Appendix H Glossary Of Terms - Microscan MS-2 User Manual

Glossary of Terms
Appendix H — Glossary of Terms
Aberration — The failure of an optical lens to produce an exact point-to-point correspondence
between the object and its resulting image. Various types are chromatic, spherical, coma,
astigmatism and distortion.
Absorption — The loss of light of certain wavelengths as it passes through a material and
is converted to heat or other forms of energy. (–)
Active Illumination — Lighting an area with a light source coordinated with the acquisition
of an image. Strobed flash tubes and pulsed lasers are examples.
ADC — See Analog-to-Digital Converter.
A/D Converter — See Analog-to-Digital Converter.
AGC — See Automatic Gain Control.
Ambient Light — Light which is present in the environment of the front end of a reader
and generated from outside sources. This light, unless used for actual illumination, will be
treated as background noise by the reader.
Analog — A smooth, continuous voltage or current signal or function whose magnitude
(value) is the information.
Analog-to-Digital Converter (A/D Converter or ADC) — A device that converts an
analog voltage or current signal to a discrete series of digitally encoded numbers (signal)
for computer processing.
Application-Specific Integrated Circuit (ASIC) — An integrated circuit that is customized
for a particular kind of use, rather than general use. All vision system elements including
firmware can be integrated into one ASIC.
Automatic Gain Control (AGC) — Adjustment to signal strength that seeks to maintain a
constant level regardless of the distance between a reader and symbol.
Auxiliary Port — RS-232 connection to an auxiliary terminal or device for remote viewing.
Baud Rate — The number of discrete signal events per second; bits per second.
CCD — See Charge-Coupled Device.
Charge-Coupled Device (CCD) — A semiconductor device with an array of light-sensitive
elements that converts light images into electrical signals.
Check Character — A Modulus 43 or Modulus 10 character that is added to encoded
symbol data for additional data integrity.
Connector — A plug or socket on a device or cable providing in/out connectivity for various
circuits and pins.
Concentrator — Intermediary device that relays data from readers to a host and commands
from the host to the readers or other devices.
DAC — See Digital-to-Analog Converter.
Daisy Chain — Linkage of primary and secondary readers allowing data to be relayed up
to the host via auxiliary port connections.
Decode — A Good Read. The successful interpretation and output of the information
encoded in a symbol.
Default — Restores ROM or flash settings and initializes serial commands.
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MS-2 CCD Reader User's Manual