DATA SHEET
VSP 94x2A
2.5.2. Digital Color Transition Improvement (DCTI)
Table 2–11: Conversion table between HCOF/BCOF
and GAINHP/GAINBP
A digital algorithm is implemented to improve horizon-
tal transitions of the chrominance signals resulting in a
better picture sharpness. A correction signal propor-
tional to the slope of the detected horizontal transition
of the input signal is added to the original input signal.
The amplitude of the correction signal is adjustable by
BCOF
0
GAINBP
−1
HCOF
0
GAINHP
−1
2
1
−0.75
−0.50
−0.25
0.00
0.25
0.50
0.75
1.00
1.25
1.50
1.75
2.00
2.50
3.00
4.00
1
−0.75
−0.50
−0.25
0.00
0.25
0.50
0.75
1.00
1.25
1.50
1.75
2.00
2.50
3.00
4.00
the I C bus parameter ASCENTCTI.
2
2
The I²C bus parameter THRESHC modifies the sensi-
tivity of the DCTI circuit. High values of THRESHC
result in an improvement of significant color transitions
only.
3
3
4
4
5
5
6
6
7
7
8
8
9
9
10
11
12
13
14
15
10
11
12
13
14
15
Table 2–12: Peaking filter adaption for 36 MHz or 27 MHz operation
Expansion Factor of
Postscaler
Corresponding Frequency of Input
Signal for Center Frequency
Bandpass (B=0.25)
Corresponding Frequency of Input
Signal for Center Frequency Highpass
(B=0.5)
CLKB36=36 MHz/27 MHZ
3.375 MHz / 2.5 MHz
...
CLKB36=36 MHz/27 MHZ
6.75 MHz / 5.06 MHz
...
0.75
...
1
4.5 MHz / 3.375 MHz
...
9 MHz / 6.75 MHz
...
...
3
13.5 MHz / 10.125 MHz
27 MHz / 20.25 MHz
Micronas
Aug. 16, 2004; 6251-552-1DS
25
MICRONAS [ MICRONAS ]
