Patent ID: 8388543
Filing Date: 2013-03-05
Classification: A61B,G06F,G06K

Abstract:
1. A digital filtering method for estimating Time-Frequency Spectra (TFS) and associated amplitudes of a photoplethysmography (PPG) signal using Variable Frequency Complex Demodulation (VFCDM), the method comprising: obtaining a first TFS of the PPG signal by performing, with a controller, a time-varying optimal parameter search; performing, with the controller, the VFCDM with the first TFS of the PPG signal to obtain at least one variable frequency complex demodulation signal having improved TFS resolution and instantaneous amplitudes associated with only specific frequencies of interest; and simultaneously deriving, with the controller, a heart rate and a respiratory rate of a subject from the at least one variable frequency complex demodulation signal.