Hitachi 51SWX20B Training page 50

DP-2X CHASSIS VIDEO SIGNAL PATH-NTSC, COMPONENT, OSD CIRCUIT EXPLANATION
(See the Chassis Video Signal Path-NTSC, Component, OSD for details)
(See Video Signal Path-NTSC Circuit Diagram for details about NTSC)
It's important to note that this Chassis horizontal deflection operates at 33.75Khz at all times. Even though this is
twice as fast as NTSC, the set will still display NTSC video with no problem. This is accomplished by the Flex
Converter. The Flex Converter will manipulate any input, be it NTSC, Component 480i, 480P, 720P, 1080i to the
appropriate Horizontal Frequency rate of 33.75Khz. This makes this chassis very versatile in it's application.
The following will discuss the Component signal path and the continuation of the NTSC signal path.
COMPONENT INPUTS 1 and/or 2:
This chassis utilizes 5 separate inputs plus a newly added input called DVI. The following will break down those
input routes to the Y Pr/Pb Selector IC IX02.
(1) INPUT 1: This input is only for Component Inputs Y Pr/Pb (31.5Khz to 33.75Khz ATSC) and will not ac-
cept Composite on the Y input.
•
The Y line is input directly into the Y Pr/Pb Selector IX02 pin 59.
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The Cr/Pr line is input directly into the Y Pr/Pb Selector IX02 pin 63.
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The Cv/Pb line is input directly into the Y Pr/Pb Selector IX02 pin 62.
(2) INPUT 2: This input will accept Component Inputs Y Pr/ Pv (31.5Khz to 33.75Khz ATSC) or Y Cr/Cb
(15,735Hz. NTSC). It will also accept Composite Video input as long as there is no Pr plug inserted.
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The Y line is input directly into the Y Pr/Pb Selector IX02 pin 5.
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The Cr/Pr line is input directly into the Y Pr/Pb Selector IX02 pin 9.
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The Cv/Pb line is input directly into the Y Pr/Pb Selector IX02 pin 7.
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Input 2 Composite Video is routed into the Selector IC IX01 pin 30.
(3) DVI INPUT (Digital Video Interface): This input will accept Component Inputs Y Pr/ Pv (31.5Khz to
33.75Khz ATSC) only. (See DVI Signal Path for further details). (NOT in the DP24 Chassis).
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The Y line is input from the PET connector pin 5 into the Y Pr/Pb Selector IX02 pin 53.
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The Pr line is input from the PET connector pin 3 into the Y Pr/Pb Selector IX02 pin 57.
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The Pb line is input from the PET connector pin 7 into the Y Pr/Pb Selector IX02 pin 55.
(4) DIGITAL TUNER (ATSC) UD2002 INPUT: These inputs are provided from the Digital Tuner (ATSC).
The ATSC Tuner output DM-Y, DM-Pb and DM-Pr. (Only in the DP26 Chassis). (See DP-26 Component,
OSD, NTSC Signal Path for specifics).
DM-HY (Luminance) from PMS2 pin 16, through PST1 pin 13 to Y Pr/Pb Selector IX02 pin 15.
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DM-Pb (Blue Chroma) from PMS2 pin 14, through PST1 pin 15 to Y Pr/Pb Selector IX02 pin 17.
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DM-Pr (Red Chroma) from PMS2 pin 12, through PST1 pin 17 to Y Pr/Pb Selector IX02 pin 19.
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NOTE: When receiving a SDTV or HDTV signal, the Digital Module also outputs Composite Video/
◊
Chroma for the Monitor Output. (See DP-26 NTSC Signal Path for specifics).
COMPONENT VIDEO PATH:
The output from the Y Pr/Pb Selector IX02 is then routed to the Video/Chroma Y Pr/Pb Switch.
IZ01 is used to select the PinP (Sub) picture source. Either from component inputs or from the separated NTSC
inputs as described in the DP-2X Chassis Video Signal Path-NTSC Circuit Diagram.
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The Sub Y component is output from the pin 50 through QX19 into the PinP (Sub) Video/Chroma Y Pr/
Pb Switch IZ01 pin 30.
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The Sub Cr/Pr component is output from the pin 46 through QX21 into the PinP (Sub) Video/Chroma Y
Pr/Pb Switch IZ01 pin 28.
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The Sub Cb/Pb component is output from the pin 48 through QX20 into the PinP (Sub) Video/Chroma
Y Pr/Pb Switch IZ01 pin 29.
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Main NTSC Y component is input into the PinP (Sub) Video/Chroma Y Pr/Pb Switch IZ01 pin 2.
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PinP (Sub) NTSC Y component is input into the PinP (Sub) Video/Chroma Y Pr/Pb Switch IZ01 pin 4.
IZ02 is used to select the Main picture source. Either from component inputs or from the separated NTSC inputs
as described in the DP-2X Chassis Video Signal Path-NTSC Circuit Diagram.
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The Main Y component is output from the pin 44 through QX24 into the Main Video/Chroma Y Pr/Pb
(Continued on page 7)
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