@staticmethod
def valid_band(freq, low, high):
    """Given an array of frequencies return a boolean array that is True bounded between high and low

        Parameters
        ----------
        freq: np.array like,
              array of frequency values
        low: int,
             lower bound of desired frequency range
        high: int,
              upper bound of desired frequency range

        Returns
        -------
        boolean_array of valid boundaries
        """
    return (freq >= low) & (freq <= high)
