This handy tool lets you test active and passive components at frequencies up to 3 GHz. I tried an early unit, using it for radiated and conducted EMI emissions testing. After almost ten years, Picotest has launched a new version of its Harmonic Comb Injector (generator). The J2150B ($495) is one of the pieces I’ve […]
oscilloscope measurements
Oscilloscope software automates automotive ASA-ML serial link tests
QPHY2-ASA software from Teledyne LeCroy lets you perform physical-layer tests on ASA-ML v1.1 devices. SerDes devices transfer data from sensors and cameras to an in-vehicle processing unit, which then sends instructions to the motion systems that drive autonomous vehicles. Teledyne LeCroy has released the QPHY2-ASA oscilloscope software, which automates testing of the Automotive Serdes Alliance […]
Phone chargers produce EMI: We compared four
The switching power supplies that regulate output voltage produce radiated emissions. Our tests compare waveforms that give clues as to how the chargers operate.
Characterize EMI from dc-dc converter ringing
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 […]
Review: PCBite circuit board holder and probe kit
The PCBite kit holds your circuit board in place while you probe it, reducing the risk of short circuits. Recently, I’ve had to test and characterize many small PC boards, including embedded processors, DC-DC converters, and other wireless-related products, for EMC issues. I’ve never really had an easy way to keep these boards from moving […]
How to calculate and apply the inverse discrete Fourier transform: part 4
In part 3 of this series, we used the inverse fast Fourier transform (IFFT) to create 100-Hz time-domain waveforms of various amplitudes and phases. We can also use the IFFT to create waveforms containing multiple frequencies. If you look closely at Figure 1 in part 1 of this series, you’ll notice that the time-domain waveform […]
Tryout: Uni-T UPO1202 200 MHz oscilloscope
You need not spend a ton of money to get a feature-packed oscilloscope, provided you don’t need high bandwidth. While the oscilloscope works well, the free software needs help. After seeing the Uni-Trend (Uni-T) UTG962E Function/Arbitrary Waveform Generator ($182), we at EE World bought one and, at the same time, ordered a UPO1202 200 MHz […]
How to calculate and apply the inverse discrete Fourier transform: part 3
The inverse transform can create a time-domain waveform where no waveform has been before. In part 2 of this series, we used the discrete Fourier transform to convert a waveform from the time domain to the frequency domain, operated on the frequency-domain data, and used the inverse transform to reconstruct the altered time-domain waveform. That’s […]
How to calculate and apply an inverse FFT: part 2
In part 1 of this series, we looked at the formula for the inverse discrete Fourier transform and manually calculated the inverse transform for a four-point dataset. Then, we used Excel’s implementation of the inverse fast Fourier transform (IFFT) to verify our work. Could we try something more realistic? Sure. We can take a signal […]
Isolated current probes eliminate ground loops
IsoVu isolated current probes from Tektronix isolate oscilloscopes from circuits used for EVs, motors, and power converters. Trying to make shunt-based current measurements with a typical oscilloscope probe is essentially impossible. That’s because one side of the probe connects to ground through the instrument. Using an ungrounded power cord is anything but safe. Differential probes […]
