PRODUCT SPECIFICATION
TMC22x5yA
VIDEOB data is always selected when theYCCOMP register
bit is HIGH, ie for YC inputs. The selection of 1HF or 0HF
depends upon the SIMP selection bit only when the
YCCOMP register bit is LOW. Therefore, whenYCCOMP is
LOW and 0Hx is selected by SIMP then 0HF is selected for
the FLAT signal, and when 1Hx is selected by SIMP then
1HF is selected for the FLAT signal. This ensures that the
FLAT and SIMPLE data selected for any comb filter is
delayed by the same amount as the data processed through
the comb filter to produce the COMB output.
Adaptive Comb Filter
The IPCF[1:0] register bits select the inputs to the adaptive
comb filter, this would normally be xHH for chroma combs,
xHF for luma combs, and xHL if the luminance signal was to
be sampled dropped on the output of the TMC22x5yA. The
Gaussian filters in the sample drop mode already limit the
chrominance bandwidth to 1.3MHz allowing a [2:1:1] data
format on the output, with the luminance signal having been
vertically filtered by a fixed 3 line comb filter.
The SIMP selection bit is an internally generated signal
based upon the comb filter selected. If a 3 line chroma, luma,
or D1 comb filter is selected, due to the internal 1H delay
inherent with this type of comb filter, the 1HL and 1HH
signals are selected for the respective luma and chroma
SIMPLE data signals. When any other type of comb filter is
selected 0HL and 0HH are selected.
The final selection is the output required for the combed
luminance and chrominance data. The output selection can
be SIMPLE, COMB, FLAT-COMB, or FLAT. Generally
COMB is selected based upon whether a luma or chroma
comb was selected and the complementary output selects
FLAT-COMB. In theYC andY & CbCr data modes the FLAT
signal selects the secondary data and SIMPLE or COMB can
be used to select the primary signal. In these modes the
bandsplit filter can be bypassed or used to remove low fre-
quency noise from the chrominance signal if chroma was
selected as the primary signal.
The DLYF selection bit is also internally generated from the
type of comb filter selected and whether or not the input is in
either the YC or Y & CbCr (ie D1 input) data formats. The
A
SIMP
2:1
MUX
B
4:1
MUX
Y Data
IPCF[1:0]
C
OHF
3:1
MUX
OHH
D
OHL
YMUX[1:0]
IPCF[1:0]
1HF
3:1
MUX
1HH
1HL
Adaptive
Comb
Filter
A: Comb
B: Simple
C: Flat - Comb
D: Flat
IPCF[1:0]
2HF
2HH
3:1
MUX
CMUX[1:0]
A
2HL
SIMP
2:1
MUX
B
4:1
MUX
C Data
C
DLYF
–
3:1
MUX
D
VideoB
65-22x5y-57
Figure 16. Signal Flow Around the Adaptive Comb Filter.
REV. 1.0.0 2/4/03
47
CADEKA [ CADEKA MICROCIRCUITS LLC. ]
