Digital Signal Processing Reference
In-Depth Information
z
z - 0.25
+
z
z - 0.5
;
F
b
(z) =
ƒ z ƒ 7 0.5.
f [n]
The poles and the ROC are plotted in Figure 11.17. Hence,
is right sided and, from
Table 11.5,
f[n] =
z
-1
[F
b
(z)] = [0.25
n
+ 0.5
n
]u[n].
z
0.25
0.5
ROC
Figure 11.17
ROC for Example 11.15.
■
Continuation of Example 11.15
EXAMPLE 11.16
Consider next the function
z
z - 0.25
+
z
z - 0.5
;
F
b
(z) =
ƒ z ƒ 6 0.25.
f [n]
The poles and the ROC are plotted in Figure 11.18. Hence,
is left sided. From Table 11.5,
f[n] =
l
-1
[F
b
(z)] = [-0.25
n
- 0.5
n
]u[-n - 1].
z
ROC
0.25
0.5
Figure 11.18
ROC for Example 11.16.
■
