Datasheet

Functional Description
17
SLES099C—March 2007 TVP5147PFP
2.4 Real-Time Control (RTC)
Although the TVP5147 decoder is a line-locked system, the color burst information is used to determine
accurately the color subcarrier frequency and phase. This ensures proper operation with nonstandard video
signals that do not follow exactly the required frequency multiple between color subcarrier frequency and video
line frequency. The frequency control word of the internal color subcarrier PLL and the subcarrier reset bit are
transmitted via terminal 37 (GLCO) for optional use in an end system (for example, by a video encoder). The
frequency control word is a 23-bit binary number. The instantaneous frequency of the color subcarrier can be
calculated using the following equation:
F
PLL
+
F
ctrl
2
23
F
sclk
where F
PLL
is the frequency of the subcarrier PLL, F
ctrl
is the 23-bit PLL frequency control word, and F
sclk
is
two times the pixel frequency. This information can be generated on the GLCO terminal. Figure 2−17 shows
the detailed timing diagram.
RTC
45 CLK18 CLK
L
S
B
0
3 CLK128 CLK
23-Bit Fsc PLL Increment
Start
Bit
1 CLK
RS
Invalid
Sample
Valid
Sample
M
S
B
22
Reserved
NOTE: RTC reset bit (R) is active-low, Sequence bit (S) PAL: 1 = (R-Y) line normal, 0 = (R-Y) line inverted, NTSC: 1 = no change
Figure 2−17. RTC Timing
2.5 Output Formatter
The output formatter sets how the data is formatted for output on the TVP5147 output buses. Table 2−1 shows
the available output modes.