User`s manual

Operation and Features

3-12 BASLER A302f

DRAFT

3.6.1 Gain settings in more detail

The output signals from the pixels in the CCD sensor normally range from 0 Volts when the pixels

are exposed to no light to 0.375 Volts when they are exposed to bright light. Within that range, the

sensor characteristics are linear. Saturation starts at 0.375 Volts. Further exposure results in a

higher sensor output signal but linearity is no longer guaranteed.

The default factory gain is set for an amplification factor of 5.33 (14.5 dB). At this setting, the

sensor’s normal linear output range of 0 V - 0.375 V is amplified to 0 V - 2.0 V. The peak-to-peak

input range of the ADC is 0 V - 2.0 V. Thus when the gain is at factory default, the amplified output

of the sensor maps directly to the input voltage range of the ADC.

Gain is adjustable and can be programmed on a decimal scale that ranges from 0 to 511 (0x000

to 0x1FF). However, only the settings from 0 to 319 (0x000 to 0x13F) are effective. Settings

greater than 319 will not increase the gain and should not be used. The settings result in the

following amplification:

• 0 = 4.5 dB

• 319 = 34.5 dB

• In between, the change in dB setting is linear.

• The gain can be adjusted in steps of 0.09 dB.

The desired 14.5 dB default gain is achieved when the gain is programmed to 106 (0x06A). You

should find that the default gain setting on your camera is near to this value.

Reducing the gain below 106 results in mapping more than the linear operating range of the

sensor to the ADC. Increasing the gain to more than 106 maps a smaller portion of the sensor’s

linear output signal to the ADC.

If you know the decimal number setting for the gain on your camera, the equivalent decibel value

can be calculated as follows:

34.5 – 4.5

319

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4.5+=