Digital Signal Processing Reference
In-Depth Information
Note that G
2
= 0 in this case.
Sinusoidal PLL: 2nd-order system equation:
/
ð
k
þ
2
Þ
2/
ð
k
þ
1
Þþ
/
ð
k
Þ¼
K
2
sin
½
/
ð
k
Þ
rK
2
sin
½
/
ð
k
þ
1
Þ;
where r
¼
1
þ
G
2
=
G
1
:
Fixed point analysis: g(x) = x has a solution x* only if
j
g
0
ð
x
Þj
\1
:
Jacobian matrix:
o
ð
u
;
v
Þ
where u, v are functions of x, y.
o
ð
x
;
y
Þ
¼
ou
=
ox
ou
=
oy
ov
=
ox
ov
=
ou
Eigenvalues {k} of a matrix X:
j
kI
X
j¼
0;
where I is the identity matrix
:
Input Signal,
x
(
k
)
Sampler &
ADC
x
(
t
)
DF
N
−bits
y
(
k
)
DCO
Output Pulses,
v
o
(
k
)
Integrator H(z) = 1/(1 - z
-1
); Differentiator H(z) = (1 - z
-1
)/T
s
Error functions:
p
Z
x
erf
ð
x
Þ¼
2
e
v
2
dv
0
Z
¼
1
1
Q
ð
x
Þ¼
1
e
v
2
=
2
dv
¼
1
2
x
2
2
1
x
p
2p
erfc
p
erf
p
2
2
x
For x [ 0 we have:
p
e
x
2
=
2
X
5
Q
ð
x
Þ
1
b
k
g
k
;
2p
where
k
¼
1
g
¼
1
=ð
1
þ
0
:
2316419x
Þ;
b
1
¼
0
:
3198
;
b
2
¼
0
:
3565
;
b
3
¼
1
:
7814
;
b
4
¼
1
:
8212
;
b
5
¼
1
:
3302
Direct forms of IIR implementation:
y
ð
n
Þ¼
b
o
x
ð
n
Þþ
b
1
x
ð
n
1
Þþþ
b
M
x
ð
n
M
Þ
a
1
y
ð
n
1
Þ
a
N
y
ð
n
N
Þ
H
ð
z
Þ¼
P
i
¼
0
b
i
z
i
!
¼
H
1
ð
z
Þ
H
2
ð
z
Þ¼
H
2
ð
z
Þ
H
1
ð
z
Þ:
1
þ
P
k
¼
1
a
k
z
k
¼
X
M
1
1
þ
P
k
¼
1
a
k
z
k
i
¼
0
b
i
z
i
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