GB569608A - Improvements in keying arrangements for signalling systems - Google Patents

Abstract

569,608. Valve relay circuits. DEHN, F. B. (Press Wireless, Inc.). July 13, 1943, No. 11367. [Classes 40 (iii) and 40 (v)] A system for keying a source of current in correspondence with fleeting impulses from a telegraph tape transmitter or with the half cycles of an alternating current or under control of D.C. impulses comprises a gas-filled discharge tube 17 which is rendered conducting when its normal grid bias is neutralized by a tape-controlled marking contact 5, 3 (or by a positive impulse from an alternating current generator or other timing source) and remains in the conducting condition until a vacuum tube 8 fed over the same anode resistance 21 is made conductive by the operation of the spacing- contact 4, 2 (or by the next half-cycle or a reverse impulse from the generator or other source). While 17 is conducting, a tube 22 in series in the cathode circuit of a push-pull amplifier 28 is rendered conducting also by the voltage drop in resistance 19 and amplified current from a source 34 reaches the output circuit. At other times, the tube 22 effectively opens the anode circuit of the amplifier 28.