Teledyne PIXIS-XF, Системное руководство

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54 PIXIS-XF System Manual Issue 5
5.6 Digitization (Rate)
After gain has been applied to the signal, the Analog-to-Digital Converter (ADC)
converts that analog information (continuous amplitudes) into a digital data (quantified,
discrete steps) that can be read, displayed, and stored by the application software. The
number of bits per pixel is based on both the hardware and the settings programmed
into the camera through the software. Refer to
Section 5.5, Readout , on page 48 for
additional information.
Factors associated with digitization include the digitization rate and baseline signal.
Because the PIXIS-XF cameras have dual digitizers, you can change the speed at which
digitization occurs. ADC offset of the baseline, however, is set at the factory and is not
user-changeable. These factors are discussed in the following paragraphs.
5.6.1 Digitization Rate
The PIXIS-XF camera has been designed with dual digitizers (i.e., 100 kHz and 2 MHz).
Dual digitization allows you to choose how quickly the data will be digitized with
optimal signal-to-noise ratios achieved at both readout speeds. Because the readout
noise of CCD arrays increases with the readout rate, it is sometimes necessary to trade
off readout speed for high dynamic range. The 2 MHz conversion speed is used for the
fastest possible data collection and the 100 kHz conversion speed is used where noise
performance is the paramount concern. Switching between the conversion speeds is
completely under software control for total experiment automation.
NOTE:
In WinX/32, the ADC rate can be changed on the Experiment
Setup
►
ADC tab.
In LightField, the speed is changed on the Analog to Digital
Conversion expander.