VDP3104B Ver la hoja de datos (PDF) - Micronas
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VDP3104B Datasheet PDF : 72 Pages
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VDP 31xxB
PRELIMINARY DATA SHEET
cross-color components, as well as cross-luminance.
The loss of vertical resolution in the luminance channel
is compensated by adding the vertical detail signal with
removed color information.
CVBS
8
Notch
filter
Chroma
Process.
Y
CrC b
Luma
8
Chroma
8
Chroma
Process.
a) conventional
b) S-VHS
CVBS
8
Notch
filter
Y
CrC b
Y
CVBS
8
Chroma
Process.
1H
Delay
c) compensated
1H
Delay
Notch
filter
CrC b
Y
Chroma
Process.
d) comb filter
Fig. 2–7: NTSC color decoding options
CrC b
CVBS
8
Notch
filter
Chroma
Process.
1H
Delay
a) conventional
Luma
8
Chroma
8
Chroma
Process.
1H
Delay
b) S-VHS
Fig. 2–8: PAL color decoding options
Y
CrC b
Y
CrC b
CVBS
8
Notch
filter
Chroma
Process.
1H
Delay
MUX
Fig. 2–9: SECAM color decoding
Y
CrC b
12
2.3.8. Luminance Notch Filter
If a composite video signal is applied, the color informa-
tion is suppressed by a programmable notch filter. The
position of the filter center frequency depends on the
subcarrier frequency for PAL/NTSC. For SECAM, the
notch is directly controlled by the chroma carrier fre-
quency. This considerably reduces the cross-lumi-
nance. The frequency responses for all three systems
are shown in Fig. 2–10.
dB
10
0
–10
–20
–30
–40
MHz
0
2
4
6
8
10
PAL/NTSC notch filter
dB
10
0
–10
–20
–30
–40
MHz
0
2
4
6
8
10
SECAM notch filter
Fig. 2–10: Frequency responses of the luma
notch filter for PAL, NTSC, and SECAM
2.3.9. Skew Filtering
The system clock is free-running and not locked to the
TV line frequency. Therefore, the ADC sampling pattern
is not orthogonal. The decoded YCrCb signals are con-
verted to an orthogonal sampling raster by the skew fil-
ters, which are part of the scaler block.
The skew filters allow the application of a group delay to
the input signals without introducing waveform or fre-
quency response distortion.
The amount of phase shift of this filter is controlled by the
horizontal PLL1. The accuracy of the filters is 1/32
clocks for luminance and 1/4 clocks for chroma. Thus
the 4:2:2 YCrCb data is in an orthogonal pixel format
even in the case of nonstandard input signals such as
VCR.
Micronas
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