Automatic video switching device

Claim 1

IN A PULSED RADAR SYSTEM ADAPTED TO DEVELOP A FIRST VIDEO SIGNAL TRAIN INCLUDING ONLY MOVING TARGET SIGNALS AND ALSO A SEPARATE SECOND VIDEO SIGNAL TRAIN INCLUDING BOTH MOVING AND FIXED TARGET SIGNALS, A DEVICE FOR AUTOMATIC SWITCHING WITHIN ANY RANGE TIME BASE INTERVAL FROM SAID SECOND TO SAID FIRST VIDEO SIGNALS ON THE BASIS OF DURATION OF ANY TARGET SIGNAL BLOCK OCCURRING IN SAID SECOND VIDEO TRAIN AND FOR REMAINING SO SWITCHED AT LEAST AS LONG AS SAID BLOCK PERSISTS, COMPRISING THE COMBINATION OF: MEANS FOR GENERATING A GATE SIGNAL BEGINNING WITHIN A PREDETERMINED DELAY PERIOD AFTER THE BEGINNING OF ONE OF SAID SIGNAL BLOCKS; VIDEO DELAY MEANS FOR DELAYING SAID FIRST AND SECOND VIDEO SIGNAL TRAINS EQUALLY BUT SEPARATELY BY AN AMOUNT EXCEEDING SAID PREDETERMINED DELAY PERIOD; MEANS FOR STRETCHING SAID GATE SIGNAL WHEREBY A CORRESPONDING ONE OF SAID BLOCKS AS DELAYED BY SAID VIDEO DELAY MEANS FALLS ENTIRELY WITHIN THE TIME OF OCCURRENCE OF SAID GATE SIGNAL; AND ELECTRONIC SWITCHING MEANS RESPONSIVE TO SAID GATE SIGNAL AND BOTH OF SAID DELAYED VIDEO SIGNAL TRAINS FOR EFFECTING SAID AUTOMATIC SWITCHING, THEREBY TO DEVELOP AN OUTPUT SIGNAL WHICH COMPRISES SAID SECOND VIDEO SIGNAL TRAIN AS WELL AS AUTOMATICALLY SELECTED PORTIONS OF SAID FIRST SIGNAL TRAIN.