| 摘要 |
In order to increase the speed at which a workpiece is tested by the ultrasonic pulse-echo method, the dead time between individual measurement time intervals is shortened by providing a minimum predetermined time interval selected for the specific test conditions. When an echo responsive signal is manifest in the receiving circuit, in order to prevent the occurrence of phantom echo signals arising in the following measuring interval, the generation of the succeeding transmit signal is inhibited for the predetermined time interval after receipt of the last echo responsive electrical signal of the measuring interval having an amplitude exceeding a predetermined minimum amplitude. The test speed therefore, is made adaptive to the condition of the receipt of the number of echo responsive electrical signals exceeding a predetermined minimum amplitude.
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