GB506573A - Improvements in or relating to telegraph systems - Google Patents

Abstract

506,573. Synchronous movements. MARCONI'S WIRELESS TELEGRAPH CO., Ltd. Oct. 13, 1938, -No. 29740. Convention date, Oct. 16, 1937. [Class 40 (iii)] Two electric charges are produced which are functions of the times between local circuit closures and the beginning and. end respectively of received telegraphic signals, and the difference between the two charges corrects departures from synchronism. The charges accumulate on condensers 5, 4, and control valves 7, 6 which are biassed to cut-off during the receipt of signals by current in a resistance 32 from a rectifier 3 which conducts during the receipt of keyed low-frequency signals. The local circuit closures by commutators 8, 9 occur simultaneously at the centre of each unit length of signal or at different times which are equally disposed on both sides of the centre. An impulse produced by the beginning of a signal causes a gas-discharge tube 26 to conduct and charge the condenser 5 until the tube is quenched by the commutator 9. When the commutator 8 closes the grid circuit of a gas-discharge tube 34 during a signal, an impulse from the tertiary winding 33 of a transformer 18 causes the tube to discharge the condenser 4 and thus quench the tube. The condenser is then charged until the end of the signal by current through a rectifier 2. During the subsequent space the valves 23, 24 pass currents, which depend on the charges on the respective condensers 4, 5, through a differential relay 22, which governs a motor 21 controlling a main driving motor 20. According to a modification, directcurrent signals are used, Fig. 3 (not shown).