@gmcsor Depending on your needs, you may be able to just use GnuRadio Companion or Pothos Flow.
You should be able to create a flow graph with your Lime as
- a source (ie transmitter), reading a file containing your signal, or using the available blocks to create the signal
- a sink (ie receiver), displaying the spectrogram/waterfall
The LimeSDR-USB can have different sampling rates for RX and TX but are not completely unrelated (basically you can have TX = RX / 2^n, see Link between RX and TX sampling rates for more, but I recall also having issues in some cases). It can have completely different frequencies though.
I think with the LimeMini the RX and TX sampling rates must be the same.