Photoplethysmography signals acquisition technique using infrared sensors. GoudjilSabrina ImestourenFatiha ArmougonAurelie RazafimanantsoaLucie MahmoudzadehMahdi WalloisFabrice LékéAndré KongoloGuy 2014 <p>Acquired signals were used to compute pulse phases corresponding to preductal (right hand sensor) and postductal (foot sensor) regions and their difference, the PPD.</p>