PlotDataItem.py 文件源码

def _fourierTransform(self, x, y):
        ## Perform fourier transform. If x values are not sampled uniformly,
        ## then use np.interp to resample before taking fft.
        dx = np.diff(x)
        uniform = not np.any(np.abs(dx-dx[0]) > (abs(dx[0]) / 1000.))
        if not uniform:
            x2 = np.linspace(x[0], x[-1], len(x))
            y = np.interp(x2, x, y)
            x = x2
        f = np.fft.fft(y) / len(y)
        y = abs(f[1:len(f)/2])
        dt = x[-1] - x[0]
        x = np.linspace(0, 0.5*len(x)/dt, len(y))
        return x, y