TMC22091/TMC22191
PRODUCT SPECIFICATION
Genlock Interface
The TMC22x91 can process digital composite video
connected to its CVBS port. It has been designed to couple
tightly with the companion TMC22071 Genlocking Video
Digitizer, but it will work with other sources as well.
Subcarrier frequency and phase data are transmitted to the
encoder over the CVBS bus as 4-bit nibbles on CVBS
3-0
during the horizontal sync period. Field identification is also
required for the TMC22x91 internal sync generator. The
14th nibble of the sequence contains no relevant data.
The digital composite video has to be in standard 8-bit
binary format at a PXCK/2 rate. Synchronization with the
internal PXCK/2 is established by the phasing of the
GHSYNC input, as shown in Figures 24 and 25.
0
1
2
3
4
5
6
7
8
9
38 39 40 41 42 43 44 45 46 47 48 49
PXCK
CVBS
PD
V
V
V
V
V
V
P
V
P
V
P
V
P
V
P
V
P
N+2
N+3
N+4
N+5
N+6
N+4
N+25
N+26
N+27
N+28
N+29
N+30
P
P
P
P
P
N
N+1
N+2
N+3
N+23
N+24
N+25
N+26
N+27
N+28
KEY MIDPOINT
FIRST KEY WORD
COMPOSITE
OUTPUT
24360A
Figure 23. Data Keying
2N+1
2N+2
2N+3
PXCK
t
t
HGI
SGI
GHSYNC
t
t
HGI
SGI
CVBS
7-0
24341A
Figure 24. Genlock Interface Timing
44
CADEKA [ CADEKA MICROCIRCUITS LLC. ]
