Samsung LW15M23C Service Manual page 7

2-3 Timing Chart
This section of the service manual describes the timing that the computer industry recognizes as standard
for computer-generated video signals.
Mode
VGA2/
70 Hz
Timing 720 x 400
fH (KHz) 31.469
A µsec 31.777
B µsec 3.813
C µsec 1.589
D µsec 26.058
E µsec 0.318
fV (Hz) 70.087
O msec 14.268
P msec 0.064
Q msec 0.858
R msec 13.155
S msec 0.191
Clock
Freq. 28.322
(MHz)
Polarity
H.Sync Negative
V.Sync Positive
Remark Separate
Separate Sync
Horizontal
Video
Video
C D E
C D E
Sync Sync
Sync
B
B
A
A
A : Line time total
C : Back porch
E : Front porch
LW15M23C
Table 2-1 Timing Chart
IBM
VGA3/ 640/75 Hz,
60 Hz 60Hz, 72Hz
640 x 480 640 x 480
31.469 37.500
31.778 26.667
3.813 2.032
1.589 3.810
26.058 20.317
0.318 0.508
59.940 75.000
16.683 13.333
0.064 0.080
0.794 0.427
15.761 12.800
0.064 0.027
25.175 31.500
Negative Negative
Negative Negative
Separate Separate
Vertical
Video
Video
Q R S
Q R S
Sync Sync
Sync
P P P
O O
O
B : Horizontal sync width
D : Active time
VESA
800/75 Hz, 56Hz,
1024/60Hz
60Hz, 72Hz
1024 x 768
800 x 600
46.875 48.363
21.333 20.677
1.616 2.092
3.232 2.462
16.162 15.754
0.323 0.369
75.000 60.004
13.333 16.666
0.064 0.124
0.448 0.600
12.800 15.880
0.021 0.062
49.500 75.000
Positive Negative
Positive Negative
Separate Separate
H/V Composite Sync
A
Horizontal Vertical
P
B
Sync-on-Green
Vertical
Green
Horizontal
P
B
O : Frame time total
Q : Back porch
S : Front porch
2 Product Specifications
1024/75Hz
1024 x 768
60.023
16.660
1.219
2.235
13.003
0.203
75.029
13.328
0.050
0.466
12.795
0.017
78.750
Positive
Positive
Separate
VIDEO
Q
R S
O
Q R S
O
P : Vertical sync width
R : Active time
2-3