ASAHI KASEI

[AK8815/16]

MS0331-E-00

27

2004 / 08

( 15 ) WSS function

The AK8815/16 supports to encode the WSS ( ITU-R. BT.1119 ) which distinguishes the aspect ratio and sets

CGMS-A etc..

Turning “ON/OFF“ of this function is made by setting both VMOD-bit = 1 and WSS-bit = 1 of { Mode Register

( 0x00 ) }. And data to be set is written into { VBID / WSS Data1 & 2 Registers ( 0x01, 0x02 )}.

WSS Data Update timing

VS YN C

NEW DATA

DATA

O LD DATA

NEW DATA

u-P D ata

Set C ontrol R egister

WSS Waveform

10.5usec

27.4usec

38.4usec

500mV +/- 5%

11.0 +/- 0.25usec

44.5usec

1.5usec

Encode line : former half of Line 23 ( Blank output during latter half )

Coding : Bi-phase modulation coding

Clock : 5 MHz ( Ts = 200 nS )

Encoding details as follows

Run-in

Start code

Group 1

Aspect ratio

Group 2

Enhanced

Services

Group 3

Subtitles

Group4 Reserved

29 elements

24 elements

24 elements

24 elements

18 elements

18 elements

Bit numbering

0 1 2 3

LSB

MSB

0 : 000111

1 : 111000

Bit numbering

4 5 6 7

LSB

MSB

0 : 000111

1 : 111000

Bit numbering

8 9 10

LSB

MSB

0 : 000111

1 : 111000

Bit numbering

11 12 13

LSB

MSB

0 : 000111

1 : 111000

0x1F1C71C7

0x1E3C1F