| 摘要 |
PURPOSE:To reproduce a digital signal with high efficiency by weighting for correction by a bit split, to either a PCM-PWM converting part or a voice coil, in case of reproducing a PCM digital signal by a loudspeaker. CONSTITUTION:A PCM digital signal 1 of plural bits is supplied to PCM-PWM converters 2, 3 and brought to PWM. A PWM signal whose pulse width has been modulated by the converters 2, 3 is brought to power-switching by switching parts 4, 5, and supplied to voice coils 7, 8 of a loudspeaker 6, respectively. In case when winding ratios of the coils 7, 8 of the loudspeaker 6 are the same, the switching voltage is weighted so as to be switched by a prescribed voltage ratio in the upper bit side and the lower bit side, and the correction of a bit split is applied. Therefore, a clock frequency of the PCM-PWM conversion does not goes to high, and the PCM digital signal can be power-amplified and reproduced with high efficiency. |
