| 摘要 |
<p>PURPOSE:To reduce the non-linearity of an impulse reponse by making a filter coefficient reverse by means of a hierarchy in a system which hierarchically uses two division sub-band filter banks and divides them into sub-bands. CONSTITUTION:The two division sub-band filter banks 50-1, 50-b and 50-a are hierarchically used and they are divided into the multiple sub-bands. The same low pass filter and high pass filter are used in all the two division filter banks 50, and the coefficient order of the filters is made reverse by the hierarchy. When the filter whose filter coefficient is made reverse is put on the bank 50-b after the non-linear filter is put on the bank 50-a, the non-linearity of a phase is cancelled. Thus, the non-linearity of the final impulse response can be suppressed by making the order of the filter coefficient reverse by the hierarchy.</p> |
