| 摘要 |
PURPOSE:To measure the propagation time of a transversal wave with high accuracy by converting the output of a probe for reception to a frequency range, extracting a desired frequency component from the conversion output, and converting the extracted signal into a time-series signal again and displaying the waveform. CONSTITUTION:A Fourier transforming means(FFT) 12 transforms the output of the probe 11 for reception which is obtained in time series to the frequency range to obtain a transversal wave component on a low frequency side and a longitudinal wave component on a high frequency side. Therefore, a signal processing means (low-pass filter) 13 consisting of a proper filter extracts only the low-frequency side transversal component and an inverse Fourier transforming means(IFFT) 14 which retransforms the signal in the frequency range into a time-series signal and inputs the signal to a display means(oscilloscope) 15, so that the signal waveform of only the transversal wave component is obtained. Therefore, the speed and propagation time of the transversal wave can accurately be known. |
