Measurement software characterises PAM-4 signals

25th March 2015

Keysight Technologies (formerly Agilent)

Mick Elliott

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Keysight Technologies has developed measurement software designed to help engineers quickly and accurately characterise PAM-4 (pulse amplitude modulation with four amplitude levels) signals using the Keysight V-Series, Z-Series, and S-Series real-time oscilloscope platforms. The Keysight N8827A PAM-4 analysis software (for V- and Z-Series oscilloscopes) and N8827B PAM analysis software (for S-Series oscilloscopes) provides comprehensive analysis of electrical PAM-4 signals.

Mobile computing applications are demanding more of the underlying computer Internet infrastructure. To enable increases in Internet and server-farm performance, higher-speed connectivity among server systems is required.

Conventional communication techniques often relied upon NRZ (non-return-to-zero) encoding. Industry experts contend NRZ will not work in a 56-GBit/s environment.

One way to overcome this challenge is to change the modulation technique from NRZ to pulse amplitude modulation. This allows engineers to dramatically increase the amount of data they can send across high-speed digital communication links.

Several industry standards bodies are actively promoting PAM-4 technology to enable the next-generation speed class and push higher data rates for a given channel compared to traditional NRZ signalling.

While PAM-4 technology leverages some traditional NRZ measurement algorithms for PAM-4 signals, to fully analyse system performance, unique PAM-4 measurements and parameters are required.

N8827A/B PAM-4 analysis software offers measurements such as eye width, eye height and eye skw, level amplitude, level noise and level skew and amplitude level linearity