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Noise Power Ratio (NPR) Settings

NPR measures the nonlinear behavior of an RF microwave amplifier under a modulated signal stimulus.

In this topic:

See Noise Power Ratio (NPR) Measurement Example

Requirements

Note: When setting up an M9383A, M9383B, or M9384B source in the External Device Configuration dialog, select MXG_Vector as the driver (they are code compatible).

Create a Spectrum Analysis Channel

  1. On the VNA front panel, press Meas > S-Param > Meas Class....

  2. Select Spectrum Analysis, then either:

  1. A Spectrum Analysis measurement is displayed.

Accessing NPR Settings

Using Hardkey/SoftTab/Softkey

Using a mouse

  1. Press Freq > Source IQ Mod. >  MXG.

  1. Click Stimulus

  2. Select SA Setup...

  3. Select the Source tab.

  4. Click in the IQMod column then select Edit.

 

Modulation settings dialog help

Modulation source - Displays the name of the modulation source.

Modulation File - Displays the modulation file name.

Load File... button - Loads an existing modulation file.

Create...- button - See Create Modulation dialog description.

Edit...- button - See Create Modulation dialog description.

Properties button - Displays the properties found in the modulation file. This is the active Modulation Filename selected in the Modulation settings dialog. This information cannot be edited.

Enable Modulation - Check to enable modulation.

DAC Scaling - Sets the scaling factor used for the waveform (full scale = 70%). This ensures that the DAC filter does not output a signal that is larger than the DAC's maximum output level, which can cause distortion in the system.

Enable Modulation Correction - Automatically checked if user exits the calibration wizard with Exit & Save Cal. This option is grayed out if a modulation calibration has not been performed.

Source Cal... button - Accesses the Modulation Cal - Setup dialog for performing source modulation calibration.

Autoset Frequencies and Coherence for current modulation - Check to allow frequencies and coherence to be set automatically for the current modulation.

Autoset NPR Markers  Enables and disables NPR markers.

Autoset ACPR Markers  Enables and disables ACPR markers.

NPR Band Guard - Guard band on each side of the notch in an NPR measurement.

ACPR Band Guard - Guard band between the end of the modulation signal and where ACPR is measured.

Immediate Autoset button - Click to adjust frequencies and markers if modulation settings are changed.

Source Power - Sets the source power level.

Source Path Amplification (= Power Offset)  - Displays the Power Offset to monitor the power budget between the source and DUT. The Power Offset setting provides a method of compensating port power for added attenuation or amplification in the source path. Learn more.