RECEIVING APPARATUS FOR ULTRASONIC FLAW DETECTION

摘要

PURPOSE:To set an ultrasonic signal to the optimum level, by a method wherein the output of the containing the reflected wave of a flaw in a received ultrasonic signal is variably amplified to detect the peak value thereof and the gain of a variable amplifier is determined on the basis of the detected peak value. CONSTITUTION:The received ultrasonic signal A from a probe is amplified by a preamplifier 1 and a time gate signal is inputted to a time gate circuit 2 and a signal containing the reflected wave of a flaw is separated from other signal to pass only for a specific period. The output signal B of the circuit 2 is amplified by a variable amplifier 3 and the variably amplified output signal C is sent to a signal processing apparatus and a peak detection circuit 4. This circuit 4 detects the first peak value P wherein the peak value of the output signal C exceeds a threshold value. The detected peak value P is inputted to a gain determining circuit 5 and a new gain optimizing the output signal C is calculated from the present gain (order) and the detected peak value P to issue a command to the variable amplifier. Therefore, the adjustment work of an inspector is made unnecessary at the time of ultrasonic flaw detection and the optimum gas is automatically determined to make it possible to enhance flaw detection accuracy.