| 摘要 |
<p>PURPOSE:To obtain a device which can automatically control the roudness characteristics most suitably in response to an acoustic signal, by separating the acoustic signal into low, intermediate and high frequency components and controlling the level in response to the level of the intermediate frequency component. CONSTITUTION:An acoustic signal is separated into low, intermediate and high frequency components, and the level of each frequency component is controlled depending on whether high or low the level of the intermediate frequency component. For example, the acoustic signal applied to an input terminal 18 is separated into low, intermediate and high frequency components at a low pass filter 1, an intermediate pass filter 2, and a high pass filter 3, and each component is inputted to boost/cut filters 11, 12, comparison circuits 4, 5 and a level detection circuit 13. The comparison circuit 4 compares the intermediate and low frequency components, and an output in response to the level difference is generated, the intermediate and high frequency components are compared at the comparison circuit 5, and an output is given. Limit voltage generating circuits 14, 15 compare the output of the comparison circuits 4, 5 with that of the level detection circuit 13.</p> |
