Texas Instruments THS7319EVM Evaluation Module THS7319EVM THS7319EVM 데이터 시트
제품 코드
THS7319EVM
TYPICAL CONFIGURATION AND VIDEO
DAC/Encoder
+2.6 V to +5 V
Enable
75 W
Out 1
Channel 1
R
75 W
LPF
3-Pole
20-MHz
6 dB
x1
Level
Shift
Out 2
Channel 2
R
75 W
75 W
LPF
3-Pole
20-MHz
6 dB
x1
Level
Shift
Channel 3
R
Out 3
75 W
75 W
LPF
3-Pole
20-MHz
6 dB
x1
Level
Shift
www.ti.com
..............................................................................................................................................................
SBOS468A – JUNE 2009 – REVISED JULY 2009
R’G’B’ (commonly mislabeled RGB) is also called
TERMINOLOGY
G’B’R’ (again commonly mislabeled as GBR) in
professional video systems. The Society of Motion
professional video systems. The Society of Motion
A typical application circuit using the THS7319 as a
Picture
and
Television
Engineers
(SMPTE)
video buffer is shown in
. It shows a DAC or
component
standard
stipulates
that
the
luma
encoder dc-coupled to the input channels of the
information is placed on the first channel, the blue
THS7319 and the output of the THS7319 dc-coupled
color difference is placed on the second channel, and
to the video line. These signals can be NTSC, PAL,
the red color difference signal is placed on the third
or
SECAM
signals
including
composite
video
channel. This practice is consistent with the Y'P'
B
P'
R
baseband signal (CVBS), S-Video Y'C', component
nomenclature. Because the luma channel (Y') carries
Y'P'
B
P'
R
video, broadcast G'B'R' video, or computer
the sync information and the green channel (G') also
R'G'B' video signals.
carries the sync information, it makes logical sense
that G' be placed first in the system. Because the
that G' be placed first in the system. Because the
Note that the Y’ term is used for the luma channels
blue color difference channel (P'
B
) is next and the red
throughout this document rather than the more
color difference channel (P'
R
) is last, then it also
common luminance (Y) term. This usage accounts for
makes logical sense to place the B' signal on the
the definition of luminance as stipulated by the
second channel and the R' signal on the third
. Video
channel, respectfully. Thus, hardware compatibility is
departs from true luminance because a nonlinear
better achieved when using G'B'R' rather than R'G'B'.
term, gamma, is added to the true RGB signals to
Note that for many G'B'R' systems, sync is embedded
form R’G’B’ signals. These R’G’B’ signals are then
on all three channels, but this configuration may not
used to mathematically create luma (Y’). Thus,
always be the case in all systems.
luminance
(Y)
is
not
maintained,
providing
a
difference in terminology.
This rationale is also used for the chroma (C’) term.
Chroma is derived from the nonlinear R’G’B’ terms
and, thus, it is nonlinear. Chominance (C) is derived
from linear RGB, giving the difference between
chroma
Chroma is derived from the nonlinear R’G’B’ terms
and, thus, it is nonlinear. Chominance (C) is derived
from linear RGB, giving the difference between
chroma
(C’)
and
chrominance
(C).
The
color
difference signals (P’
B
/P’
R
/U’/V’) are also referenced
in this manner to denote the nonlinear (gamma
corrected) signals.
corrected) signals.
Figure 50. Typical THS7319 System with DC-Coupled Encoder/DAC and DC-Coupled Line Driving
Copyright © 2009, Texas Instruments Incorporated
17
Product Folder Link(s):