公开(公告)号：GB2196212A

公开(公告)日：1988-04-20

申请号：GB8720940

申请日：1987-09-05

Applicant: IBM

Inventor： MOREL JEANNE ELLEN ,  RACKLEY DARWIN PRESTON ,  TRYNOSKY STEPHEN WAYNE ,  WALL WILLIAM ALLAN

IPC: G09G5/00 ,  G09G1/16 ,  G09G1/28 ,  G09G5/06 ,  G09G5/36 ,  G09G5/39 ,  G09G5/391 ,  G06F15/62

Abstract: An all points addressable raster scan graphics display system is operable in two modes. In the first mode, data is extracted from a refresh store (10, 11, 12, 13), serialised (21, 22, 23, 24), modified, and applied to a display device at a first frequency. In the second mode, data is extracted from the refresh store, serialised and partially modified at said first frequency, but it is then further modified and passed to the display device at an even sub harmonic, for example half, of the first frequency. The further modification includes concatenation of successive groups of display data bits. Accordingly, with the raster scan device operating at a constant scan velocity, the first mode provides a high picture element definition but relatively low colour definition display, and the second mode provides a display with an even submultiple, for example half, the picture element definition but considerably greater colour definition. In the first mode, groups of data bits are clocked through first (32) and second (33) and third (54) gates at the first frequency, and in the second mode the combined (35) output of the first and second gates (32 and 33) is, clocked through the third gate (54) at the even sub harmonic frequency.

公开(公告)号：FR2605131A1

公开(公告)日：1988-04-15

申请号：FR8713336

申请日：1987-09-21

Applicant: IBM

Inventor： WALL WILLIAM ALLAN ,  MOREL JEANNE ELLEN ,  RACKLEY DARWIN PRESTON ,  TRYNOSKY STEPHEN WAYNE

IPC: G09G5/02 ,  G09G5/06 ,  G09G1/02 ,  G06F3/153

Abstract: A frame scanning graphic display system in which all the points can be addressed according to two operating modes. In the first mode, data are extracted from a revision memory M0 to M3, serialised, modified and applied to a display device at a first frequency. In the second mode, the data are extracted from the revision memory, serialised and partially modified at the said first frequency and are then further modified and transferred to the display device at an even sub-harmonic, for example a half, of the first frequency. The additional modification comprises the chaining of successive groups of display data bits. Consequently, when the frame scanning device operates at a constant scanning speed, the first mode provides high definition for the image elements but a relatively low colour definition display and the second mode provides a display with an even sub-multiple, for example half, of the definition of the image elements but with a considerably higher colour definition.