_filtering.py 文件源码

def _getFiltDesign(sf, f, npts, filtname, cycle, order, axis):
    """Get the designed filter
    sf : sample frequency
    f : frequency vector/list [ex : f = [2,4]]
    npts : number of points
    - 'fir1'
    - 'butter'
    - 'bessel'
    """

    if type(f) != np.ndarray:
        f = np.array(f)

    # fir1 filter :
    if filtname == 'fir1':
        fOrder = fir_order(sf, npts, f[0], cycle=cycle)
        b, a = fir1(fOrder, f/(sf / 2))

    # butterworth filter :
    elif filtname == 'butter':
        b, a = butter(order, [(2*f[0])/sf, (2*f[1])/sf], btype='bandpass')
        fOrder = None

    # bessel filter :
    elif filtname == 'bessel':
        b, a = bessel(order, [(2*f[0])/sf, (2*f[1])/sf], btype='bandpass')
        fOrder = None

    def filtSignal(x):
        return filtfilt(b, a, x, padlen=fOrder, axis=axis)

    return filtSignal