| 摘要 |
PURPOSE:To execute such a compression control as a viewer does not feel it noisy, by detecting a data corresponding to a level component exceeding a prescribed level of an analog data, from a digital data, and also, generating a data corresponding to a zero crossing point, and controlling an attenuation quantity of the analog data by multiplying the digital data by a prescribed coefficient. CONSTITUTION:An output of an OR gate circuit 14 and an output of an EX-OR circuit 18 are supplied to a counter 20. This counter 20 counts the number of times by which a level of an analog audio signal go to a state exeeding a prescribed level, and the number of times by which the output of the EX-OR circuit 18 goes to an H level. In a ROM 21, a coefficient table in which a prescribed attenuation ratio epsilon is stored in advance is formed in an address designated by a count value of the counter 20. Therefore, from the address designated by the count value of the counter 20, a coefficient having the prescribed attenuation rotio epsilon is outputted to a multiplying circuit 22. In such a way, the multiplying circuit 22 multiplies the inputted coefficient and an input digital data, and the input digital data is attenuated by a prescribed quantity and outputted, and the dynamic range compression quantity is controlled. |
