The columns contained in this SI/PI/EMC & EMI Fundamentals section come from members of the Signal Integrity Journal community who are experts in their field and have a commitment to providing training and education in SI/PI/EMI issues for other engineers.

## Shielding and Filtering Are Not Independent of One Another

I have lost count of the number of times I have been asked to fix an EMC problem, only to find that a shielding box has been designed or purchased to provide XdB up to fMAX. Or a filter has been designed or purchased with a similar specification, but to reduce cost the filter has been mounted on a printed circuit board (PCB) inside the box, with a cable from it entering or exiting the box through a plain connector.

## Impedance: The Most Confusing Term in Signal Integrity

In more than 30 years of teaching signal integrity, I find the most confusing topic for engineers, even those working in the field for years, is the question of what is the impedance of a transmission line?  Read on to learn about the 5 types of impedance.

## Back to Basics: Bandwidth and Rise Time

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.

## Life beyond 10 Gbps: Localize or Fail!

Yuiry Shelpnev argues that simulating a link in isolation from the rest of the board (localization) is probably the most important requirement to simulate interconnects predictably. Read on to understand this important concept.

## Moving from 28 Gbps NRZ to 56 Gbps PAM-4 - is it "free lunch"?

If we know how to design interconnects that correlate with the measurements for 28 Gbps NRZ, is it going to be a "free lunch" to move to 56 Gbps NRZ? Not so easily, as I learned recently. Read on to see how you can benefit from some analysis and validating your tools.

## The Signal Integrity Perils of Power Via Stubs

We are usually not worried about having via stubs on power and ground planes and shapes. Does it mean they are completely harmless?  When it comes to potential damage to high-speed signals, power-via stubs can be almost equally as bad as signal-via stubs.  Here is how and why.

## Signal Integrity Basics: Technical Terms

Nyquist frequency, first harmonic, clock frequency, fundamental frequency, and some other intimidating terms might be thrown at you by an SI engineer. Read on to get up to speed on these and other terms you need to know.