Prima PH50D8, Руководство по обслуживанию

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In which: Pin 71 is used for the input of C signal of SVHS;
Pin 72 VIN1 is used for the input of Y signal of CVBS or SVHS of AV;
Pin 73 VIN2 is used for the input of TV signal;
Pin 75 VIN4 is used for the input of Y signal of YCRCB to synchronously identify
YCRCB.
Main channel: The digital YCRCB signal in the format of CCIR601 after being decoded in N102 is
fed into non-interlace processor N204 PW1230 for treatment from alternate-line into non-interlace.
VD1_CLK,VD1_HSYNC VD1_VSYNC, VD1_ACTIVE and VD1_FIELD sent from VPC3230 is used as a
key signal to identify modes. If certain channels become abnormal the corresponding pictures will also
become abnormal. In addition to the function PW1230 has to process the signal from alternate-line into
non-interlace, it can also function to enhance the picture and convert the movie modes 3:2/2:2. The
adjustment of brightness and contrast of the main channel is performed by this chip whereas the
adjustment of chroma and definition is performed by N102. The digital 24 bit RGB signal output from
PW1230 after treatment is fed into V PORT of N501 PW181 for further processing. The signals of VCLK
(clock)
、 VVS （ field synchronization ） 、 VHS （ line synchronization ） 、 VPEN （ enable signal ） are the basic
reference for the image processing of lower level.
For TV set of mono N system, this series has an additional 3D Y/C separation function in the main
channel, which is performed by ND02 Upd64083 so as to enhance the quality of the image.
In this case the signal flow process of the main channel is different. Video signal and AV/SVHS signal
sent from TUNER1 first undergo switching in the switch circuit ND01, then are fed into ND 02 for
separation of brightness from color and output as signal Y and C. For N102, no matter whether it’s TV or
AV/SVHS, finally the signals are all fed in the form of Y/C into the input port of VIN1and CIN. Yet the
setup for the software is somewhat different.
The decoding for the text of main channel or CCD/V-CHIP is performed by auxiliary CPU. Video
signal is directly fed to pin 12 of NM5 for decoding. The decoded text or CCD/V-CHIP signal is output in
the form of R, G, B, FB and fed into N102 for character superposing.
Sub-channel:
Signal CCIR601 after being decoded in VPC3230 is directly fed into PW181
的
G PORT where direct
processing is carried out by PW181. The non-interlace conversion in this channel is performed by the
non-interlace processor inside PW181. Relatively speaking, the efficiency of the internal non-interlace