A signal on a transmitter tracks noise on a ground node in a manner decoupled from a positive node of a power supply. The signal is transmitted from the transmitter to the receiver. A reference voltage is generated on the receiver to track noise on a ground node in the receiver. Consequently, the received signal and the reference voltage have substantially the same noise characteristics, which become common mode noise that can be cancelled out when these two signals are compared against each other. In a further embodiment, the reference voltage is compared against a predetermined calibration pattern. An error signal is generated based on a difference between the sampler output and the predetermined calibration pattern. The error signal is then used to adjust the reference voltage so that the DC level of the reference voltage is positioned substantially in the middle of the received signal.