Gain And Black Level; Analog Domain - GigE VA Series User Manual

VA GigE series

9.10 Gain and Black Level

You can set the analog (VGA) and digital gain factor to adjust the gain. The black level is adjusted by removing
the optical black offset from the CCD so that the effect of dark current will be minimized.
9.10.1

Analog Domain

The VA GigE camera has one Analog Signal Processor (or Analog Front End (AFE)) for each channel. This AFE
consists of Correlated Double Sampler (CDS), Variable Gain Amplifier (VGA), Black Level Clamp and 14-bit A/D
converter.
ANALOG CDS VGA 14-BIT 14-BIT
CCD IN GAIN GAIN ADC LVDS
1~40 times
LEVEL
CLAMP
Figure 9.19 AFE Block Diagram
You can change the gain and black level value by inputting proper value into the registers for gain and black
level adjustments inside the AFE. The CDS gain value is set in the factory during the manufacturing process,
therefore you cannot change the value. The VGA gain is the same as the analog gain. You can set the analog
gain for all analog taps or each tap. You can determine whether to control the gain balance between each tap
manually or automatically by setting the Gain Auto Balance parameter to Off or Once. To balance the black
level between each tap, use the Black Level parameter.
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