SIGNAL PROCESSING UNIT AND SIGNAL PROCESSING METHOD FOR ULTRASONIC FLAW DETECTION

摘要

PROBLEM TO BE SOLVED: To suppress the extinguishment of a defect echo by the influence of an end surface echo even in the case of a defect present in the vicinity of the side end surface of a subject to be tested and precisely detect the defect.;SOLUTION: Although the output of a window function generation part 46 is HIGH when the output signal of an FF 45 is LOW, a window function W (t) gets close to zero while gradually reducing from 1 when the output signal of the FF 45 is built up to LOW. The value of the window function W (t) is zero in the part where the time t is larger than c. The input signal branched to a path b is delayed by a prescribed time in a delay part 50, and then multiplied by the window function W (t) outputted from the window function generation part in an arithmetic part 51. When the delay time of the delay part 50 is set larger than c, the end surface echo is zero in the signal obtained by multiplying the signal branched to the path b by the window function W (t), and only the end surface eco is selectively removed.;COPYRIGHT: (C)2001,JPO