Motorola SYMBOL LS7708, Руководство по продукции

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Symbol LS7708 Product Reference Guide GL-4
Print Contrast Signal
(PCS) Measurement of the contrast (brightness difference) between the bars and spaces of
a symbol. A minimum PCS value is needed for a bar code symbol to be scannable.
PCS = (RL - RD) / RL, where RL is the reflectance factor of the background and RD the
reflectance factor of the dark bars.
Programming Mode The state in which a scanner is configured for parameter values. See SCANNING
MODE.
Quiet Zone A clear space, containing no dark marks, which precedes the start character of a bar
code symbol and follows the stop character.
Reflectance Amount of light returned from an illuminated surface.
Resolution The narrowest element dimension which is distinguished by a particular reading
device or printed with a particular device or method.
RSS Reduced Space Symbology: A family of space efficient symbologies developed by
UCC.EAN.
Scan Area Area intended to contain a symbol.
Scanner An electronic device used to scan bar code symbols and produce a digitized pattern
that corresponds to the bars and spaces of the symbol. Its three main components are:
1. Light source (laser or photoelectric cell) - illuminates a bar code.
2. Photodetector - registers the difference in reflected light (more light reflected from
spaces).
3. Signal conditioning circuit - transforms optical detector output into a digitized bar
pattern.
Scanning Mode The scanner is energized, programmed, and ready to read a bar code.
Scanning Sequence A method of programming or configuring parameters for a bar code reading system
by scanning bar code menus.
Self-Checking Code A symbology that uses a checking algorithm to detect encoding errors within the
characters of a bar code symbol.
Space The lighter element of a bar code formed by the background between bars.
Specular Reflection The mirror-like direct reflection of light from a surface, which can cause difficulty
decoding a bar code.
Start/Stop Character A pattern of bars and spaces that provides the scanner with start and stop reading
instructions and scanning direction. The start and stop characters are normally to the
left and right margins of a horizontal code.
Substrate A foundation material on which a substance or image is placed.
Symbol A scannable unit that encodes data within the conventions of a certain symbology,
usually including start/stop characters, quiet zones, data characters, and check
characters.
Symbol Aspect Ratio The ratio of symbol height to symbol width.
Symbol Height The distance between the outside edges of the quiet zones of the first row and the
last row.
Symbol Length Length of symbol measured from the beginning of the quiet zone (margin) adjacent
to the start character to the end of the quiet zone (margin) adjacent to a stop
character.