Patent GB-612398-A (GB)
Title: Improvements in or relating to radio telecontrol systems
IPC: G08C19/24
Filed: 1946-05-24
Abstract: 612,398. Electric selective signalling. SADIRCARPENTIER. May 24, 1946, No. 15884. Convention date, Dec. 3, 1943. [Class 40 (i)] A radio-telecontrol system comprises a transmitter wherein an impulse is fed to a tapped delay line, pulses being taken from selectable fixed tappings on the line to constitute a pulse train, including a synchronising signal, which is radiated and reconstituted at the receiver where the synchronising signal is isolated and fed to a delay line identical with that at the transmitter. Selectors connected each to individual tappings in this delay line also receive the reconstituted pulse train and each responds only when simultaneously fed with a pulse from its appropriate line tapping and a pulse from the train, so that the selectors respond according to the selective characteristic of the signal. Transmitter, Fig. 1. As shown, an impulse generator 1 supplies a single impulse to one end of a delay line 4 upon each operation of a timed relay 2 by a push-button 3. The delay line ends in a resistance 20 equal to the characteristic impedance of the line to avoid reflection and is tapped at predetermined intervals so that the impulse appears at each tap in succession with a delay determined by the tap position. Each tap is connected through a selector switch 5 to a modulator 6 so that by closing a selected combination of the switches 5 a corresponding train of impulses is fed to the modulator 6 and radiated at 8 by the radio transmitter 7 which by the control indicated at 15 is switched on only during signal transmission... The first two taps on the delay line are connected directly to the modulator 6 and result in the first impulse of a train being double the width of the subsequent constant duration signal pulses. This double width pulse serves to condition the receiver for reception of the signal pulses. The switches 5 may be controlled in any known manner. Receiver, Fig. 2. The radiated signal received at 9 is amplified and demodulated at 10 and fed to a filter 11 which passes only the initial double width pulse of the train to a delay line 12 similar to the delay line 4 in the transmitter. The corresponding taps on line 12 lead to identical selectors 13 to which the whole train of impulses is also led over line 15. Each selector, e.g. a multi-grid tube, responds in known manner only if energized simultaneously over both impulse paths leading thereto. Thus each selector will respond only to the impulse in its appropriate position in the train and will operate its associated relay 14 only if this impulse is present. Thus, after reception of a train the combination of relays 14 operated corresponds to the combination of operated switches 5 at the transmitter and effects the control operation in any desired manner. Modifications. Predetermined impulses in the train may be suppressed for protection against parasitics, the selectors corresponding to these positions in the train serving, if operated by a parasitic pulse, to prevent any control action. The invention is applicable to the selective radio control of several mobile craft.