GB237547A - Improvements in electrical apparatus for the elimination of aperiodic disturbances - Google Patents

Abstract

237,547. Regnauld de Bellescize, H. J. J. M. de. July 22, 1924, [Convention date]. Addition to 226,784. Atmospherics and undesired signals, eliminating or limiting.-Signal currents with superposed perturbations are fed from an input circuit A, A Fig. 1, to a receiver R through two branch circuits. One branch C1, L1, L2, S1 transfers both desired and undesired 'frequencies alike to the grid circuit of the valve D. The other branch comprises means for blocking out the signal frequencies. but passes the undesired disturbances. The latter are then balanced against their counterparts in the first circuit, leaving the signal currents alone to influence, the grid of the triode D and reappear in the receiver R. The passage of the signal frequencies is prevented by a polarized electromagnet in the plate circuit of the valve D1, the armature F1 of which is fitted with a rubbing contact H, G which imparts sufficient mechanical friction to prevent the armature from responding to the signal frequencies although it is ineffective to stop thetransfer of aperiodic disturbances of relatively large amplitude. The same principle underlies the arrangement shown in Fig. 2. The complex current is fed to an artificial line C, L from which tappings at P1 and P3, separated by an effective signal wave-length, are taken to the grid and filament of the valve X. The signals proper therefore do not affect the output from that valve apart from a slight shock corresponding to impact and end effects, which are eliminated by the frictional action of the parts G, H on the armature F1. The disturbances, on the other hand, gives rise to two impulses, separated by one signal wave length, which are opposed in their action on the armature F@, so as to leave only a small residual effect. This, in turn is balanced out across the grid and filament of the valve Y by means of tapping P2, which transfers the signal frequency in full, and that fraction of the disturbance (regulated in intensity by the tapping Q2) necessary to counterbalance the residual effect from the armature F1. The signal alone therefore reappears in the plate circuit of the valve Y.