 of four Gaussian components\' signal.](sensors-00-00000f0){#f0-sensors-00-00000}  ![Wigner--Ville distribution of four Gaussian components\' signal.](sensors-00-00000f0){#f0-sensors-00-00000}  ![Pseudo Wigner--Ville distribution of four Gaussian components\' signal.](sensors-00-00000f0){#f0-sensors-00-00000}  ![