| 摘要 |
PURPOSE:To perform high-resolution measurement with high sensitivity and a high S/N by outputting a transmission pulse having a pulse width wider than the vibrating period of an ultrasonic vibrator or than the period of a received frequency by an integer multiple to the ultrasonic vibrator. CONSTITUTION:A transmission circuit 11 generates a square-wave pulse having a pulse width wider than the center frequency period of a receiving amplifier circuit 13 by an integer multiple and excites an ultrasonic vibrator in a wide-band frequency probe 12 by impressing the pulse upon the vibrator. The excitation of the vibrator is performed at both the trailing edge and leading edge of the pulse. As a result, ultrasonic waves are generated and made incident to a material 4 to be measured. The ultrasonic waves made incident to the material 4 are reflected at a flaw, base of the material 4, etc., and reflected echoes are received by means of the probe 12. Received signals are inputted to a measurement circuit 14 after they are amplified at the amplifier circuit 13. When the signals are inputted to the circuit 14, the number of vibration of the signals is reduced, because the amplitude of the corresponding signal part after the leading edge of the transmitted pulse is offset by synthesization and interference. Therefore, a high-resolution waveform having a less number of vibration can be obtained. |
