GB358064A - Improvements in and relating to radio communication with very short waves - Google Patents

Abstract

358,064. Valve circuits. GERHARD, E., 1, Zõhstrasse, Fiirth, Bavaria, Germany. March 31, 1930, No. 10237. Convention date, April 2, 1929. [Class 40 (v).] In a valve arranged to generate ultra shortwave oscillations by virtue of a highly positively charged grid and a plate nearly at zero potential, an oscillatory circuit of a different natural frequency from the primary oscillations is connected in the plate or grid circuit, the voltages on the electrodes being so chosen that the valve is operating on the drooping part of the dynamic characteristic. This results in modulation of the ultra high-frequency primary oscillations by secondary oscillations of a lower radio frequency. As a transmitter, the valve 2, Fig. 2, is coupled to a dipole aerial 1 and the secondary oscillatory circuit 10, 11 is coupled to a low-frequency winding 22, through an iron core 21, this winding being supplied with low-frequency modulating currents. As a receiver the oscillatory circuit 10, 11, Fig. 1, is coupled to a coil 12 connected to an ordinary high-frequency amplifier 13, detector 14 and low-frequency amplifier 8. If the received wave is not modulated by an audiofrequency, the circuit 10, 11 may produce oscillations which will heterodyne the high-frequency modulation of the incoming signals. The Specification as open to inspection under Sect. 91 (3) (a) comprises also a transmitting modulating system in which the high-frequency oscillations of the circuit 10, 11, Fig. 3 (Cancelled) are amplified by the valve 17 and fed back into the circuit 10, 11 the low-frequency modulating potentials being applied between the grid and cathode of the valve 17. This subject-matter does not appear in the Specification as accepted.