| 摘要 |
PROBLEM TO BE SOLVED: To reduce masking over high frequency components by low frequency components of sound and to relax requirements of an amplifier for the high frequency components. SOLUTION: A processing circuit is provided with a level reduction circuit 15 that reduces a level of a lower frequency component of a received audio signal, a 1st detection circuit 23 that detects a start point of a high frequency component of the audio signal, a 2nd detection circuit 23 that detects an end point of the high frequency component of the audio signal, and a level control circuit 24 that controls a degree of level reduction by the level reduction circuit 15 according to an output detected by the detection circuit 23. The level control circuit 24 gives a control signal to allow the level reduction circuit 15 to increase the level reduction degree when the detection circuit 23 detects the start point of the high frequency component and gives a control signal to allow the level reduction circuit 15 to restore the level reduction degree when the detection circuit 23 detects the end point of the high frequency component. |
