Application of FFT in frequency domain characteristics test system for ultrasonic flaw detector

To test the frequency domain characteristics of ultrasonic flaw detector, this paper designs a test system which based on the Fast Fourier Transform (FFT) algorithm and VC++ platform. After sampling the time domain waveform of launching and the receiving amplifier of ultrasonic flaw detector, amplitude spectra of frequency domain was got through the C++ program which had a core of fast Fourier transform (FFT) processing discrete data. Then the system obtained the characterization parameters (center frequency and bandwidth) of the output pulse frequency of ultrasonic flaw detector's launching amplifiers and the frequency response of ultrasonic flaw detector's receiving amplifier. At the same time, test interface of the detector frequency domain characteristics parameter was designed with VC++ platform. Experiments results showed that the system had the capability to quickly and accurately test the frequency domain characteristics of ultrasonic flaw detector, and visually displayed them.