TIME FREQUENCY MAPPING OF THE HEART-RATE, BLOOD-PRESSURE AND RESPIRATORY SIGNALS

The discrete Wigner distribution (DWD) was implemented for the time/frequency mapping of variations of R-R interval, blood pressure and respiratory signals. The smoothed cross-DWD was defined and the modified algorithm for the smoothed auto- and cross-DWD was proposed. Spurious cross-terms were suppressed using a smoothing data window and a Gauss frequency window. The DWD is easy to implement using the FFT algorithm . Examples show that the DWD follows well the instantaneous changes of spectral content of cardiovascular and respiratory signals which characterise the dynamics of autonomic nervous system responses.