GB663782A - Improvements in and relating to multi-channel electric pulse signalling systems - Google Patents

Abstract

663,782. Multiplex pulse signalling. GENERAL ELECTRIC CO., Ltd. Jan. 3, 1950 [Dec. 3, 1948], No. 31380/48. Class 40 (v). In a multi-channel pulse communication system, each channel comprises a valve producing broad amplitude modulated pulses, the valves being arranged in groups with a common output and the outputs being associated with means for selecting a narrower portion of each pulse the resulting narrow amplitude modulated pulses being interlaced for transmission. The pulses may be converted to time or duration modulated pulses before transmission. In the embodiment described, which accommodates eighty channels, eight cathoderay distributers are used, of the type described in Specification 619,785, of which each provides ten of the channel valves. Each distributer has a common cathode which provides an electron beam which is magnetically rotated to serve each valve in turn. Four of these distributers D1 ... D4, are shown in Fig. 1, the common anodes A1 ... A4 respectively being connected to gating devices M1 ... M4 respectively. The signals from channels 1, 9, 17 ... 65, 73 are applied to the grids G1 of distributer Dl, the signals from channels 2, 10, 18 ... 66, 74 to grids G2 of distributer D2 and so on, and the electron beams B1 ... B4 rotate in synchronism under the control of quadrature deflecting oscillations from a generator Q, Fig. 3. The beams of distributers D5 ... D8 (not shown) are controlled from terminals Q1, Q2 of generator Q and rotate in synchronism but in such a phase that the broad amplitude modulated pulse outputs O, O<SP>1</SP>, Fig. 2, from the two sets of distributers interlace in time. For convenience these superposed channel pulses are shown of constant unmodulated amplitudes. The gating circuits M1 ... M4 are controlled by narrow pulse trains GP1 ... GP4, Fig. 2, respectively, applied to terminals TG1 ... TG4, and pulse trains GP5 ... GP8 are applied to the other four gating circuits, not shown. The resulting interlaced narrow amplitude modulated channel pulse trains are fed to a common output terminal TO. The gating pulse trains are derived from tappings TG1 ... TG8, Fig. 3, on a delay line DL fed with pulses from a generator PG which, with the generator Q, is controlled by a synchronizing oscillator SS. In a modification, the gating functions are all performed by a further cathode-ray distributer of the same type, to the eight grids of which are connected the common anodes Al ... A8, Fig. 5 (not shown). The amplitude modulated pulses may be converted into time or duration modulated pulses by a known type of cathoderay tube modulator, Fig. 6 (not shown). Other arrangements are described in which the distributers D1 . . . D8 are replaced by gated pentode valves.