Claims
- 1. A nondestructive testing apparatus comprising:a wave transmitter for injecting an acoustic elastic wave into an measurement object on the basis of a magnetically excited current; a magnetically excited current feeding device for feeding the magnetically excited current to said wave transmitter; a wave receiver for detecting an acoustic elastic wave propagating through the measurement object and for outputting a received wave signal; a filter for putting a band limit to the received wave signal; an automatically amplifying rate controlling function-equipped amplifier for amplifying a signal outputted from said filter to a given amplitude and for outputting the signal to said magnetically excited current feeding device; and a signal processor for extracting from said wave receiver a signal of an oscillation frequency of a positive feedback loop composed of said wave transmitter, the measurement object, said wave receiver, said filter, said amplifier and said magnetically excited current feeding device and for processing the signal.
- 2. The nondestructive testing apparatus according to claim 1, wherein said wave transmitter is a magnetostrictive vibrator composed of a magnetostrictive element, a magnetically exciting coil and a magnetic biasing magnet.
- 3. The nondestructive testing apparatus according to claim 2, further comprising a display device for displaying the signal waveform detected by said wave receiver or the process result obtained by said signal processor.
- 4. The nondestructive testing apparatus according to claim 3, wherein said filter is a variable filter for selectively extracting a single frequency out of a plurality of resonance frequencies determined by a shape and an internal structure of the measurement object.
- 5. The nondestructive testing apparatus according to claim 3, wherein said amplifier has a circuit for outputting a correction amount of an amplifying rate so that said signal processor obtains state information of the constitution of the measurement object in accordance with the correction amount.
Priority Claims (1)
Number |
Date |
Country |
Kind |
10-247520 |
Sep 1998 |
JP |
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CROSS REFERENCE TO RELATED APPLICATION
This is a continuation of International Application PCT/JP99/04719, with an international filing date of Aug. 31, 1999.
US Referenced Citations (4)
Continuations (1)
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Number |
Date |
Country |
Parent |
PCT/JP99/04719 |
Aug 1999 |
US |
Child |
09/562037 |
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US |