Browse Prior Art Database

Increased Density Self Clocking Bar Code

IP.com Disclosure Number: IPCOM000074220D
Original Publication Date: 1971-Mar-01
Included in the Prior Art Database: 2005-Feb-23
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Drew, RS: AUTHOR [+2]

Abstract

A recently proposed bar coding technique does not require clocking information and relies solely on the recorded information for decoding the represented data. The technique involves comparing each bar code element with the next previous bar code element for determining the significance of the coded element. In view of this, accelerations and decelerations of the reading device are minimized to the extent that hand-propelled code detectors are feasible.

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Increased Density Self Clocking Bar Code

A recently proposed bar coding technique does not require clocking information and relies solely on the recorded information for decoding the represented data. The technique involves comparing each bar code element with the next previous bar code element for determining the significance of the coded element. In view of this, accelerations and decelerations of the reading device are minimized to the extent that hand-propelled code detectors are feasible.

Each encoded character is represented by alternating bars of different reflective or magnetic characteristics. A fixed width timing bar is utilized to delineate the beginning of the character and the first character bit is represented by the adjacent bar of differing characteristics. This adjacent bar may have a width equal to or different from the timing bar. If the bit to be represented is a binary "one", it is made equal; and it is made unequal if a binary "zero" is to be represented.

The density of the above code can be increased by using two different widths for the timing bit, whereby an additional bit may be represented without increasing the space required to represent a character. This technique may be implemented by using the first wide/narrow or narrow/wide transition for decoding the width of the timing bit. While the determination of the width of the timing bit is delayed, it is nevertheless independent of intervening accelerations or decelerations since the in...