Ultrasonic Detection Of Spectral Analysis And Software Design

According to Fourier Transform Principle, a program is designed with C and Assemble words to analyze the high frequency ultrasonic signals in frequency domain in this paper. There are functions such as drawing the chart of amplitude-frequency and phase-frequency, calculating and displaying the highest peak value, the total sum of amplitude and the effective line-breadth of the signal in the program. So an effective technical means is supplied for the analysis of ultrasonic signal.The research results show that the influence of sampling frequency, sampling error of peak value, strobe-position and strobe-width on FFT and IFFT is obvious. For 15MHz immersion focusing ultrasonic testing signal, the proper sampling frequency is 90MHz, the appropriate strobe-width is 1.2us and the sampling error less than 20%.The 45 steel samples, which were treated by different heating and cooling methods, were tested and the testing signal were analyzed elementarily in frequency domain using the program. The results show that for the ultrasonic testing signals of different microstructure, the difference in frequency domain is distinguishable. So the technique of analysis in frequency domain is feasible for the nondestructive testing of different heating treatment microstructure.