chirp.py 文件源码

def window_plot():
    """Makes a plot showing a sinusoid, hamming window, and their product.
    """
    signal = thinkdsp.SinSignal(freq=440)
    duration = signal.period * 10.25
    wave1 = signal.make_wave(duration)
    wave2 = signal.make_wave(duration)

    ys = numpy.hamming(len(wave1.ys))
    window = thinkdsp.Wave(ys, wave1.framerate)

    wave2.hamming()

    thinkplot.preplot(rows=3, cols=1)

    pyplot.subplots_adjust(wspace=0.3, hspace=0.3, 
                           right=0.95, left=0.1,
                           top=0.95, bottom=0.05)

    thinkplot.subplot(1)
    wave1.plot()
    thinkplot.config(axis=[0, duration, -1.07, 1.07])

    thinkplot.subplot(2)
    window.plot()
    thinkplot.config(axis=[0, duration, -1.07, 1.07])

    thinkplot.subplot(3)
    wave2.plot()
    thinkplot.config(axis=[0, duration, -1.07, 1.07],
                     xlabel='time (s)')

    thinkplot.save(root='windowing2')