The minreal function works with discrete systems.
Example —
n = [1 -9 26 -24];
d = [1 -12 41 -42];
tfs = tf(n,d);
figure
bode(tfs)
[ps,zs] = pzmap(tfs)
rs = minreal(tfs)
tfz = tf(n, d, 0.1)
figure
bode(tfz)
[pz1,zz1] = pzmap(tfz)
rz = minreal(tfz)
For the continuous system:
rs =
s - 4
-----
s - 7
and for the discrete system:
rz =
z - 4
-----
z - 7
In both, it cancels the poles-zeros at 2 and 3.
