RJS Inspector D4000 Auto Optic (FIRMWARE version A.05 and Earlier) - Manual (Page 74)

Operator
’
s Guide Appendix K
002-5564 RJS, Minneapolis, MN 67
Modulation (MOD)
(Scanners and verifiers perceive the narrower bars and spaces to have less intensity than
wider bars and spaces; the comparison of this diminished intensity of narrow elements to
wide elements is called modulation. This condition is affected by aperture size.)
This parameter grade can be “A,” “B,” “C,” “D” or “F.”
The modulation grade is based on the relationship between minimum edge contrast
(Ecmin) and symbol contrast (SC).
MOD = ECmin/SC
The greater the difference between minimum edge contrast and symbol contrast, the
lower the grade.
Since “ink spread” will reduce the width and intensity of single module space within a
symbol, this is one thing to check in seeking to correct a low modulation grade.
Module
The narrowest expected bar or space width.
Moving Beam Scanner
A laser device that dynamically searches for a bar-code pattern by sweeping a moving
optical beam through a field of view.
N (wide to narrow ratio)
In symbologies with two element widths, the wide to narrow ratio of elements is
calculated by summing the average wide bar width and average wide space width and
dividing the sum by 2 times Z. Inter-character gaps, if applicable, are not included.
N = (avg.wide bar + avg. wide space) / (2*Z)