bt829bkrf ETC-unknow, bt829bkrf Datasheet - Page 51

• Manufacturer Part Number: bt829bkrf
• Description: Video Streamii Decoders
• Manufacturer: ETC-unknow

Bt829B/827B
VideoStream II Decoders
Figure 1-23. CC/EDS Data Processing Path
Figure 1-24. CC/EDS Incoming Signal
Composite
Analog
–40
50
25
0
HSync
ADC
Color
Burst
Decimation
Filter
Clock Run-in
1.10 Closed Captioning and Extended Data
In a system capable of capturing Closed Captioning and Extended Data Services
adhering to the EIA-608 standard, 2 bytes of information are presented to the
video decoder on line 21 (odd field) for CC and an additional two bytes are pre-
sented on line 284 (even field) for EDS.
video input. The signal contains information identifying it as the CC/EDS data
and is followed by a control code and 2 bytes of digital information transmitted
by the analog signal. For the purposes of CC/EDS, only the luma component of
the video signal is relevant. Therefore, the composite signal goes through the dec-
imation and Y/C separation blocks of the Bt829B before any CC/EDS decoding
takes place. See Figure 1-23 for a representation of this procedure.
ing bits in the Extended Data Services/Closed Caption Status Register
(CC_STATUS;0X1C). The CC and EDS are independent and the video decoder
may capture one or both in a given frame. The CC/EDS signal is displayed in
Figure 1-24. In CC/EDS decode mode, once Bt829B has detected that line 21 of
the field is being displayed, the decoder looks for the Clock Run-In signal. If the
Clock Run-In signal is present and the correct start code (001) is recognized by
Bt829B, then the CC/EDS data capture commences. Each of the 2 bytes of data
transmitted to the video decoder per field contains a 7-bit ASCII code and a parity
bit. The convention for CC/EDS data is odd parity.
The data presented to the video decoder is an analog signal on the composite
The Bt829B can be programmed to decode CC/EDS data via the correspond-
Services Decoding
Separation
Filter
Start Bits
Y/C
S1 S2 S3 b0 b1 b2 b3 b4 b5 b6 P1 b0 b1 b2 b3 b4 b5 b6 P2
Luma
D829BDSA
1.10 Closed Captioning and Extended Data Services Decoding
Interpolation
Character One
CC/EDS
Decoder
Filter
YCrCb
4:2:2
CC/EDS
FIFO
Character Two
1.0 Functional Description
CC_Status
CC_Data
Register
Register
I
I
2
2
C
C
41