GB601655A - Improvements in or relating to electric remote control or indicating systems - Google Patents

Abstract

601,655. Synchronous movements. JONES, W., and PYE, Ltd. April 29, 1943, No. 6775. [Class 40 (iii)] [Also in Groups XXXVIII and XL (c)] In a pulse-repetition system-for reproducing movements at a distance, e.g. for causing the deflecting coils of a cathode-ray indicator to move with a speed and in a direction corresponding to the movement of a directional aerial, separate-pulses are modulated (e.g. in width) in dependence upon the direction and speed of the movement to be reproduced, the difference in modulation being used to control, e.g. a splitfield motor driving the deflecting coils. In Fig. 1, the pulses d, e are modulated as described above, pulses a are used for synchronizing a radial time base, pulses b for conveying echo or other signals and pulses c for alignment purposes. In the transmitter shown in Fig. 2, the aerial 1 when moved in one direction or the other drives a D.C. generator 7 or 8 which modulates in width pulse generator 5 or 6, the outputs of which are mixed with each other at 9, and at 10 with the time-base pulses a, the signal pulses b and the aligning pulses c, and transmitted at 12 by cable or wireless. The pulse generators 5, 6 consist of " slicing " valves which extract "slices" " from the sawtooth waves from generator 4, the position of the " slice " being dependent on the D.C. voltage from generators 7, 8. In the receiver, Fig. 3, the pulses d,e are separated at 14 from pulses a, b, c, and are separated from each other at 15, amplified at 16, 17, and applied separately to the coils of a split-field motor 18 .which rotates the deflecting coils of the indicator 19 in a direction determined by which pulse is modulated and at a speed determined by the difference in width of the two pulses, i.e. at the speed of the aerial 1. The time-base pulses a are separated by amplitude-discrimination at 20 and control a time-base generator 21 for the radial'scan, the signal pulses b are separated at 22 and applied to a modulating electrode of the C.R. tube, and the pulses c control a mechanical coupling between-the motor 18 and the deflecting coils, as in Specification 577,796, for ensuring the angular alignment of the rotating scan with the rotating aerial 1. The pulse' separators 14, 15, 22 comprise gating valves controlled by the time-base generator 21. Specifications 562,211 and 577,795 also are referred to.