Coherent Modulation Analysis of Photoplethysmographic Signal s by Time -varying Filterbank

Abstract

In spite of its usefulness to early detect cardiovascular disease, photoplethysmographic (PPG) signals are prone to motion artifacts due to its typical measurement locations. These artifacts consequently affect the reliability of systolic peak detection-based PPG parameter calculations. In this paper, the PPG signals are modeled by a small number (3 to 6) of Amplitude-Frequency Modulation (AM-FM) modulated signals such that the synthesis signal preserves its harmonics structure in time-frequency domain. We propose a coherent AM modulating signal detection by which the filterbank tracks Instantaneous Frequency (IF) of each harmonic component. This time-varying filterbank method offers bandwidth preservation of the AM components. Furthermore, the experimental results show that motion artifact (MA) noise reference for the input of the adaptive filter is generated from the corrupted PPG signal itself by using one of applications of our method.