Further results in Walsh domain filtering
A. Gerheim, John W. Stoughton · IEEE Transactions on Acoustics Speech and Signal Processing · 1987
Zarowski and Yunik [1] demonstrated that an FIR filter can be realized with fewer multiplications in the fast Walsh transform (FWT) domain than in the fast Fourier transform (FFT) domain for some transform lengths. This correspondence investigates the symmetry and sparseness of the Walsh gain matrices. An efficient sparse matrix algorithm is used to calculate the Walsh gain matrix.