The Sensitivity of ENRZ to Skew - In Comparison to NRZ, PAM3, and PAM4

This work studies the sensitivity of ENRZ (Ensemble NRZ) to inter-wire skews, in comparison to NRZ (Non-Return-to-Zero), PAM4 (Pulse Amplitude Modulation of 4-level), and PAM3. Two typical skew patterns across the four-wire of a ENRZ channel is investigated. The simulation results and the underlying causes are analyzed. The performances of the four signaling techniques with respect to skew are compared. The result shows that due to its intrinsic algorithm, ENRZ is more robust than the other three competitors in terms of keeping the eye open even under sever skews.