Bicoherence: Difference between revisions

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== Bispectrum ==
== Bispectrum ==


Denoting the Fourier transforms of the signals ''X<sub>i</sub>(t)'' by
The Fourier transforms of the signals ''X<sub>i</sub>(t)'' are denoted by


:<math>\hat X_i(\omega)</math>
:<math>\hat X_i(\omega)</math>


the bispectrum is defined as
Thus, the bispectrum, computed as the Fourier transform of the bicorrelation ''C<sub>2</sub>'', becomes:


:<math>B(\omega_1,\omega_2) = \hat X_1^*(\omega)\hat X_2(\omega_1) \hat X_2(\omega_2)</math>
:<math>B(\omega_1,\omega_2) = \hat X_1^*(\omega)\hat X_2(\omega_1) \hat X_2(\omega_2)</math>
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:<math>\omega = \omega_1 + \omega_2</math>
:<math>\omega = \omega_1 + \omega_2</math>
Hence, the bispectrum is interpreted as a measure of the degree of three-wave coupling.


== Bicoherence ==
== Bicoherence ==