Pulse oximeter waveform

Common pulsatile signals on a pulse oximeter.
(A) Normal signal showing the sharp waveform with a clear dicrotic notch.
(B) Pulsatile signal during low perfusion showing a typical sine wave.
(C) Pulsatile signal with superimposed noise artifact giving a jagged appearance.
(D) Pulsatile signal during motion artifact showing an erratic waveform.