GB416464A - Improvements in electromagnetic wave receiving arrangements - Google Patents

Abstract

416,464. Valve circuits for wireless reception. ARMSTRONG, J. J. V., 12, Church Street, Liverpool.-(Telefunken Ges. f³r Drahtlose Telegraphie ; 12, Hallesches Ufer, Berlin.) March 16, 1934, No. 8260. [Class 40 (v).] In a short -wave receiver of the "retarding field " type in which a high positive voltage is applied to the valve grid a direct current voltage proportional to the signal is produced in the circuit of the retarding electrode and used to control the gain. Fig. 6 shows an arrangement in which the detector V2 has its output taken from Rg and produces a gain control voltage across resistance R which is applied to the high frequency amplifier V1. The detector in this arrangement operates at the lower bend of its characteristic. In a modification (Fig. 7 not shown), the control is applied to a grid adjacent the cathode in the detector valve which may be screened as shown in Fig. 8, the electrode S at cathode potential serving as an electron emergence surface, the electrode SG being maintained at a fixed high potential and the control voltage being applied to the grid G. With this arrangement the influence of the grid anode GA on the supply of electrons from the cathode is suppressed.