GB423189A - Improvements in or relating to radio receivers - Google Patents

Abstract

423,189. Valve circuits for wireless reception. MARCONI'S WIRELESS TELEGRAPH CO., Ltd., Electra House, Victoria Embankment, London, and GILL, E. W. B., Merton College, Oxford. July 27, 1933, No. 21164. [Class 40 (v)] A short or ultra-short wave radio receiver comprises a frequency changing stage in which the received signals are applied to the anode of the valve while local oscillations of longer wave-length are applied to the grid, the anode potential being adjusted so that rectification occurs in the anode circuit. In the case of a triode valve the received oscillations are applied through a tuned circuit connected across anode and cathode or anode and grid, the local frequency source being between grid and cathode, (Figs. 1 and 2, not shown). Or, as in Fig. 3, a dipole aerial 10, 11, of natural frequency equal to the received frequency is connected to anode and grid, the local frequency 9 and coupling impedance 7 being connected as before. To avoid oscillation in the anode circuit at the local frequency, a tetrode may be employed with the tuned circuit between anode and screen grid or anode and cathode, the local frequency being applied between control grid and cathode, (Figs. 4 and 5, not shown). Or a dipole aerial may be employed as shown in Fig. 6. A rectification stage may precede the frequency changer shown, and the output may be applied to an ordinary superheterodyne receiver.