Clamp Operation; Figure 71: Position Of Voltage Clamp Window - Analog Devices Advantiv ADV7604 Hardware Manual

The CP also has the following capabilities:
• Generates HSync, VSync, FIELD, and Data Enable (DE) timing reference outputs
• Detects the source from which the video is to be synchronized
• Measures noise and calibration levels
• Measures the depth of the horizontal synchronization pulse used for AGC
• Detects the presence of Macrovision
• Color space conversion
• Color control adjustment

10.2 Clamp Operation

For analog signals that enter the CP block, there are two clamp methods applied to the video signal:
• An analog voltage clamp block prior to the ADCs
• A digital fine clamp that operates after the DPP block
The analog voltage clamp signal operates on the input video prior to digitization.
the position within the active video lines where the voltage clamp switches on. The position of the
window is changed automatically, dependent on
video standard in question.
Hsync
Analog
voltage
clamp
Digital
fine
clamp
Rev. F August 2010
encoded signals
P P P P
CP_ANVC_POS_DURATION[7:0]=20dec =20LLC clock
15 LLC
clock
CP_ANVC_POS_START[7:0] = 0dec
15+ 20+ 6=41 LLC clock

Figure 71: Position of Voltage Clamp Window

PRIM_MODE[3:0] and VID_STD[5:0],
DFC_POS_START(24 dec) + offset(2 clocks)
6 LLC
clock
227
ADV7604
Figure 71 shows
to suit the