Optimized designs require less electromagnetic interference (EMI) shielding and other materials, improving sustainability. Improved EMI performance extends system life and reduces e-waste, further enhancing sustainability. More sustainable shielding materials are being developed for use when shielding is required. This article reviews the basics of EMI, examines common shielding materials to provide a baseline for comparing […]
FAQ
Engineers use AI/ML to improve test
Engineers can use AI/ML to reduce test development time, analyze test data from manufacturing, automate visual inspection and calibration, and identify counterfeit components. Here’s how some do it. Testing takes too much time; just ask any engineering or production manager. Shortening test-development time can reduce time to market. Shortening production test time lowers manufacturing costs. […]
How to determine noise figure: part 4
Two incompatible definitions of noise factor can lead to confusion, which you can alleviate by understanding where the differences lie.
How to determine noise figure: part 3
Noise factor and noise figure as defined in an IEEE standard can be derived from a two-port device’s equivalent noise temperature. In part 1 and part 2 of this series we discussed several ways to indicate the noise performance of a device under test (DUT). We first introduced the concept of noise factor based on […]
How to determine noise figure: part 2
The relationship between noise and temperature prompted a precursor of the IEEE to promulgate an alternative definition of noise figure in 1959. In part 1 of this series, we described the work of the Danish-American radio engineer Harald Friis, who described noise factor F of a device or system as the ratio of the input-power […]
What information does an eye diagram depict?
An eye diagram is a powerful visualization tool in digital communications and high-speed electronics to assess signal quality and channel performance. This FAQ will briefly explain an eye diagram and the overall and specific metrics engineers should know to understand an eye diagram. When capturing signals from a digital bitstream such as Ethernet or USB, […]
How to determine noise figure: part 1
A noise figure consolidates the effects of various noise types to provide a single specification for the noise performance of a component or system. In electronic circuits and systems, noise is an undesirable, inevitable disturbance in currents and voltages. Noise has many underlying fundamental causes. Thermal noise, also known as Johnson–Nyquist noise, results from random […]
How to interpret a QAM display: part 3
Error vector magnitude characterizes actual QAM signals’ deviations from their ideal locations due to nonlinearity and phase noise. In part 1 of this series, we discussed quadrature amplitude modulation (QAM), which results from summing orthogonal amplitude-modulated cosine and sine waves of the same frequency. In part 2, we looked at assigning bit sequences to QAM […]
How to interpret a QAM display: part 2
Sixteen unique 16-QAM symbols can each convey a unique 4-bit sequence. In part 1 of this series, we discussed quadrature amplitude modulation (QAM), which results from summing amplitude-modulated cosine and sine waves of the same frequency. We also looked at the constellation diagram, which a test instrument such as an oscilloscope or vector signal analyzer […]
How to interpret a QAM display: part 1
A constellation diagram plots a quadrature amplitude modulation (QAM) signal’s in-phase and quadrature components. The EE World article “Should I use a spectrum, signal, or vector network analyzer?” in part 3 mentioned that vector-signal analyzers (VSAs) can display modulation-domain and frequency-domain information. Other instruments incorporating digital signal processing (DSP) capabilities, including oscilloscopes, can provide insights into […]
