attributes.py 文件源码

def valid_frequencies(self, obj):
        """ returns a list of all valid filter cutoff frequencies"""
        #valid_bits = range(0, self._MAXSHIFT(obj)-1)  # this is possible
        valid_bits = range(0, self._MAXSHIFT(obj)-2)  # this gives reasonable results (test_filter)
        pos = list([self.to_python(obj, b | 0x1 << 7) for b in valid_bits])
        pos = [val if not np.iterable(val) else val[0] for val in pos]
        neg = [-val for val in reversed(pos)]
        valid_frequencies = neg + [0] + pos
        if obj is not None and not hasattr(obj.__class__,
                                           self.name+'_options') and not hasattr(obj, self.name+'_options'):
            setattr(obj, self.name+'_options', valid_frequencies)
        return valid_frequencies

    # empirical correction factors for the cutoff frequencies in order to be
    # able to accurately model implemented bandwidth with an analog
    # butterworth filter. Works well up to 5 MHz. See unittest test_inputfilter