Patent GB-723762-A (GB)
Title: Improvements in or relating to means for recording data
Inventor: GIFFARD JOHN ANTHONY HARDINGE
IPC: G09G1/22
Filed: 1949-12-22
Abstract: 723,762. Digital electric calculating-apparatus. NATIONAL RESEARCH DEVELOPMENT CORPORATION. Dec. 15, 1950 [Dec. 22, 1949], No. 32877/49. Class 106 (1). [Also in Group XL (b)] An arrangement for recording data, derived, for example, from an electrical computing machine comprises a cathode-ray tube having a screen with areas carrying the forms of the symbols to be employed in expressing the data and which have a secondary emission ratio different from that of the rest of the screen, with means for selectively scanning the areas corresponding to the data to be recorded, and a second cathode-rav tube with means for scanning areas of its screen in synchronism with the scanning of the areas of the first tube, the parts of the screen which are successively scanned in the second tube being arranged in an ordered sequence so that the symbols scanned in the first tube and selected by data signals are reproduced in an orderly succession on the screen of the second tube. In the system shown, the symbols 13 comprising the digits 0... 9, the signs +, - are formed with material having a secondary emission ratio less than unity, the remainder of the areas having a ratio greater than unity and the screen is divided into sixteen equal areas 11. The beam is controlled to scan a raster equal to the areas 11 by X, Y time bases 14, 15, and the actual area scanned is controlled by X-shift and Y-shift generators 19, 20 which may be controlled by a staticisor 21 in accordance with the signal output from the corresponding machine. The areas 0 ... 9, + ... &c. are scanned in sequential order and alternately with the desired symbols in order that the screen of the tube is periodically restored to normal, this action being controlled by counter circuits 16, 18, 22, 23 producing square waveforms of the appropriate frequencies. The signals derived from the signal plate 25 of the tube 10 are fed to the grid of a second cathoderay tube 26 controlled by X, Y, time bases 29, 30 and by X-shift and Y-shift generators 27, 28 which are operative to control the reproduction of the symbols in ordered sequence, e.g. in a line or in a succession of lines across the screen. The symbols created on the tube 26 may also be reproduced for a longer time on a Williams type storage tube 31. In view of the relation of the number of digits which can be stored and reproduced in the storage tube 31, normally 1280, with respect to the number of symbol areas, viz. 16 on the screen of the cathode-ray tube 10, the scanning wave forms are correspondingly modified and the reproduction of the symbols in the areas scanned for screen restoration is prevented. The storage tube 31 is provided with a regenerative loop comprising amplifier 33 and the gate circuits of reading unit 34 and writing unit 35 which may operate in the dot-dash mode as described in Specification 657,591. When tube 10 is not being controlled by the calculating machine dots are reproduced in each digit portion of the tube 31. On application of the write instruction signal from the calculating machine, the halver wave-form is fed via gate circuit and the output of cathode-ray tube 10 opens gate circuit 37 in the path of the dash wave-form so that the symbol scanned on the first tube 10 is reproduced as a series of dashes on the tube 31. The scanning of the desired symbol 13 of the screen 12 may be controlled by the binary representation of the number in the scale two-the two least significant digits selecting the column and the two most significant digits selecting the horizontal row of the areas of the screen 12. The symbols reproduced on the tube 26 may be photographed. Specifications 645,691, 682,156, 705,474 and the Proceedings of the Institution of Electrical Engineers, Part III, March 1949, also are referred to.