Preliminary
HT9015
·
Noise detector
control register setting. The high state ex-
presses noise level more than 0.4V and the
low state expresses noise level under 0.4V.
Figure 8 is a band pass filter which can detect
noise energy on N_REC pin. There is also a
pass through the noise comparator to deter-
mine two states on SIG_OUT pin by internal
V
D
D
H
i
g
h
-
P
a
s
s
F
i
l
t
e
r
F
C
=
2
5
k
H
z
B
a
n
d
-
P
a
s
s
F
i
l
t
e
r
E
x
t
e
r
n
a
l
F
O
=
3
1
k
H
z
R
5
N
o
i
s
e
C
o
m
p
a
r
a
t
o
r
N
o
i
s
e
D
e
t
.
V
e
O
U
T
N
F
o
i
s
A
M
P
R
4
i
l
t
e
r
C
3
N
_
F
I
L
_
I
N
N
_
F
I
L
_
O
U
T
N
_
R
E
C
I
E
n
t
e
r
n
a
l
x
t
e
r
n
a
l
R
3
C
4
A
u
d
i
o
S
i
g
n
a
l
C
1
C
2
R
1
R
2
Figure 8 Noise detector
17
April 10, 2000
HOLTEK [ HOLTEK SEMICONDUCTOR INC ]
