Subcarrier Reference Points (5G NR/5G-Advanced)
selects whether the reference subcarrier symbols are auto detected or manually configured with the internal reference values saved by the Copy to User-Specified button.
When is selected, the reference subcarrier symbols are auto detected from the signal. When a signal is clean, the reference subcarrier symbols can be reliably detected during the demodulation process and the EVM Error vector magnitude (EVM): A quality metric in digital communication systems. See the EVM metric in the Error Summary Table topic in each demodulator for more information on how EVM is calculated for that modulation format. is accurate. When a signal is noisy and the SNR Signal-to-Noise Ratio is very low, the reference detection may not be reliable especially for high order modulation format, which may result in inaccurate EVM. In this case, if you are able to generate the same signal with high SNR, you can click to copy and save the auto detected reference symbols into the internal state dictionary, to use with the low SNR signal measurement. After the reference symbols are successfully copied, the parameter selection changes to and the saved reference symbols will be used with the low-SNR measurement and the EVM results will be more accurate. If there are no reference symbols saved in the internal state, this parameter will be coerced to Nearest Ideal Constellation Points. Currently there is no API 1) Access Preamble Indicator, or 2) Application Programming Interface provided to access the reference subcarrier symbols from the internal state, but it can be saved in a VSA setx file.
Default: Nearest Ideal Constellation Points
See Also
