| 摘要 |
PURPOSE:To set the number of tap coefficients regardless of arithmetic processing ability within a sample period by updating tap coefficients with a filter input and an error signal, storing updated tap coefficients in plural memories, and updating the tap coefficients in plural divided sample periods. CONSTITUTION:When the number of tap coefficients is (n) and the update of tap coefficients is divided into two sample periods, (n) tap coefficients are divided into (m) and (n-m) and coefficient update is performed in every four sample periods. Tap coefficients a0-an-1 in a tap coefficient memory 9-1 are used in the 1st sample period and the arithmetic of a filter is performed by a filter arithmetic part; and tap coefficients b0-bm-1 in a tap coefficient memory 9-2 are updated on the basis of an equation I under the control of a tap coefficient updating circuit 10. Similarly, tap coefficients are updated on the basis of equations II, III, and IV in the 2nd, the 3rd, and the 4th sample periods under the control of the tap coefficient updating circuit 10. When the update of tap coefficients is divided into >=3 sample periods, the tap coefficients are updated similarly. |
