INVERSE Z-TRANSFORM
Def.
Inverse Z-transform
If Z[x(n)] =
X(z) then Z -1[X
(2)] = [x (n)]
Z-1[X
(2)] can be found out by any one of the following methods.
(METHOD I). PARTIAL FRACTIONS METHOD
X.
Problems based on Inverse Z-transform
Find
the inverse Z-transform of
1.
Find Z-1 [10z (z-1) (z-2)]
(Method : II). Inverse of Z-transform by Inverse integral
method. (Cauchy's residue theorem)
From the
relation between the Z-transform and Fourier transform of a sequence we get
i.e., x(n) Sum
of the residues of X(z) 2-1 at the isolated singularities.
Note:
Take the contour C such that all the poles of the function X(z) zn-1 lie
within the contour.
Find
the inverse Z-transform of