Switching power supplies produce radiated and conducted emissions caused by ringing. Oscilloscope and spectrum-analyzer measurements let you see them. DC-DC converters are ubiquitous in most electronic products. While more efficient than linear regulators, they can also produce considerable amounts of interference that can affect nearby circuits. The measurements in this article show how ringing occurs […]
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EMI from LED light fixture often exceeds regulatory limits
Conducted emissions from LED light fixtures at frequencies from 1 MHz to 30 MHz can interfere with amateur radio and several broadcast bands. Radiated emissions reach into the lower cellular bands. After recently moving to northern Colorado and setting up my EMC lab and amateur radio station in the basement, I wanted to update the […]
Should I use a spectrum analyzer, signal analyzer, or vector network analyzer? Part 4
A vector network analyzer can fully characterize components by deriving their scattering parameters. In earlier parts of this series, we looked at analog spectrum analyzers (part 1 and part 2) and vector signal analyzers (part 3), both of which monitor unknown signals, whether emanating from a system, device under test (DUT), or an enemy’s transmitter […]
How to separate differential and common-mode harmonic noise currents
Differential-mode and common-mode currents can cause your product to produce radiated and conducted emissions. These three techniques can help you measure them.
How to locate EMI emissions with near-field probes: Part 3
Part 3 of a series on using near-field probes for detecting EMI sources shows you how to set up a spectrum analyzer and how to detect emissions problems. Now that we’ve discussed the theory of measuring near-field emissions (Part 1) and how to use near-field probes (Part 2) to make the measurements let’s discuss how to […]
IMS 2023 roundup: test equipment
Test equipment plays a major role in product development and production, which was apparent at IMS 2023. In the photos and videos below, you’ll get a taste of test developments at RF, mmWave, and sub-THz frequencies. This year, D-band (110 GHz to 170 GHz) seized a larger portion of the exhibit hall than in past […]
Handheld two-channel 100/200-MHz scopes combine multimeter, recorder, trend plot functions
The new and improved Siglent SHS-X Handheld Two-channel Digital Oscilloscopes are available in 100 MHz and 200 MHz analog bandwidths and isolated or non-isolated versions, with 1 GSa/sec sample rate and 12 Mpts memory depth. The SHS800X versions have two non-isolated scope channels and one isolated multimeter channel, while the SHS1000X models feature full isolation: […]
