Teledyne Princeton Instruments Lansis, System Manual

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EAR99 Technology Subject to Restrictions Contained on the Cover Page.
Chapter 8: Analog to Digital Conversion
After the programmed exposure time has elapsed, accumulated charge stored in the
CCD array must be:
• Read out;
• Converted to a digital format;
• Transferred to the application software where it can be displayed and/or stored.
Analog-to Digital conversion factors are configured within LightField on the Analog to
Digital Conversion expander. The following parameters are able to be configured:
• Speed;
• Analog Gain.
See Figure 8-1 .
Figure 8-1: Typical Analog to Digital Conversion Expander
The following sections describe the impact each of these parameters has on acquired
image data.
8.1 Digitization
After gain has been applied to the signal, the Analog-to-Digital Converter (ADC)
converts analog information (continuous amplitudes) into digital data (quantified,
discrete steps,) that can be read, displayed, and stored by the application software. The
number of bits per pixel is, by design, set to 16.
Factors associated with digitization include:
• Speed
This is software configurable within LightField, and specifies the rate at which
data are digitized.
•
ADC Offset (Bias)
.
This is not a user-configurable value; it is set at the factory at the time of
manufacture.
These factors are discussed in the following paragraphs.
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