Philips LC4.2E Service Manual page 68

EN 68 9. LC4.2E AA
9.6
Video: TV Part (diagrams A1, A2, and A3)
+VTUN
+5VSW
1328
2321 VIF1
4327 2
7
1302 6,7 9
11
TV
VIF2
4331 8
3
FM
3311
1
RF_AGC
1330
VSIF1
4333 7
2
VSIF2
8
A 3
10
SCART 2
21
20 Y/CVBS-In
16
MON-Out
15
15 C-In
7138
EF
16
P50
Status
SCART 1
21
10 7119
20 CVBS-In EF
9
9 TER-Out
FBL-In
7
R-In
7
6
6 G-In
5
Status
5 B-In
SIDE AV
C
SVHS 2 Y
VIDEO
AV3
The video processing is completely handled by the Hercules
•
IF demodulator.
•
Chrominance decoder
•
Sync separator.
•
Horizontal & vertical drive.
•
RGB processing.
•
CVBS and SVHS source select.
It has also build in features like:
•
CTI.
•
Black stretch.
•
Blue stretch.
•
White stretch.
•
Slow start up.
•
Dynamic skin tone correction etc.
Further, it also incorporates sound IF traps and filters, and
requires only one crystal for all systems.
9.6.1
Histogram (YUV picture improvement) IC
The demodulated video-signal can be checked on pins 74, 75,
and 76 of IC7011 and is fed to pins 70, 71, and 72. In this path,
the Histogram IC TDA9171 is inserted.
This TDA9178 can control various picture improvements:
•
Histogram processing.
•
Colour transient improvement.
•
Luminance transient improvement.
•
Black and white stretch.
•
Skin tone correction.
•
Green enhancement.
•
Blue stretch.
•
Smart peaking.
•
Video dependent coring.
•
Colour dependent stretching.
Since the TDA9171 is connected to the Hercules, picture
improvement works only for signals that are routed trough the
Hercules and not for signals directly connected to the Scaler.
Circuit Descriptions, Abbreviation List, and IC Data Sheets
SYSTEM 7011
A 4 PAL-MULTI/SECAM TDA12021
NTSC TDA12001
CHINA/NTSC-AP TDA12011
7011 - IF
24
Sound CVBS1
25 Traps
31 AGC
Detect
CVBS/Y-X
29
QSS/FM
QSS Mixer/
AM Demod.
30
AM C-X
P50
STATUS_2
STATUS_1
A 2
SC1_CVBS_IN 55
SVHS_AV2_Y_CVBS_IN
58
SC2_Y_IN 51
SVHS_C_IN
59
SC2_C_IN 52
SC2_CVBS_RF_OUT
43
SC2_CVBS_MON_OUT 64
SC1_FBL_IN
SC1_COMP_R_V_IN
SC1_COMP_AV1_G_Y_CVBS_IN
SC1_COMP_B_U_IN
Figure 9-2 Block diagram video processing
Input
sw.
RGB Matrix
Blue & Black
cvbs/y Stretch
Gamma Corr.
Y
int
Dig. 2H/4H
INA..D
Combfilter
Y Delay Adj. Skin Tone
Chroma U/V Tint
Saturation
c
YUV
PAL/NTSC/ U
int
SECAM
CS1A..D
H/V Decoder &
Peaking
V
int
Baseband
SCAVEM
Delay
U/V Delay
Output
sw.
YUV IN/OUT
RGB/YP P Insert
+
R B
YUV Interface
cvbs
77 78 79 80 74 75 76 70 71 72
6 8 9 16 17 19
Pix Improvement
(Histogram)
7560
11 14 1
A2 A2
9.7
Video: Scaler Part (diagram A7 and A13)
The Genesis gm1501 Scaler is a dual channel graphics and
video processing IC for LCD monitors and televisions
incorporating Picture in Picture, up to SXGA output resolutions.
The Scaler controls the display processing in an LCD TV, e.g.
like the deflection circuit in a CRT-based TV. It controls all the
view modes (e.g. like "zooming" and "shifting"). Features like
PC (VGA) or HD inputs, are also handled by this part.
CON BRI
85 7013
RO
RGB Matrix
EF
GO
Blue & Black 86
Stretch
BO 87
Gamma Corr.
2020
SAT
7018
7016#
8
SCAVEM
VCC
6
2
on Text
THR
TR
cvbs/y 4
RES
7
DISC
3
OUT
CTRL
67
HOUT
Sync Sep
5
H-OSC 2062 2028
H-Shift
H/V FB/SC 66
H-Drive
# = NE555 TIMER
2022
7019
3058
VDRA
23
7017#
Vertical & East-
VCC
West Geometry
6
VDRB
22
THR
7
DISC
CTRL
2034
7014
EF
R_SDTV
A13
G_SDTV
A13
7012
EF
B_SDTV A13
+5VSW
7015#
8
VCC
6
2
THR
TR
4
RES
7
DISC H_CS_SDTV
A13
OUT
CTRL 3
5
2042 2021
SANDCASTLE
+5VSW
8
2
TR
4
RES
V_SDTV
A13
3
OUT
5
2045
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