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Acceleration Insensitive Delta Distance Decoding

IP.com Disclosure Number: IPCOM000080275D
Original Publication Date: 1973-Nov-01
Included in the Prior Art Database: 2005-Feb-27
Document File: 3 page(s) / 28K

Publishing Venue

IBM

Related People

Kulikowski, RJ: AUTHOR [+2]

Abstract

A delta distance B encoded space or bar represents a binary 1 if this space or bar is of the same width, within a tolerance, as the preceding bar or space, respectively. A binary 0 is encoded if the widths are different. When delta distance B code is printed by an impact printer such as a typewriter, increased impression force increases bar width and reduces space width and visa versa. However, leading edge to leading edge and trailing edge to trailing edge dimensions of adjacent bars do not vary with impression control, when each group of bars representing a character is carried on a single-type face. For example, bars and spaces may nominally be 8 mils or 16 mils wide.

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Acceleration Insensitive Delta Distance Decoding

A delta distance B encoded space or bar represents a binary 1 if this space or bar is of the same width, within a tolerance, as the preceding bar or space, respectively. A binary 0 is encoded if the widths are different. When delta distance B code is printed by an impact printer such as a typewriter, increased impression force increases bar width and reduces space width and visa versa. However, leading edge to leading edge and trailing edge to trailing edge dimensions of adjacent bars do not vary with impression control, when each group of bars representing a character is carried on a single-type face. For example, bars and spaces may nominally be 8 mils or 16 mils wide. In this example, edge-to-edge dimensions of adjacent bars will nominally be 16 mils (small), 24 mils (medium), or 32 mils (large), depending upon their width and spacing as necessary to encode a character. The decoding includes the following steps:
1) Begin each encoded message with a start character, which is

constrained to have a medium dimension between the leading

edges of the first two bars.
2) When scanning the encoded message with a single-aperature

scanner, detect the time count between the leading edges of

the first two bars of the start character as the initial

reference count R.
3) Detect the time count X between the leading edges and the

trailing edges of each subsequent bar of each subsequent

character.
4) Inhibit time counting after each fourth trailing edge is

detected, to skip over intercharacter gaps.
5) Decode each edge-to-edge count X into a binary 1 or 0 and

updat...