A system and method for displaying an interactive screen, such as an end-user license agreement or verification form, on the graphic display of a wireless device when the wireless device connects to a network server on a wireless network and attempts to access or download software applications and data. The system is preferably operated with an odd number of phases, to reduce system bias error due to the higher order harmonics, while maintaining good modulation contrast, without unduly increasing system memory requirements. A sensor measures the RF signal provided to the load and outputs signals that vary in accordance with the RF signal.