Patent ID: 7432760
Filing Date: 2008-10-07
Classification: H03F

Abstract:
1. A digital amplifier apparatus, comprising: gain-adjusting means for adjusting a gain of a digital audio signal; dither-superposing means for superposing a predetermined dither on the digital audio signal; pulse-width-modulated signal generating means for generating a pulse-width-modulated signal corresponding to the digital audio signal; amplifying means for causing a switching element to perform a switching operation in accordance with the pulse-width-modulated signal; pulse-width changing means for changing a ratio between a “high” state and a “low” state of the pulse-width modulated signal; and control means for performing a muting process by causing the gain-adjusting means to set the gain of the digital audio signal to a zero level, the dither-superposing means to stop superposing the dither, and the pulse-width changing means to change, step by step, the ratio between the “high” state and the “low” state of the pulse-width modulated signal toward the “low” state upon receipt of a predetermined muting signal for muting the digital audio signal, thereby maintaining the “low” state and stopping the switching operation performed in accordance with the pulse-width modulated signal.