System and Method for Heart Rate Detection with Motion Artifact Reduction

An electronic device comprising an electronic system for heart rate detection, wherein the electronic system for heart rate detection comprises:

• a random sampling sensor module comprising:
• a first sensor circuit configured to provide nonuniform random samples below a Nyquist rate of a photoplethysmographic signal;
• and
• a second sensor circuit configured to provide nonuniform random samples below a Nyquist rate of a motion signal, wherein the motion signal is sampled with an equivalent nonuniform pattern as the photoplethysmographic signal;
• and
• a heart rate detection module configured to:
• receive a plurality of the nonuniform random samples below the Nyquist rate of the photoplethysmographic signal;
• calculate a power spectral density value set based on a Lomb-Scargle periodogram of the nonuniform random samples below the Nyquist rate of the photoplethysmographic signal;
• receive a plurality of the nonuniform random samples below the Nyquist rate of the motion signal;
• calculate a power spectral density value set based on a Lomb-Scargle periodogram of the nonuniform random samples below the Nyquist rate of the motion signal;
• normalize the calculated power spectral density value sets corresponding to the photoplethysmographic signal and the motion signal;
• subtract the normalized power spectral density value set corresponding to the motion signal from the normalized power spectral density value set corresponding to the photoplethysmographic signal;
• renormalize the power spectral density value set corresponding to the photoplethysmographic signal;
• and
• calculate a heart rate value based on a frequency corresponding to a highest power peak value of the calculated power spectral density value set corresponding to the photoplethysmographic signal in a frequency range of interest.

A method for heart rate detection comprising:

• receiving a plurality of nonuniform random samples below a Nyquist rate of a photoplethysmographic signal;
• receiving a plurality of nonuniform random samples below a Nyquist rate of a motion signal, wherein the motion signal being is sampled with an equivalent nonuniform pattern as the photoplethysmographic signal;
• calculating a power spectral density value set based on a Lomb-Scargle periodogram of the plurality of nonuniform random samples below the Nyquist rate of the photoplethysmographic signal;
• calculating a power spectral density value set based on a Lomb-Scargle periodogram of the plurality of nonuniform random samples below the Nyquist rate of the motion signal;
• normalizing the calculated power spectral density value sets corresponding to the photoplethysmographic signal and the motion signal;
• subtracting the normalized power spectral density value set corresponding to the motion signal from the normalized power spectral density value set corresponding to the photoplethysmographic signal;
• renormalizing the power spectral density value set corresponding to the photoplethysmographic signal;
• detecting a frequency corresponding to the highest power peak value of the power spectral density value set corresponding to the photoplethysmographic signal in a frequency range of interest;
• and
• calculating a heart rate value based on the detected frequency.