Table 2.

Maximum values of the cross bicoherence of the PPG2 signal with respect to tri-axis acceleration data.

Dataset	x-axis				y-axis				z-axis
	${\mathit{f}}_1$ (Hz)	${\mathit{f}}_2$ (Hz)	Coherence		${\mathit{f}}_1$ (Hz)	${\mathit{f}}_2$ (Hz)	Coherence		${\mathit{f}}_1$ (Hz)	${\mathit{f}}_2$ (Hz)	Coherence
data1	3.052	−1.587	0.568		4.517	−3.052	0.521		7.446	−5.981	0.595
data2	1.465	1.343	0.657		57.495	0.000	0.698		6.958	−4.150	0.641
data3	3.784	−2.563	0.506		2.441	−1.221	0.481		7.690	−6.470	0.507
data4	5.737	−4.272	0.631		4.273	−2.808	0.642		43.579	0.000	0.854
data5	49.927	−0.610	0.688		2.808	−1.343	0.664		61.401	0.000	0.743
data6	2.441	−1.221	0.682		2.441	−1.221	0.695		2.441	−1.221	0.698
data7	5.127	−3.784	0.742		2.686	−1.343	0.712		2.563	−1.221	0.728
data8	1.587	1.465	0.722		60.913	0.000	0.857		1.587	1.465	0.724
data9	7.202	−6.104	0.517		2.319	−1.221	0.610		57.739	0.000	0.757
data10	3.662	0.122	0.795		12.940	−0.122	0.935		3.784	0.366	0.915
data11	3.052	−1.465	0.631		58.838	0.122	0.919		7.446	−5.859	0.643
data12	2.930	−1.343	0.799		3.052	−1.465	0.795		4.395	−2.808	0.803