| タイトル | Ultrasonic correlator versus signal averager as a signal to noise enhancement instrument |
| 著者（英） | Pietsch, Benjamin E.; Kishoni, Doron |
| 著者所属（英） | NASA Langley Research Center|College of William and Mary|Industrial Quality, Inc. |
| 発行日 | 1989-01-01 |
| 言語 | eng |
| 内容記述 | Ultrasonic inspection of thick and attenuating materials is hampered by the reduced amplitudes of the propagated waves to a degree that the noise is too high to enable meaningful interpretation of the data. In order to overcome the low Signal to Noise (S/N) ratio, a correlation technique has been developed. In this method, a continuous pseudo-random pattern generated digitally is transmitted and detected by piezoelectric transducers. A correlation is performed in the instrument between the received signal and a variable delayed image of the transmitted one. The result is shown to be proportional to the impulse response of the investigated material, analogous to a signal received from a pulsed system, with an improved S/N ratio. The degree of S/N enhancement depends on the sweep rate. This paper describes the correlator, and compares it to the method of enhancing S/N ratio by averaging the signals. The similarities and differences between the two are highlighted and the potential advantage of the correlator system is explained. |
| NASA分類 | INSTRUMENTATION AND PHOTOGRAPHY |
| レポートNO | 91A19665 |
| 権利 | Copyright |
| URI | https://repository.exst.jaxa.jp/dspace/handle/a-is/350991 |
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