Figure 4

Example of skin–electrode interface impedance and the motion artifact signal of one experiment session, and a close up of the ECG during the same session. a The first 25-s of the graph shows the effect of increasing the speed of motion while keeping the amplitude almost constant (see Figure 1). After a 1-s pause, the second 25-s segment shows the effect of motion with amplitude and speed increasing in the same ratio. b The ECG affected by the motion artifact. The y-axis scale of the ECG and the motion artifact in are same while the scale of the x-axis of the ECG has been increased by a factor of 4 relative to the x-axis of the motion artifact to better present the ECG components. The signals are filtered between 0.2 and 40 Hz.