Resumen de Time-Frequency Analysis: What We Know and What We Don’t
We discuss the basic ideas and motivations of time-frequency analysis from the point of view of what is known, what is not, what is mathematically possible, and what is not. We address the issue of whether a fully consistent theory of time-varying spectra is possible and the arguments given against the possible formulation of a proper theory. Historically, discussions of joint densities in time and frequency have been intimately tied with the question of the existence of manifestly positive joint densities, the marginals, and the uncertainty principle. We discuss the relations between these ideas.
