| 摘要 |
PURPOSE:To attain efficient coding by monitoring a signal level and adaptively controlling the regulated value of a minimum audible level and threshold level. CONSTITUTION:An input signal is segmented to a prescribed orthogonally transformed length by a window means 1, inputted to the succeeding orthogonal transforming means 2 and power calculating means 3, orthogonally transformed by the means 2 and then outputted to the succeeding cutting-off means 5. The power level of the input signal is calculated by the means 3 also in the section of the orthogonally transformed length or a longer section and the calculated level is outputted to the means 5 together with data obtained from aduible characteristic data 4. The minimum audible level regulated value of hearing sense on a frequency axis after the orthogonal transformation is adaptively controlled by the means 5 in accordance with the inputted power level. Consequently, the proper minimum audible value can be always regulated and the number of codes can be reduced. |
