Interference in the 900 MHz band appears to produce random errors in a gas station price sign. Spectrum analyzers help track it down. I received a call recently from a former client who manufactures electronic signs. A gas station was experiencing intermittent loss of wireless control of its signs, which displayed the price of various […]
EMI/EMC/RFI
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.
TinySA Ultra: A low-cost spectrum analyzer that fits in your pocket
This palm-sized, battery operated instrument can help you diagnose EMC problems.
Product tryout: Tektronix 4 Series B oscilloscope
EE World gets its hands dirty on the latest Tektronix oscilloscope. So many features, so little time. When Tektronix gave the press a preview of the 4 Series B 12-bit mixed-signal oscilloscope and TekScope software, I asked to try the software. Days later, the real thing arrived in a transit case. Fortunately and unfortunately, today’s […]
How to use simple antennas for EMI troubleshooting
For general troubleshooting, you can use consumer-grade antennas such as for TV. Pre-compliance tests require calibrated antennas. Antennas are important for capturing radiated harmonic emissions from electronic products. You can use them for simple troubleshooting or for calibrated pre-compliance testing. For troubleshooting purposes, you can use almost any uncalibrated antenna. I’ve even seen engineers use […]
R&S enters eight-channel oscilloscope game
The Rohde & Schwarz MXO 5 series of eight-channel and four-channel oscilloscopes feature fast capture and low-level triggering so you can see signal details.
How do I choose an electric motor, and how do I test it? part 3
Motors follow the path of less reluctance to rotate. Thus, you need timing of applied power to get them moving. Part 1 and Part 2 of this FAQ looked at brushed and brushless DC motors, permanent-magnet and wound-rotor synchronous motors, and induction motors. These motors all have drawbacks, including mechanical wear of commutators, slip rings […]
How to use RF current probes for EMI: Part 2
In Part 2, you will learn how to use an RF current probe to calculate E-fields and troubleshoot EMI emissions from cables. Free and low-cost software tools let you customize the calculations based on your current probe’s data. As I mentioned in Part 1, RF current probes are one of my most useful troubleshooting tools. […]
How to use RF current probes for EMI: Part 1
DIY and commercial RF current probes let you find which cables act as EMI-emitting antennas. RF current probes are one of my most useful troubleshooting tools. Because most radiated emissions failures are due to attached cables acting as transmitting antennas, clamping an RF current probe around a wire or cable will measure the common mode […]
EMC summit gives engineers tips and fundamentals
An IEEE EMC Society chapter provided training on FCC Part 15, shielding effectiveness, and EMC art & science. Boxborough, Mass — Interference among electronic devices never goes away. Engineers who aren’t EMC experts seem to need constant introductions and reminders of how to reduce interference because every design is different. EMI/EMC issues keep popping up, […]