Embodiments of the present disclosure relate to methods and device for receiving PAM data stream. In an embodiment, a method comprises receiving a signal stream modulated with pulse amplitude modulation (PAM) associated with a plurality of bit patterns; determining boundary voltages for the plurality of bit patterns; and calibrating, based on the boundary voltages, a threshold voltage for use in recognition of the plurality of bit patterns. In this way, bit patterns may be accurately recognized based on the calibrated threshold voltage.