GB628683A - Electric multi-channel two-way pulse communication system - Google Patents

Abstract

628,683. Multiplex pulse signalling. STANDARD TELEPHONES & CABLES, Ltd. Aug. 14, 1947, No. 22605. Convention date, Aug. 24, 1946. [Class 40 (v)] A two-way multiplex system for communication by time-modulated pulses employs cathode-ray tubes as modulators and demodulators at each terminal station, and means are provided for synchronizing the sweep of the tubes at both stations. Figs. 1 and 2 show the respective stations. In Fig. 1, the modulation inputs 13 to the several channels are applied to deflecting electrodes 11 to deflect the electron beam radially and to give output pulses at the collector electrode as described in Specification 603,188, which are applied through cathode follower stage 18 to a radio transmitter 19. The electron beam is swept over a conical path by quadrature voltages applied to electrodes 3 which are connected to a phasesplitting circuit 9 fed by a stable oscillator 8. Once per revolution of the beam, a synchronizing pulse, broader than the signalling pulses, is emitted. The receiver 20 of the Fig. 1 terminal station is supplied with quadrature oscillations from 9 to synchronize the demodulator tube. Fig. 2 shows the receiving circuit and demodulator tube for the second terminal station. The detector pulses from the radio receiver 21 are supplied to a grid 30 of the tube 27 which is arranged as in Specification 603,614, and the synchronizing pulse is separated at 22 and is used to synchronize the generator 23 which feeds the sweep electrodes 25 through a phasesplitter 24. The generator 23, or a second generator also synchronized by the marker pulser, also feeds the modulator tube 33 of the transmitter 32 through a delay circuit 34.