3.0 Digital Processing and Functionality
3.2 Effects
Bt860/861
Multiport YCrCb to NTSC/PAL /SECAM
Figure 3-18 illustrates a typical WSS signal, where WSSDAT[14:1] = 0x00.
Note that WSS uses bi-phase coding of its data bits. The amplitude of the WSS
pulses is 500 mV above black when high, and black when low. For further WSS
details, see specification ETS 300294 or ITU-R BT.1119.
Figure 3-18. WSS Waveform
0.5 V
0.0 V
Start
Code
Bit 14
Bit 1
Run-In
14 Data Bits
861_002
3.2.17 Copy Generation Management System
Copy Generation Management System (CGMS) is used in 525-line systems on
lines 20 and 283 (a.k.a. line 20, field 2). The CGMS data is 20 bits long and is
entered on register bits WSSDAT[20:1].
•
•
•
Set register bit EWSSF1 to 1 to enable CGMS on field 1, line 20.
Set register bit EWSSF2 to 1 to enable CGMS on field 2, line 283.
Set register bit SQUARE to 0 if the clock is at CCIR clock speeds
(27 MHz).
•
Set register bit SQUARE to 1 if the clock is at square pixel speeds
(24.5454 MHz).
Although there is no clock run-in in CGMS, a reference pulse is provided
automatically.
3-28
Conexant
D860DSA
CONEXANT [ CONEXANT SYSTEMS, INC ]
