Image Processing Reference
In-Depth Information
TABLE 3.3
z-Transform of Elementary Sequences
x(n)
X(z)
ROC
d( n )
1
Entire z-plane
z k
d( n k )
Entire z-plane
z
z 1
u ( n )
j z j > 1
z
z a
a n u ( n )
j z j > j a j
z
z a
a n u ( n 1 )
j z j < j a j
)
( z a )( z a 1
z ( z þ a a 1
1
a
a j n j
a < j z j <
0 < a < 1
)
z
( z 1 )
nu ( n )
j z j > 1
2
az
( z a )
na n u ( n )
j z j > j a j
2
az ( z þ a )
( z a )
n 2 a n u ( n )
j z j > j a j
3
n ( n 1 ) ( n m þ 1 )
m !
z
( z a )
a n m u ( n m þ 1 )
j z j > j a j
m þ 1
z ( z cos v 0 )
cos (v 0 n ) u ( n )
j z j > 1
z 2
2z cos v 0 þ 1
z sin v 0
sin (v 0 n ) u ( n )
j z j >
1
z 2
2z cos v 0 þ 1
z ( z a cos v 0 )
a n
cos (v 0 n ) u ( n )
j z j > j a j
z 2
2az cos v 0 þ a 2
za sin v 0
a n
sin (v 0 n ) u ( n )
j z j > j a j
z 2
2za cos v 0 þ a 2
z ( z þ a a 1
)
( z a )( z a 1
1
a
a j n j
a < j z j <
0 < a < 1
)
and
Z
x 2 ( n ) !
X 2 ( z )
,
ROC ¼ R 2
(
3
:
49
)
then
Z
a x 1 ( n ) þ b x 2 ( n ) !
a X 1 ( z ) þ b X 2 ( z )
,
ROC ¼ R ¼ R 1 \ R 2
(
3
:
50
)
This means that the z-transform of linear combination of two sequences
is the linear combination of their respective z-transforms and the ROC is
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