GB1518149A - Graphic display device - Google Patents

Abstract

1518149 Cathode ray tube displays YOKOGAWA ELECTRIC WORKS Ltd 24 Sept 1975 39090/75 Heading H4T An alphanumeric or graphic display device receives instruction from an external computer 1 and, by scanning a succession of rasters in individual display matrices, displays alphanumeric or graphic patterns on a c.r.t., the device having a pattern generator 4 for storing pattern data in raster form and for generating a series of raster display signals for the display matrices upon receiving a raster designation signal designating the pattern and the individual rasters of the selected pattern to be scanned, the device including pattern shifting means for shifting the pattern display in a direction transverse to the scanning direction, the shifting means including means for modifying the raster designation signal whereby a selected portion of the pattern may be displayed at a shifted position so that a pattern may be displayed over two different matrices (Fig. 4b, not shown) without requiring the pattern generator memory to store extra formation data. Raster modification and shift direction signals are applied to modification circuit 5 which modifies the raster designating signal from the timing circuit 7 according to the modification and shift direction signals and supplies an effective raster designating signal to generator 4. In Fig. 2 (not shown) blinking, colour and pattern address signals from memory,3 are supplied to generator 4. The raster modification circuit 5 includes a register (51), selector (52), adder (53) and raster counter (54) (Fig. 3, not shown), and its operation is described in detail.