  We propose two experiments suited for high school and/or undergraduate
physics laboratory which are aimed to the discovery of the practical meaning
and usefulness of the FFT analysis as a mathematical and graphical instrument,
intended to discriminate different periodic signals in various situations,
ranging from basic, demonstrative measurements to very complex, real-research
experiments. In our proposal, quite inexpensive digital instruments can be
used, yet with accurate out-of-the-box results.
