Probing signals with a bandwidth below 100 MHz and voltage sensitivity above 100 mV is a no-brainer. Regardless of the type of signal or the source impedance, the venerable 10x passive probe is the answer. However, at bandwidths >100 MHz and with voltage sensitivity <100 mV, the 10x passive probe may not be the best option. In this article, SIJ technical editor Eric Bogatin introduces an easy-to-implement, low-cost alternative to the 10x passive probe specifically for power-rail measurements.

Verifying the modulation profile of SSC has historically been challenging because it involves a frequency shift as a function of time. Mike Hertz explains that by tracking the frequency measurement parameter, an oscilloscope can display the SSC modulation profile as a function of frequency versus time. Read on to see how it’s done.

Designers pushing the limits in their application can run into situations where the XO performance is inadequate for their next design due to the way it reacts to the noise and ripple in the power supply. To achieve optimal performance, they most likely will find they will need to do more than a simple datasheet evaluation to select their next XO. Read on for details on a PSNR test method to help select an optimal XO.

We searched for a superior cable for PDN measurements, then decided to create our own. Here’s the story.

Understanding how to make and interpret power supply impedance is very useful for optimized, low noise power supply design. With a simple pair of homemade probes, it’s easy to make the measurements using a compact VNA. Read on to find out how.

A TDR (time domain reflectometer) is an instrument that probably has the fastest rise time of any instrument in your lab, but how accurate is it? Eric tests accuracy using a DC Ohmmeter in this piece.

I received a demo version of a new quick and easy TDR. I decided to take it for a test drive by measuring all the cables I had lying around my lab. The results were surprising!

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.

Now in its fourth generation, which sports data-transfer rates up to 16 Gb/s, Peripheral Component Interface Express standard (PCI Express, or PCIe) requires challenging physical-layer test requirements (Figure 1). We've covered electrical compliance test for PCIe 3.0 in some detail, but with the test specifications for PCIe 4.0 rounding into shape, it's time for a deep dive into electrical compliance test for this ubiquitous peripheral interface protocol.

In this DDR 101 introductory piece, learn about the fundamentals of a DDR interface and some basics of physical-layer testing.