XOCECO LC20H3D, Service Manual

Page: 20 / 55

TDA4470
Block Diagram
ÏÏ Ï
ÏÏ
ÏÏ
ÏÏ
ÏÏ
AGC
(VIF)
Tuner
AGC
ÏÏ
ÏÏ
ÏÏ Ï
ÏÏ
ÏÏ
ÏÏ
AGC
(SIF)
Ï
Ï
Ï
Ï
Ï
Ï
Ï
11
10
Tuner
Ï Ï
Ï
Ï
Ï
Ï
Ï
Ï
27
28
3
1
2
Ï
Ï
5
SIF 2
SIF 1
VCO
+
phase shift
AFC
Standard
Supply
ÏÏ
ÏÏ
ÏÏ
L’ switch
VCO
21
20
18
Loop
filter
14
Ï
Offset
comp.
(optional)
26
FPLL
0
°
90
°
VIF amp
6
7
8
15
VIF
C
AGC
C
BL
Take over
point
SIF input
switch
C
AGC
22
12
4,9,16
13
Standard
switch
23
V
S
Ï
Ï
17
C
Ref
Intercarrier
(FM / NICAM)
24
FM det.
AM det.
SIF amp
25
AF
(AM)
AFC
Video
95 10851
Ï
Video det.
Control
ÏÏ
ÏÏ
19
AFC
switch
Ï
Ï
ÏÏ
Figure 1. Block diagram