GB400273A - Improvements in wireless transmission systems - Google Patents

Abstract

400,273. Wireless signalling. WALTON, G. W., 2, Dean Street, London. April 23, 1932, No. 11724. [Class 40 (v).] Two components of the same carrier-wave, phase-displaced by 90‹, are radiated simultaneously from separate aerials, after being modulated by signal currents in phase-opposition. For reception it is necessary to supply a local oscillation of the same frequency but de-phased from the incoming carrier so that the signals cause minimum interference in any normal type of receiver. In transmission, Fig. 1, carrier energy from a source 1 is applied in push-pull to two valves 3, 4 having phaseadjusting impedances 20, 21 so that the currents in the two aerials 9, 10 are 90‹ out of phase. Signal energy is fed to the modulating valves 13, 14 in push-pull and is combined with two carrier components in phase opposition. In reception, Fig. 2, an auxiliary valve 35 feeds back to the incoming carrier an out-of-phase component through a coil 37, the phasedisplacement being adjusted by the condenser 34 and resistance 36. According to the Provisional Specification reception is possible on a normal type of set having a low-loss tuned circuit ; or on a, superheterodyne or a receiver in sustained oscillation.