| 摘要 |
PURPOSE:To eliminate unnaturality of switching, by deciding a switching timing of coefficients of prestored transfer functions based on the output of a digital filter. CONSTITUTION:A digital filter device consists of by adders 1, 2, multipliers, 4, 5, 8, 9, 10, ROM6 storing the coefficients of a transfer function, a coincidence circuit 11, and a latch 16. A ROM6 is addressed by the cut-off frequency data from the latch 16, coefficients a1, a2, b1, b2, (k) are selected and they are applied to the multipliers 4, 5, 8, 9, 10. When a cut-off frequency fc is changed, the latch 16 stores the fc with a read-in signal R from the coincidence detecting circuit 11, the addressing of the ROM is made and the coefficients are changed. Thus, the transient effect is minimized and the unnaturality at switching can be reduced. |
