Characterization of the chronobiological signals based on the continuous wavelet transform

Chronobiology, which studies periodic patterns or rhythms in living beings, often needs to characterize the observed chronobiological time series (CTS) and to study the stability and adaptability of the periodic patterns in different environmental conditions. Fourier transform (FT) based methods and the complex demodulation (CD) approach have been widely used in such studies. However, the former lacks temporal resolution and the later needs to extract the temporal behaviors of individual frequencies. In this paper, we propose a new approach to characterize the CTS based on the continuous wavelet transform (CWT). It allows us to investigate the time-frequency dynamics of different rhythmic-band activities in the CTS simultaneously. Two application results are presented to illustrate the proposed method.