GB430491A - Improvements in or relating to remote control or indicating systems or apparatus - Google Patents

Abstract

430,491. Electric signalling and distant control systems. HERINK, H. J., 9, Page's Hill, Muswell Hill, and REID, D. G., 56, Forestdale, Southgate, both in London. Dec. 16, 1933, No. 35465. [Class 40 (i)] In signalling or control systems for repeating at a distance the movements of a member, the transmission is effected by a mixture of current of two components each having a fixed frequency, the amplitudes of one or both of the components being varied in accordance with the movement to be signalled. The signals may be transmitted over power, telegraph or telephone lines, over a separate line or by wireless. As shown the master instrument I controls differentially a condenser K the plates of which are connected so as to control the amplitudes of the outputs of two oscillators O<1>, O' of fixed frequencies. The mixed frequency current received at the receiver is separated out by the detector-amplifiers V11, V111 ; V22, V222 and applied to a crossed-coil instrument which is operated in accordance with the relative magnitudes of the two components of the signalling current. Instead of a condenser, an inductance or resistance may be employed. In a modification, the two components are separated and rectified and applied to respective variable-mu valves the outputs of which are modulated by carrier currents of different frequencies. In a further modification one component only is varied. Reference has been directed by the Comptroller to Specification 405,018.