| 摘要 |
PROBLEM TO BE SOLVED: To set detecting sensitivity so that non-sensitive band is minimized when pulse compression processing by digital signal processing is applied in ultrasonic flaw detection. SOLUTION: In this method, a received signal is amplified by an amplifier 1, and A/D converted by an A/D converter 2, the correlation between a reference signal similar to a transmitted signal and the A/D converted received signal is taken by use of an FIR filter 3, whereby pulse compression of the received signal is performed, and the sensitivity of an ultrasonic detector for judging a defect is set in an evaluation part 4 on the basis of the pulse compressed received signal.. In this case, the amplification degree of the amplifier 1 is set so that the boundary surface echo of the received signal, is not saturated by the A/D converter 2, and the output bit of the FIR filter 3 inputted to the evaluation part 4 is determined so that the defect echo after pulse compression is within the range of a desired size in the evaluation part 4. |
