Signal Integrity

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Those Pesky Half-Wave Resonances

“Over the years I’ve come to realize that, particularly in signal integrity, half-wave resonances are often the cause of ugly S-parameters. You can argue that any type of resonance would cause problems, and you would be right. However, half-wave resonances are easily formed in topologies.” This article summarizes observations from Gustavo Blando on the formation and mitigation of half-wave resonances, and includes an in-depth study on the topic in PDF format from the author.


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Range and Standard Deviation: Comparing the Stochastic Model with Real-World

How well do statistical models predict the behavior of real-world systems?  How can we make predictions about the likeliness and severity of worst-case system behavior?  In this article, the authors explain how they used a function generator and oscilloscope to collect varying population sizes of measurement parameter results in order to investigate the accuracy of a statistical model's predictions.


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Validation of Bend Models with Measurements

Bends in PCB traces look like very basic, simple structures that are easy to simulate. Technically, one can do the analysis with any electromagnetic solver with sufficiently accurate port de-embedding capabilities. The reflections from a bend in fine-line, high-speed digital interconnects are relatively small and may not even be detectable with measurement. So, who cares? Read on to find out more.


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SIJ EXECUTIVE INTERVIEW_

Executive Interview: Timothy Vang, Semtech

SIJ recently caught up with Timothy Vang, vice president of marketing and applications for Semtech’s Signal Integrity Products Group about the company’s latest product for 50Gbps PAM4 5G front haul deployments, how signal integrity and RF/wireless design overlap, and what is next for the team at Semtech.


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112 G for Quickest Data Transfer

Data usage is increasing every year, and the communications industry is working diligently to support the increased demand. This article discusses why we need more data, what data center physical layer architecture changes are needed to support higher data rates, and how connector manufacturers are improving designs to support higher data rate systems.


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Ansys Releases Free Electronics Desktop Student Product Download

In the January 2021 print issue and the April 2021 online issue of the Signal Integrity Journal, I wrote an editorial in which I threw down a gauntlet to tool vendors to offer low cost or free versions of their tools to help engineers accelerate up the learning curve. Ansys picked up that gauntlet and now offers a free version of their industry standard electromagnetic simulator suite, Electronics Desktop. 


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Stackup Beware: Case Study of the Effects on Transmission Line Losses Due to Mixed Reference Plane Roughness

Designing the right PCB stackup can make or break product performance. If the product has circuitry that is impedance and transmission loss sensitive, then paying attention to conductor surface roughness is paramount. Sometimes, however, the roughness of adjacent reference plane(s) is overlooked. If the adjacent high-speed signal layer uses smoother copper than one or both reference planes, a higher insertion loss than expected for that layer will occur and possibly cause a product to fail compliance. So, how is this determined before finalizing the stackup? Read on to find out.


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