N1085A Datasheet, PDF (2/11 Pages) Keysight Technologies – PAM-4 Measurement Application

Introduction
Several industry groups and standards bodies are using, or actively considering using, Pulse
Amplitude Modulation 4-Level (PAM-4) technology to jump to the next-generation speed class.
PAM-4 signaling enables higher throughput for a given channel bandwidth compared to traditional
non-return-to-zero (NRZ) signaling.
Working groups within the Optical Internetworking Forum - Common Electrical Interface (OIF-CEI 4.0)
and IEEE 400G Ethernet (P802.3bs) are leveraging many of the PAM-4 measurements outlined in
Clause 94 of IEEE Std 802.3bj-2014. Examples of Standards or Implementation Agreements (IA) that
propose PAM-4 signaling include:
–– IEEE 400G Ethernet (P802.3bs)
–– OIF-CEI-4.0 (56G)
–– OIF-CEI-56G-XSR-PAM4 (Extra Short Reach interface)
–– OIF-CEI-56G-VSR-PAM4 (Very Short Reach interface)
–– OIF-CEI-56G-MR-PAM4 (Medium Reach interface)
–– OIF-CEI-56G-LR-PAM4 (Long Reach interface)
While the PAM-4 parameters are still in the development stages, companies are moving forward with
their PAM-4 development and need measurement tools to help analyze their designs quickly and
accurately.