Category: Knowledge Base RSA5000 Series

When using a differential probe with a real time spectrum analyser you will be using the instrument in General Purpose mode and then you will need to create a reference signal that can be referenced when using the differential probe to compare the two signals, then once the reference has been created next you will then use the build in trace math feature to compare the reference signal that was created to the currently measured signal, this will create the actual differential signal.

First create a reference trace – to do this you will need to connect the Vout+ to the positive end of the differential probe and then the negative end of the differential probe to ground.  Once these have been connected set the spectrum analysers frequency span to equal the differential probe’s span, for the RP1100D it is 9kHz to 100MHz and for the RP1050D it is 9kHz to 50MHz.  With the span set now turn on the spectrum analysers reference amplitude in the amplitude menu to 0 dBm, this may need to be changed depending on the signal. 

With the spectrum analyser configured set the differential probe to X100 and then configure the amplifier so that it is producing a single tone at 9 kHz with an amplitude set to the amplifiers maximum output.  Then enter the trace/p/f menu on the spectrum analyser, select the 2^nd trace and then set the trace type to max hold and then begin to sweep across the frequency range with the amplifier.  Use as small of steps as possible between the frequency points as this will make the reference more accurate.  Now that you have created a reference signal freeze this signal, to do this now change the trace type to freeze in the trace/p/f menu.  You will then have a reference signal similar to the one pictured below. 


(Reference signal is pictured in blue)

Next use the trace math function to create the actual measured differential signal – Next leave Vout+ connected to the positive probe and then connect the negative probe to Vout-.  Then use the spectrum analyser’s trace math feature to the compare the reference trace on trace 2 to the real time differential trace on trace 1.  For this test I have terminated Vout+ and Vout- to a 50-ohm load, after the probe connection.  This will create the green signal shown below.



(Note that I do not have Vout+ or Vout- currently turn on in the image. Reference trace in blue, math comparison and differential signal in green.) 

In order to confirm the results, I have set both Vout+ and Vout- to output a 50 MHz sine wave with 0dBm of amplitude and they are shown below to have the same amplitude resulting in a math signal with an amplitude of 0 dBm.  Shown below. 



(Reference trace in blue, math comparison and differential signal in green.)

To take amplitude measurements use the marker function – To measure the amplitude use the marker function with the marker trace set to math.  Below shows the reference signal with Vout+ with an amplitude of -10dBm and Vout- with an amplitude of 0 dBm and shown below is the difference in amplitude.  Due to how it is calculated the amplitude is half of the difference which in terms of dB is roughly -3.5 dBm.



(Reference trace in blue, math comparison and differential signal in green.)

The Rigol EMI Test System Software is designed to make precompliance scanning with a Rigol DSA family of Spectrum Analyzer easy. 

This Note is an addendum to the Software User’s Guide. We will set up a prescan, create an amplitude correction table, set limit lines, and perform a final scan. 

Initial Setup: 

–    Download the latest version of UltraSigma and the EMI Test System Software from the Rigol website. 
–    Connect your instrument (USB, LAN, or other) and set up the physical test environment (cabling, Device-Under-Test, etc..) 
–    Start UltraSigma 
–    USB connected instruments should appear in the UltraSigma Resource tree as shown below: 


–   Right-click on the resource and select EMI Test System 
  

–    The EMI Test System will perform a screen grab of the Spectrum Analyzer and open: 
 
      

Configure Prescan Parameters 
 
–    Press Edit Scan to open the scan parameters window 
 
 
–    A Pre Scan consists of subrange elements. You can use the Pre Scan Configure window to set the overall Scan Start, Scan Stop, Range, and Detector type to use throughout the test: 
 
      
Pre Scan Configuration sets the overall test parameters used in each subrange scan. Using a Positive Peak detector will allow you to perform a faster scan and identify problem areas: 
 
In this example, we have configured the first subrange to sweep from 9kHz to 10MHz  at an RBW of 1MHz, no attenuation, and no preamplifier. 
 
