PXIe VNA Help
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Frequency Converter Application

Option M937xA-009, P937xA-S97080 and S97082A, and M9485A-009 allows Scalar Mixer Converter (SMC) measurements on a maximum of four ports.

Note: With the FOM measurement on, the receiver gain is fixed to “Low” although “Auto” is shown in the dialog box. Set "High" manually if the high gain is required.

In this topic:

See Also

FCA Options Explained

Note: The VMC of the M9485A is provided by macro.

SMC Overview

 

Scalar Mixer Calibration

See Hardware setup

Overview

Provides highest Scalar accuracy for measurements of conversion loss/gain.

Optionally measures phase

Combines SOLT and power-meter calibration.

Measurements Offered

Both forward and reverse directions.

DUT can be connected to any VNA ports.

Equipment Required

Power meter and sensor

Common equipment for SMC

  • Mechanical cal kit or ECal module

See Comparison of Mixer Characterization using New Vector Characterization Techniques.

Requirements and Limitations

The following VNA features are NOT available with FCA:

How to make SMC Measurements

The following is an overview of how to make an FCA measurement:

  1. CREATE an SMC Measurement.

  2. SETUP the measurements.

  3. CALIBRATE your measurement.

Create an SMC Measurement

  1. Press Setup > Main > Meas Class....

  2. Select SMC, then either:

  1. See SMC measurements to learn about the parameters that are offered in each.

How to make SMC settings

Using Hardkey/SoftTab/Softkey

Using a mouse

  1. Press Freq > Main > SMC Setup... .

  1. Click Stimulus

  2. Select Frequency

  3. Select SMC

Valid Mixer Configuration / Sweep Type Combinations

Configuring the SMC Setup dialog can be challenging at first.  RED messages like this one appear at the bottom of the Setup dialog to notify you of an invalid setup.

At least one range (Input, LO, or Output) MUST be Fixed.

The following are the Valid Mixer Configurations:

Sweep Type

Input

LO

Output

Linear

Swept

Swept

Fixed

Swept

Fixed

Swept

Fixed

Swept

Swept

CW Time

Power

Fixed

Fixed

Fixed

 

Tips

Although you will soon become comfortable navigating these tabs, at first it may be best to complete the dialog in the following order:

  1. For 2-stage mixers, select Mixer Setup settings.

  2. Select Sweep tab settings.

  3. Select Mixer Frequency settings.

  4. Select Power settings.

  5. Select Mixer (LO) Power settings.

 

Sweep Tab - SMC dialog box help

Sweep Type

Linear  Sweep frequency. Measurements are displayed on a standard grid with ten equal horizontal divisions.  Learn how to select the range to display on the X-Axis.

CW Time  All ranges are set to a Fixed (CW) frequency, and the data is displayed versus time.

Segment Sweep  Sweep user-defined segments. Learn more.

Power  Sweep Input or LO power.

 

X-axis Point Spacing (Available only with Segment Sweep) - Learn about this feature

Number of Points  Learn about this feature.

IF Bandwidth  Learn about this feature.

Phase Reference Point (SMC ONLY) Learn about this feature.

 

Learn about these buttons.

 

Power Tab - SMC dialog box help

Note: Set LO Power on the Mixer (LO) Power tab.

Configures Input and Output power settings for an FCA measurement. Use the Mixer Power tab to set LO power.

Power ON (All channels)  Check to turn RF Power ON or clear to turn power OFF for all channels.

Port Powers Coupled   Check to set the same power level at the DUT Input and Output ports. The LO power is NOT coupled. Clear to set power levels independently for each test port. Uncouple power, for example, to apply more power in the reverse direction than in the forward direction  Learn more about Setting Independent Port Power

DUT Input / Output Port

Select the VNA port that is connected to the DUT Input and Output. For VMC, the DUT input must always be connected to VNA port 1 because of the need for a reference mixer on port 1.

Power Level  Set the power level to the DUT Input port. To set power at the Output port, clear the Port Powers Coupled checkbox.

Source Attenuator Auto  Check to automatically select the correct attenuation to achieve the specified input power. Clear, then select attenuator setting that is used achieve the specified Power Level. Learn more about Source Attenuation.

All VNA channels in continuous sweep must have the same attenuation value. Learn more.

Receiver Attenuator  Specifies the receiver attenuator setting for the DUT port.

Source Leveling   Choose from: Internal (normal operation), Open Loop (used only for Wideband Pulse measurements), or Receiver - R1 for Receiver Leveling.

DUT Input and Output Port Power Sweep

Available when Power (sweep) is selected on the Sweep tab.

Input Start and Stop Power  To set Start and Stop power at the Output port, clear the Port Powers Coupled checkbox.

