Keysight Technologies, Inc. has announced innovative enhancements for the M8040A high-performance bit error ratio tester (BERT) solution for testing PAM-4 and NRZ devices that operate up to 64 GBaud. Engineers in validation labs and R&D who characterise receivers on the physical layer for emerging 400G data centre interconnects will benefit from simplified test setups and repeatable and accurate results.
Today’s data centre infrastructure is continuously optimised to address bandwidth capacity growth, power, reach and service differentiation. Higher transmission rates, more transmission lanes, and new multi-level data formats, such as PAM-4, address the increased transmission bandwidth demand for the next-generation data centre interconnects.
The latest revisions of IEEE 802.3bs and OIF CEI-56G implementation agreements define PAM-4 and NRZ interfaces for electrical chip-to-chip, chip-to-module, backplane connections and optical interfaces for up to 400 Gb/s bandwidth. R&D and validation labs that need to characterise receivers for data centre interconnects with PAM-4 or NRZ data rates up to 64 GBaud are facing new test challenges, such as tighter timing margins, channel loss, non-linearity, level interference and crosstalk effects—making test efficiency and accuracy essential.
Overcoming channel loss in electrical interfaces, such as chip-to-chip, chip-to-module interfaces and backplanes, is a big challenge with higher symbol rates. Pre-distortion techniques, such as de-emphasis, are used in the transmitter and equalisation in the receiver to help re-open closed eyes caused by inter-symbol interference.
“The M8040A is the most integrated receiver test solution for PAM-4 and NRZ signals,” said Joachim Peerlings, vice president and general manager of Keysight’s networks and data centres solutions business. “With the new built-in equalisation, we continue to streamline our receiver test to help our customers bring their solutions to market faster. The M8040A enables R&D and test engineers to master the receiver test challenges for 400G data centre interconnects.”
The new M8040A is the latest member of the modular AXIe based M8000 series of BER test solutions and is a highly integrated BERT that supports PAM-4 signals up to 64 Gbaud and NRZ signals up to 64 Gbit/s. The pattern generator module provides built-in de-emphasis, jitter injection and an optional second channel. Engineers and designers can select PAM-4 and NRZ by software in the user interface, eliminating the need for external combiners, cabling and deskew to provide PAM-4 signals. For best signal quality, remote heads reduce the distance to the device under test. The analyser module provides true PAM-4 error analysis in real-time for long PRBS and QPRBS patterns—allowing proofing even low-bit error ratios and symbol error ratios with the required confidence.
The error analyser now supports symbol rates up to 64 Gbaud for NRZ signals and built-in adjustable equalisation. Users can control the M8040A from a graphical and remote-control interface.