Airborne triggering system for proximity fuse or the like

Claim 1

AN AIRBORNE TRIGGERING SYSTEM RESPONSIVE TO ECHOES OF HIGH-FREQUENCY ELECTROMAGNETIC WAVES REFLECTED FROM A TARGET, COMPRISING ABOARD A VEHICLE: A SOURCE OF EQUISPACED PULSES CONSTITUTING BURSTS OF A HIGHT-FREQUENCY CARRIER OSCILLATION OF CONSTANT FREQUENCY, SAID CARRIER OSCILLATION VARYING RANDOMLY IN PHASE RELATIVE TO AN UNMODULATED REFERENCE WAVE OF LIKE FREQUENCY THROUGHOUT A TRAIN OF SAID PULSES WHOSE DURATION IS LARGE COMPARED WITH THE RECURRENCE PERIOD OF SAID PULSES; TRANSMITTING MEANS COUPLED TO SAID SOURCE FOR CONSECUTIVELY SENDING OUT SAID PULSES OVER AN OUTGOING RADAR BEAM CENTERED ON A DIRECTION SUBSTANTIALL PERPENDICULAR TO THE FLIGHT PATH OF SAID VEHICLE; RECEIVING MEANS RESPONSIVE TO ECHOES OF SAID PULSES REFLECTED FROM EXTRANEOUS OBJECTS; A DELAY CIRCUIT CONNECTED TO SAID SOURCE; RANGE-GATE MEANS COUPLED TO SAID RECEIVING MEANS AND CONTROLLED VIA SAID DELAY CIRCUIT BY SAID SOURCE FOR BLOCKING INCOMING ECHO PULSES AT ALL TIMES EXCEPT FOR A BRIEF INTERVAL OCCURRING A PREDETERMINED TIME AFTER THE TRANSMISSION OF EACH OUTGOING PULSE; CORRELATING MEANS COUPLED TO SAID SOURCE AND TO SAID RANGE-GATE MEANS FOR COMPARING THE PHASE OF ANY INCOMING ECHO PULSE, PASSED BY SAID RANGE-GATE MEANS, WITH THAT OF AN IMMEDIATELY PRECEDING OUTGOING PULSE AND FOR DERIVING THEREFROM AN OUTPUT OF A MAGNITUDE DEPENDENT UPON THE DEGREE OF MATCH BETWEEN THE PHASES OF THE TWO PULSES THUS COMPARED; AND A LOAD CIRCUIT CONNECTED TO SAID CORRELATING MEANS FOR RECEIVING SAID OUTPUT THEREFORM, SAID LOAD CIRCUIT INCLUDING THRESHOLD MEANS FOR PRODUCING A TRIGGERING SIGNAL UPON SAID OUTPUT EXCEEDING A PREDETERMINED MAGNITUDE.