42 U9361C/F/G/M RCal Measurement Guide
Making Measurements
Using Complex Cal to Improve EVM in a 128 QAM Signal
Using Complex Cal to Improve EVM in a 128 QAM Signal
This measurement example requires N9054C or N9054EM0E Vector
Modulation Analysis (VMA) application.
Compatible Signal Generators:
— N5166B (CXG)
— N517xB (all EXG)
— N518xB (all MXG)
— N519xA (all UXG)
This measurement shows how to perform a complex calibration on a QAM
signal, correcting for both absolute power accuracy and Error Vector
Magnitude (EVM). This will also demonstrate how to add an additional
calibration state to improve measurement flexibility, specifically for handling
multiple RF paths. Normally you would not make digital demodulation
measurements through the YTF preselected path; however, using the built-in
YTF allows for an easy way to demonstrate using RCal to correct for a
bandpass filter’s roll-off.
On the Signal Generator:
1. Connect the signal generator RF Output to the signal analyzer RF input
without an attenuator in between.
2. Select Preset to set the signal generator to a known state.
3. Set Frequency > 5 GHz.
4. Set Amptd > -10 dBm.
5. Select Mode> ARB Custom Modulation > Single Carrier Setup >
Modulation Type > Select > QAM >128QAM.
6. Select Return > Symbol Rate > 10 Msps.
7. Select Return > Digital Modulation On.
8. Set RF On.
On the Signal Analyzer:
1. Select Mode/Meas > Vector Modulation Analyzer Mode > OK.
2. Select Preset > Mode Preset to set the analyzer to a known state.
If accessing the instrument via a Remote Desktop connection, select the
Screen tab (at the top left of the display) to open the
Mode/Measurement/View Selector window.
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