10
(8) AD converter (IC6501, IC6701) block
IC6501 and IC6701 are the ICs intended for the conversion of analog RGB signals into 8-bit digital signals.
(However, there are 48 output lines in total, each RGB color 8 bits x 2.) In addition to the functions of AD
converter, this type of IC is also provided with the various functions of analog amplifier and PLL/VCO. Each
function is controlled by the I2C bus SCL6 and SDA6 from IC9501.
IC6501 accepts signal inputs of motion pictures such as video signals, DVD, HDTV, etc. IC6701 picks up
RGB signal inputs of still pictures from PC, etc.
With the aid of the analog AMP incorporated in the IC, various adjustments are carried out, such as contrast
adjustment, brightness adjustment, and white balance adjustment in the factory service mode.
In addition to video signals, the IC receives inputs of horizontal and vertical sync signals. Based on these
sync signals, sampling of video signals is conducted by the use of the sampling clock produced in the built-
in VCO. The sampling frequency differs according to each signal input entered. The clamp signal (Pin 113)
is fed from IC7501.
(9) Panel link block
During the entry of RGB3 input, the digital RGB signal input from the PL1 connector is of serial data, and
hence the signal is converted into parallel data at the panel link receiver, IC7002.
While the RGB3 input is not displayed, the microcomputer IC9501 turns the potential of the PD0 terminal
(Pin 9) to be at the “L” level to set up a high impedance for the outputs of video signals, clock signals, sync
signals, and DE (data enable). If a condition of no signal occurs during the entry of RGB3 input, the SCTD
output terminal (Pin 8) is turned to be at the “L” level and this causes the PDO terminal to be at the “L” level,
and a condition of high impedance is secured for the outputs. The PDO terminal gains an AND input of the
SCDT output and microcomputer output in IC7003.
In IC7004, the Plug & Play data for the panel link (for RGB3 input only) are stored. The power supply and
control for IC7004 are maintained from the connected equipment (personal computer, etc.) through the PL
connector.
(10) Gate array (Pre G/A IC7501) block
For video signal processing, IC7501 is provided mainly with the four functions specified below. These
functions are controlled by bus SIK2, SID2, and CSYUMA from the microcomputer IC9501.
1
The video signal from the AD converter IC6501/IC6701 or IC7002 is selected according to the type of
the input signal, and the output is sent to IC8502 and IC8003.
2
The RGB signal input from IC6501 is converted into a chrominance signal of 4:4:4 or 4:2:2. The chromi-
nance signal is converted into an RGB signal.
3
For the chrominance signal that passes through the IC inside, processing is carried out in regard to the
color depth and tone.
4
The peak brightness and the mean brightness of the video signal are measured.
(11) I-P conversion and profile emphasis processing, RGB chrominance conversion (IC8003) block
In IC8003, the horizontal 15kHz interlace signals like video signals, DVD signals, etc., are converted into
31kHz progressive signals, and the 33kHz interlace signals of the HDTV system are converted into 67kHz
progressive signals. (I-P conversion) In the case of other input signals, processing of profile emphasis and
noise reduction is performed. In the case of dual screen processing, processing of enlargement and con-
traction is carried out. To perform processing of I-P conversion and that of enlargement and contraction, a
RAM (IC8004) is used.
IC8004 is a control IC for IC8003. The method of image display for I-P conversion and profile emphasis
processing is controlled by I2C bus (SDA1, SCL1) from the microcomputer IC9501.
X8000 is a clock signal source for IC8003 system operation (10 MHz). IC6550 operates when the potential
of the system reset terminal XRST is at the [H] level. IC8001, IC8002, and IC8006 function as the power
source to drive IC8003. They generate outputs of 1.4V, 1.9V, and 2.5V, respectively.
Summary of Contents for PlasmaSync 50MP1
Page 1: ...USE THIS SERVICE MANUAL WHEN SERVICING Model PLA 50V1 ...
Page 10: ...PlasmaSync Plasma Monitor User s Manual NEC Technologies ...
Page 64: ...TROUBLESHOOTING 4 1 ...
Page 80: ...METHOD OF ADJUSTMENTS 5 1 ...
Page 98: ...CIRCUIT DESCRIPTION 6 1 ...
Page 113: ...METHOD OF DISASSEMBLY 7 1 ...
Page 134: ...PACKAGING 8 1 ...
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Page 147: ...PART LIST 9 1 ...
Page 158: ...CONNECTION DIAGRAMS 10 1 ...
Page 160: ...BLOCK DIAGRAMS 11 1 ...
Page 163: ...SCHEMATIC DIAGRAMS 12 1 ...
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