| 摘要 |
PROBLEM TO BE SOLVED: To suppress generation of beat noise without compromising performance in using a self-oscillating class D amplifier as an amplifier for amplifying an audio signal of each channel.SOLUTION: N self-oscillating class D amplifiers 11-1, 11-2, 11-3, ..., 11-N are configured with a controllable switching frequency. Frequency counters 12-1, 12-2, 12-3, ..., 12-N measure the switching frequency of the respective self-oscillating class D amplifiers 11-1, 11-2, 11-3, ..., 11-N. A control circuit 13 controls the self-oscillating class D amplifiers 11-1, 11-2, 11-3, ..., 11-N to match the switching frequency on the basis of values of the switching frequency measured by the respective frequency counters 12-1, 12-2, 12-3, ..., 12-N. This can prevent generation of beat noise due to a difference in the switching frequency. |
