| 摘要 |
PURPOSE:To reduce discomfort by providing a 1/f filter generating an additional sound signal corresponding to the noise detected by a microphone and proportionating the power spectrum of the additional sound signal inversely to the frequency. CONSTITUTION:The noise is detected by a microphone 1, amplified by an amplifier circuit 1, converted to a digital signal by an A/D conversion circuit, and outputted to an additional sound signal generation part 3. Whether the noise is actually eliminated near a man 5 or not is detected by a microphone 4, and based on the detected sound, a digital filter 14 performs feedback control. The output of the filter 14 passes through a 1/f filter 16 after being converted to an analog signal by a D/A conversion circuit 15, and the additional sound signal proportionating the distribution of the power spectrum inversely to the frequency is outputted from a loud-speaker 2. Thus, even when the additional noise is heard because the noise can not be canceled enough by interference, the discomfort can be reduced by making the 1/f noise close to natural noise different from artificial noise. |
