RMS Error Vector Time (MB-OFDM)
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The composite trace shows the computed difference between IQ Measured vector time and IQ Reference vector time as an RMS average 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. across each symbol for all subcarriers within the Measurement Interval. For example, if the Measurement Interval is setup for (6) symbol-times, then the trace displays (6) vertical lines for symbols 0 to 5. Each vertical line displays the RMS calculation for all 122 subcarriers, -61 to -1, and +1 to +61, for the burst that includes this symbol. The RMS = 122 parameter at the top of the trace confirms the number of subcarriers used for each symbol RMS calculation. This trace displays all occupied bands.
The number of symbol-times included in the RMS Error Vector Time corresponds to the settings for Result Length, Measurement Offset, and Measurement Interval. The Start and Stop readings on the x-axis of the trace reflect these parameter settings. For example Start = 12 and Stop = 17 indicates a = 12 for Start, and a = 6 (symbols 12, 13, 14, 15, 16, 17) for Stop. To learn more, see Lengths, Intervals, and Offsets.
To view the computed difference between IQ Measured vector magnitude and IQ Reference vector magnitude, see RMS Error Vector Spectrum.
See Also
Available Trace Data (MB-OFDM)
