
Philips Semiconductors
Preliminary specification
1999 Sep 28
46
TV signal processor-Teletext decoder with
embedded
μ
-Controller
TDA 935X/6X/8X series
Multi Rate Video Input Processor
The multi rate video input processor is a Digital Signal Processor designed to extract the data in serial form and
recover the clock from a digitised CVBS signal.
D
ATA
S
TANDARDS
The data and clock standards that can be recovered are shown in Table 12.
Data Capture Timing
The Data Capture timing section uses the Synchronisation information extracted from the CVBS signal to
generate the required Horizontal and Vertical reference timings.
The timing section automatically recognises and selects the appropriate timings for either 625 (50Hz)
synchronisation or 525 (60Hz) synchronisation. A flag TXT12.Video Signal Quality is set when the timing section
is locked correctly to the incoming CVBS signal. When TXT12.Video Signal Quality is set another flag
TXT12.625/525 SYNC can be used to identify the standard.
Acquisition
The acquisition sections extracts the relevant information from the serial data stream received from the MulVIP
section and writes it in to display memory.
WST A
CQUISITION
The device is capable of acquiring level 1.5 625 Line and 525 Line World System Teletext (see Reference [3]
and Reference [4]]).
B
ROADCAST
S
ERVICE
D
ATA
D
ETECTION
When a packet 8/30 is detected, or a packet 4/30 when the device is receiving a 525 line transmission, the
TXT13. Pkt 8/30 flag is set. The flag can be reset by writing a logic 0 into the SFR bit.
F
ASTEXT
D
ETECTION
When a packet 27, designation code 0 is detected, whether or not it is acquired, the TXT13. FASTEXT bit is set.
If the device is receiving 525 line teletext, a packet X/0/27/0 is required to set the flag. The flag can be reset by
writing a logic 0 into the SFR bit.
Data Standard
Clock Rate
625WST
6.9375 MHz
525WST
5.7272MHz
VPS
5.0MHz
WSS
5.0MHz
Closed Caption
500KHz
Table 12 Data Slicing Standards