Patent ID: 7054896

Claim:
A method for implementing a multiplier-less FIR filter that performs the convolution of H ⁡ ( z ) = ∑ k = 0 N - 1 ⁢ h k ⁢ z - k , where H(z) is a system transfer function of the FIR filter, h k is the k-th coefficient of the FIR filter, and x(n) and y(n) denote the input and the output signals at time instance n, respectively, the method comprising the steps of: (A) compressing the dynamic range of the coefficients of the FIR filter by a transformation: H ′ ⁡ ( z ) = H ⁡ ( z ) ⁢ ∏ i = 1 m - 1 ⁢ ( 1 + α i ⁢ z - β ) m ∏ i = 1 m - 1 ⁢ ( 1 + α i ⁢ z - β ) m , where parameters α and β are chosen depending on filter type, −1≦α i ≦1, and m denotes iteration numbers of a coefficient operation of transformation; and (B) quantizing the compressed coefficients obtained in step (A) into SPT numbers.