TMC22053KHC Fairchild Semiconductor, TMC22053KHC Datasheet - Page 40

• Manufacturer Part Number: TMC22053KHC
• Manufacturer: Fairchild Semiconductor

Specifications of TMC22053KHC

• Screening Level: Commercial
• Package Type: MQFP
• Pin Count: 100
• Lead Free Status / RoHS Status: Compliant

TMC22x5y
phase relationship to the chroma on 1H. Therefore normally
0H and 2H are added together to produce the average luma
across 3 lines and this is then subtracted from 1H to produce
the combed chroma.
YC Line-Based Comb Filters
The luminance and chrominance signals, are by definition,
already separated for YC inputs. However, if the original
source was composite, there is a distinct possibility that there
is some residual luminance (cross color) in the chrominance
signal and some residual chrominance (cross luma) in the
luminance signal. It is therefore legitimate to treat these
signals as if they were simply the output from bandsplit
filters and process the luma and chroma signals accordingly.
D1 Line-Based Comb Filters
A D1 data stream consists of multiplexed Y, C
component data. If the original source was composite there
maybe luminance (cross color) in C
(cross luma) in Y. In the first case any luminance that was
passed through a demodulator along with the chroma to
produce the baseband C
have the same characteristics as chroma. That is to say, the
cross color would advance by 180° every line in NTSC and
every 2 lines in PAL. It is therefore possible to remove this
cross color in a comb filter. In the latter case any chromi-
nance that is still in the Y data can obviously be removed in a
comb filter as well.
The original source for the D1 signal could also have been
computer graphics. In this case, the comb filter can be used
to remove the picture flicker and convert the output to RGB.
40
Figure 7. Chrominance Vector Rotation in PAL and NTSC
FIELD
0
0
0
0
0
1
1
1
1
LINE no
N
N+1
N+2
N+3
N+4
M
M+1
M+2
M+3
B
V
U
C
PAL
U
V
U
R
color difference signals would
U
V
U
V
V
B
C
R
2H
1H
0H
and chrominance
b
Q
Q
and C
NTSC
I
65-22x5y-48
I
R
I
Q
Q
NTSC Frame and Field Based
Decoders
Composite Frame-Based Comb Filters
In NTSC the chrominance vectors advance by 180 degrees
every line, therefore after 525 lines the 2 adjacent frame lines
0H and FR0H and the two consecutive field lines FR0H and
FR1H are 180 degrees apart. The flat color on FR0H and
FR1H can be added or subtracted to provide the luminance
or chrominance to subtract from 0H.
Composite Field-Based Comb Filters
In NTSC field based comb decoders, there is an external
delay of 263 lines, therefore the 2 adjacent picture lines 0H
and F0H and the two consecutive field lines F0H and F1H
are 180 degrees apart. The flat color on F0H and F1H can be
added or subtracted to provide the luminance or chromi-
nance to subtract from 0H.
PAL Frame- and Field-Based
Decoders
Composite PAL Frame-Based Comb Filters
In PAL the chrominance vectors advance by 270 degrees
every line. After 625 lines the two adjacent frame lines 0H
and FR0h are 90 degrees apart. It is therefore necessary to
delay the FR0H data by an addition line so that 0H and
FR0H are 180 degrees apart. The flat color on 0H and FR0H
can now be added to provide the luminance or subtracted to
produce chrominance.
LINE no
22
23
24
21
283
284
285
286
Figure 8. Chrominance Vector Rotation Over 4
Q
Q
FIELD 1
I
I
I
(1H)
(0H)
I
Q
Q
Fields in NTSC
Q
Q
FIELD 2
I
I
I
I
(F1H)
(F0H)
Q
Q
PRODUCT SPECIFICATION
Q
Q
FIELD 3
I
I
I
I
(FR1H)
(FR0H)
Q
Q
Q
Q
65-22x5y-49
FIELD 4
I
I
I
I
Q
Q