This 50 MHz pulse generator was built as solid as a rock. It’s almost all metal. We take the unit completely apart and look at it from a system and board level. On a visit to the MIT swapfest in 2024, I came across an HP 8112A 50 MHz pulse generator. For $20, I brought […]
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Understanding ADC specs and architectures: part 2
Specifications such as gain error, offset error, and differential nonlinearity help define an analog-to-digital converter’s performance. In part 1 of this series, we discussed an ideal analog-to-digital converter (ADC), noting that it would have infinite resolution and bandwidth. Then we looked at the real world of practical inverters and how their resolution, expressed in a […]
Understanding ADC specs and architectures: part 1
Analog-to-digital converters are the heart of most test equipment, setting the stage for the digital processing of analog signals. Several posts over the past year or so have involved digital signal processing. For example, we have covered the fast Fourier transform (FFT), the inverse FFT, and discrete convolution. To perform these operations on real-world signals, […]
OFC 2025: Test equipment
This year’s OFC in San Francisco featured one thing, or so it seemed: 1.6T. Every company making optical modules was showing them lest they be left behind in the always accelerating data rate race. As with any emerging technology, test equipment must lead the way. After all, how do you know if anything works unless […]
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: Micsig TO3004 tablet oscilloscope
If you’re looking for a portable oscilloscope for field troubleshooting or for demonstrations, look at the Micsig TO series. Here’s my take on the four-channel 300 MHz variant, TO3004. The Micsig TO3004 oscilloscope (Figure 1) is an 8-bit, four-channel, tablet-sized portable oscilloscope that’s also available with 100 MHz and 200 MHz varieties with two or […]
APEC 2025 test equipment: power sources and loads
Powering electronic devices requires the testing of power supply and charging circuits, battery management systems (BMSs), and battery cells. Many of these circuits require voltage, current, and power measurements, plus numerous others. Oscilloscopes and probes let you see the waveforms in power-delivery circuits, but the circuits themselves may need simulated batteries and simulated loads. That’s […]
APEC 2025 test equipment: oscilloscopes and probes
Oscilloscopes and probes play a vital role for engineers designing and testing power electronics. Delivering electrical power to analog and digital circuits and systems is more than just DC measurements. That’s because nearly all power-converter circuits use switching techniques to maximize efficiency. Silicon carbide (SiC and gallium nitride (GaN) transistors, with their higher voltage and […]
How to use convolution to implement filters: part 4
A windowed sinc function can implement a low-pass filter, and a two-dimensional convolutional filter can blur or sharpen images. In part 3 of this series, we introduced a low-pass filter based on the Sinc function and described the need for windowing to compensate for sampling and truncation. Q: How can we apply this filter? A: […]
