Service manual

CP-850FX Service Manual
Europe R&D
56
5.5.6 AUTOMATIC PICTURE FORMAT SWITCHING
When AUTO mode is selected by the user, the television will automatically select the picture
format for the user. If the user does not want to accept this selected format, he can always
override the setting by use of the ZOOM control on the remote control.
The received information used for automatic picture format control (only while AUTO is selected)
is supplied from two sources;
 By WSS data (Wide Screen Signalling Information : see the WSS European
Telecommunication Standard ETS 300 294).
 The voltage level from SCART 1 or SCART 2, pin 8 (slow switching)
5.5.6.1 WSS Data
This digital signal is a received at the beginning of line 23 in each frame. It is not a teletext signal,
but the controller uses the same decoder resources to receive and decode the digital signal.
This is bi-phase encoded using a clock frequency of 5 MHz. In total, 14 data bits are available, in
4 groups.
 Group 1 : Aspect Ratio (b0, b1, b2, b3)
 Group 2 : Enhanced Services (b4, b5, b6, b7)
 Group 3 : Subtitles (b8, b9, b10)
 Group 4 : Reserved (b11, b12, b13)
The signal contains bits in Data Group 1 which define an Aspect Ratio label, and in Data Group 3
(b10) which defines if subtitles are available in the video. The other data groups have no
application in this TV for picture format selection.
The TV decoder recognises 5 bits of data (where b3 is an odd parity bit for Data Group 1).
Aspect WSS Bits Format Name
Position Ratio label 0 1 2 3 10 Tube 16:9 Tube 4:3
N/A FORMAT_4_3 0 0 0 1 0 4:3 FULL SCREEN
CENTRE FORMAT_14_9 1 0 0 0 0 ZOOM 14:9 FULL SCREEN
TOP FORMAT_14_9 0 1 0 0 0 DEFAULT DEFAULT
CENTRE FORMAT_16_9 1 1 0 1 0 ZOOM 16:9 FULL SCREEN
TOP FORMAT_16_9 0 0 1 0 0 FULL SCREEN FULL SCREEN
CENTRE FORMAT_16_9_PLUS 1 0 1 1 0 ZOOM 16:9 FULL SCREEN
CENTRE FORMAT_14_9_FULL 0 1 1 1 0 FULL SCREEN 14:9
N/A FORMAT_16_9_ANAM 1 1 1 0 0 FULL SCREEN 16:9
N/A SUBTITLE_OUT_IMAGE X X X X 1 FULL SCREEN FULL SCREEN
There are the following output possibilities;
 4:3
 14:9
 16:9
 ZOOM 14:9
 ZOOM 16:9
 FULL SCREEN (for either 4:3 or 16:9 tubes)
DEFAULT refers to a signal for which there is no implementation, so is treated as if there is no
signal data available.
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