ADC-SDI
Rev.
6
3.6 Selection of luma/chroma separation filter
Filter type
Luma Bandwidth
Limitations
Applications
No comb filter
(filter 3)
PAL ~= 4MHz
NTSC ~= 3MHz
Limited bandwidth.
Cross colour artefacts
visible in luma
VHS, Umatic and other
sources with lower
bandwidth
Fixed 2-line comb filter
(filter 2)
Full bandwidth
available
Cross chroma errors at
vertical transitions.
For PAL: Some cross
colour artefacts in luma
Full bandwidth
processing.
Not suitable for graphics
or material with high
saturation levels.
Adaptive 3-line comb
filter
with filter coefficients
(½,0,½)
(filter 0 for PAL)
(filter 1 for NTSC)
Full bandwidth
available
Some cross colour
artefacts at vertical
transition.
Graphics material with
high saturation may
produce artefacts at
vertical edges.
Best suited for PAL
signal sources.
Very good for most PAL
applications.
Adaptive 3-line comb
filter
with filter coefficients
(¼, ½, ¼)
(filter 0 for NTSC)
(filter 1 for PAL)
Full bandwidth
available
Graphics material with
high saturation may
produce artefacts at
vertical edges.
Some Cross colour
artefacts visible in luma
for PAL signal sources.
Best suited for NTSC
signal sources.
Very good for most
NTSC applications.
Also a good alternative
for PAL sources if
artefacts in (½, 0, ½) are
unacceptable.
Table 1: Selection of luma /chroma separation filter.
The factory default filter setting is: Adaptive 3-line comb filter with filter coefficients (½,0,½).
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