Fig. 1.

Schematics, showing a single wave period of a symmetric and an asymmetric waveform, having the same energy and the same time duration T of a single wave period. a Single wave period of a “symmetric waveform”. b Single wave period showing an adapted waveform in which the negative phase is flattened and spread out, while the positive phase is narrowed and higher (“asymmetric waveform”). The parameter β indicates the ratio of the duration of the long phase to the duration of the short phase