Oscilloscope measurement support for 400G PAM4

April 08, 2016 // By Graham Prophet
Two software updates for real-time oscilloscope products from Keysight Technologies support IEEE 400G applications as well as real-time, multi-frame-based oscilloscope measurements, adding enhanced bit error ratio measurement for the N8827A PAM-4 analysis software; and the ability to use the N8834A MultiScope software on Keysight InfiniiVision oscilloscopes

The N8827A PAM-4 analysis software update adds a BER and symbol error ratio (SER) measurement tool designed to help engineers perform BER and SER measurements on PAM-4 signals. Measuring the BER or SER of a PAM-4 signal allows designers to fine tune the transmitter or receiver equalisation parameters of their PAM-4 devices by highlighting where burst error failures can impact a receiver’s forward error correction (FEC) protocol. The N8827A software is supported on Keysight’s Infiniium S-Series, 90000A, V-Series and Z-Series oscilloscopes; as well as the discontinued 90000 X- and 90000 Q-Series oscilloscopes.


Historically, since many PAM-4 implementations take advantage of forward error correction, it is possible to operate a communication link that uses PAM-4 operating at a BER of 10e-6 or 10e-5 or even greater. By comparison, traditional non-return-to-zero (NRZ) or PAM-2 based signalling technologies operate at a BER level of 10e-12 or lower. At 10e-6 or greater, such BER calculations for PAM-4 signals are now well within the reasonable measuring capacity of the Infiniium Z-Series and V-Series real-time oscilloscopes. In addition to BER measurement, this new feature allows engineers to also identify and locate burst errors on a continuous repeating patterns.


“The new BER feature of our N8827A PAM-4 analysis software gives customers confidence that their receiver architecture is correct,” said Dave Cipriani, vice president and general manager of Keysight’s oscilloscope business. “The software now allows engineers to isolate the causes of burst errors, which can significantly reduce their debug time.”


The N8834A MultiScope software enables engineers to connect multiple Infiniium and InfiniiVision oscilloscopes, allowing them to have up to 40 time-correlated analogue channels available for signal acquisition. Designers working on high-speed, multilane applications, such as optical networking, MIMO (multiple input multiple output) antennas, power rail analysis, DDR memory and high-speed serial standards, can gain insight faster, save money and improve their productivity using the N8834A MultiScope application to make simultaneous measurements across multiple lanes. The