Datasheet

Bandpass
Filter
x
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
TVP5146M2
SLES141H –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. High-frequency components of the luminance
signal are enhanced by a peaking filter (sharpness). Figure 2-9 shows the characteristics of the peaking
filter at four different gain settings that are programmable via the host port.
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 (CTI)
CTI enhances horizontal color transients by delay modulation for both color difference signals. The
operation must be performed only on YCbCr-formatted data. The color difference signal transition points
are maintained, but the edges are enhanced for signals that have bandwidth-limited color components (for
example, CVBS and S-Video).
22 Functional Description Copyright © 2005–2012, Texas Instruments Incorporated
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