The above was not clear to me.
A spectrogram (from Wikipedia) is:
A common format is a graph with two geometric dimensions: one axis represents time, and the other axis represents frequency; a third dimension indicating the amplitude of a particular frequency at a particular time is represented by the intensity or color of each point in the image.
When doing a polar plot\sweep the radius is the frequency, the angle sweeps with the passage of time and the amplitude of a particular frequency can be represented with a color.
:)