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6. Adjustment Mode
B
Black level
0.7V
Image 6-3
Black level
∆
G
∆Β
∆
R
R
G
B
Image 6-4
One can conclude here that a good color tracking can only be met by using three previously (input) balanced
color signals
Analog Digital Conversion
The analog color signals must pass through an Analog/Digital conversion circuit prior to any digital processing in the PMP.
A typical ADC transforms the analog value into an 8 bit coded digital signal.
The graphic shows that when converting a signal containing a DC offset component the range of the converter is not optimally used.
Black level
∆
R
ADC
0
255
i1 : superfleous information
i2 : video information
Image 6-5
One can conclude here that a good data conversion can only be met by using three previously (input) balanced
color signals
The objective of input balancing
The objective in input balancing is to “set” the same black level and the same white level for the three colors of a particular input
source.
Black level setting : brightness
White level setting : contrast
The same absolute black and white level for the three colors allow the same reference for Brightness and contrast control of the
picture !
These two references also set the range in which the ADC will work for that particular source (this explains also why each input
balance setting is linked to a particular source and thus saved in the image file).
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R5976690 XLM H25 03/09/2004
Summary of Contents for XLM H25
Page 1: ...XLM H25 Owner s manual R9010100 R5976690 02 03 09 2004 ...
Page 4: ......
Page 8: ...Table of contents 4 R5976690 XLM H25 03 09 2004 ...
Page 12: ...1 Packaging and Dimensions 8 R5976690 XLM H25 03 09 2004 ...
Page 26: ...2 Installation Guidelines 22 R5976690 XLM H25 03 09 2004 ...
Page 40: ...3 Connections 36 R5976690 XLM H25 03 09 2004 ...
Page 50: ...4 Getting Started 46 R5976690 XLM H25 03 09 2004 ...
Page 96: ...9 Programmable Function Keys 92 R5976690 XLM H25 03 09 2004 ...
Page 102: ...B Standard Source Set up files 98 R5976690 XLM H25 03 09 2004 ...