Efficient structurally symmetric algorithms for least squares FIR filters with linear phase

Two novel least-squares algorithms are derived for the computation of the FIR coefficients of multichannel filters with linear (affine) phase. One is for block processing and requires 2 Np+4.25 p ² additions and 2 Np+3p² multiplications, with N being the number of input data samples and p the order of the filter. The second algorithm computes the linear (affine) phase filter´s coefficients in an adaptive manner with a computational complexity of 8.5 p additions and 6.5 p multiplications per time recursion. Thus, a reduction in computational complexity of the order of 40-50% is obtained compared to previously derived algorithms. A Fortran subroutine is presented for the time recursive algorithm