| 摘要 |
PURPOSE:To improve sound quality while effectively removing howling. CONSTITUTION:A howling detection signal is received from a howling detection means 30, a howling removing filter means 28 is operated and the howling is removed. Thereafter, the gain of a test signal mixed in a sound by a mixing means 34 is lowered by a gain adjusting means 24 and when it becomes equal to or less than a threshold value, a howling stopping signal is outputted from a test signal reduction detection means 36. The howling stopping signal is received and the operation of the howling removing filter means 28 is stopped. Thus, the howling is automatically removed when the howling is generated in the sound signal, the operation of the howling removing filter means 28 is automatically prevented when the howling is stopped, the degradation of high band frequency characteristics is prevented and the sound quality can be improved. |
