The demand for big data is driving technology changes as companies look for ways to cost-effectively increase network capacity, according to Beate Hoehne, new product introduction manager for the Digital & Photonic Test Division of Keysight Technologies Inc. She cited estimates that 20 billion devices will connect to wireless networks by 2020. The goal of 5G networks, she said, include a 10-Gb/s user experience with data centers operating at 100 Tb/s. Today, she said, 100-Gb/s performance is commercially available and 400-Gb/s technology is in research, yet 1-Tb/s is not yet cost effective.
Hoehne outlined trends in coherent optical communications; digital interfaces; physics and advanced research; and aerospace, defense, and wireless markets as she described why Keysight is rolling out its new high-speed, wide-bandwidth M8195A arbitrary waveform generator—a 65-GS/s, 20-GHz modular instrument that allows engineers to generate digital multilevel (for example, PAM4, MIPI C-PHY) signal scenarios and test their electrical and optical links with complex modulated signals up to 32 Gbaud and beyond.
Coherent optical communication systems, Hoehne said, offer challenges in that OSNR and fiber nonlinearity limit spectral efficiency, and there is no single solution for different distances. The industry, she said, is investigating various transmission schemes, including QPSK/8QAM and possibly 16QAM for long distances while looking at higher-order modulation schemes at 32 Gbaud and beyond for short reach. Work in these areas, she said, requires a test instrument that offers the flexibility to address multiple modulation schemes while providing a clean signal at a bandwidth of at least 20 GHz. And four channels are necessary to support dual polarization (two pairs of I/Q signals).
Digital interfaces are operating at higher data throughput rates, which can be achieved by faster toggle rates (with jitter and frequency-dependent losses), more parallel signals (whose implementation runs up against chip I/O and board real-estate limitations), and using modulation formats other that NRZ (such as multilevel signaling and complex modulation formats such as PAM4 and DMT). Digital interface applications require test instruments that cost-effectively offer multilevel, multichannel capacity.
Meanwhile, scientists involved in physics and advanced research need to be one step ahead of industry and need to generate arbitrary shapes to stimulate individual electrons. They need to generate precisely timed pulses on several channels in parallel to fire multiple high-energy lasers, for example. “High-speed AWGs are now fast enough to address these applications directly,” Hoehne said. “They are the most flexible stimulus instruments to work at the edge of technology.”
And finally, she said, engineers working in aerospace and defense require signal fidelity combined with wide bandwidth, modulation bandwidths of 2 GHz and more, fast hopping across a frequency band, and the ability to simulate multiple emitters and complete electronic-warfare environments. “High-speed AWGs can now generate RF signals in the C, L, S, X, and Ku bands up to about 20 GHz directly,” she said, “They provide the ultimate flexibility for pulse patterns, wide modulation bandwidths, and fast hopping.”
The M8195A, she said, serves all these application areas. Read more details about the instrument here.