  
 
–    Subrange Configuration sets the parameters used for each subrange step: 
 
In this example, we add a second step that goes from 10MHz to 30MHz in  at an RBW of 300kHz: 
 
  
Build successive subrange configurations using Range Start and Range Stop values and use the Add, Insert Before, After, and Delete to arrange the scan 
 
–    Press OK after you have built the Pre Scan list: 
 
  
 
–    Press Prescan to collect prescan data: 
 
  
      
After the scan is complete, you should have a graphical display of each subrange stitched together onto one graph: 

  
 
–    Now you can add amplitude correction by pressing Ampt Corr: 
 
    
–    You can select Antenna, Cable, Other, or the User tab to specify which correction table to edit.  
 
–    Enter the frequency point and corresponding  correction level. Press Add to add the correction point to the table. Repeat until the full correction table is built. 
 
–    To apply a correction table, select the type (Antenna, Cable, Other, or User) from the check boxes and press Correction: 
  
 
–    You can save the correction files for later use by pressing the Save button. 
 
You can add limit lines by pressing Peak Search to bring up the Peak Search window: 

      
–    You can add points to the limit line one-at-a-time by entering the frequency and level, then press add. Here, we have built a limit line comprise of four sections. You can also save the limit lines to recall them later by pressing Save: 
 
  
–    Use History to recall saved limit lines 
 
–    Press OK to apply the limit lines 
 
 
–    All of the peaks that have failed the limit test are shown at the bottom of the display: 
 
      
–    You can find specific peaks by clicking on the Peak number: 
 
  
–    You can also change the Vertical and Horizontal Scales by selecting the scales from the Y Unit and X Axis drop down boxes: 
  
 
–    You can print out a report of scanned data by pressing the Report button and filling in any information that you need. 

 
–    If you have found areas that fail the limit lines, you can save time by performing another prescan. This time, set the start and stop frequencies to encompass the failing peak(s). 
 
–    In this more focused scan, you may also want to use a Quasi Peak detector and FCC RBW settings (if your analyser is equipped with those options.

To reset the RSA3000, RSA3000E and the RSA5000 series to factory settings without using the System menu:

1) Power cycle the instrument
2) During the boot sequence, quickly and repeatedly press the Back button directly below the keypad on the instrument. 


To upgrade the firmware on the RSA3000, RSA3000E and the RSA5000 series to factory settings without using the System menu:

1) Power cycle the instrument
2) Insert a flash drive into the front of the instrument with the latest firmware version loaded onto the root directory of the drive. 
3) During the boot sequence, quickly and repeatedly press the Preset button in the upper right hand corner of the instrument.

RIGOL’s RSA3000/3000E/5000 series product uses a number of open source software packages. This document lists the open source software packages used in RSA3000/3000E/5000 series product. 

https://beyondmeasure.rigoltech.com/acton/attachment/1579/f-be0541d6-bc36-481f-b448-ec059be1b26e/1/-/-/-/-/RSA3000_3000E_5000.pdf

In order to take a screen shot on the RSA5000, RSA3000 or RSA3000E and have it automatically save to your flash drive follow the steps below.
1) Insert flash drive into the instrument and confirm that you can identify it in the File Explore menu.
2) Press the Save button
3) Press Quicksave Path
4) Press Set Path
5) Select your flash drive
6) Press OK.
This will change the quick save buttons path from saving a screen shot internally to your flash drive.

Relative measurements are critical in EMI: How does the good board compare to the failed board? How does this look with the CISPR Average detector or against another limit line? Is that coming from the device or the environment? Learn how to create, organise, and open complete test setups for comparison and data recording. Setups can include data traces and instrument configuration details.

Make EMI measurements simpler and faster by automating the process. Combine scans, searches, and interactive measurements. Also conduct further analysis on signals of interest with a single button on the same instrument engineers use for advanced debugging of emissions and signals.

Access the built in limit lines or configure your own for custom testing. Use the limits and margins when searching for signals of interest or for interactive measurements using multiple detectors.