Disclosed examples include heart rate monitor systems and methods to estimate a patient heart rate, in which a processor filters digital photoplethysmogram (PPG) sample values representing transmission or reflection of a light signal in the patient during a time window, performs motion compensation processing on the filtered values, computes a gain value for individual segments of the time window using the motion compensated values, applies the individual gain values to the motion compensated values of blocks associated with the corresponding segments, and determines a heart rate estimate value representing the patient heart rate according to the frequency content of the adjusted values.