:param symbol: Bit to modulate
        :return: Modulated signal in baseband
        :rtype: Complex

def main(self, symbol):
        """
        :param symbol: Bit to modulate
        :return: Modulated signal in baseband
        :rtype: Complex
        """
        if symbol:
            phase_step = self.sensitivity_pos
        else:
            phase_step = self.sensitivity_neg

        cout = self.nco.main(phase_step)
        return cout