Browse Prior Art Database

Rom Symbol Generator Zero Segmented Detection in DDTV

IP.com Disclosure Number: IPCOM000088484D
Original Publication Date: 1977-Jun-01
Included in the Prior Art Database: 2005-Mar-04
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Hogan, WJ: AUTHOR [+2]

Abstract

In the dynamic digital television (DDTV) disclosed in U. S. Patent 3,996,585 some symbols will have segments of all zeroes. This article describes a technique to detect these symbol segments prior to accessing the partial raster assembly storage (PRAS) and to eliminate the PRAS cycles, thus making them available to either the vector or conic generator.

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Rom Symbol Generator Zero Segmented Detection in DDTV

In the dynamic digital television (DDTV) disclosed in U. S. Patent 3,996,585 some symbols will have segments of all zeroes. This article describes a technique to detect these symbol segments prior to accessing the partial raster assembly storage (PRAS) and to eliminate the PRAS cycles, thus making them available to either the vector or conic generator.

Implementation of the symbol set in the DDTV of U. S. Patent 3,996,585 is in ROM (read-only memory) which has spare bits. One of the spare bits can be assigned in each segment word to denote an all zeroes segment. This would occur on symbols such as period, comma, lower case symbols, small symbols, etc. When any symbol segment is accessed from ROM, the all zeroes bit is used to abort a request for PRAS cycles. Those cycles could then be utilized by one of the other video generator, ultimately increasing total system video generation performance.

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