Texas Instruments TVP5147M1PFP - Manual (Page 21)

Functional Description
13 SLES140A—March 2007 TVP5147M1PFP
Figure 2−4. Color Low-Pass Filter Frequency
Response
f − Frequency − MHz
−70
−60
−50
−40
−30
−20
−10
0
10
0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0
ITU-R BT.601 −3 dB
@ 1.42 MHz Amplitude − dB
Figure 2−5. Color Low-Pass Filter With Filter
Characteristics, NTSC/PAL ITU-R BT.601
Sampling
f − Frequency − MHz
−70
−60
−50
−40
−30
−20
−10
0
10
0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0
Amplitude − dB
Filter 3
−3 dB @ 554 kHz
Filter 2
−3 dB @ 844 kHz
Filter 1
−3 dB
@ 1.03 MHz
Filter 0
−3 dB @ 1.41 MHz
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 2−6 and Figure 2−7. The TI 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.
f − Frequency − MHz
−40
−35
−30
−25
−20
−15
−10
−5
0
5
10
0 1 2 3 4 5 6 7
No Notch Filter
Notch 3 Filter
Notch 1 Filter
Amplitude − dB
Figure 2−6. Chroma Trap Filter Frequency
Response, NTSC ITU-R BT.601 Sampling
Notch 2 Filter
−40
−35
−30
−25
−20
−15
−10
−5
0
5
10
0 1 2 3 4 5 6 7
Figure 2−7. Chroma Trap Filter Frequency
Response, PAL ITU-R BT.601 Sampling
f − Frequency − MHz
Amplitude − dB
No Notch Filter
Notch 2 Filter
Notch 1 Filter
Notch 3 Filter