Ultrasonic testing apparatus

Claim 1

ULTRASONIC INSPECTION APPARATUS COMPRISING: PULSER MEANS FOR DERIVING ELECTRICAL SIGNAL PULSES DURING REPETITIVE INTERVALS SPACED IN TIME FROM ONE ANOTHER BY RECEPTION INTERVALS; A SEARCH UNIT INCLUDING TRANSDUCER MEANS ELECTRICALLY COUPLED TO SAID DPULSER MEANS FOR CONVERTING THE AFORESAID ELECTRICAL SIGNAL PULSES TO ULTRASONIC WAVE ENERGY PULSES PROPAGATING FROM A SURFACE THEREOF AND FOR CONVERTING ULTRASONIC WAVE ENERGY PULSES INCIDENT ON SAID SURFACE TO ELECTRICAL SIGNAL PULSES AND INCLUDING AN ACOUSTIC DELAY ELEMENT HAVING ONE SURFACE ACOUSTICALLY COUPLED TO THE AFORESAID SURFACE OF SAID TRANSDUCER MEANS AND ANOTHER SURFACE ADAPTED TO BE ACOUSTICALLY COUPLED TO AN OBJECT UNDERGOING INSPECTION; FIRST AND SECOND GATE CIRCUITS, EACH INCLUDING INPUT, OUTPUT AND CONTROL CIRCUIT PORTIONS AND BEING NORMALLY INOPERATIVE TO TRANSLATE ELECTRICAL SIGNALS BETWEEN SAID INPUT AND SAID OUTPUT CIRCUIT PORTIONS, BUT ADAPTED TO BE OPERATIVELY CONDITIONED IN RESPONSE TO AN ELECTRICAL SIGNAL AT SAID CONTROL CIRCUIT PORTION; MEANS FOR SUPPLYING A REPLICA OF ELECTRICAL SIGNAL PULSES DERIVED BY SAID TRANSDUCER MEANS TO SAID INPUT CIRCUIT PORTION OF EACH OF SAID GATE CIRCUITS; MEANS FOR DERIVING FIRST CONTROL PULSES INITIATED IN SYNCHRONISM WITH THE ELECRICAL SIGNAL PULSES FROM SAID PULSER MEANS FOR APPLICATION TO SAID CONTROL CIRCUIT PORTION OF SAID FIRST GATE CIRCUIT, EACH OCCURRING SUBSTANTIALLY ONLY DURING ONE OF SAID RECEPTION INTERVALS; MEANS RESPONSIVE TO THE FIRST ELECTRICAL SIGNAL PULSE TO OCCUR DURING EACH OF SAID RECEPTION INTERVALS AT SAID OUTPUT CIRCUIT PORTION OF SAID FIRST GATE CIRCUIT FOR DERIVING TIME VARYING PULSES EACH INITIATED IN SYNCHRONISM WITH THE AFORESAID FIRST ELECTRICAL SIGNAL PULSE AND TERMINATING DURING THE CORRESPONDING RECEPTION INTERVAL; MEANS INCLUDING ELECTRICAL DELAY MEANS CONNECTED TO THE OUTPUT OF THE FIRST GATE CIRCUIT FOR DERIVING ADDITIONAL CONTROL PULSES, EACH INITIATED AT A TIME DELAYED FROM A CORRESPONDING ONE OF SAID FIRST ELECTRICAL SIGNAL PULSES BY A SELECTED INTERVAL AND TERMINATING DURING THE CORRESPONDING RECEPTION INTERVAL; MEANS FOR SUPPLYING SAID ADDITIONAL CONTROL PULSES TO SAID CONTROL CIRCUIT PORTION OF SAID SECOND GATE CIRCUIT; AND UTILIZATION MEANS RESPONISVE TO BOTH THE OUTPUT OF SAID SECOND GATE CIRCUIT AND SAID TIME VARYING PULSES AND ARRANGED TO DETECT THE TIME LAPSE BETWEEN INITIATION OF EACH OF SAID TIME VARYING PULSES AND THE SUCCEEDING ELECTRICAL SIGNAL AT THE OUPUT CIRCUIT PORTION OF SAID SECOND GATE CIRCUIT AND PROVIDE AN INDICATION THEREOF.