NEC PlasmaSync PX-42M2A, Руководство по обслуживанию

Страница: 129 / 197

6-7
CIRCUIT DESCRIPTION
IC5008 (NTSC/PAL
; TA1222)
IC5012 (TA8814
; CTI)
IC5017
(UPD4066 ; SW)
Signal Y input
Pin 15
DL5001
(DELAY LINE)
SIGMAL Y input
Pin 53
The C signal is processed for system’s discrimination. If the signal is PAL or NTSC, it is processed for APC,
ACC, carrier reproduction, and phase detection. It is turned into the R-Y/B-Y signal and once output from Pin
5 and Pin 6 of IC5008. It is then applied to Pins 12 and 13 of IC5010 (SECAM demodulation). It passes through
the internal switching circuit and is output from Pins 10 and 11, and it is then input in the next stage.
Regarding information about system’s discrimination, a control signal output is generated from Pin 3/7, in order
to control IC5010 (SECAM demodulation) and IC5009 (1H DELAY).
The amplified signal from IC5009 (1H DELAY) is output from Pins 29 and 30, and the input is applied to Pins 7
and 8 of IC5012.
IC5012 is in charge of profile correction for color signals. The output is generated from Pins 11 and 12, and is
returned to Pins 51 and 52 of IC5008.
Demodulation processing is effected in IC5008 for the generation of color-difference signal, and the signal is
sent to the RGB matrix circuit.
IC5008
(NTSC/PAL
; TA1222)
IC5010
(TA1229; SECAM)
IC5009
(TA872 ; 1H
DELAY)
IC5012
(TA8814; CTI)
Signal C input
R-Y/B-Y
Control
signal
Control signal
R-Y/B-Y R-Y/B-Y
R-Y/B-Y
In the RGB matrix block, an analog RGB signal is generated at the RGB matrix circuit based on this color-
difference signal and the brightness signal. The output is obtainable from Pins 1, 3, 5 of the “VD” connector.
(2) SECAM demodulation
When a color signal is received from the SECAM system, a control signal from Pin 3 of IC5008 (PAL/NTSC) is
sent to IC5010 (SECAM demodulation).
In IC5010 (SECAM demodulation), the C signal input at Pin 24 is processed for band limitation at the bell filter.
After amplification at the limiter circuit, the signal is further processed for FM demodulation and de-emphasis,
and is changed over by the previous control signal. Since then, a color-difference signal output is generated
from Pin 10/Pin 11. When this signal is applied to Pins 26 and 27 of IC5009 (1H DELAY), complementary
operation is effected every hour. The output is generated from Pins 29 and 30, and applied to Pins 7 and 8 of
IC5012 (CTI).
IC5012 is in charge of profile correction for color signals. The output is generated from Pins 11 and 12, and is
returned to Pins 51 and 52 of IC5008. An analog RGB signal is generated at the RGB matrix circuit based on
this color-difference signal and the brightness signal. The output is obtainable from Pins 1, 3, 5 of the “VD”
connector.