Design of a photoplethysmographic sensor for biometric identification

Photoplethysmographic (PPG) signals contain rich personal information that can be used to distinguish individual subjects. This paper discusses the design of an analog amplification circuit for PPG signals to remove the DC component of the signal. By adding an amplifier bias-adjusting circuit, a high signal-to-noise ratio AC signal can be acquired from the raw PPG signal. This hardware improvement results in better signal quality and makes identification data-processing easier.