【python常用函数】——傅里叶变换

def FFT(wave, fs, length):
    fre = np.arange(0,int(len(wave)/2),1) * (fs/len(wave))
    window = sgn.hann(len(wave))
    spec = abs(np.fft.fft(wave*window)) * 2 / (len(wave))
    spec2 = spec[range(int(len(wave)/2))]
    spec2 = spec2[:length]
    fre = fre[:length]
    return fre, spec2

使用时可选择返回值，例如：
F,a = FFT(x, fs, -1)
plt.plot(F,a)