Electromagnetic interference related common mode noise analysis for NRZ/PAM-4 signals in wireline communication link (Invited paper)

This paper presents an analysis for the electromagnetic interference (EMI) related common-mode (CM) noise in differential high-speed data links with different signal modulation schemes, e.g. non-return-to-zero (NRZ) and 4-level pulse amplitude modulation (PAM-4). The CM noises, introduced by the mismatch of data rising and falling edges in both cases, exhibit the similar positive correlation with signal swing, but due to the complexity of PAM-4 signal, the amplitude distortion leads to different CM noise behavior.