GB441370A - - Google Patents

Abstract

441,370. Directive wireless signalling. TELEFUNKEN GES. FUR DRAHTLOSE TELEGRAPHIE, 12, Hallesches Ufer, Berlin. June 4, 1935, No. 16239. Convention date, June 4, 1934. [Class 40 (v)] In a cross-coil visual indicator for use when steering on an overlapping-beam system, the mean direct-current component of the co-operating signals, Figs. 2 and 3, is filtered out so that the final form of the impulses applied to the indicator is as shown in the bottom-line of those Figures. In this form the impulses are applied to the crossed coils S1, S2, Fig. 1, through reversed rectifiers G1, G2. The object is to prevent the growing strength of the impulses, as the aeroplane approaches the transmitting beacon, from affecting the accuracy of the readings. The system is applicable to modulated signals or to unmodulated signals received by a local heterodyne. The output from the last valve Nf, Fig. 1, of the receiver is rectified at GO and applied across a resistance R1 and condenser C1 to produce the voltageform UR1, Figs. 2 and 3. The direct-current component is then filtered out by a condenser C2, and applied across a resistance R2 to give the voltage-form UR2, which is applied to the crossed coils S1, S2 through reversed rectifiers G1, G2. To produce a dead-beat swing of the pointer P, each coil is shunted by reversed rectifiers G3, G4 and variable resistances r3, r4 ; also the gap of the magnet M is of elliptical cross-section.