The Bi-Spectrum: Some Properties in Relation to Multiple Rhythm

Some properties of the bi-spectrum are derived and compared to those of the (mono-) spectrum (spectral density function). The advantages and disadvantages of the bi-spectrum are illustrated with the help of a model. When studying a rhythm with multiple dominant frequencies, the ordinary spectrum indicates the value of these frequencies and their bandwidth. It is shown that the bi-spectrum, in addition, provides information about the degree of eventual coupling between the components.