Patent ID: 6625628
Filing Date: 2003-09-23
Classification: H03H

Abstract:
A digital filter including multiplying means for multiplying input data and predetermined coefficients and adding means for adding the multiplication results, comprising:N (N is a natural number) multipliers in which, of first to (2N+1)-th multiplying means, M-th (M=1 to N) multiplying means and M-th (M=N+2 to 2N+1) multiplying means are shared, and to which the input data is inputted as a first input, the input data changing at a first cycle; N selectors, provided corresponding to the N multipliers, for inputting to the N multipliers first and second coefficient groups to the corresponding multipliers by time-sharing, the coefficients changing at a second cycle double that of the first cycle; a first adder group for cumulatively adding, between corresponding multipliers, the results of multiplications by the N multipliers when the first coefficient group is inputted; a second adder group for cumulatively adding, between corresponding multipliers, the results of multiplications by the N multipliers when the second coefficient group is inputted; and an output selector for outputting the results of additions of the first and second adder groups by time-sharing, the results of additions being output at a third cycle double that of the first cycle, the second and third cycles being out of phase with one another.