QPHY 2 software lets you test DisplayPort 2.1 links for compliance to industry standards Engineers designing DisplayPort 2.1 into devices need a way to verify compliance with standards and that the interface will interoperate with other devices. This involves viewing physical-layer (PHY) eye diagrams at both transmitters and receivers. DisplayPort 2.1 PHY compliance test software […]
oscilloscope measurements
Locate ESD sources using an oscilloscope and two antennas
The key to identifying the location of an ESD source is by measuring the time of arrival between the two antennas. ESD discharges are tough to locate because they don’t occur periodically. Rather, they occur intermittently. I earlier wrote an application note on how to use an oscilloscope to trace the path of ESD current […]
Review: Picotest J2150B comb injector
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 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 […]
