The influence of the photoplethysmographic sensors passband to the possibility of analyzing of low-frequency processes of autonomic control

We developed a digital broadband finger photoplethysmogram (PPG) sensor and compared its characteristics with a standard certified PPG recorder. During testing, we recorded the frequency responses (FR) of the sensors, and also compared the spectrums of the PPG signals recorded synchronously. An example of a system based on a microcontroller is also given, with the helped to record PPG signal. The study is important for understanding the influence of the passband of the PPG sensor and the bit depth of the analog-to-digital converter (ADC) of PPG sensor on the possibility of analyzing the synchronization of low-frequency processes of autonomic regulation.