While a 3rd party mm-wave module measurement example was shown in the previous section, the details of this measurement can be nuanced so this section will explore the setup in additional detail.

As the general external module selection is not available in the spectrum analysis configuration dialog, the setup is always going to be somewhat manual in multiple source control. Considerable information on the multiple source system is provided in Multiple Source Control (Option 7) but below are some more spectrum-analysis-specific hints.

Following the example above, here are some comments on the table entries. Of particular importance is how the receiver equation is configured. If an external source is being used as stimulus, it would have to have the appropriate equation and that source would be made active on the menu.

Note that external module control shown in Figure: External Module Control must be used to properly setup the 3739x/3736x test set(s). This dialog is accessible from the multiple source menu. If one goes to the Spectrum Analysis configuration dialog, the settings in the external module control dialog are reset and may need to be re-edited.

After the above dialog is complete, the external module control menu button should show the proper mode: mmWave[3739].

 

 

On the multiple source menu, don’t forget to select ‘Done Editing’ when the configuration is complete.

Because of the large multiplication factors that may be involved, the spectral width of the source signal (if used) may be wide. Working with the RBW setting may be useful to get more resolvable spectral lines. Too narrow and power will be excluded. Too wide and neighboring measurement points can obscure the peak. Values in the 100s of Hz to 10s of kHz are commonly used.

With wide RBWs and high multiplication factors, the image rejection algorithm can sometimes get confused. This largely happens because the desired tone responses can fluctuate wildly from point to point with an overly-wide RBW so the identification of the ‘real’ tones becomes complicated. A narrower RBW can help or image rejection can be disabled.