Browse Prior Art Database

Hand Scanning with Two Port Scanner

IP.com Disclosure Number: IPCOM000079482D
Original Publication Date: 1973-Jul-01
Included in the Prior Art Database: 2005-Feb-26
Document File: 2 page(s) / 52K

Publishing Venue

IBM

Related People

Melas, CM: AUTHOR

Abstract

This circuit arrangement A resolves "bar, no-bar" coding under hand scanning. The clock period is proportional to the time differential of the detection of the same transition, by the first and second ports of the scanner. This period is determined at every transition.

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Hand Scanning with Two Port Scanner

This circuit arrangement A resolves "bar, no-bar" coding under hand scanning. The clock period is proportional to the time differential of the detection of the same transition, by the first and second ports of the scanner. This period is determined at every transition.

A probe, not shown, has two light receiving apertures 10 and 11 which are moved from left to right across the bar coding B, representing the binary number
10101011001111100001. The light-dark signal from the aperture 10 is shown in line C and that from the aperture 11 in line D. The signal from the aperture 11 is inverted and combined with that from the aperture 10 by an inverter 12 and an AND gating circuit 14. The resultant signal CD is integrated over the dark area by a resettable integrating circuit 16. The signal D is applied to another resettable integrating circuit 18. Reset pulse voltage is derived in two subcircuits. A differentiating circuit 20, and a converting circuit 21 develop resetting potential on negative and positive going transitions of the signal D. The former is applied to the integrating circuit 16, and the latter is applied to the integrating circuit 18 through an OR gating circuit 22. Further reset pulse voltage is derived on equal output voltages of the integrating circuits 16 and 18. A comparing differential amplifier 24, the output of which is shown in line E and a converting circuit 25 of conventional form provide this reset voltage pu...