Multi-bit digitizer
First Claim
1. A multiple bit digitizer for a bar code reader, comprising:
- a. a sensor means for sensing light reflected from a bar code symbol and for producing an analog scan signal representative thereof;
b. means for detecting positive and negative edges in the analog scan signal and for developing timing signals representative thereof;
c. means for measuring the strength of each detected edge in the analog scan signal and for developing digital signals representative thereof; and
d. decoder means, receiving said timing signals and said digital signals as inputs, for performing multiple threshold processing on each individual analog scan signal by processing each analog scan signal a multiple number of times at different detection threshold levels.
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Accused Products
Abstract
A multi-bit digitizer for a bar code reader for detecting and reading bar code symbols, which are generally printed on a label or on the surface of an article. The multi-bit digitizer detects the presence of edges of a scanned bar code symbol, and also measures the strength of each detected edge therein. During a scanning operation, a sensor senses light reflected from a bar code symbol and produces an analog scan signal representative thereof. Positive and negative edges in the analog scan signal are detected, and timing signals are developed representative thereof. The strength of each detected edge in the analog scan signal is also measured, and digital signals are developed representative thereof. The timing signals and digital signals are directed as inputs to a decoder which performs multiple threshold processing on each individual analog scan signal by processing each analog scan signal a multiple number of times at different detection threshold levels. The ability to perform multiple thresholding on a single scan is significant for the development of very aggressive wands in which only a single scan is available for processing.
59 Citations
20 Claims
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1. A multiple bit digitizer for a bar code reader, comprising:
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a. a sensor means for sensing light reflected from a bar code symbol and for producing an analog scan signal representative thereof; b. means for detecting positive and negative edges in the analog scan signal and for developing timing signals representative thereof; c. means for measuring the strength of each detected edge in the analog scan signal and for developing digital signals representative thereof; and d. decoder means, receiving said timing signals and said digital signals as inputs, for performing multiple threshold processing on each individual analog scan signal by processing each analog scan signal a multiple number of times at different detection threshold levels. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A method of reading a bar code symbol, comprising:
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a. sensing light reflected from a bar code symbol and producing an analog scan signal representative thereof; b. detecting positive and negative edges in the analog scan signal and developing timing signals representative thereof; c. measuring the strength of each detected edge and developing digital signals representative thereof; and d. performing multiple threshold processing on each individual analog scan signal by processing each analog scan signal a multiple number of times at different detection threshold levels. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20)
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Specification
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- Resources
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Current AssigneeSymbol Technologies, Inc. (Zebra Technologies Corporation)
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Original AssigneeSymbol Technologies, Inc. (Zebra Technologies Corporation)
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InventorsGoren, David P.
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Primary Examiner(s)Nelli, Raymond A.
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Application NumberUS07/862,471Time in Patent Office740 DaysField of Search235/462, 235/463US Class Current235/462.27CPC Class CodesG06K 7/10851 Circuits for pulse shaping,...
