The source signal power in time and frequency domain.

The 1 sec sample from intramuscular signal that was used as source signal is shown at the top (A). The total power of this signal is shown in the time domain (B) and in the frequency-time domain (C). From this plot it is possible to distinguish bursts of activity that occur during the isometric contraction. These are represented by high frequency peaks in the time domain, amplitude peaks in the power plot and red yellow region in the time-frequency domain. It can be seen that the power peaks are mainly at higher frequencies.