LimeSDR Mini Permanent Calibration?

Projects LimeSDR
1

Hi,

I am sorry if this is answered somewhere in the documentation, but I spent some time to try and figure this out on my own, but failed miserably.

I am working with the LimeSDR and LimeSDR Mini boards and developing an application for them with GNU Radio.

I connect a Signal Generator( generating a sine wave at 433MHz) to the LimeSDR for calibration.
I open up LimeSuite GUI, set the frequency to 432MHz and use the built-in FFT Viewer to look at the signal received by the LimeSDR.
Initially without any calibration I can see the signal at +1MHz from the local oscillator as expected, but there is also a big SSB at -1MHz from the LO.

I then use the Calibrations Tab and manually tweak the settings until the SSB drops below the noise floor.

I was wondering, do these settings somehow get saved to the LimeSDR Board?
I seem to see that they always get reset to some default settings, and the SSB is back.
If not automatically, is there a way to save the Calibration Settings to the LimeSDR?

When working with the GNU Radio Companion LimeSDR Source Block, I don’t see any settings for IQ and DC offset Calibration, so does that mean that I cannot have my program run with a calibrated LimeSDR?

Thanks.

2

Calibration values are not saved in the board.
GRC initiates internal calibration procedure so your values get overwritten: https://github.com/myriadrf/gr-limesdr/blob/master/grc/limesdr_source.xml#L40

3

To add to @ricardas, calibration values will get overwritten each time you start the flowgraph https://github.com/myriadrf/gr-limesdr/blob/master/lib/common/device_handler.cc#L103 but if you want to use your specific settings you could save .ini file from LimeSuiteGUI and use it in your LimeSDR Source Block.

4

Yes and no, it really depends on what you are doing, because dumping all the current registers values and uploading them all at a later date does not always put the LMS7002M back into the exact same state:

e.g. [LimeSDR-USB] Synchronization and Toggle TDD/FDD Mode - #5 by Zack