IQ Mag Error and IQ Phase Error (Digital Demod)

When Digital Demod is enabled, the IQ Mag Error and IQ Phase Error traces show the error between the I/Q measured and the I/Q reference signals. IQ Mag Error displays the magnitude error and IQ Phase Error displays the phase error.

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If the IQ Mag Error trace is selected, the VSA compares the magnitude of the I/Q measured signal with the magnitude of the I/Q reference signal. The VSA then displays the difference, in magnitude, between the two signals.

If normalization is OFF, the VSA displays the magnitude error in units of Volts (normalization factor = 1). If normalization is ON, the magnitude error is expressed as a percentage. See Normalize IQ Traces for information about the calculation of the normalization factor.

If the IQ Phase Error trace is selected, the VSA compares the unwrapped phase, point-by-point, of the I/Q measured signal with the unwrapped phase of the I/Q reference signal. The VSA then displays the phase difference between the two signals.

IQ Mag Error and IQ Phase Error compare all points in the measured IQ signal and reference IQ signal (not just symbol decision points).

Correspondingly, when using band-power markers, all the points on the IQ Mag Error and IQ Phase Error traces within band-power markers are included in band-power calculations, unlike the Mag Err and Phase Err metrics in the Error Summary table which only use the symbol decision points for calculating error summary information.

For EDGE demodulation format the Magnitude/Phase Error data results may vary for different points/symbol settings. When points/symbol is set to 1 (default), the trace data results are compensated for ISI Inter-Symbol Interference: An interference effect where energy from prior symbols in a bit stream is present in later symbols. ISI is normally caused by filtering of the data streams. (inter-symbol interference). For points/symbol greater than one, the trace data results are not compensated for the effects of ISI.