After time-frequency analysis, we will get a complex number at a specific time-frequency point, which represents the useful information of magnitude and angle. Here, we discuss the analysis of intertrial EEG signals from the angular perspective.

1. The Average of Angles
   Firstly, of course the angles cannot be averaged like the values or powers, since they are circular, for example, pi equals to 3*pi, their averaged angle should be the same as them, but if you just take their average like the real numbers, you will get 2*pi, which is obviously wrong.
   So, how should we calculate the averaged angle? Let’s consider the complex vector.

2.