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 […]
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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 […]
Flea market vintage test equipment, September 2024
The monthly “Flea at MIT” featured an abundance of test equipment. We even bought some.
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 […]
14-bit oscilloscope delivers low noise, fast updates
Keysight’s InfiniiVision HD3 series oscilloscopes let you see signals with 4x the resolution of 12-bit instruments.
Free online tools perform RF calculations
RF engineers often need to calculate parameters such as VSWR and RLC networks. Ampleon provides these and other free RF design tools for you to use. Ampleon, a maker of RF components, provides engineers with a free RF online tools page where you can find four sets of useful tools. Each of the four tools […]
Verify, test, and troubleshoot 5G Wi-Fi FWA gateways
By Xiang Li, Keysight Technologies Follow these three steps to ensure your fixed-wireless access designs will be compatible with the Wi-Fi fronthaul and 5G backhaul. Many areas lack the wired infrastructure to bring residential broadband access. Making those connections has become costly and inefficient. Fixed Wireless Access (FWA) has emerged as a compelling alternative to […]
Should I use a spectrum analyzer, signal analyzer, or vector network analyzer? Part 4
A vector network analyzer can fully characterize components by deriving their scattering parameters. In earlier parts of this series, we looked at analog spectrum analyzers (part 1 and part 2) and vector signal analyzers (part 3), both of which monitor unknown signals, whether emanating from a system, device under test (DUT), or an enemy’s transmitter […]
OFC 2024: How AI and silicon photonics will drive network test
EE World spoke with Sarah Boen, Director of Technology and ASIC Strategy at Tektronix, who spoke at a panel session on how AI and silicon photonics are changing networks and the challenges facing test engineers and reliability engineers.
Should I use a spectrum, signal, or vector network analyzer? part 3
In part 2 of this series, we looked at a swept-tuned spectrum analyzer and how it could sweep a frequency span of interest from 1 MHz to 1.1 MHz with a sweep time of 50 msec. As Figure 1 shows, the analyzer readily identifies a signal at 1.03 MHz but misses the intermittent signals shown […]
