| 摘要 |
PURPOSE:To measure the thickness of concrete by making an electromagnetic- wave pulse incident on the concrete inside and multiple reflection at the inside and analyzing the frequencies of plural transmitted pulses transmitting through the surface of the concrete. CONSTITUTION:A transmission part 11 drives a transmitting antenna 10 by a trigger signal S1 from a control part 18. A part of energy of the pulses emitted from the antenna 10 is reflected by the surface 2 and made the reflected waves, but the rest is made incident on the inside 4 and the multiply reflected waves and further, its part is made the transmitted pulses transmitting through the ground inside 6 and the transmitted pulses transmitting through the air 5 every time these are reflected by the base 3 and the surface 2. These transmitted pulses are caught by a receiving antenna 12 and converted into the low-frequency signals with a sampler 13. These low-frequency signals are amplified to the sufficient intensity with an amplification part 14 and converted into the digital values with an A/D conversion part 15. Then, a Fourier transformation part 16 analyzes the frequencies of the digital values converted with the conversion part 15 and a display part 17 calculates the thickness D of the concrete 1 based on a result of the frequency analysis. |
