[Representation of physiologic functions in the modulation domain ].

The axes: amplitude, frequency, time, define a trihedral where the most usual representations occur in time domain (plane defined by the axes amplitude-time). The frequency of an action with respect to time is represented in the plane defined by the axes frequency-time in the so called "Modulation Domain", it is being considered very useful, expressive and easy to construct in the automatic treatment of signals.