fft.py 文件源码

 复制代码def plot_wav_fft(wav_filename, desc=None):
    plt.clf()
    plt.figure(num=None, figsize=(6, 4))
    sample_rate, X = scipy.io.wavfile.read(wav_filename)
    spectrum = np.fft.fft(X)
    freq = np.fft.fftfreq(len(X), 1.0 / sample_rate)

    plt.subplot(211)
    num_samples = 200.0
    plt.xlim(0, num_samples / sample_rate)
    plt.xlabel("time [s]")
    plt.title(desc or wav_filename)
    plt.plot(np.arange(num_samples) / sample_rate, X[:num_samples])
    plt.grid(True)

    plt.subplot(212)
    plt.xlim(0, 5000)
    plt.xlabel("frequency [Hz]")
    plt.xticks(np.arange(5) * 1000)
    if desc:
        desc = desc.strip()
        fft_desc = desc[0].lower() + desc[1:]
    else:
        fft_desc = wav_filename
    plt.title("FFT of %s" % fft_desc)
    plt.plot(freq, abs(spectrum), linewidth=5)
    plt.grid(True)

    plt.tight_layout()

    rel_filename = os.path.split(wav_filename)[1]
    plt.savefig("%s_wav_fft.png" % os.path.splitext(rel_filename)[0],
                bbox_inches='tight')

    plt.show()