GATE CIRCUIT OF ULTRASONIC FLAW DETECTOR

摘要

PURPOSE:To sense precisely the location of a defect existing in the inside by furnishing a calculating means to calculate the defect position relative to the surface from the output values of three address counters accommodated in a memory means. CONSTITUTION:A gate circuit 16 sets No. 1 gate for sensing the surface position of an object to be inspected 1, senses the max. value of a surface echo signal due to the surface part existing in the measuring extent and the depth position at which the max. value appears, and further senses the value on an address counter for threshold value. Another gate circuit 17 installed in parallel with the first named gate circuit 16 sets No. 2 gate for sensing the defect position in the object 1 and senses the max. value of defect echo signal due to a defect existing in the measuring extent and the depth position where the max. value lies. Because the defect position sensed by the No. 2 gate circuit 17 is determined by reference to the position of the corresponding surface, this No. 2 gate circuit 17 operates in association with the surface sensing motion of the No. 1 gate circuit 16. That is, the defect sensing motion is started in conformity to a start signal given by the No. 1 gate circuit 16.