8.2 Discrete-Time Signals 463
− 5 0 5 10 15
0
5
10
15
n
y[
n]
=
x[
n+
3]
+x
[n
−3]
− 5 051015
n
x[
n
+3]
0
2
4
6
8
10
12
x[
n−
3]
− 5 0 5 10 15
n
0
2
4
6
8
10
12
0
2
4
6
8
10
12
x[
−n
]
− 10 010 − 10 010
0
2
4
6
8
10
12
n n
x[
n]
− 15 − 10 − 5 0 5 10 15
0
2
4
6
8
10
12
n
z[
n]
=x
[n
]+
x[
−n
]
(a)
(b)
(^0) − 5 0 5 10 15
2
4
6
8
10
12
n
x[
n]
FIGURE 8.2
Generation of (a)y[n]=x[n+3]+x[n−3]and (b)z[n]=x[n]+x[−n].