GB679360A - Improvements in or relating to receiving devices for pulse code signal transmission systems - Google Patents

Abstract

679,360. Cathode-ray tubes. SOC. ALSACIENNE DE CONSTRUCTIONS MECANIQUES. June 6, 1951 [July 13, 1950], No. 13462/51. Class 39 (i). [Also in Group XL (c)] In the receiver of a pulse code modulation signalling system (see Group XL (c)), a step wave, with levels corresponding to the pulse amplitudes, is applied to amplifier 10, the pushpull output of which is fed to the vertical deflecting plates 3 of a cathode-ray tube 1. The horizontal deflecting plates 4 are supplied with a push-pull sawtooth voltage from amplifier 13 supplied from the scanning generator 12. The cathode-ray beam in tube 1 is thereby moved vertically to a position depending upon. the levels of the step wave from circuit 10 and scanned horizontally across the mask 6 and anode 5 once during the occurrence of each level. The solid portion of the mask is shown shaded in Fig. 2 in which A is the rest position of the beam, AB a typical vertical deflection and BC the corresponding horizontal deflection. During the latter, a current pulse of duration corresponding to the distance BD is produced in the anode 5, this duration being uniquely related to the corresponding vertical deflection AB. The mask is so cut that the durations of the pulses at the anode 5 are proportional to the signal amplitudes represented by the incoming code groups.