| 摘要 |
PURPOSE:To compose the arithmetic unit of minimum circuits by repeating addition and subtraction according to the shift quantity of an input and obtaining an optional coefficient value. CONSTITUTION:This unit consists of a shifter 11 which shifts an input signal, an arithmetic circuit 12 which performs arithmetic operation with the output of the shifter 11 and an output signal, a multiplexer 13 which selects an initial value with the output of the arithmetic circuit 12 and the output signal, and a register 14 which holds the output of the multiplexer 13 for a unit time. Then the shifter 11 operates in such a direction that the power of 2 is obtained and addition or subtraction is carried out only when a necessary shift quantity is obtained during the period and the arithmetic value is stored in the register 14. Then a shifter 11 operates in such a direction that one over the power of 2 is obtained, and addition or subtraction is performed by a necessary quantity to obtain a desired coefficient value. Consequently, the optional coefficient values are obtained without entailing an increase in circuit area. |
