Daewoo dsc-3220e-3220l Manuel D’Utilisation

Page de 86
Service manual SC-150
-28-
Pin No.
Pin Name
Type
Short description
59
ANA_IN1-
In
IF common
60
NC
Not Connected
61
TESTEN
In
Test pin
62
XTAL_IN
In
Crystal oscillator
63
XTAL_OUT
Out
Crystal oscillator
64
NC
Test pin
4-3 TDA 4470-Multistandard Video-IF and Quasi Parallel Sound Processor
4-3-1- Description
The TDA 4470 is an integrated bipolar circuit for multi-standard video/sound IF (VIF/SIF) signal  processing in
TV/VCR and multimedia applications. The circuit processes all TV video IF signals with negative modulation
(e.g., B/G standard), positive modulation (e.g., L standard) and the AM, FM/NICAM sound IF signals.
4-3-2- Features
- 5V supply voltage ; low power consumption.
- Active carrier generation by FPLL principle (frequency-phase-locked-loop) for true synchronous demodulation.
- Very linear video demodulation, good pulse response and  excellent intermodulation figures.
- Alignment-free AFC without external reference circuit, polarity of the AFC curve is switchable.
- VIF-AGC for negative modulated signals (peak sync. detection) and for positive modulation
(peak white/black level detector).
- Tuner AGC with adjustable take over point.
- Alignment-free quasi parallel sound (QPS) mixer for FM/NICAM sound IF signals.
- Intercarrier output signal is gain controlled (necessary for digital sound processing).
- Complete alignment-free AM demodulator with gain controlled AF output.
- Separate SIF-AGC with average detection
- Two independent SIF inputs
- Parallel operation of the AM demodulator and QPS mixer (for NICAM-L stereo sound).
4-3-3- Pinning
Pin
Symbol
Function
1,2
V
i,SIF1
SIF1 input ( symmetrical)
3
V
SW
Input selector switch
4,9,16
GND
Ground
5
V
AGC
SIF-AGC (time constant)
6,7
V
i,VIF
VIF input (symmetrical)
8
C
AGC
VIF-AGC (time constant)
10
R
TOP
Take Over Point, tuner AGC
11
I
tun
Tuner AGC output current
12
V
O,VID
Video output
13
V
SW
Standard switch
14
V
SW
L’switch
15
C
bl
Black level capacitor
17
C
ref
Internal reference voltage
18
LF
Loop Filter