Author: James

How to check the version of UltraSpectrum software

• Start UltraSigma software
• Select the spectrum analyser that you wish to control by left-clicking on the instrument ID string
• Right-click and select UltraSpectrum

• Select Advanced Operation near the upper-right-hand-side of the window and then select About along the lower tab as shown below:

If you experience a defective UltraSpectrum display while connected to a DSA800 series spectrum analyser the most likely cause is due to a UltraSpectrum software version mismatch. Software version  00.01.00.27 corrects the issue and can be downloaded from the blue Downloads tab at:

https://www.rigolna.com/products/spectrum-analyzers/dsa800/

Here is an example of the UltraSpectrum display using an incompatible version of software:

Spectrum analysers can be used to observe modulated signals. But, some settings may have to be adjusted to observe the signals clearly.
In this example, we are going to show how the sweep time and selected detector type can effect the displayed data.

Source: Rigol DG4062 60MHz Dual Channel Arbitrary waveform generator.
Signal: Sine wave, linear sweep from 230KHz – 270KHz, Sweep frequency of 120Hz (~8ms period)
From the factory preset default mode, many spectrum analysers such as the Rigol DSA815-TG select an automatic sweep time which is determined by the frequency span and the RBW setting. In this example, we set the DSA to sweep from 150KHz to 600KHz at an RBW of 10KHz. The sweep rate default value for these parameters is 10ms.

In addition, the DSA815-TG collects 601 frequency “bins” per sweep. This means that the data in each bin is collected at a rate of 16us/point (10ms/601 points).
In this experiment, note that the modulation period (1/120Hz = 8ms) is much lower than the sweep rate (10ms) of the instrument.

When the sweep time is faster than the modulation, the data collected per sweep may not accurately represent the total span of the modulation. You can use the “Peak Hold” feature that will display the maximum values for successive scans and hold them on the display.

The figure below is a Peak Hold Scan for the experimental modulated signal described above. 


You can see that the sweep time is 10mS.

Also note that the Yellow scan was collected using a Peak detector and the Pink was collected using an RMS Voltage detector.
How can the Peak and RMS Voltage detectors give the same trace?
The scan rate is too fast. This results in very small data sets at each frequency bin and can cause the data collected with different detectors to appear very similar.
Now, let’s change the sweep rate and observe the differences.

Here is the same input signal with the sweep time set to 1.5s (Peak Hold Disabled/Trace Clear Write selected):


You can now see that there are some differences in the Positive Peak Data (Yellow) and the RMS Average Voltage (Pink). This includes some of the modulation peaks and a different noise floor.
Here is the same input signal with the sweep time set to 5s (Peak Hold Disabled/Trace Clear Write selected):

Now you can observe quite different traces that more accurately represent the modulated data.

Here is the same input signal with the sweep rate set to 10s (Peak Hold Disabled/Trace Clear Write selected):

Conclusions: When observing modulated or pulsed signals, you can use the Peak Hold feature to “build” a trace from successive scans.

You can also gain more visibility into the signal type by changing the detector, but keep in mind that this may require lengthing the sweep time. This will allow the instrument to collect enough data at each frequency value to make more meaningful measurements.

The latest revision of firmware (DSA815 00.01.12) has the ability to save a prefix for use with file saves. This can make data entry a bit easier.

–    Press SYSTEM > Down arrow to page 2 > Select Name Prefix

–    Select EDIT PREFIX and use the keypad to enter the text you want to start the files with

–    Press OK

–    Here, we have saved TEST as the prefix

–    Set PREFIX SWITCH to ON when you want to use the prefix

NOTE: You can leave the text box in the numeric control (“1” shown in lower corner) when you close the text entry window. It will appear in the same state next time you save a file. You can simply press 1,2,3..etc.. to increment the file.

Select Tools at the top of the S1210 application window.



You can now open the Data Manager and select CSV to convert a CSV file into a correction file.

To save a trace as a CSV: 

1) Insert USB stick into the USB port on the front panel 
 
NOTE: The format of the USB stick must be FAT32 
 
2)    Press STORAGE > Set BROWSER to DIR. You can press the button next to the Browser label to toggle the selection. 
 
 
NOTE: The spectrum analyzer uses binary files (*.trc) and cannot use CSV files (*.csv) natively. CSV will not be available as a valid format if you are trying to save the file to the local drive (D:) 
 
 
 
3)    Use the scroll wheel to select Mobile Disk (E:) 
  
       
 
4)    Change File Type to Trace and press the back arrow to get back to the storage screen 
 
  
 
5)    Set Format to CSV  
 
  
       
6)    Press Save, use the keypad to write a filename (I use numbers, they are faster), and press OK 
 
  

If your DSA800 series spectrum analyser does not boot when powered up it may be possible to correct the issue by booting off of a USB memory stick.

When the spectrum analyser is powered on you will see a message at the bottom left corner of the display that says:

Waiting Input… (Press ‘Preset’ to boot from the U-Disk)

At this time press the green Preset key on the left side of the display. You will need to do this pretty quick as the message quickly disappears. Once Preset is pressed you should then see a second message that says:

Testing  U-Disk…(Please Insert U-Disk)

Now insert the USB memory stick that contains the firmware image in the root directory.

If successful the spectrum analyser will complete the boot up sequence using the memory stick and the firmware image will be restored on the instrument.