GB784999A

GB784999A - Waveform handling devices for binary coded pulse signalling systems

Info

Publication number: GB784999A
Application number: GB33827/54A
Authority: GB
Original assignee: Societe dElectronique et dAutomatisme SA
Current assignee: Societe dElectronique et dAutomatisme SA
Priority date: 1953-11-20
Filing date: 1954-11-22
Publication date: 1957-10-23

Abstract

784,999. Electric selective signalling systems. SOC. D'ELECTRONIQUE ET D'AUTOMATISME. Nov. 22, 1954 [Nov. 20, 1953], No. 33827/54. Class 40 (1). [Also in Group XL (c)] In a pulse code system in which a binary code expressed by "on-off " pulses is converted into one in which the pulses occur in either the first or the second half of the pulse period (for magnetic storage in a digital computer); the first pulses are differentiated and applied to one side of a trigger pair of valves, whilst a pulse train of opposite sense is derived from the first, differentiated and applied to the other side of the trigger pair from which the converted pulses are obtained. The duration of code pulses c, Fig. 2, is first lengthened to half the pulse period to provide the pulses S1, by applying the code pulses c and gating pulses T (which.are of the required duration) to diodes 3, 6, 7, Fig. 1, which are so biased with respect to the voltage levels of pulses c, T that a regenerative amplifier I conducts only when the pulses coincide. Due to the feedback over diode 4, valve I will continue to conduct until the end of the gating pulse. The lengthened code pulses S1 are differentiated at 14, 16 to form wave-train d1 and applied to one valve 20 of a trigger pair. A second train of pulses c, of opposite phase to the first (and derived from the first) is added to an auxiliary pulse train t by rectifiers 12, 13 to form a train c(-). These pulses are lengthened as above to form pulses S2, a train in which pulses occur whenever there is no pulse in train S1. The pulses S2 are differentiated at 17, 19 as at d2 and applied to the other valve 21 of the trigger pair. The output of valve 21 is passed via cathode follower V to the output. This output train C consists of pulses occurring in the first half of the period corresponding to " 1 " due to the positive spikes of d1 triggering valve 20, and pulses occurring in the second half of the period corresponding to "0" due to the negative spikes of d2 cutting off valve 21. A complementary pulse train output C is obtained from a second trigger pair IV to which the trains d1, d2 are oppositely connected.