Phase noise requires more than one instrument unless you use a phase-noise analyzer.
What is phase noise, and how can I measure it? part 1
Phase noise is an artifact of a nonideal oscillator and is best investigated in the frequency domain. Phase noise accompanies the generation of any real-world sinusoidal signal. You can think of it as the analog equivalent of digital jitter, which we covered in an earlier series (read part 1 and part 2). Recall that jitter […]
How to test the automotive SENT protocol
Oscilloscopes and dedicated software can help analyze SENT data. In “What is the automotive SENT protocol?” we looked at the Single Edge Nibble Transmission (SENT) protocol, as defined in accordance with the Society of Automotive Engineers (SAE) J2716 standard. We reviewed the SENT message frame, which includes a synchronization/calibration pulse followed by a status nibble, […]
How do I choose an electric motor, and how do I test it? part 4
You indeed can measure three-phase power in a motor with just two wattmeters. Part 3 of this FAQ concluded with a simplified diagram showing a test setup that included a programmable power supply, a motor under test, a mechanical load, a power analyzer, and host computer. The programmable power supply could simulate the AC line […]
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 do I choose an electric motor, and how do I test it? part 2
Learn the basics of back EMF, how to measure it, and the advantages and disadvantages of different motor types. In Part 1 of this FAQ, we looked at brushed DC and brushless DC (BLDC) motors, with the latter having some similarities to a permanent-magnet synchronous motor (PMSM). The simplified PMSM diagram in Figure 1 resembles […]
How to choose and test an electric motor: part 1
Motors bridge electronics with electromechanical devices. To learn how to test motors and their electronics, you should first understand how motors work. Electric motors are ubiquitous, appearing in everything from electric toothbrushes to electric locomotives. There are, however, seemingly almost as many motor types and configurations as there are applications, which makes choosing and testing […]
That Maxwell book that was returned to a library 115 years late: what’s it about? Part 2
Work on resistance measurement, described in An Elementary Treatise on Electricity, helped pave the way to successful trans-Atlantic telegraphy. In Part 1, I discussed An Elementary Treatise on Electricity by James Clerk Maxwell. One volume made national news earlier this summer when it was returned to New Bedford, Mass. Free Public Library 115 years overdue. […]
That Maxwell book that was returned to a library 115 years late: what’s it about? (Part 1)
Published in 1881, An Elementary Treatise on Electricity evolved from notes Maxwell had written in preparation for lectures on electricity at the Cavendish Laboratory. In June 2023, the national media carried a story about a book 115 years overdue that was returned to the Free Public Library in New Bedford, Mass. The book turned out […]
What is PCIe gen 6 and how do I test it? Part 2
PAM4 modulation boosts throughput but adds test challenges. Part 1 of this two-part series described the evolution of the PCI Express (PCIe) standard, including the move from non-return-to-zero (NRZ) signaling in PCIe 5 to four-level pulse-amplitude modulation (PAM4) signaling in PCIe 6. What unique test challenges does PCIe 6 present? As mentioned in Part 1, […]
