PURPOSE: A method and apparatus for outputting audio signal are provided to create modulation signals for stacking some parts of time domain which has a high level state. CONSTITUTION: A receiver(110) receives an audio signal. A carrier wave generating unit(120) creates carrier waves with different phase. A modulation signal generator(130) generates modulated signals by comparing the carrier waves with the audio signal. An amplifier(140) amplifies the modulated signals. An output unit(150) outputs the amplified modulated signals. The modulated signals have a first or a second logic state.
