[Time variant bispectral analysis based on adaptive recursive Fourier transformation].

An appropriate investigation of quadratic phase couplings (QPC) in non-stationary signals requires time-variant methods of bispectral analysis. A new approach for time-variant estimation of power spectrum and bispectrum based on an adaptively, recursively estimated Fourier transform (ADFT) is presented in this paper. A reduced calculation effort and the possibility of the calculation of the bispectrum for selected frequency triples are important advantages of this method. Because of the recursive calculation, the ADFT is convenient for analysing ongoing signals. This will be demonstrated for simulated and real biomedical signals.