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4
6
2
8
2.25
5.5
( )
1 0.5
z
z
H z
z
−
−
−
−
−
=
−
(
)
(
)
(
)
(
)
4.25
4.25
SCP1
1024
128
20632
27
4.40625
4.40625
SCP2
1024
128
21390
27
OB
OR
f
MHz
MHz
MHz
f
MHz
MHz
MHz
=
=
×
×
=
=
=
×
×
=
1
27
1024
128
x
FM
D
f
MHz
=
×
×
Internal Modules
121
SPRUHI7A – December 2012 – Revised June 2016
Copyright © 2012–2016, Texas Instruments Incorporated
High-Definition Video Processing Subsystem (HDVPSS)
1.2.6.2.7.3.3 FM Modulation
The low-frequency, pre-emphasized DbDr is then applied to FM modulation. The frequency of the FM
modulated sub-carrier is determined by the following equation:
Prior to the modulation, the offsets corresponding to the nominal subcarrier frequency of Db and Dr are
added to the low-frequency, pre-emphasized DbDr. The Db and Dr offsets are set by the sub-carrier
parameter register SCP1 and SCP2, respectively, as shown in
Figure 1-66. Sub-carrier Parameter Registers
The amplitude of the FM modulated sub-carrier is specified by the CBLVL register. While the CBLVL
register specifies the burst amplitude for NTSC/PAL mode, it works differently in SECAM as the sub-
carrier amplitude.
For color synchronization, the VENC does not support field identification, but line identification.
The phase of the sub-carrier is reset every line.
1.2.6.2.7.3.4 Bell Filter
A high-frequency pre-emphasis is performed on the FM modulated sub-carrier. The filter has a bell
characteristic expressed by:
Finally, SECAM chroma is available from the bell filter output.
1.2.6.2.7.4 Luma Delay
The Y signal delay on the CVBS path can be adjusted by the CYDLY register. It adjusts the Y delay right
before mixing Y and C to generate CVBS. The adjustable range is from –8 to 7 cycle of clk2x. S-Video Y
is not affected.