Applications of FFT and DFT in amplitude-frequency characteristic test of seismic data recorders

During the process of amplitude-frequency characteristic test of seismic data recorders, when the frequency of calibration signal reached one-fifth of the sampling frequency of seismic data recorder, we cannot manually get the peak-value of output sine-wave by seismic data recorder due to distortion of sine-waveforms. In order to solve this problem, this paper proposed aDFT(discrete Fourier transformation)-based numerical integration method. Then FFT (fast Fourier transformation) method and DFT numerical integration method were used to compute real amplitude-frequency characteristic test data of one high-precision seismic data recorder. The result shows that these two methods are high precision and standardization, and can compute the calibrating data of amplitude-frequency characteristic. Compared with FFT method, DFT-based numerical integration method is simple to operation. And it can also be applied to linearity test of seismic data recorders.