Datasheet

75 W
S-VideoY'Out
CVBS
R
SOC/DAC/Encoder
S-Video Y’
R
S-Video C’
R
Y'/G'
R
1
2
3
4
5
6
7
8
9
10
20
19
18
17
16
15
14
13
12
11
SD1OUT
SD2OUT
SD3OUT
DisableSD
GND
DisableSF
SF1OUT
SF2OUT
SF3OUT
BypassSF
SD1IN
SD2IN
SD3IN
NC
V
S+
NC
SF1IN
SF2IN
SF3IN
BypassSD
THS7368
Bypass
SDLPF
Bypass
SFLPF
P' /B'
B
R
CVBS
P' /R'
R
R
75 W
75 W
S-VideoC'Out
75 W
75 W
75 W
Y'/G'Out
75 W
P' /B'Out
B
75 W
75 W
P' /R'Out
R
75 W
75 W
75 W
+2.7Vto
+5V
DisableSF
DisableSD
THS7368
www.ti.com SBOS497 –DECEMBER 2009
TYPICAL CONFIGURATION AND VIDEO departs from true luminance because a nonlinear
TERMINOLOGY term, gamma, is added to the true RGB signals to
form R’G’B’ signals. These R’G’B’ signals are then
A typical application circuit using the THS7368 as a
used to mathematically create luma (Y’). Thus,
video buffer is shown in Figure 37. It shows a DAC or
luminance (Y) is not maintained, providing a
encoder driving the input channels of the THS7368.
difference in terminology.
One channel is a CVBS connection while two other
channels are for the S-Video Y’/C’ signals of an SD This rationale is also used for the chroma (C’) term.
video system. These signals can be NTSC, PAL, or Chroma is derived from the nonlinear R’G’B’ terms
SECAM signals. The other three channels are the and, thus, it is nonlinear. Chominance (C) is derived
component video Y’/P’
B
/P’
R
(sometimes labeled from linear RGB, giving the difference between
Y’U’V’ or incorrectly labeled Y’/C’
B
/C’
R
) signals. These chroma (C’) and chrominance (C). The color
signals are typically 480i, 576i, 480p, 576p, 720p, difference signals (P’
B
/P’
R
/U’/V’) are also referenced
1080i, or up to 1080p60 signals. Because the filters in this manner to denote the nonlinear (gamma
can be bypassed, other formats such as R'G'B' video corrected) signals.
up to QXGA or UWXGA can also be supported with
the THS7368.
Note that the Y’ term is used for the luma channels
throughout this document rather than the more
common luminance (Y) term. This usage accounts for
the definition of luminance as stipulated by the
International Commission on Illumination (CIE). Video
(1) SF indicates selectable filter.
Figure 37. Typical Six-Channel System Inputs from DC-Coupled Encoder/DAC with DC-Coupled Line
Driving
Copyright © 2009, Texas Instruments Incorporated Submit Documentation Feedback 21
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