| 摘要 |
PROBLEM TO BE SOLVED: To provide a high-degree digital filter with a small circuit scale and less power consumption. SOLUTION: A 6-degree IIR type digital filter is provided with two variable multiple multiplier circuits 11, 12 placed in a feedback loop section, three variable multiple multiplier circuits 13-15 placed in a cyclic loop section, four adder circuits 16-19 that conduct sum arithmetic operation in the feedback loop section and the cyclic loop section and two delay circuits 21, 22 that are shared in common by the feedback loop section and the cyclic loop section. Furthermore, a delay circuit 23 latches an output of the adder circuit 18 when the adder circuit 18 outputs the result of multiplication and addition by using each multiple. A multiplexer circuit 25 selects either of a received digital signal and an output of the delay circuit 23 and outputs the selected signal. Thus, in this digital filter, after multiplication and addition are repeated, a digital filter output with a desired degree is obtained. |
