Question

所以你试图实现一个低通数字滤波器，它可以从.wav文件切换5000 hz以上的所有频率，它的采样率= 38000 所以我使用signal.butter来获得系数
但当我的功能添加6000的频率时，它不会过滤它，实际上它开始从15000赫兹过滤谁能知道原因在哪里

    from scipy import signal
    nyq =0.5 *38000
    b, a = signal.butter(5,5000/nyq, btype='low', analog=False, output='ba')

def browse_txt(self):

    filepath = QtGui.QFileDialog.getOpenFileName(self, 'Single File', "C:\Users\Hanna Nabil\Desktop",'*.txt')

    y=[0,0,0,0,0,0]
    x=[0,0,0,0,0,0]
    with open(filepath, "r") as f:
        content = f.readlines()
    content = [s.strip() for s in content]
    print len(content)
    index = 0

    p=[]
    while index < len(content):
        x[0] = x[1]
        x[1] = x[2]
        x[2] = x[3]
        x[3] = x[4]
        x[4] = x[5]
        x[5] = float(content[index])
        y[0] = y[1]
        y[1] = y[2]
        y[2] = y[3]
        y[3] = y[4]
        y[4] = y[5]
        #x = float(content[index])
        y[5] =0.00405468* x[5] + 0.0202734 * x[4] +0.0405468 * x[3] + 0.0405468 * x[2] +0.0202734* x[1] +  0.00405468 * x[0]
        - (-2.34299118)*y [4]-  2.58241136*y[3] -(-1.5249425)*y[2] -0.47760386 *y[1]- (-0.06233179)*y[0]
        #p0 = float(content[index])
        p.append(y[5])


        index += 1
    self.signal=np.array(p)

    self.time = np.linspace(0, 1, 38000 * 1)

    freq = fftfreq(self.signal.size, 1.0/38000)
    self.xfourier =freq[:int(len(freq) / 2)]

    mag= abs(fft(self.signal))
    self.yfourier = mag[:int(len(mag) / 2)]



    self.drawOn1()
    self.drawOn3()

使用黄油的数字滤波器系数

0 个答案: