Patent GB-1367532-A (GB)
Title: Method and arrangement for the recording of written and/or picture symbols
IPC: G06K15/22
Filed: 1971-07-26
Abstract: 1367532 Cathode-ray tube displays DR ING RUDOLF HELL GmbH 26 July 1971 [1 Aug 1970] 35036/71 Heading H4T The Specification describes a cathode-ray tube symbol display and recording system for weather chart information the system including means for storage data specifying a comparatively small number of symbols or symbol parts from which required symbols may be synthesized under the control of a remote station which need only transmit data specifying which of the stored symbols &c. are to be reproduced together with control data specifying any translational and/or rotational position adjustment required.  Fig. 1 shows the general arrangement of a weather chart transmission system in which data from weather stations 1-4 are fed to a control room 5 for evaluation and coding by a computer 6 and transmission via control 7 over a line or radio channel 8 to a receiving station 9 including a transmission control 11 and display apparatus 12 which is similar to monitoring display apparatus 10 at the control room. Fig. 2 shows the arrangement of the display apparatus which includes a central control system 14 comprising a digital computing unit, a display control unit and a store in which data representative of symbols or symbol parts and input control data are stored, the symbol data being derived by photo-electric point-by-point (vertical line scanning) analysis of an original containing the symbols. Under the direction of input control data symbol display data are fed via lines 22, 23 to a function generator 24 which produces via respective generators 25, 26, X and Y deflection quantities for a vertical line raster on which by beam intensification the required weather symbols are displayed. Thus, as shown in Fig. 9, the weather station identification circle 114 and the wind arrow 116 (shown rotated through angle γ and "assembled" from a number of separate symbol parts 117, 118, 118, 120) are produced by "bright-up" of an initially vertical line raster which is subsequently displaced and/or rotated as required. This is effected as directed by input control data by a displacement means 27, analogue rotation means 28 and a further displacement means 29 which allows displacement of individual symbols. When characters are to be displayed the displacement means 27 or coupling between the X and Y deflection generators may be employed to produce cursive or italic writing. The outputs of the function generator 24 is then supplied to a summer 21 in which it is combined with basic position co-ordinate data from D/A converters 17, 18 and additionally, with deflection quantities from a sector generator 30 for producing polygonal (curved) traces. Generator 30 also supplies signals to brightness control means 37 which is additionally controlled by data from control system 14 and further data which controls a spot size (focus) means 39. The output of summer 21 is fed via a format rotation means 41, display tube linearity corrector 42 and respective amplifiers 43, 44 to the beam deflection coils 46, 45 respectively, the format rotation means 41 being employed to match the format (e.g. a non-square gate) of the recording medium (e.g. film), which is exposed to the tube screen, to that of the displayed picture. In Fig. 9, in addition to the station identifying circle 114 already referred to, a symbol 115 indicates cloud cover and the wind arrow 116, also previously referred to as "assembled" from a number of symbols parts, indicates wind velocity by the addition of the values associated with symbol parts of different shapes. Thus part 117 represents 50 knots, part 118, 10 knots, part 119, 5 knots and part 120 0 knots. The translational co-ordinate transformation and the co-ordinate rotation involved in the display of the wind arrow 116 is discussed. The arrangements for address coding of stored data and for the coding of rotation orders are described with reference to block circuit diagrams, Figs. 3 and 4 respectively (neither shown); a circuit for displacement and analogue rotation is described with reference to Fig. 5 (not shown) and a particular form of the latter in which the angular rotations are specified as fixed function values is described with reference to Fig. 6 (not shown). Function generators for the cosine and for the sine of the angles of rotation are described with reference to Figs. 7 and 8 respectively (neither shown).