Effective Return Loss: A New Metric for SerDes Channel or Package Characterization

White Paper Overview

A new metric for SerDes channel and package characterization is emerging. Effective Return Loss (ERL) is replacing the traditional frequency-domain Return Loss (RL) metric as a more effective means of characterizing SerDes channels.

This paper from Siemens Digital Industries Software describes why ERL is being introduced and adopted and how ERL is computed. This resource also discusses ERL as a figure of merit for the characterization of 112G and 56G Ethernet channels. It provides an example of a “false negative” return loss based on results simulated in HyperLynx to demonstrate that ERL is a superior metric compared with traditional RL and its associated limit.