mtlb_freqz - Z-transform digital filter frequency response
[H,W]=mtlb_freqz(B,A,N) returns the N-point frequency vector W and the N-point complex frequency response vector G of the filter B/A: given numerator and denominator coefficients in vectors B and A. The frequency response is evaluated at N points equally spaced around the upper half of the unit circle.
This function has been imported from MatLab and one or two improvements for SciLab has been done.
[B,A]=butter(8,0.25); [H,W]=freqz(B,A,256); f=gcf(); subplot(211); plot2d(W,abs(H),style=3); subplot(212); plot2d(W,atan(imag(H) ./real(H)),style=3); disp(length(H));
mtlb_filter , butter ,