bt865a Conexant Systems, Inc., bt865a Datasheet - Page 33

• Manufacturer Part Number: bt865a
• Description: Ycrcb To Ntsc/pal Digital Video Encoder
• Manufacturer: Conexant Systems, Inc.

Bt864A/Bt865A Data Sheet
1.7.2
Figure 1-17. DAC Sinx/x Response
100138C
02/17/03
DAC Coding
–0.5
–1.5
–2.5
–3.5
–4.5
For all video formats, the input luma and chroma values are scaled internally such
that, after sync and setup (if enabled) are added, the output from sync to 100% white
(for CVBS/Y outputs) is approximately 1.00 V.
In addition, the chroma is boosted to compensate for the sinx/x rolloff due to the DAC
(see
Table 1-4
values as a function of SETUPDIS.
Table 1-4. DAC Coding
–1
–2
–3
–4
–5
0
SETUPDIS
0
Figures 1-17
0
1
summarizes the blank, black, and 100% white DAC codes and chroma gain
2
and 1-18). The amount of boost is determined by SETUPDIS.
4
Blank
Frequency (MHz)
Conexant
228
224
CLK = 27 MHz
6
8
Black
272
224
10
12
100% White
801
800
100138_018
Chroma Gain
Circuit Description
1.02944
1.0458
1-23