| 摘要 |
PURPOSE:To reduce noise in an audible sense with simple constitution by setting a characteristic of a noise filter to a characteristic in which a quantization error reduction processing in response to an equi-loudness curve is implemented and a processing to reduce the quantity error in a low frequency component is decreased. CONSTITUTION:A filter characteristic of a noise filter 13 is set to a filter characteristic, in which a noise shaping processing in response to an equi-roundness curve RC in response to a human audible sense characteristic and to decrease a quantity error for a low frequency component are implemented. Thus, it is possible to easily calculate a filter coefficient and to reduce noise in an audible sense with simple constitution. Thus, when the quantization error reduction device is applied to, e.g. a digital audio equipment whose standards are unified, a reproduction sound with a higher dynamic in an audible sense is obtained than the dynamic range obtained actually according to the unified standards. |
