Table 2. Example Of Controller Gain {Analog Gain} Vs. Readout Port - Princeton PIXIS-XB System User Manual

Chapter 5
Output Amplifier {Quality} Selection
The output amplifier amplifies the collected charge from the output node and outputs it as
electrons/count. Although Figure 18 shows an array with two output nodes and amplifiers
(one set at each end of the shift register), some PIXIS-XB systems are available with a
single output node and amplifier. If your system has two output amplifiers, you can
choose the output amplifier to be used (High Capacity or Low Noise) via the
Acquisition|Experiment Setup...|ADC tab { Quality on the Analog to Digital
Conversion expander}:


Note: The choice of output amplifier {Quality} and controller gain {Analog Gain} setting
should be considered together for the best signal capture. Examples of the interaction of
output amplifier and controller gain selections are shown in Table 2, page 43.
Controller Gain
Controller gain (a function of the preamplifier) is software-selectable and is used to
change the relationship between the number of electrons acquired on the CCD and the
Analog-to-Digital Units (ADUs or counts) generated. Selecting the amount of gain is
done on the Acquisition|Experiment Setup...|ADC tab { Analog to Digital
Conversion expander}. The choices are 1 {Low}, 2 {Medium}, and 3 {High}. Users
who measure high-level signals may wish to select Low to allow digitization of larger
signals. Medium is suitable for experiments within the mid-level intensity range. Users
who consistently measure low-level signals may wish to select High, which requires
fewer electrons to generate an ADU and reduces some sources of noise.
The "Certificate of Performance" supplied with the camera lists the measured gain values
at all settings.
Example: The following descriptions assume the Low Noise Readout Port has been
selected and that the actual incoming light level is identical in all three instances. The
numbers used illustrate the effect of changing a controller gain setting and may not
reflect actual performance: gain at the 1, 2, and 3 settings depends on the CCD
installed.
High Capacity amplifier: Provides a spectrometric well capacity that is
approximately 3 times the well capacity for the Low Noise amplifier selection.
High Capacity is suitable when you have intense light signals or signals with
high dynamic range.
Low Noise amplifier: Provides the highest sensitivity performance and is
suitable when you have weak signals.
Readout Port
{Quality}
Low Noise
High Capacity

Table 2. Example of Controller Gain {Analog Gain} vs. Readout Port

Operation
Controller Gain {Analog Gain} Selection
1 {Low} 2 {Medium}
- -
4 e /count 2 e /count
- -
16 e /count 8 e /count
43
3 {High}
-
1 e /count
-
4 e /count
43