Patent GB-184282-A (GB)
Title: Improvements in and relating to methods of controlling the relative phases of alternating currents, especially applicable to wireless signalling
IPC: H01Q3/30
Filed: 1921-05-13
Abstract: 184,282. Eccles, W. H. May 13, 1921. Coupling oscillating and radiating circuits; directive signalling; keying and modulating systems.-Two or more separately excited oscillating circuits or aerials are coupled together for the purpose of maintaining or controlling the phase relation between the oscillations in them. If when operating independently two such circuits have slightly different " natural " frequencies, when they are coupled together both circuits adopt a common " forced " frequency, but the oscillations in the two circuits differ in phase, the phase relation being variable by slight alterations in the " natural " frequency of either circuit. An example is given in which two threeelectrode valve generators of slightly different " natural " frequencies are coupled together, the resulting phase difference in the " forced " oscillations in the two oscillatory circuits being adjustable by varying the constants of one of the oscillatory circuits, or the magnitude of the currents or voltages of either of the valves. According to another example an oscillatory circuit energized by a valve is coupled to a second oscillatory circuit supplied by a source of highfrequency alternating current. The valve may be arranged to oscillate only when its oscillatory circuit is coupled to the second oscillatory circuit. The invention is described as applied to the production of compound radiation fields by multiple antennae systems. An arrangement of two adjacent separately-excited antennae is described, one at least excited by a regenerative valve. If the difference between the "natural" frequencies of the two systems is not too great, when the two antennae are coupled inductively through the air or by means of conductors or loaded lines, both adopt the same " forced " frequency, but the waves of the two systems have a phase relationship depending upon and variable by adjustment of (1) the difference between the " natural " frequencies of the two systems, (2) the position and form of the antennae, and (3) the characteristics of the coupling if this comprises conductors. Thus two similar antennae half-a-wave-length, or an integral of half-a-wave-length apart, coupled together and separately excited at the same " natural frequency, will force each other into opposite phase and a radiation field will result having a figure-of-eight characteristic. The phase difference produced in an arrangement of several coupled antennae by the above-enumerated conditions (2) and (3) may be counterbalanced by adjustment of their " natural " frequencies so that symmetrical radiation is produced or in the same manner the phase relation may be varied to produce a strongly directional field. A directive arrangement is described consisting of a row of coupled antennae halfa-wave-length apart adjusted so that alternate antennµ oscillate in opposite phase. Similarly a triangle of coupled antennµ can be made to vary its direction of strongest radiation by phase control. Separate antennµ may be coupled by small open or coil aerials coupled to the respective grid circuits of valve generators are used. The separate antennµ may also be coupled to and forced into accord with a master oscillating system, which may be non-radiating. All the antennae systems may be supplied from a common high voltage source, and signalling may be effected by interruption or reduction of the supply current. If desired, the supply conductors may be utilized also for coupling the antennµ. Signalling may also be accomplished by interrupting the oscillations in one or more of the antennae, by varying the amplitude of the waves in one or more of the antennµ, by varying the " natural " frequency of one or more of the antennµ or oscillation generators, or by changing the direction of the radiating beam in accordance with signals by means of phase control.