Finding Power Peaks in a Spectrum with RFmx Soft Front Panel

In this article, you will learn how to configure the Markers in the RFmx Soft Front Panel in order to study more in detail the spectrum seen in the software. You will study how to implement them and where to locate the information.

You will require an NI device capable of RF capabilities like our Vector Signal Transceivers (VST) or Vector Signal Analyzers (VSA). A PXIe-5644 first generation VST was used to get the results shown in this document. On the software side, you require to install the RFmx driver in order to use the basic functionalities of the RFmx Soft Front Panel.

1. Make sure the input signal is connected to the hardware. In this article, the input signal is a CW at 1 GHz generated by the same PXIe-5644.
2. Confirm you have RFmx installed. 
   1. Open NI MAX.
   2. In the left panel, expand the Software tab.
   3. Scroll down in alphabetical order until you reach letter R.
   4. Verify you can see the packages RFmx Development and/or RFmx Runtime.
3. Search for the program RFmx Soft Front Panel.
4. If you have multiple instruments capable of analyzing spectrums, the software will ask you to select one. Otherwise, the software will automatically load with the instrument capable of acquiring the data. Be aware the software loads with pre-configured device settings.
5. Configure the right-side panel to match the settings you want to tune your device to:

   

6. Click the Markers button located on the top-right corner above the spectrum:

   

7. This will display a new submenu on top of the spectrum and a new section called Markers below the spectrum:

   

8. You can insert up to 12 different markers in the spectrum. To change from marker to marker, expand the drop-down menu that highlights Marker 0:

   

9. Make sure the marker you select is set to Normal.
10. Click the first mountain-like icon next to the menu where you select the marker. That button will place your marker on top of the highest detected peak. 

Once you have configured the markers properly, you will be able to detect and read information from specific peaks of your spectrum. Below is shown a session where two markers were configured, Marker 0 and Marker 2. Marker 0 was placed on top of the highest peak, and Marker 2 was moved to the top of an intermodulation product the spectrum presented. The information of both was captured successfully in the summary section below the spectrum.