Figure 3From: Motion artifact removal from photoplethysmographic signals by combining temporally constrained independent component analysis and adaptive filter Synthetic signals with different SNRs. (a1): Clean PPG signal- s(t); (a2): MA noise- MA(t); (a3)-(a5): Mixed signals- x(t) with SNR equaled to −5 dB, 0 dB, 5 dB respectively; (b1)-(b5): Frequency spectrum corresponding to (a1)-(a5).Back to article page