GB335443A - Improvements in or relating to radio receiving systems - Google Patents

Abstract

335,443. Marconi's Wireless Telegraph Co., Ltd., (Assignees of Moore, J. B.). Nov. 16, 1928, [Convention date]. Fading, preventing; thermionic valve circuits. -Tbe signals from a plurality of aerials, which are either geographically spaced or in different planes of polarization and thus have different fading characteristics, are amplified, rectified and combined, and the combined energy utilized to control the gain of each of the amplifiers, in addition to passing to a utilization circuit. Signals from aerials 2, 4, 6 are passed by transmission lines 8, 10, 12, to amplifiers 14, 16, 18, the output from which is fed to heterodyning devices and detectors, or autodyne circuits 20, 22, 24. The intermediate frequencies thus produced are amplified by amplifiers 26, 28, 30, and detected by valves 32, 34, 36, the output from which passes through low-pass filters 38, 40, 42, a volume control impedance 54, and a condenser 56 for providing the correct time-constant to the volume-control action. The impedance 54 is connected on the earth side of the source 52 of anode potential, and a lead 58 is taken from one side of it, to control the grid bias of valves in each of the amplifying systems. In parallel with the impedance 54 is an impedance 68, from which potentials may be drawn for utilization by an amplifying stage 70, followed by a stage of pushpull amplification 76. The coupling impedance and volume-control impedance may be in series, and the time-constant condenser and volume,- control impedance, in parallel.