GB533352A - Improvements in or relating to phase delay devices suitable for multiplex telegraph systems - Google Patents

Abstract

533,352. Multiplex telegraphy. MARCONI'S WIRELESS TELEGRAPH CO., Ltd. Oct. 31, 1939, No. 29092. Convention date, Nov. 1, 1938. [Classes 40 (iii) and 40 (v)] In distributer multiplex systems, and particularly channel extension systems, the phase of a repeated signal is determined by adjusting a shunt to an impedance in the input circuit of a gas discharge valve used in repeating the signal, and so determining the instant at which the valve strikes. Signals received over channel III of distributer 61 are repeated by a "locking unit" 62 to triodes A, B which repeat them to gasdischarge valves C, D controlling the output relay 23, whose armature 47 repeats the signals over distributer 55 to the outgoing circuit. The instant at which the valves C, D strike is determined by adjusting resistances 40, 43 around condensers 37, 41, or around inductances, Fig. 2 (not shown) in their input circuits. The striking point can also be adjusted by varying their grid bias or the capacity 44 across the anodes of the two valves. When the unit 62 makes lead 63 positive and lead 64 negative, valve A passes current and makes the grid of valve C negative. valve B being open and the grid of valve D positive, so that current passes through the lower winding of relay 23 and connects negative potential to the distributer 55, condenser 45 being charged so that its terminal 69 is positive relative to terminal 70. When the locking unit 62 reverses the potentials on leads 63, 64, valve B passes current and energizes valve C, current passing through the upper winding of relay 23 and reversing the charge on condenser 45, which stops the current through valve D.