PAM4 Demands Accurate S-Parameters

As high speed serial data rates advance from 15 Gb/s to beyond 50 Gb/s, we face a fundamental shift. Conventional logic-emulating NRZ (non-return to-zero) signaling is being replaced by PAM4, a 4-level pulse amplitude modulation scheme that takes half the bandwidth to transmit the same payload as the equivalent NRZ signal. This white paper assists in the understanding on how to use S-parameters, how to think of channel response and crosstalk in terms of S-parameters, and how to look for problems that could be caused by inaccurate S-parameter measurements. Download the full paper for more information.