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Method of Measuring Ultrasonic Propagation Time Using Chirp Signal

A linear frequency modulation signal and propagation time technology, which is applied in the analysis of solids using sonic/ultrasonic/infrasonic waves, can solve the problems of low efficiency, low accuracy, long time, etc. Effect

Inactive Publication Date: 2018-03-16
ZHEJIANG FORESTRY UNIVERSITY
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

As a result, the entire process of implementing the method takes a long time, has low efficiency, and low accuracy

Method used

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  • Method of Measuring Ultrasonic Propagation Time Using Chirp Signal
  • Method of Measuring Ultrasonic Propagation Time Using Chirp Signal
  • Method of Measuring Ultrasonic Propagation Time Using Chirp Signal

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Embodiment

[0051] First, the excitation signal is generated by the linear frequency modulation signal generator, and the excitation signal is amplified by the power amplifier to excite the transmitting transducer to emit ultrasonic waves, and the emitting ultrasonic waves are u x (t), Let A=100v,f 0 =1.15MHz, B=2.1MHz, T=50us, at this time, ultrasonic waves are emitted x The spectrogram of (t) is as follows image 3 as shown, Figure 3-1 Indicates the ultrasonic signal u x The amplitude of (t) changes with time, the time unit is us, Figure 3-2 Indicates the ultrasonic signal u x The amplitude of (t) varies with the ultrasonic signal u x (t) frequency change law, the frequency unit is MHz;

[0052] Then send the ultrasonic signal u x (t) After passing through a wooden board with a thickness of 6mm, it reaches the receiving transducer. The amplitude of the ultrasonic signal received by the receiving transducer is attenuated at this time, and the phase is delayed. The spectrum dia...

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Abstract

The invention discloses a method for measuring ultrasonic propagation time by using a linear frequency modulation signal, which comprises the following steps: generating an excitation signal through a linear frequency modulation signal generator to excite a transmitting transducer to transmit ultrasonic waves, and the transmitted ultrasonic signal passes through the material to be tested and is received and converted After receiving by the transducer, perform wavelet filter processing, then shift the ultrasonic signal to the left, multiply the processed ultrasonic signal with the transmitted ultrasonic signal to obtain the product signal, perform Fourier transform on the product signal to obtain the amplitude spectrum of the product signal and use the maximum The value function determines the frequency of the peak value in the amplitude spectrum, and finally calculates the propagation time of the ultrasonic wave in the material to be tested; the present invention only needs to perform a Fourier transform FFT and signal multiplication operation, and the operation is greatly reduced, thereby realizing the short cycle and high efficiency of the method; The linear frequency modulation signal is used to excite the ultrasonic pulse, which improves the penetration ability of the ultrasonic wave and the time resolution of the ultrasonic detection, thereby improving the detection accuracy.

Description

technical field [0001] The invention relates to a method for measuring ultrasonic propagation time in the technical field of ultrasonic nondestructive testing, in particular to a method for measuring ultrasonic propagation time by using a chirp signal. Background technique [0002] Ultrasound is one of the most widely used methods in non-destructive testing. In ultrasonic non-destructive testing, the commonly used method is to measure the speed of the material to be tested based on the propagation time or propagation speed of the ultrasonic wave in the material to be tested (equal to the propagation distance divided by the propagation time). Dynamic Young's modulus, density, moisture content, cracks and holes, etc., because this method has the advantages of simple implementation and convenient use, it has been widely used, so it is very important to accurately measure the propagation time of ultrasonic waves in the material to be tested academic and practical significance. ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G01N29/07
Inventor 蔺陆军方益明李剑冯海林
Owner ZHEJIANG FORESTRY UNIVERSITY
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