VDP313XY Datasheet, PDF (18/76 Pages) Micronas – Video Processor Family

VDP 313xY
ADVANCE INFORMATION
2.10.7.Chrominance Transient Improvement
The intention of this block is to enhance the chromi-
nance resolution. A correction signal is calculated by
differentiation of the color difference signals. The differ-
entiation can be selected according to the signal band-
width, e.g. for PAL/NTSC/SECAM or digital component
signals, respectively. The amplitude of the correction
signal is adjustable. Small noise amplitudes in the cor-
rection signal are suppressed by an adjustable coring
circuit. To eliminate ‘wrong colors’, which are caused
by over and undershoots at the chrominance transi-
tion, the sharpened chrominance signals are limited to
a proper value automatically.
2.10.8.Inverse Matrix
A 6-multiplier matrix transcodes the C_R and C_B signals
to R-Y, B-Y, and G-Y. The multipliers are also used to
adjust color saturation in the range of 0 to 2. The coef-
ficients are signed and have a resolution of 9 bits. The
matrix computes:
R−Y = MR1×C_B+MR2×C_R
G−Y = MG1×C_B+MG2×C_R
B−Y = MB1×C_B+MB2×C_R
The initialization values for the matrix are computed
from the standard ITUR (CCIR) matrix:
L
a)
C_R in
C_B in
R
10
1.402
Y
G=
1 −0.345 −0.713
C_B
B
1 1.773 0
C_R
For a contrast setting of CTM+32, the matrix values
are scaled by a factor of 64 (see Table 2–5 on
page 32).
b)
Ampl.
2.10.9.RGB Processing
t
After adding the post-processed luminance, the digital
RGB signals are limited to 10 bits. Three multipliers
are used to digitally adjust the whitedrive. An average
beam current limiter using the same multipliers is
implemented (see Section 2.11.1. on page 21).
t
c)
C_R out
C_B out
t
a) C_RC_B input of DTI
b) C_RC_B input + Correction signal
c) sharpened and limited C_RC_B
Fig. 2–15: Digital Color Transient Improvement
2.10.10.Picture Frame Generator
When the picture does not fill the total screen (height
or width too small) it is surrounded with black areas.
These areas (and more) can be colored with the pic-
ture frame generator. This is done by switching over
the RGB signal from the matrix to the signal from the
internal picture frame generator.
The width of each area (left, right, upper, lower) can be
adjusted separately. The generator starts on the right,
respectively lower side of the screen and stops on the
left, respectively upper side of the screen. This means,
it runs during horizontal, respectively vertical flyback.
The color of the complete border can be programmed
in the format 3 × 4 bit RGB. The contrast can be
adjusted separately.
18
Micronas