Min Zhang

During conducted emission tests, one of the challenges manufacturers face is the resonance peaks in the harmonic noise somewhere between 10 MHz and 30 MHz. Often, no amount of filtering will eradicate or attenuate the peak.

When it comes to in-situ radiated emission measurements, the combination of near- and far-field measurements is often the best approach.

In this column, we discuss several important features of a spectrum analyzer not covered in previous articles that are worth your consideration.

Many individual components in electrical and electronic systems and devices are integrated into systems that are required to function as a whole. Examples of such systems include large electric vehicles, fixed industrial installations, novel scientific products such as quantum computers, and more. There are two EMC-related aspects to consider: intra-system EMC and inter-system EMC. This article focuses on the intra-system EMC aspect while also considering the inter-system aspect.

Although most modern RF amplifiers have a high voltage device rating against impedance mismatch, special care is needed to prevent impedance mismatch. To avoid impedance mismatch of the power amplifier, often an attenuator is also recommended to be connected between the output of the power amplifier and the flying probe.

Most EMI issues are caused by a resonance that is excited somewhere in the system. It may be a resonance of a cable acting as an antenna or a heatsink energized by the power electronics switches bolted to it, becoming a good radiator. In this article, we look at the indicators that signal the presence of structural resonances and provide techniques for fixing the EMI issues. Practical case studies are presented to demonstrate the techniques.

An AM radio can be useful for finding both radiated emissions and ESD events. Understanding how radio works is essential for engineers to use this low-cost technology to troubleshoot complex EMI issues.

Implementing a process of EMC compliance for a specific project is much more than simply ensuring that the design engineers follow a long list of “do’s and don’ts” in the form of EMC design rules. Following this process will reap benefits when EMC performance is evaluated at the end of the design process.

In this column, the author offers a brief summary of a more systematic approach for using ferrite cores on cables. This summary can serve as a “ferrite core checklist” for design and test engineers.

Low-frequency magnetic fields, a type of electromagnetic disturbance commonly found in electric vehicles, can pose potential health hazards to humans and affect the operation of critical EV components. Here are some design techniques to help mitigate the problem.