Note: If your DUT requires more input power than this setting allows below 3.2 GHz, use the PNA-X Hi-power mode, available from the RF Path Configuration dialog. The disadvantage to this is higher harmonic content.

Power Points  Number of power points to measure.

Power Step (Size)  Calculated value from current Start, Stop, and Points settings. This setting can NOT be changed directly.

 

Learn about these buttons.

The following tabs are shared with all Mixer / Converter Applications:

Mixer Frequency tab - SMC Setup -dialog box help

Learn about this dialog

 

Mixer Setup tab - SMC Setup -dialog box help

Learn about this dialog

 

Mixer (LO) Power tab - SMC Setup -dialog box help

Learn about this dialog

FCA Segment Sweep

The following settings appear on the Mixer Frequency tab when Segment Sweep is selected on the Sweep tab.

Mixer Frequency tab - Segment Sweep - SMC dialog box help

How to configure a segment using the GUI:

  1. Click Add. Click Delete to remove a segment and renumber all subsequent segments.

  2. State is ON by default. Click OFF and that segment will not be included in the sweep.

  3. Configure Frequency settings for Input, LO, and Output ranges.

  • For each segment, the same sweep requirements apply as a standard (non-segment) sweep. For example, at least one range MUST be Fixed (Start = Stop frequencies).

  • The Input, Output, and LO frequencies of segments ARE allowed to overlap other segments.

  • All segments must sweep in either the forward (Start<Stop) or reverse (Start>Stop) directions. Mixed sweep directions are NOT allowed.

  • The following settings can be set independently for each segment:

How to add multiple segments using the GUI and Excel *.csv file:

Start with the GUI to set up mixer settings and to create the first segment then save it as a *.csv file. The *.csv file will then be opened in Excel and the additional segments will be entered. Learn more.

  1. Click Add.

  2. State is ON by default. Click OFF and that segment will not be included in the sweep.

  3. Configure Frequency settings for Input, LO, and Output ranges.

  4. Click on the Save... button.

  5. Select CSV (Comma delimited) (*.csv) to save the settings and first segment to a *.csv file.

  6. Open the *.csv file in Excel.

  7. Highlight the segment row then copy it.

  8. Paste the copied segment row to add the desired number of segments into the Excel file.

  9. Modify the settings for each added segment as necessary. The following is an example showing 3 segments:

  10. Save the *.csv file.

  11. In the GUI, load this *.csv file.

Learn about these buttons

Apply and Interpolate FCA Cal Sets

In general, when a Cal Set covers a wider frequency range than the channel, the VNA will offer to interpolate the Cal Set when it is applied. Learn more. However, with FCA measurements the LO frequency range may also be considered.

These same general concepts apply to segment sweeps. However, if ALL applicable frequency ranges (SMC: Input and Output) are NOT within those ranges of the measurement for ONE segment, then the Cal Set is NOT applied for ANY segment.

Select X-axis Display for FCA Measurements

Click Sweep > Main > X-Axis Type, then select the desired type.

When Sweep Type = Linear, you can choose to show the frequency range of any of the swept parameters on the X-axis.

For example, the following image shows an SMC Fixed Output response with the Input frequency range on the X-axis:

Output: 100 MHz (data trace)

Input: 2 GHz to 23 GHz (X-axis)

LO: 1.9 GHz to 22.9 GHz (not shown)

Marker annotation shows Output power at Input frequency.  

Save Trace Data

You can save your FCA measurement data in several standard formats.

Click Save Recall > Save Other > Save Data....

The following shows how CSV and SNP files are saved.

Mixer Trace Data

When you select Mixer Trace Data, the FCA data is saved to a CSV file in the following format:

#MIXER TRACE FILE,A.01.00

SegIndex, InputFreq, OutputFreq, LO1Freq, InputPower, LO1Power, SC21 Mag (dB), SC21 Phase (Deg)

SNP Format

Each record contains 1 stimulus value and 4 parameters (total of 9 values) as follows:

Stim  Real(p1)   Imag(p1)   Real(p2)   Imag(p2)   Real(p3)   Imag(p3)   Real(p4)   Imag(p4)

where pX is the parameter depending on measurement type:

Measurement Type

p1

p2

p3

p4

Scalar

S11

SC21 (FWD)

SC12 (REV)

S22

All files contain the following Header Information: Brackets [  ] contain parameters.

!Keysight [Instrument Model Number]: [version]
!Mixer S2P File: [Mixer Measurement Type]
!Parameters: [Parameter List]
!Calibration State: [On/Off]

!# Begin Mixer Setup
![Mixer Setup parameters listed here]
![Mixer Parameter 1]
.
.
![Mixer Parameter n]
!# End Mixer Setup

# [S2P data here]