ADV7181 AD [Analog Devices], ADV7181 Datasheet - Page 34

• Manufacturer Part Number: ADV7181
• Description: Multiformat SDTV Video Decoder
• Manufacturer: AD [Analog Devices]

ADV7181B
COMB FILTERS
The comb filters of the ADV7181B have been greatly improved
to automatically handle video of all types, standards, and levels
of quality. The NTSC and PAL configuration registers allow the
user to customize comb filter operation, depending on which
video standard is detected (by autodetection) or selected (by
manual programming). In addition to the bits listed in this
section, there are some further ADI internal controls; contact
ADI for more information.
NTSC Comb Filter Settings
Used for NTSC-M/J CVBS inputs.
NSFSEL[1:0] Split Filter Selection NTSC, Address 0x19 [3:2]
The NSFSEL[1:0] control selects how much of the overall signal
bandwidth is fed to the combs. A narrow split filter selection
gives better performance on diagonal lines, but leaves more dot
crawl in the final output image. The opposite is true for selecting
a wide bandwidth split filter.
CCMN[2:0] Chroma Comb Mode NTSC, Address 0x38 [5:3]
Table 44. CCMN Function
CCMN[2:0]
0xx (default)
100
101
110
111
YCMN[2:0] Luma Comb Mode NTSC, Address 0x38 [2:0]
Table 45. YCMN Function
YCMN[2:0]
0xx (default)
100
101
110
111
Description
Adaptive comb mode.
Disable chroma comb.
Fixed chroma comb (top lines of line memory).
Fixed chroma comb (all lines of line memory).
Fixed chroma comb (bottom lines of line memory).
Adaptive comb mode.
Description
Disable luma comb.
Fixed luma comb (top lines of line memory).
Fixed luma comb (all lines of line memory).
Fixed luma comb (bottom lines of line memory).
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Table 42. NSFSEL Function
NSFSEL[1:0]
00 (default)
01
10
11
CTAPSN[1:0] Chroma Comb Taps NTSC,
Address 0x38 [7:6]
Table 43. CTAPSN Function
CTAPSN[1:0]
00
01
10 (default)
11
Configuration
Adaptive 3-line (3 taps) luma comb.
Use low-pass/notch filter; see the Y Shaping Filter section.
Fixed 2-line (2 taps) luma comb.
Fixed 3-line (3 taps) luma comb.
Fixed 2-line (2 taps) luma comb.
Configuration
Adaptive 3-line chroma comb for CTAPSN = 01.
Adaptive 4-line chroma comb for CTAPSN = 10.
Adaptive 5-line chroma comb for CTAPSN = 11.
Fixed 2-line chroma comb for CTAPSN = 01.
Fixed 3-line chroma comb for CTAPSN = 10.
Fixed 4-line chroma comb for CTAPSN = 11.
Fixed 3-line chroma comb for CTAPSN = 01.
Fixed 4-line chroma comb for CTAPSN = 10.
Fixed 5-line chroma comb for CTAPSN = 11.
Fixed 2-line chroma comb for CTAPSN = 01.
Fixed 3-line chroma comb for CTAPSN = 10.
Fixed 4-line chroma comb for CTAPSN = 11.
Description
Do not use.
NTSC chroma comb adapts 3 lines (3 taps) to 2
lines (2 taps).
NTSC chroma comb adapts 5 lines (5 taps) to 3
lines (3 taps).
NTSC chroma comb adapts 5 lines (5 taps) to 4
lines (4 taps).
Description
Narrow
Medium
Medium
Wide