LimeSDR Mini test signal

Projects LimeSDR
1

Hi,

I am looking for a solution to generate a test signal via LimeSuite, something similar like this one:

https://wiki.myriadrf.org/Testing_the_LimeSDR#Verifying_the_Test_Signal

As much as I understand, the WCDMA and LTE test waveforms are not available for the Mini due to FPGA/memory limitations.

The question is, is it possible to run something simpler , like a single carrier QAM signal or something to test the output signal of the Mini with a VSA?

Thanks!

2

Since it doesn’t have DDR memory you will need to stream samples from the host. Probably best seeing if you can find Octave or GNU Radio etc. code to do what you want.

3

@andrewback

Hi Andrew,

Thanks for the answer. My biggest issue is that I need to generate the test signal and have access to the device with limesuite. As while I am generating the test signal, I also need to be able to tune the DAC settings, so I can calibrate the clocking of my mini (as at 2GHz it is off by about 12kHz…).

It might be worth putting a simple FM or similar generator into limesuite, so these kind of calibrations can be done easily.

4

Not sure what would be involved, but added a enhancement request here and hopefully @IgnasJ can review and comment:

5

Hi Andrew,

Is there a tutorial about how to use it?

FYI, I recently used my LimeSDR-Mini for an NMT-450 network emulation project, and it was so off in therms of frequency error, the it was not able to detect the phone’s precise uplink transmission… 3.7kHz frequency error on 460MHz.

So anybody who tries to create LTE, 2G, NMT or other two way radio systems with a Mini should first calibrate the DAC, as it seems the drift is so big, that even a very tolerant analog radio system can fail with it.

6

Not that I know of I’m afraid, but looking at the commit, it appears to be using the waveform player capability, which is not available on LimeSDR Mini (doesn’t have DDR memory like the larger LimeSDR USB).

If you just want to generate a carrier would suggest using something like SDRangel or SDR Console, else GNU Radio.

7

Given the fact how off Minis are, it would be lovely to see at least a CW generator in LimeSuit, as you cannot connect the Mini to the LimeSuit and SDRangel in the same time. That means the calibration looks like this:

  1. Generate tone with SDRangel, then stop it.
  2. Blindly set the DAC value in LimeSuit.
  3. Go back to SDRangel and see how much the DAC change altered the frequency error.

Do this for quite a lot of rounds. Of course it is doable, but not very nice.