GB1340806A - Cathode ray display system - Google Patents

Abstract

1340806 Cathode-ray tube displays WESTINGHOUSE CANADA Ltd 15 May 1972 [26 May 1971] 22639/72 Heading H4T The invention relates to an information storage and display system in which the information, e.g. Alpha-Numeric symbols, is displayed on a cathode-ray tube by " bright-up " of appropriate portions of a vertical line scanned raster the information having a time sequential variation in the horizontal direction but being stored, in memories associated with the display, in the sequence of its appearance in the vertical scan. A particular advantage of this arrangement is that the memory may be updated to produce a " roll-up ", i.e. eliminating the first (horizontal) line of information from the top of the display and adding a new line at the bottom by delaying the stored information such that new information may be entered at the required location and the old information rejected. Fig. 1 shows the general appearance of the display in which the beam of the display tube is scanned, from top-to-bottom in a line raster having a five-fold interlace, the symbols being produced by bright-up of appropriate positions in a notional 7 Î 5 dot matrix to produce a complete display of eighty (vertical) columns each containing twenty symbols. Interlace control means are provided which, by adjusting the spacing between the vertical line scans allows the horizontal spacing between the symbols to be adjusted. Thus in the generation of the display the elements forming the portion of each symbol which lies on the first scan line of each group of five scan lines, are produced followed in succession by the elements lying on the second to fifth scan lines. An embodiment is described with reference, Figs. 2 and 3 (neither shown), and the organization of the memories (shift registers) is described with reference to Figs. 4 and 4a (neither shown).