| 摘要 |
FIELD: physics.SUBSTANCE: method comprises transmitting a probing electromagnetic signal to a transducer which excites surface acoustic waves (SAW) in the inspected sample, wherein a probing electromagnetic pulse is periodically transmitted to the transducer, wherein the frequency discretely varies on a linear law; measuring the frequency dependency of the complex reflection coefficient S11 of said SAW transducer and subsequent Fourier transform of the obtained frequency dependency, from where the location and size of the defect can be determined based on the amplitude and delay of SAW reflected therefrom, wherein the duration of the probing electromagnetic pulse is selected such that measurements at each frequency are taken over a certain period of time during which the SAW travels a distance greater than double the distance between the transducer and the defect; the basic frequency of the electromagnetic pulse is generated by a digital frequency synthesiser.EFFECT: measuring not only the delay, but also the amplitude of reflected surface acoustic waves even in the presence of various interference.3 dwg |
