Datasheet

Bandpass
Filter
×
Gain
Peaking
Filter
IN
+
OUT
Delay
Peak
Detector
f − Frequency − MHz
−1
0
1
2
3
4
5
6
7
0 1 2 3 4 5 6 7
Gain = 0
Gain = 2
Gain = 1
Gain = 0.5
Peak at
f = 2.64 MHz
Amplitude − dB
TVP5147M1
SLES140G –JULY 2005–REVISED FEBRUARY 2012 www.ti.com
2.2.3 Luminance Processing
The digitized composite video signal passes through either a luminance comb filter or a chroma trap filter,
either of which removes chrominance information from the composite signal to generate a luminance
signal. The luminance signal is then fed into the input of a peaking circuit. Figure 2-8 illustrates the basic
functions of the luminance data path. In the case of S-video, the luminance signal bypasses the comb filter
or chroma trap filter and is fed directly to the circuit. A peaking filter (edge enhancer) amplifies high-
frequency components of the luminance signal. Figure 2-9 shows the characteristics of the peaking filter at
four different gain settings that are user-programmable via the I
2
C interface.
Figure 2-8. Luminance Edge-Enhancer Peaking Block Diagram
Figure 2-9. Peaking Filter Response, NTSC/PAL ITU-R BT.601 Sampling
2.2.4 Color Transient Improvement
Color transient improvement (CTI) enhances horizontal color transients. The color difference signal
transition points are maintained, but the edges are enhanced for signals that have bandwidth-limited color
components.
22 Functional Description Copyright © 2005–2012, Texas Instruments Incorporated
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