iir_theory.py 文件源码

def finiteprecision(self, coeff=None, totalbits=None, shiftbits=None):
        if coeff is None:
            coeff = self.coefficients
        if totalbits is None:
            totalbits = self.totalbits
        if shiftbits is None:
            shiftbits = self.shiftbits
        res = coeff * 0 + coeff
        for x in np.nditer(res, op_flags=['readwrite']):
            xr = np.round(x * 2 ** shiftbits)
            xmax = 2 ** (totalbits - 1)
            if xr == 0 and xr != 0:
                logger.warning("One value was rounded off to zero: Increase "
                               "shiftbits in fpga design if this is a "
                               "problem!")
            elif xr > xmax - 1:
                xr = xmax - 1
                logger.warning("One value saturates positively: Increase "
                               "totalbits or decrease gain!")
            elif xr < -xmax:
                xr = -xmax
                logger.warning("One value saturates negatively: Increase "
                               "totalbits or decrease gain!")
            x[...] = 2 ** (-shiftbits) * xr
        return res