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DATA SHEET
12
Aug. 16, 2004; 6251-552-1DS
Micronas
2.1.6. Luminance Processing
A luminance notch filter is implemented to separate
the chroma information from the luminance. Depend-
ing on the color standard, one out of three different
notch
characteristics
is
chosen
(‘PAL’,
‘NTSC’,
‘SECAM’) automatically.
For PAL and Secam the respective notch filters have 5
different characteristics each. The luminance notch fil-
ter for NTSC can be set to 4 different filter response
curves. They can be selected by NTCHSEL. Alterna-
tively, no notch should be used for Y/C input
(NOTCHOFF). The filter characteristics can be found
in
Figure 2–8. In SECAM operation, the notch filter can
be fixed to one frequency or toggle between 4.4 MHz
and 4.25 MHz depending on the transmitted color (Dr,
Db) (SECNTCH).
A simple lowpass-filter can be enabled by LPPOST to
further reduce high-frequency noise component from
the CVBS signal.
Fig. 2–8: Filter Characteristics for NTSC, PAL M and
PAL N
Fig. 2–9: Filter Characteristics for PAL B/G, NTSC44,
PAL60
Fig. 2–10: Filter Characteristics for SECAM
(SECNTCH=’01’, 4.25 MHz)
Fig. 2–11: Filter Characteristics for Y/C mode.
The black level can be shifted by the parameter
LMOFST. This is required to compensate 7.5 IRE off-
sets in some input signals (e.g. NTSC) The positive or
negative offset is added to the Y signal before scaling.
Fig. 2–12: Adjustment of ‘Black’ to ‘Blankingvalue’ at
Analog Output.
3.58
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
5
5.5
6
30
25
20
15
10
5
0
5
characteristic for NTSC
frequency [MHz]
attenuation
[dB]
’x00’
NTCHSEL=
’x01’
’x10’
’x11’
4.43
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
5
5.5
6
30
25
20
15
10
5
0
5
characteristic for PAL
frequency [MHz]
attenuation
[dB
]
NTCHSEL=
’000’
’100’
’010’
’011’
’001’
4.25
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
5
5.5
6
30
25
20
15
10
5
0
5
characteristic for SECAM (4.25 MHz)
frequency [MHz]
atte
nua
tion
[
dB]
NTCHSEL=
’000’
’100’
’010’
’011’
’001’
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
5
5.5
6
30
25
20
15
10
5
0
5
characteristic for Y/C
frequency [MHz]
atte
nua
tion
[
dB]
LPPOST=1
LPPOST=0
LMOFST='01'
LMOFST='11'
LMOFST='00'
LMOFST='10'
BLANKING BLACK
LMOFST='01'
LMOFST='11'
LMOFST='00'
LMOFST='10'
BLANKING
BLACK
Input signals without 7.5IRE offset
Input signals with 7.5IRE offset