Observability of Spectral Components beyond Nyquist Limit in Nonuniformly Sampled Signals
Figure 8
HRV spectra obtained by means of different methods: (a)equidistantly repositioned HR samples with frequency axis scaled according to the mean heart period; unevenly sampled heart rate sequence resampled to evenly spaced signal- (b) cubic-spline interpolation, (c) nearest neighbour interpolation, (d) Berger method; spectra computed without resampling-, (e) Lomb-Scargle periodogram, (f) spectrum of counts.
