결과로 나온 신호가 인과적이고, 복소수를 포함하지 않도록 다음 역 z-변환을 구해보자.

ex4_10.cem

/*   Chapter 4: Example 4.10   Check of residue functions rf2pfez and pfe2rfz
*/
 
  b = [1,0.4*sqrt(2)]; a=[1,-0.8*sqrt(2),0.64];
  [R,p,C] =resid_z(b,a)  Mp=abs(p')   /* pole magnitudes */ 
  Mp 
  Ap=angle(p')/pi   /* pole angles in pi units */ 
  Ap 
 
  [delta,n] = implseq(0,0,6);
  x = filter(b,a,delta) /* check sequence */
  x = ((0.8).^n).*(cos(pi*n/4)+2*sin(pi*n/4))