Datasheet

14
SLES084C − August 2007TVP5146
2.2.2.2 Y/C Separation
Y/C separation can be done using adaptive 5-line (5-H delay) comb filters or a chroma trap filter.
The comb filter can be selectively bypassed in the luma or chroma path. If the comb filter is
bypassed in the luma path, then chroma trap filters are used which are shown in Figure 2−8
through Figure 2−11. TI’s patented adaptive comb filter algorithm reduces artifacts such as
hanging dots at color boundaries. It detects and properly handles false colors in high frequency
luminance images, such as a multiburst pattern or circle pattern. Adaptive comb filtering is the
recommended mode of operation.
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f – Frequency – MHz
No Notch Filter
Notch 3 Filter
Notch 2 Filter
Amplitude − dB
Figure 2−8. Chroma Trap Filter Frequency
Response, NTSC Square Pixel Sampling
Notch 1 Filter
f – Frequency – MHz
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No Notch Filter
Notch 3 Filter
Notch 1 Filter
Amplitude − dB
Figure 2−9. Chroma Trap Filter Frequency
Response, NTSC ITU-R BT.601 Sampling
Notch 2 Filter
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Figure 2−10. Chroma Trap Filter Frequency
Response, PAL ITU-R BT.601 Sampling
Figure 2−11. Chroma Trap Filter Frequency
Response, PAL Square Pixel Sampling
f – Frequency – MHz
Amplitude − dB
No Notch Filter
Notch 2 Filter
Notch 1 Filter
Notch 3 Filter
f – Frequency – MHz
−40
−35
−30
−25
−20
−15
−10
−5
0
5
10
01234567
Amplitude − dB
No Notch Filter
Notch 2 Filter
Notch 1 Filter
Notch 3 Filter