Daewoo 14A5 Service Manual page 24

STV8225 ( AM SIF Circuit )
(1) General Description
The STV8225 is intended for the demodulation of the AM sound of the L standard.
(2) Feature
• sound AM synchronous demodulator
• AM/FM audio switch and AV/TV audio switch
(3) Block Diagram
(4) Pin Description
PIN SYMBOL
1, 14 IF in
2 AGC
3 GND
4 level sw
5 FM in
6 mute
7 main in
8
9 ext out
10 sw in
11 ext in
12 Vcc
13 mean cap
DESCRIPTION
IF input
AGC capacitor
ground
level switch of AF output voltage (pin7,9)
- open : 250 mVrms
- ground : 500 mVrms
FM sound input
mute input
main sound input
n.c
external sound output
switching input
voltage mode
2.3V below TV/FM
4.6V below TV/AM
6.8V below AV/AM
6.8V above AV/FM
external sound input
supply voltage (+9V)
mean capacitor
connection
pin7 pin 9
A C
A A
B A
B C
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