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Pin
38
Data bus control
39
Vacant pin
40
Vacant pin
41
Vacant pin
42
Power supply
Pin
1
Output (BU)
2
Output (BH)
3
Control input
4
Control input
5
Grounding terminal
6
Power input terminal 1
7
Output (BL)
8
Vacant pin
9
Power input terminal 2
3. Signal processing
(1)
Picture intermediate signal processing
Having been under tuning and selective calling, high frequency amplification and frequency
mixing in tuner U101, the high frequency signals are output through the intermediate
frequency signal output terminal (IF) of U101 to the base electrode of intermediate frequency
pre-amplifier V101 via the coupling matching network. The intermediate signals are added to
Pin 6 and 7 of the symmetric terminals of the intermediate difference channel of the TV
signal monolithic processing circuit N201 (TB1238AN). The intermediate signals are
amplified in N201 and the PLL picture modulated. The mixed signals of picture video and the
second sound are output from Pin 47 and then divided into two.
(2)
Picture signal processing
The signals from Pin N201 (47) go through the sound intermediate frequency wave trap Z268
(D/K system) or Z265 (B/G system) and the emitter follower V212 so that the video complete
TV signals are got out and sent to TV/AV electronic switch circuit through Pin (43). One part
of the output signals go into the video signal processing circuit, the other go in the color
Function
N101
Function
Reference Voltage(V)
With signal
Without signal
3.2
3.0
0
0
5.9
5.9
0.1
0.1
5.2
5.2
LA7910
Reference Voltage(V)
With signal
Without
signal
0
0
0
0
0
0
1.6
1.6
0
0
10.4
10.4
8.8
8.8
3.4
3.4
8.8
8.8
Reference
Resistance(KΩ)
Forward
Backward
0.4
0.5K
0
0
7.9
7.9
8.0
8
1.5K
27
Reference
Resistance(KΩ)
Forward
Backward
4.3
4.3
4.6
4.6
18
22
43.4
0.5K
0
0
22
18
3.0K
5.6K
4.6K
0
1.2
1.3
23
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