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DP-4X COMPOSITE VIDEO SIGNAL PATH - 1H NTSC EXPLANATION
COMPOSITE VIDEO SIGNAL PATH –1H NTSC EXPLANATION.
(See Composite Video Select Path - 1H NTSC for Details)
The inputs to I402 were described in the previous explanation, Video Signal Selection Path. This discussion will
take up the signal flow for 1H NTSC video out of I402.
PIN 56 MAIN 1H NTSC VIDEO SIGNAL FLOW.
The Composite Video signal is output via pin 56. Then through Q407 to the following buffers; QV01 and QV02.
From here it splits into two paths;
1.
To OV03 and into the Microprocessor Sync Path where the composite Sync is used by the Microproces-
sor I004 for Station Detection, Closed Caption data slicing and V. Chip data stripping.
2.
And to QV04, QV11, QV13 and QV52.
From QV52 the composite signal is input to the 3D Y/C comb filter IC IV02 pin 93.
3D Y/C Inputs and Outputs:
The 3D Y/C comb filter separates the Luminance (Y) Signal and the Chrominance (C) signal.
1.
Luminance: The Y signal is output from pin 89. Then to QV15, XV06 which eliminates an high fre-
quencies that are incorporated into the signal by the 3D Y/C comb filter digital circuits. Then to QV26
and QV36 to IV06 pin 6.
IV06 Main Y Selector:
Dependant upon the customer's selection Pin 56 of I401 outputs either S-Y 3, 4 or 5 inputs. This signal
is routed through Q407. Then its received by IV06 pin 6 and dependant upon the customer's selection
outputs on pin 2 either Y from the Comb Filter input on pin 6 or Y from the S-Inputs input on pin 4 .
2.
Chrominance: The C signal is output from pin 88 of the 3D Y/C. Then to QV17, XV07 which elimi-
nates an high frequencies that are incorporated into the signal by the 3D Y/C comb filter digital circuits.
Then to QV27, QV37, QV18 and QV22 to IV07 pin 6.
IV06 Main C Selector:
Dependant upon the customer's selection Pin 55 of I401 outputs either S-C 3, 4 or 5 inputs. This signal
is routed through Q408. Then its received by IV07 pin 4 and dependant upon the customer's selection
outputs on pin 2 either C from the Comb Filter input on pin 6 or C from the S-Inputs input on pin 4 .
IV08 Main 1H Video/Chroma:
The Y signal arrives at IV08 pin 40 of the Main 1H Video/Chroma IC.
The C signal arrives at IV08 pin 6 of the Main 1H Video/Chroma IC.
This IC takes the Y and C separate 1H NTSC signals and converts them to Y Cr/Cb components which are
the appropriate signal format for the next IC, I502 which is the Main Y Pr/Pb Selector. The outputs from
IV08 are Y pin 37, Cr pin 48 and Cb pin 47.
I502 Inputs: This IC Receives the following 3 types of Inputs;
1.
1H NTSC: The outputs from IV08 are received by I502. They will be either the Main Tuner, Composite
Video 2, 3, 4 or 5, S-In 3, 4 or 5, Component NTSC Y Pr/Pb. Any of these inputs that have been se-
lected by IV08 are received by I502 on the following pins; Y pin 66, Cb pin 68 and Cr pin 70.
2.
Component 1 or 2, HDMI 1 or 2 Inputs: I502 receives the Component 1 or 2 and/or HDMI 1 or 2 in-
puts at the following pins, Y pin 78, Pb pin 80 and Pr pin 2.
3.
ATSC (Digital Tuner) Inputs: I502 receives the Digital Tuner (1080i) inputs at the following pins, Y
pin 72, Pb pin 74 and Pr pin 76.
I502 Outputs;
Dependant upon the Customer's selection for the Main Picture, I502 outputs the component signals on the
following pins; Y pin 20, Pr pin 16 and Pb pin 18.
The Signals Continues on the RGB Processor Circuit Diagram.
(Continued on page 04-05)
PAGE 03-04
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