Epicycloid 2 

This animation illustrate a mechanical realization of the harmonic synthesis of a general periodic signal.
Sine wave can be generated along epicycloids (i.e. the movement around a circle) ; see our previous video. The superposition of many of such mouvements happening at various frequencies, and each offset by a phase and scaled by an amplitude, can produce any periodic signal.
This animation is part of a joint article by Hajer Bahouri & François Vigneron about signal analysis (images.math.cnr....