Picosecond Pulse Labs has released a 32-Gbps Pulse Amplitude Modulation 4 (PAM4) bit error ratio test (BERT) system. The system comprises a PatternPro programmable pattern generator plus a Model 5380 broadband PAM4 combiner module that together create PAM4 signals and a PatternPro error detector with PAM4 software to measure the BER of the multi-level signal. Interest in multi-level signaling approaches such as PAM4 is increasing as technology and standards developers grapple with how to keep up with increasing bandwidth demands, particularly in the data center. PAM4 was discussed within the IEEE’s current Next Generation High-Speed Ethernet effort as a means to support a low-cost 100 Gigabit Ethernet interface for applications of about 500 m. While it no longer looks like the 100G standards effort will pursue such a specification, the technology is expected to be taken up again as part of standards efforts for 400 Gigabit Ethernet (see “ECOC Reporter's Notebook: Day 3”). Meanwhile, it forms the basis of the pending 802.3bj PAM4 electrical link. Because of their multi-level nature, PAM4 data signals require different measurement capabilities than standard NRZ data signals. Picosecond Pulse Labs says its new 32-Gbps PAM4 BERT System meets these requirements. With support from the elements mentioned above, the system’s software tools can perform in-depth analysis of the data signal, the company says. For example, the system can produce bathtub curves (both horizontal and vertical) to characterize the jitter and noise characteristics of the PAM4 signal. The PAM4 software also can produce contour plots that simultaneously show both the noise and jitter characteristics to very low BER rates, the company adds. “Bathtub and contour analysis are particularly valuable tools to identify PAM4 signal issues at low bit error rates. This is very important since PAM4 applications will utilize forward error correction (FEC) and accurate knowledge of the BER is critical,” explains Joe Allen, senior applications engineer at Picosecond. “By comparison, a sampling scope measures only a small number of samples and cannot see deeply into the PAM4 contour.” For more information on test equipment and suppliers, visit the Lightwave Buyer’s Guide.