GB370888A - System of radio telephony and telegraphy - Google Patents

Abstract

370,888. Wireless signalling : valve modulating circuits. INTERNATIONAL RADIOPHONE CORPORATION, 810, Colorado Building, Washington, U.S.A.- (Assignees of Polin, H. S. ; 2, East 54th Street, New York, U.S.A.) Oct. 2, 1930, No. 29555. Convention date, Oct. 31, 1929. [Class 40 (v).] In a combined transmitting and receiving system, both transmitter and receiver are tuned to the same frequency and are directly connected together so that the former aids the amplification of the latter. Thev are also inductively coupled so that each regenerates the signal of the other. As shown a common aerial 1 is connected to a solenoid 2 adjustably mounted relative to a plate 3 connected t o earth through transmitter and receiver coupling coils 4, 32 respectively, the filament circuits of transmitter and receiver being connected directly to the aerial circuit by conductors 30, 48 respectively. The transmitting screen-grid valve 6 has a plate coil 5 coupled to coil 4, a grid coil 19 connected with grid-leak 20 and the secondary 21 of a microphone transformer in the grid circuit, a stabilizing piezo-crystal 15 between grid and filament, and a variable condenser 29 between grid and plate. The receiving screen-grid valve 34 has its grid coil 33 coupled to aerial coil 32, the circuit differing from that of valve 6, by the omission of piezocrystal, grid-leak and microphone transformer, and the addition of headphones 47 in the plate circuit.