Patent ID: 7099907

Claim:
A Finite Impulse Response (FIR) filter comprising: a selection control means for selecting input data, the selection control means including: a first n-bit shift register (n being a natural number) for progressively shifting the input data through successive stage bits, n switching means respectively provided for outputs of the n stage bits of the n-bit shift register for controlling the outputs of these n bits, and a control means for controlling the n switching means, the control means outputting n unique control signals respectively to the n switching means, the control means further being constituted by a second n-bit shift register for shifting a ramp-up/-down signal through successive bit stages under control of a shift clock for the first n-bit shift register; and a multiplying means for multiplying data selected by the selection control means and a predetermined filter coefficient, wherein a FIR filter output is derived from the product outputs of the n multiplying circuits means.