An apparatus for wireless communications is disclosed including a signal generator adapted to generate a substantially periodic signal including a plurality of cycles, and a modulator adapted to modulate an amplitude, a phase or both the amplitude and the phase of the periodic signal on a per cycle basis. In one aspect, the modulator is adapted to modulate the amplitude, the phase, or both the amplitude and phase of the periodic signal with a defined modulation signal. In another aspect, the defined modulation signal includes a substantially root raised cosine signal. In yet another aspect, the defined modulation signal is configured to achieve a defined frequency spectrum for the modulated periodic signal.