THE WHALE FORGETTING FACTOR IN RECURSIVE AR SPECTRAL-ANALYSIS OF HEART-RATE-VARIABILITY SIGNALS

Spectral parameters extracted from the heart rate variability signal a re obtained on a beat-to-beat basis by means of autoregressive recursi ve identification, In this paper a whale forgetting window is introduc ed, instead of the classical exponential one, in order to reduce the n oise influence on the estimated parameters, After proper simulation it was found that the whale forgetting window markedly reduces the noise in the identification, but maintains a good response to abrupt change s in the signal. The algorithm was thus applied to the analysis of the HRV data recorded during different transient situations in physiologi cal and pathological conditions, The spectral parameters were obtained on a beat-to-beat basis and their trends were smoother and more accur ate with respect to the traditional exponential window also in presenc e of noise or artifacts in the time series (sudden and short time chan ges, ectopic beats, etc.), without losing the signal variations of phy siological interest.