
Application to biomedical signals 201
FIGURE 4.46: Plots of 8-s duration signal showing the output from the four post-
processing methods. (A) Hilbert. (B) ICA. (C) Hilbert + ICA. (D) Filtered. In (B),
the ICA component shows a momentary polarity inversion that results in missed
beats. In (C), the Hilbert method applied to ICA components removes the polarity
inversion. From [Wilson et al., 2008, Fig. 6].
4.3.1 Measurement techniques and physiological background
The EMG characteristics depend on the kind of applied electrodes. EMG may be
recorded by means of intramuscular (needle or fine wire) or surface electrodes. The
range of measured potential difference ...