PPG signal processing for pulse delay computing by using adaptive comb filter

Abstract

Pulse delay is measured between ECG signal R-peak and 50% of PPG signal rising front value. Registered PPG signal can be with low noise-to-signal ratio. For better PPG rising front detection, the PPG signal is preprocessed with adaptive comb filter, which is using ECG signal as reference. Comb filter averages the signal over constant number of periods. Due to it, the computed result for pulse delay is averaged as well.