GB400289A - Improvements in and relating to a method of and means for transmitting signals electrically to a distance - Google Patents

Abstract

400,289. Electric signalling systems. MIDWORTH, C., 116, Ridgeway Road, Osteriey, Middlesex. April 26, 1932, No. 11976. [Class 40 (i).] Signals are transmitted by making an alternating current asymmetrical, the receiver measuring the degree of asymmetry of the received signals. As shown in Fig. 6, wherein the position of the contactor 4 is to be signalled, the alternating current from generator 12 passes over Wire 14 tocohtactor 4 where it divides and passes over two paths to point 7, the two paths having rectifiers 1 and 2 arranged to suppress the positive half wave in one path and the negative half in the other. As the contactor 4 divides the impedance 3 unequally, the wave form of the alternating current is made unequal as is indicated diagrammatically. The two half waves are reunited at 7 and pass to 19 as an asymmetric current. At 19 the two halves of the waves are again divided by rectifiers 15, 16 and ampere-meters 17, 18 measure the degree of asymmetry of the current. The arrangement shown in Fig. 7 is similar to that shown in Fig. 6 except that the receiving devices 17, 18 are replaced by the coils 171, 181 of a known type of indicating instrument in which the two coils act on the armature 28 carrying pointer 29. In other arrangements fully described in the Specification the variable impedance comprises resistance, inductance, capacitance or degree of coupling, the rectifiers are dry, electrolytic or thermal, the circuits are transformer-coupled, a number of receivers respond to a single transmitted value, the symmetry is restored at the receiver, the degree of control necessary giving the signal transmitted, and relay motors are employed. Means for checking the transmitted reading are also described.