Electromagnetic compatibility (EMC) is the desired condition for electronic devices. In an ideal world, radio-frequency emissions and transient events would not cause failures or disruptions to electronic equipment. But as much as we (and the product manufacturers) wish otherwise, we are not in an ideal world. Radiated emissions, whether intentional from transmitters or … [Read more...]
Free eBook: From a Hod to an Odd EM Wave
A Remarkable Journey Through Engineering, Humanity, and History In From a Hod to an Odd EM Wave, David A. Weston invites readers into a vivid, deeply personal memoir that weaves together a lifetime of engineering innovation, global experiences, and unforgettable human encounters. From humble beginnings carrying bricks on a construction site in post-war England to … [Read more...]
IoT Systems with mmWave Sensors
One of the most common applications of Internet of Things (IoT) devices is sensing, followed by transmission of raw data back to a base station or server for storage and further analysis. The most common of these sensing tasks seems to be environmental sensing, such as monitoring gas concentrations, temperature, humidity, etc. These devices are so ubiquitous that they … [Read more...]
Design for Compliance Essentials
INTRODUCTION While unrealistic to discuss all aspects of product design in a single article, I’ll try to describe the most common design issues I find in the hundreds of client products I’ve had a chance to work on. These issues generally include PC board design, cables, shielding, and filtering. More detailed information may be found in the Reference section below. As … [Read more...]
Filter Installation Issues Pt. 3: Mounting and More
This article is the 3rd and final part of a three-part Filter Installation Issues series. Read Part 1: Input and Output Conductors here. Read Part 2: The Synergy of Filtering and Shielding here. There are now many suppliers of PCB-mounted shielding-cans that can be used with three-terminal filters, and they have many types that can be automatically assembled like any … [Read more...]
Filter Installation Issues Pt. 2: The Synergy of Filtering and Shielding
This article is part 2 of a three-part Filter Installation Issues series. Read Part 1: Input and Output Conductors here. Some mains filter manufacturers only design and specify their filters to provide attenuation over the frequency range of the conducted emissions tests (typically up to 30MHz for commercial and industrial products), to keep costs low. Unfortunately, if … [Read more...]
Simultaneous Operations (SIMOPS) of Radio Systems Due to Antenna to Antenna Coupling on an Aircraft
Although specifically dealing with aircraft systems, the methods described in this article are applicable for other platforms where a number of antennas are in close proximity. The number of antennas in use and in close proximity on mission specific aircraft are as many as 22 on a small search and rescue aircraft. ANALYSIS METHODS The methods of coupling analysis include … [Read more...]
Use of Ferrite-Loaded Absorber to Reduce Wireless Self-Interference
Self-generated EMI from DC-DC converters, as well as digital and video processing, has long plagued designers of wireless and IoT devices, especially since physical sizes have trended smaller. The broadband harmonic content often extends up through 1.5 GHz, which includes most wireless protocols, cellular LTE and GPS/GNSS bands. One new mitigation technique I’ve been trying … [Read more...]
5 Ways to Eliminate Ground Loops — Part 2
As we discussed in Part 1, Ground Loops, while often not obvious, can be a significant source of frustration for system operators and integrators. This phenomenon manifests as unwanted electrical noise – audible hums in speakers, jitter on screens, noisy measurements, and bad measurement data – and it can even lead to unexpected communications loss and equipment … [Read more...]
5 Ways to Eliminate Ground Loops — Part 1
A Brief Introduction Most workers already know that proper grounding is a fundamental safety precaution for all kinds of electrical equipment. However, it’s less well known that while grounding can prevent and resolve many safety and power issues, improper grounding can create problems in data logging, data acquisition, and measurement and control systems. One of the most … [Read more...]
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