words, the unit spike has the minimum-phase spectrum, which is equal to zero for all frequencies.