GB645264A - Code identification systems - Google Patents

Abstract

645,264. Electric selective signalling systems. BENDIX AVIATION CORPORATION. Aug. 7, 1947, No. 21747. Convention date, Aug. 14, 1946. [Class 40 (i)] A receiver comprises a number of elements, e.g. drop-indicators R33 ... R55, any one of which can be selected by the joint action of uniselectors I, II which respond-respectively to two trains of short impulses separated by a long impulse. As shown, impulse-relay 25 repeats all impulses to release-relay 40 which operates and to relay 33 which repeats them somewhat delayed to change-over relay 36. The impulses to 36 are terminated by the impulse-relay directly and so are of shorter duration than the original impulses and 36 makes no response to the first train which thus operates the reverse drive stepping magnet 52 of uniselector I. The prolonged intertrain impulse also energizes the stepping magnet 52 which is cut-off before the end of the impulse to allow the final step by the operation of change-over relay 36. Stepping magnet 63 of uniselector II thus responds to the second half of the prolonged impulse and then to the impulses of the second train, 36, once energized, being held by the shortened train impulses. In response to the final relapse of the impulse-relay, slow-to-operate relay 45 pulls up, making its contact 47 before breaking its contact 49 and so making a momentary circuit for the drop-indicator selected jointly by the uniselectors. Shortly afterwards, the relapse of release-relay 40 completes homing circuits for the selectors and the circuit is restored to normal.