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SIJ talked with Dave Kohlmeier about industry trends, how to foster innovation, and what today’s EDA customers need most.

In high-speed digital channel design, vias are everywhere and are becoming very crucial elements to the channel performance. Especially with the higher data rate requirements in mobile, networking, and data center applications, the effect of vias in a design is very noticeable. Design engineers have traditionally used time domain reflectometry (TDR) as a tool to characterize and optimize via designs, yet the TDR approach comes with shortcomings such as demanding shorter rise-time step signal or larger bandwidth S-parameters, and inaccurate read-out on the via impedance.

In this article, we propose a simple and effective Z-input impedance method that augments the traditional TDR method for characterizing and optimizing via designs in much faster speed systems.

For this project, we will use an Atmel 328 microcontroller demo board, prepared with firmware to control it explicitly for our purposes, and with coaxial cables connected between the I/O pins and the input to the active probes of the scope. This interconnect provides a high bandwidth transmission line path for the signals.

If the die's I/O power rails are shared by the core power rails, here's a way to get your core power-rail measurements anyway.

How do you achieve high bandwidth in your measurements while minimizing current load on your DUT? Given that your DUT is a power rail, you really don't want to draw too much current from it., or your measurement system will distort the rail. But these two measurement criteria are at loggerheads with each other. It's a quandary, and it has to do with the fundamental nature of signals on interconnects.

Measuring the noise on a power rail seems to be a straightforward task. However, there are some basic pitfalls that can cause incorrect, or even downright strange, results. Let's look at one of these challenges: RF pickup. We'll demonstrate the effect of RF pickup on a power-rail measurement, and then we'll show you an effective means of mitigating that effect.

Eric Bogatin explains the figures of merit in the time and frequency domain, and he steps through how to get a rough measure of the highest frequency components in a signal.

Teledyne LeCroy today announced the WavePro HD high-definition oscilloscopes, which combine for the first time HD4096 12-bit technology and 8 GHz bandwidth for low noise and signal fidelity. With a maximum of 5 Gpoints of fast acquisition memory, WavePro HD oscilloscopes are designed to acquire extremely fine waveform details over long periods of time. A deep, powerful toolset quickly exposes underlying system behaviors. 

Receiver sensitivity and noise coupling to antenna are two major concerns when developing mobile devices such as smart phones and tablets. There are various causes of degradation of receiver sensitivity. However, most of the time they are due to the noise generated by digital signal harmonics on printed circuit board (PCB) patterns, which couple to the antennas. This article presents a methodology to predict noise to antenna coupling and antenna desense.

Eric Bogatin will lead this special session again at EDI CON USA, taking on the topic of how to deliver more than 100A with less than 10 mV of noise to digital devices. See how you can get involved.