Patent GB-709910-A (GB)
Title: Improvements relating to positional data transmitting systems
Inventor: TAYLOR MAURICE KENYON
IPC: G08C21/00
Filed: 1950-12-15
Abstract: 709,910. Recording-apparatus. FERRANTI, Ltd. Dec. 10, 1951 [Dec. 15, 1950], No. 30590/51. Class 106 (4). [Also in Group XXXVIII] In a data transmission system wherein the instantaneous position of an object is defined relative to a predetermined co-ordinate system of two intersecting families of curves, trains of coded signals representing the respective coordinates of the object operate corresponding decoding devices which energize one selected conductor of each of two arrays of intersecting but individually insulated conductors corresponding to the co-ordinate system at the transmitter, the point of intersection of the two energized conductors corresponding to the position of the object at the transmitter and operating to record such position on an electrically sensitive display at the receiver. Fig. 5 shows the receiver of a system wherein the position of the object is defined relatively to a co-ordinate system of 7 straight lines' parallel to the x-axis intersecting 7 straight lines parallel to the y axis, each line being numerically designated by numbers 001, 010, 011, 100, 101, 110 and 111, according to the binary scale and the instantaneous co-ordinate position of the object being transmitted by a coded combination of one or more of the non- harmonic frequencies f1, f2, f3 for the x axis and frequencies f4, f5, f6 for the y axis. Such code signals are transmitted over a communication link CL to a separating filter 54, and the component frequencies are fed over corresponding'channels 53f1, 53f2, 53f3, to an X decoder 50, which comprises, Fig. 6, a series of three insulating strips 60, 61, 62 corresponding to the respective frequencies and longitudinally moyable against restoring spring 66 by the energization of the respective solenoids 63, 64, 65 at the occurrence of frequency f1, f2, or f3 in the transmission channel. Each strip is irregularly punched with 7 holes 67 and moves between 7 equally spaced H.T. connected electrodes 68 on one side and corresponding electrodes 69 on the other side connected to respective X-receiver conductors 46. A similar coder is provided for the Y co-ordinates responsive to frequencies f4, f5, f6 and having its electrodes on one side connected to the opposite H.T. pole and on the other side connected to respective Y conductors of the receiver, disposed at right angles to the X conductors and separated therefrom by an illuminated waxed paper sheet 48. The insulating strips 60, 61, 62 in each decoder are punched so that the arrival of the frequency combination corresponding to a particular X and Y coordinate of the object positions the strips so that when the holes align opposite the electrodes connected to the receiver X and Y conductors intersecting at the same co-ordinate positions as the object, a spark passes between the electrodes 68, 69 and the relevant X and Y conductors are energized to break down the waxed paper dielectric and mark the positions thereon. The marks appearing on the waxed paper beneath the graticule 49 follows the movement of the object. The number of X and. Y conductors may be increased indefinitely to improve the resolution. In modifications, the co-ordinate systems may be intersecting confocal hyperbolae, or coplanar concentric circles and straight lines passing through a common origin at the centre thereof, or a circular are intersecting a rectangular coordinate system. Specification 709,921 is referred to.