Error Summary Data (Custom IQ)

Menu Path: Trace > Data > Syms/Errs

The following subjects are discussed in this topic:

Averaging and Error Summary Data

When averaging is on, averaging is applied to the numeric error data in the symbol/errors table with the following exception. Averaging only applies to peak 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., peak magnitude and peak phase error data for the Peak Hold/Continuous Peak Hold averaging types. For more information see Averaging with Digital Demodulation.

Error data from the current scan is not included in the average if any of these conditions exist:

How EVM and Magnitude Error Data is calculated (%RMS)

In the symbol table, the VSA displays the error-vector magnitude (EVM), magnitude error (Mag Err), and phase error (Phase Err) as a percentage.

To compute this percentage, the VSA first normalizes the points in the IQ reference and I/Q measured signals to the EVM Normalization Reference. Then the VSA computes the percent error by calculating the error-vector magnitude, magnitude error, and phase error at each symbol time.

Next, the VSA derives the rms average for each parameter. For example, to compute the rms average for the magnitude error, the VSA takes the square root of the sum of the squares of the individual magnitude-error values at each symbol time.

Then the value is multiplied by 100% and the value is shown on the Syms/Errs table.

For more information, see the description for each of these metrics.

Querying summary table data results programmatically

To programmatically query the Trace Summary Table data results using the Summary() and SummaryUnit() methods in the MeasurementData object.

See the How To Query Summary Table Data Results topic for more information.

See Also

About the Symbol Table

Error Summary Data