Gabor's expansion of a signal into a discrete set of properly shifted and modulated versions of an elementary signal is introduced, and it is shown how the expansion coefficients can be determined via the Zak transform. An arrangement is described which is able to generate Gabor's expansion coefficients of a rastered, one-dimensional signal by coherent-optical means.
KEYWORDS: Gabor expansion, Zak transform, local frequency spectrum, phase-space signal description, sliding-window spectrum, windowed Fourier transform.