| 摘要 |
PROBLEM TO BE SOLVED: To provide a digital filter which can deal with the change of the number of stages via the setting from a host with no redesigning and also releases the host during filter processing to attain the parallel execution of other processes. SOLUTION: This digital filter device includes a host interface 112 which can set a multiplication coefficient and data via a host 108 and also can transfer the data to the host 108, the memories 113 and 114 which store the multiplication coefficient and the data respectively, an arithmetic circuit 118 which executes the filter processes to the multiplication coefficient and data and a control circuit 115 which performs control to successively execute the filter operations of at least two or more stages of different multiplication coefficients. In such a constitution, the interface 112 has the number of filter stages setting register 123 which can be written via the host 108 and the circuit 115 has the number of stages counter 125 in addition to an end deciding circuit 124 which reads the multiplication coefficient of the necessary number of stages and the data out of the memories 113 and 114 and transfers them to the circuit 118 based on the contents of the register 123.
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