bt865a Conexant Systems, Inc., bt865a Datasheet - Page 26

• Manufacturer Part Number: bt865a
• Description: Ycrcb To Ntsc/pal Digital Video Encoder
• Manufacturer: Conexant Systems, Inc.

Circuit Description
Table 1-3.
1-16
NTSC CCIR601
PAL–M CCIR601
NTSC Square
PAL–M Square
PAL-B CCIR601
PAL–Nc CCIR601
PAL–B Square
PAL-Nc Square
GENERAL NOTE:
1. HCNT refers to the number of luminance pixel periods; there are twice as many CLK periods as HCNT periods.
2. Odd counts at front porch transitions indicate invalid chroma framing.
FOOTNOTE:
(1)
(2)
Operating Mode
In slave mode, since Front Porch timing is triggered by the previous HSYNC pulse, any deviation from nominal line length can
affect the front porch duration.
PAL-Nc refers to the PAL format used in Argentina (Combination N).
Horizontal Counter Values for Various Video Timings
(2)
HCNT
Equalization
Pulse Width
32
32
29
29
32
32
35
35
Table 1-3
color burst, end of color burst, and the first active pixel for the various modes of
operation. The front porch is the interval before the next expected falling HSYNC*
when outputs are automatically blanked.
The horizontal sync width is measured between the 50% points of the falling and
rising edges of horizontal sync.
The start of color burst is measured between the 50% point of the falling edge of
horizontal sync and the first 50% point of the color burst amplitude (nominally +20
IRE for NTSC/PAL–M and 150 mV for PAL–B, D, G, H, I, N, Nc above the blanking
level).
The end of color burst is measured between the 50% point of the falling edge of
horizontal sync and the last 50% point of the color burst envelope (nominally +20 IRE
for NTSC/PAL–M and 150 mV for PAL–B, D, G, H, I, N, Nc above the blanking
level).
2.37
2.37
2.36
2.36
2.37
2.37
2.37
2.37
µ
s
lists the horizontal counter values for the end of horizontal sync, start of
HCNT
Pulse Width
Horizontal/
58
63
63
58
63
63
69
69
Serration
4.67
4.67
4.73
4.73
4.67
4.67
4.68
4.68
µ
s
Conexant
HCNT
Start of Burst
72
78
65
71
76
76
83
83
Horizontal Counter Value
5.33
5.78
5.30
5.79
5.63
5.63
5.63
5.63
ms
HCNT
Duration of
34
34
31
31
30
34
33
37
Burst
2.52
2.52
2.53
2.53
2.22
2.52
2.24
2.51
µ
s
HCNT
127
127
115
115
142
142
155
155
Back Porch
10.52
10.52
10.51
10.51
Bt864A/Bt865A Data Sheet
9.41
9.41
9.37
9.37
ms
Front Porch
HCNT
20
20
18
18
20
20
22
22
100138C
02/17/03
1.48
1.48
1.47
1.47
1.48
1.48
1.49
1.49
µ
s
(1)