摘要 |
Recursive digital filter deriving the samples of a filtered output signal at a present sampling instant from the samples of an input signal to be filtered at said present sampling instant and at two preceding consecutive sampling instants and from samples of said filtered output signal at said two preceding consecutive sampling instants. It comprises a first memory means and a second memory means for respectively storing the samples of the input signal at the present instant and the two preceding instants and the samples of the filtered output signal at the two preceding consecutive instants; a digital adder means; means for connecting the output of said digital adder means to said second memory means; a first digital multiplier means comprising multiplier units connecting the parts of the first memory means storing respectively the samples of the input signal at the present instant and two preceding consecutive instants to the adder means, a second digital multiplier means comprising multiplier units connecting the parts of the second memory means storing respectively the samples of the filtered output signal at the two preceding consecutive instants to the adder means and a third digital multiplier means comprising a last multiplier unit connecting the adder means to the filter output. All the multiplier units are powers of two multiplier units and the last multiplier unit multiplies by a negative power of two greater than five.
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