An electronic system for estimating a subject's blood pressure, comprising a feature extraction module configured for receiving a subject's photoplethysmogram signal, detecting a plurality of signal characteristic points on the received photoplethysmogram signal, calculating a plurality of distances in both time and amplitude between any two of the detected photoplethysmogram signal characteristic points, and providing a feature information signal comprising information about the calculated distances; and a blood pressure calculation module configured for receiving the photoplethysmogram signal, the feature information signal and anthropometric characteristics of the subject, and calculating systolic, diastolic and continuous mean blood pressure values of the subject.