Emergency alarm circuit for use with aircraft detection and recognition systems

Claim 1

IN A AIRCRAFT RECOGNITION SYSTEM, A SOURCE OF REPETITIVE RADAR PULSES ADAPTED TO TRIGGER A RECOGNITION TRANSMITTER ON A REMOTE AIRCRAFT, A CATHODE RAY TUBE, SWEEP MEANS OPERATIVELY ASSOCIATED WITH SAID CATHODE RAY TUBE AND FORMED AND ARRANGED TO SWEEP THE BEAM THEREOF OVER THE SCREEN THEREOF AT THE SAME REPETITIVE RATE AS SAID RADAR PULSES, SAID SWEEP MEANS INCLUDING ROTARY BEAM DEFLECTION COILS OPERATIVELY ASSOCIATED WITH SAID CATHODE RAY TUBE, MEANS DRIVINGLY CONNECTED TO SAID BEAM DEFLECTION COILS AND BEING FORMED AND ARRANGED TO NORMALLY ROTATE SAME CONTINUOUSLY, MEANS TO MODULATE SAID BEAM TO PROVIDE A PLURALITY OF FIXED SPACE REFERENCE RANGE MARKERS ON SAID SCREEN, A DISCHARGE TUBE HAVING A PLATE, A CATHODE, AND A PAIR OF CONTROL GRIDS, A SOURCE OF CURRENT CONNECTED IN CIRCUIT WITH SAID PLATE AND CATHODE, MEANS NORMALLY BIASING EACH GRID BEYOND CUT-OFF, RESPECTIVE SIGNAL CHANNELS CONNECTED TO SAID GRIDS, MEANS TO APPLY A RECOGNITION SIGNAL SIMULTANEOUSLY TO SAID SIGNAL CHANNELS, DELAY MEANS IN ONE OF THE SIGNAL CHANNELS FORMED AND ARRANGED TO DELAY THE SIGNAL PASSING THERE-