GB550814A - Multiplex signal-translating system - Google Patents

Abstract

550,814. Multiplex systems. HAZELTINE CORPORATION. Aug. 29, 1941, No. 11060. Convention date, May 28, 1940. [Class 40 (iv)] [Also in Group XL] In a system using cathoderay distributers, scanning takes place at a high speed under the control of a known circuit involving a valve 62 through which the horizontal scanning potentials are built up on a condenser 56 when the beam is traversing the targets connected to idle channels but is retarded when the beam is on the targets of operative channels. This is brought about with the aid of a second distributer tube 50 at the sending end controlled synchronously with the main tube 27 and having its targets energized from the signal channels through rectifiers such as 51 and limiters such as 52. When the beam of this second tube encounters a live target, it gives an impulse to an amplifier 78 which biasses the tube 62 in a direction to increase its impedance and so slow up the charging of the scanning condenser 56. If it is desired that the scanning cycle, when any channel is in use, should be more nearly of constant duration, the circuit shown within the rectangle 93 is provided. In this arrangement, a condenser 100, which is normally charged from battery 97 and determines the gain of amplifier 78, is partially discharged through a tube 95 each time the beam on tube 50 encounters a live target. The potential of the condenser and therefore the gain of amplifier 78 is thus progressively reduced and takes up a value which depends on the number of operative channels so that with a large number of channels the delay on'each target is small and vice versa.