Patent Number: 6,311,203

Title: Multiplier, and fixed coefficient FIR digital filter having plural multipliers

Abstract: A multiplication device for performing a multiplication operation on a multiplicand X and two fixed coefficients C1 and C2 where C1>C2. The multiplication device comprises a multiplier for multiplying multiplicand X and the average CA of the two fixed coefficients C1 and C2; a shift register for obtaining a sum of the multiplicand X data after being shifted up according to a position of a "1" bit in bit data where the bit data is the remainder coefficient obtained by subtracting average CA from fixed coefficient C1; and a selector for selecting a product obtained for one of the fixed coefficients C1 and C2. When the fixed coefficient C1 is selected, the selector outputs the sum of the product returned by the multiplier and the accumulated value obtained by the shift register; when fixed coefficient C2 is selected, the selector outputs the difference of the product returned by the multiplier minus the accumulated value obtained by the shift register. A fixed coefficient FIR digital filter having a plurality of multiplication devices above-mentioned is also disclosed.

Inventors: Wada; Yasushi (Tokyo, JP), Murakami; Shuji (Tokyo, JP)

Assignee: Mitsubishi Denki Kabushiki Kaisha

International Classification: G06F 7/48 (20060101); G06F 7/52 (20060101); H03H 17/06 (20060101); G06F 007/52 (); G06F 017/10 ()

Expiration Date: 10/30/2018