| 摘要 |
PROBLEM TO BE SOLVED: To constitute an FIR filter which realizes excellent frequency characteristics in extremely small hardware scale. SOLUTION: The digital filter comprises an FIR filter 10 configured to repeatedly apply simple moving-average operations to input data by cascade connecting n stages of multiple processing parts 1<SB>-1</SB>, 1<SB>-2</SB>, ..., 1<SB>-n</SB>for performing the moving-average operation of adding or subtracting the input data and data preceding thereto just by a predetermined delay amount by using an adder 13 and outputting the result after regulating its amplitude by using a shift computing element 14 repeatedly m times in a time division multiplex manner according to a clock m*ck of an m-fold frequency. Thus, a multiplier which is conventionally required for multiplying each tap output of a tapped delay line by a filter coefficient can be eliminated and m times of moving-average operations are performed in the time division multiplexing manner, thereby remarkably reducing also the number of times of usage of the adder. COPYRIGHT: (C)2005,JPO&NCIPI
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