Is it possible to have the LimeSDR do to demodulation/Modulations on the FGPA?

System Development
#1

Hi everyone!

Brand new here and to the LimeSDR ecosystem. My team and I just acquire a LimeSDR - USB (USB A) board and having a blast playing around with it.

Our intentions is to have the LimeSDR do the demodulation/modulations on the board itself oppose to using GNU Radio, SDR Console, and others to do it. (Correct me if I am wrong).

I notice that the FPGA source code is available over on GitHub and was wondering if we were to alter the source code would it then be feasible to have the FGPA start doing the demodulation/modulations?

Once again we are brand new to this so we dont know if this is possible or not. Any feedback is much appreciated. Thank you.

#2

“demodulation” and “modulation” could literally be anything at all e.g. 8PSK, 32768QAM, 65536QAM, AM, ASK, APSK, BSK, CPM, FM, FSK, GMSK, GFSK, MFSK, MSK, OOK, PM, PPM, PSK, QAM, QPSK, SC-FDE, SM, SSB, TCM, WDM …

So I would assume that your question is can you delete most of the existing FPGA code and replace it with your own to custom gateware and then transfer the fully, or partially, demodulated signal over USB to your own custom application. I honestly do not think that anyone can answer your question. It is like asking can you fit an elephant in a mini, and the answer is always going to be maybe, unless it is a tiny elephant or the closest living relative of the elephant - a Dassie.

Look at the current free space in the FPGA would be my first step.

You will hit a problem straight away, Intel who bought Altera in their infinite wisdom appears to have decided to delete nearly all Altera software older than 5 years old from their download servers, and this unfortunately includes "Altera Quartus prime 15.1 Lite Edition". What this means for you is that you will need to rewrite/migrate the current gateware that you want to keep into a later version of Intel Quartus that still supports the “Cyclone IV” FPGA chips, in addition to creating your own custom code!

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#3

Hi @mzs thank you for the reply. Not exactly and I am sorry if I came off confusing.

In the end we will be using one type of demod and mod and that will just be determined through testing, but only ONE demod and mod scheme will be picked.

So, it does seem possible to do this.