fir.py 文件源码

def _design(self):
        # Compute the order and Kaiser parameter for the FIR filter.
        N, beta = signal.kaiserord(self.ripple_db,
                                   self.bandwidth / self.fs * 2)

        # Use firwin with a Kaiser window to create a lowpass FIR filter.
        fir = signal.firwin(N, self.fc / self.fs * 2, window=('kaiser', beta))

        # the filter must be symmetric, in order to be zero-phase
        assert np.all(np.abs(fir - fir[::-1]) < 1e-15)

        self.fir = fir / np.sum(fir)
        return self