Finger PPG shape changes when performing different external cuff pressure with a long cuff

The data was from 100 healthy normotensive volunteers. For each subject, five separate finger PPG signals were recorded, each with a different external cuff pressure (0, 10, 20, 30 and 40 mmHg) applied to the whole right arm through the long cuff, with a 1 min gap for rest between each recording.The finger PPG was recorded at a sample rate of 2500 Hz for 120s.