Noblex 21TC657, Service Manual

Page: 6 / 30

IC Block Diagrams
-6-
IC201 <IF System Block Diagram> LA76818A
11
12
BU
S
Interf
ace
SA
W
5 6
4
8 7
PIF In1
PIF In2
IF In
9V
30K
RF A
G
C
Out
120K
IF VCC
IF
GND
VIF AMP
VIF 1
VIF 2
VIF 3
IF A
GC
Dr
iv
e
RF
AG
C
2ndIF AG
C
RF A
G
C
Dela
y
6bit
IF A
G
C
Def
1bit
+
-
(6 Vcc)/7
To
BU
S
3
0.022u
PIF
AG
C
IF
AG
C
Data
Cloc
k
APC
Det
+
π
/4
-
π
/4
Snd
Det
Amp
52
SIF
.Out
Sound
Tr
a
p
Video
Det
Buzz
Canceller
50
APC
Filter
330
0.47u
+
PLL Pull-in SW
To
BU
S
Loc
k
Det
Video
.Le
v
el
3bit
Amp
54
10p
SIF
.In
Sound
BPF
VCO
.Coil
VCO
COIL1
VCO
COIL2
48
49
VIF
VCO
Chroma Counter
B/N INV
IF
Ident
OSC C/D
Amp
SIF
. Sys
2bit
pre-
scaller
SIF
VCO 500K
BPF
SIF
APC Filter
1K
0.01u
1000p
53
LIM
AMP
FM Det
FM.Le
v
e
l
5bit
Chroma
C/D
APC
Det
500K
Det
To
BU
S
Chroma
VCO
VIF
Counter
Reset Pulse
VCO Ident
VIF
.Sys
2bit
Phase
Detector
A.MUTE
1bit
V
OLUME
D/A
V
OLUME Filter
A.SW
1bit
Input Select
V
OLUME (A
TT)
-
+
- +
2.5V
Amp
FM Gain
1bit
Deem-TC
1bit
De- emph
FM Mute
1 bit
2
9
46 51
1
A.Fil.Def
1bit
V
OLUME
7bit
47
VCO
Alignment
AFT
10
AFT
Vcc
100K
100K
0.1u
VCO Filter
+
0.47u A
udio
.out
+
A
udio in
10u
Video
Out
FM Filter
+
1u
FM Out
0.01u
+
to B
US Line
+