Ransom Stephens

Ransom Stephens

Ransom Stephens, Ph.D. helps engineers advance to the highest data rates by teaching the concepts engineers need to design better systems, better serdes, and better ways to find problems and come up with solutions. Ransom started in basic research at labs in the US and Europe specializing in digging weak signals out of strong backgrounds. He brought those skills to high speed electronics in 1999 and invented new techniques for signal and noise analysis. Since 2005, when he started Ransom’s Notes, his seminars have helped thousands of EEs understand key nuances of their work. Ransom was named the 2017 Jim Williams ACE Contributor of the Year for content that advances engineering and design.

ARTICLES

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Noise in Traffic: Signal Emulation for Automotive Apps

DesignCon 2023 Best Paper Award Winner

Automotive applications present new challenges to high-speed serial technology. Asymmetric, multi-gigabit signaling between sensors, processors, and displays in the unique noise environments of both electric and internal combustion engine vehicles create new problems for signal and power integrity engineers. This paper introduces the signal impairments required for receiver testing in the emerging automotive standards like ASA, MIPI's A-PHY, Automotive Ethernet, and more. Standards specify different sources of noise in different ways, some in the form of time evolutions, others as spectra. This paper focuses on techniques for generating and calibrating each noise source while describing advanced de-embedding techniques and addressing test equipment limitations.


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PAM4: For Better and Worse

Is PAM4 worth the hassle?

That’s the question that will trigger your amygdala’s fight or flight response as you encounter the many annoyances that PAM4 brings to your world. Since you’re in a lab rather than a jungle, that fight or flight response might translate into sarcastic cracks like: “Right, that higher BER requirement makes it all so much easier—not.” “Good old NRZ, those were some fine bits. Remind me why I asked for this?” And, “dear NRZ, I never knew how much I loved you until I lost you.”


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