Minimal Steps/Procedure for Manual Calibration of RX via LimeSuite

#1

Hello,

I’ve spent a good amount of time trying to follow along with the Manual Calibration of the RX Path found here: https://wiki.myriadrf.org/Getting_Started_with_LimeSDR-USB_and_LimeSuiteGUI

However, despite following all the other steps as outlined in the guide, I’m unable to reproduce figure 19 from section 9. In the FFTviewer, the time plot just shows static and the constellation diagram is a tiny blob of points, rather than the waveform or set of points as depicted. I see the three peaks in the spectrum, but it’s very noisy and changing phase, I, or Q doesn’t seem to have an effect any of the peaks.

What exactly is the minimum set of steps for using LimeSuite to calibrate the RX side? From my experience, calibrating TX works fine, but it’s RX that’s having issues.

Thanks!

#2

Having the same issue here, not sure how to fix it.

#3

Hi @lkev747,

What board do you use? What LimeSuiteGUI version? Post a print screen of your FFTViewer here, please.

#4

Hey, thanks for the response.

I’m using a LimeSDR-USB, and my LimeSuite version is 19.04.
Here is a screenshot from the self-test, which worked well:

Proceeding along with the steps outlined in the Getting Started guide, I’m able to get the following:

Which turns into this when I enable digital loopback:

Following along to the manual calibration step, no amount of changes to the I, Q, or phase has any impact on the FFT, and I can’t seem to figure out why I don’t also get the I versus Q or IQ samples plot like in the guide.

Thanks for the help,

Kevin

#5

Hi @lkev747,

It looks like you have USB communication issues. Check the cable, try another USB port or even machine. You should not get these yellow lines in the log window first of all.

Next, keep gain corrector value at the maximum of one channel (for instance Q) when adjusting another one (for instance I). You have to adjust gain of only one channel.